# Integrated the Medical Procedure Analyze Seismic Resilience of Healthcare System: A Critical Review from the Resilience of Healthcare System vs. Medical Demand Perspective

Authors: Bin Liang; Qian Tao; Wuping Gao; Quanchang Ren; Xinqiang Yao
Journal: Advances in Civil Engineering
 (2023)

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## Abstract

The healthcare system is the bearer of treating the wounded and the victims of earthquakes. The functional integrity of the healthcare system is critical to the process of postearthquake medical rescue. Thus, the requirements for seismic resilience of the medical functions of the healthcare systems are increasing. Many studies have applied resilience research to address critical issues in the medical rescue of postearthquake casualties, such as medical diagnosis, emergency surgery, and intensive care. However, systematic construction is still lacking. System resilience is one of the most promising systemic management theories with great potential to address the abovementioned challenges. This article puts forward a scientific concept that system resilience can improve the efficiency of earthquake relief in medical rescue. Firstly, a scientific review of medical demand and medical resilience was conducted, summarizing resilience and resilience of healthcare system concepts. In addition, the postearthquake medical demand was reviewed, and the classification and distribution probability of postearthquake injuries were summarized. Furthermore, by reviewing the postearthquake medical rescue process, the weak points of each medical link were summarized. Combined with the key points in the medical rescue process, the application of resilience studies in the medical system is reviewed, and the progress of medical resilience is illustrated. In summary, combined with medical demand, the article provides some guidance for the deep integration between medical rescue processes and medical resilience and identifies the challenges of system resilience to reduce the waiting time of the injured future medical rescue in the earthquake.


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## Body

## 1. Introduction

The casualty data in the historical earthquakes have proved the importance of the resilience of the healthcare system. According to the statistics of the international disaster database from EM-TAD [1], 1,489,333 people were injured in 467 earthquakes around the world from 2000 to 2021. There are more than 10,000 people who were injured in the earthquake. The degree of the wounded's injury varies. The patient's condition is complicated. It requires various specific medical procedures to achieve medical rescue. Meanwhile, the healthcare system accommodates damaged hospitals and still needs to maintain medical services continued after the earthquake. Therefore, higher requirements are put forward for medical rescue [2, 3].The healthcare system is not only the undertaker of postearthquake medical rescue but also the victim of earthquakes. The historical earthquake data show that regional hospitals that have been damaged by the earthquake have declined the efficacy of medical rescue. For example, in the Mw7.6 Izmit earthquake, 10 hospitals suffered severe damage, which led to a large-scale emergency transfer of casualties [4]. In the Mw8.0 Wenchuan earthquake, because several hospitals were damaged, the medical rescue had to be carried out in temporary hospitals [5]. The Haiti earthquake caused total paralysis in local hospitals, which means that complex surgical operations could not be completed [6]. The healthcare systems suffered huge losses in the earthquake. Meanwhile, a large number of casualties were unable to receive timely and high-quality medical treatments which indirectly led to an increase in casualties and deaths [7]. Because the function of hospitals is interrupted, the casualties have to be transferred between the regional hospitals.However, by improving the seismic resilience of the hospitals, the regional imbalance between medical demand and supply cannot be solved. An efficient operation mechanism of the regional healthcare system is also important to improve the efficiency of medical rescue. Thus, it is necessary to assess the functional seismic resilience of the regional healthcare system. The World Health Organization (WHO) and the Pan American Health Organization (PAHO) urged countries to develop policies to strengthen the capacity of healthcare systems to work collaboratively and improve the rational and efficient use of medical resources in regional healthcare systems [8, 9]. Based on the “Hyogo Framework for Action 2005–2015, Components of National and Community Disaster Resilience” [10], the 2015 world conference on disaster reduction proposed the “2015–2030 Sendai Disaster Risk Reduction Framework” [11]. It states that the country should undertake the main responsibility for disaster prevention and mitigation. The governments should improve medical disaster relief capabilities and support various organizations and departments to participate in coordinated medical operations. Due to the lack of data and transparency, the specific role of the first wave of medical rescue provided from countries all over the world to Haiti during the earthquake in 2010 could not be determined [12]. Postearthquake medical rescue forces include hospitals that retain functions after the earthquake, temporary emergency medical rescue, and medical evacuation. By utilizing medical resources rationally, the efficiency and quality of postearthquake medical rescue could be improved, and the number of postearthquake casualties could be reduced.The resilience of the healthcare system is the key to guaranteeing the dynamic balance between the medical demands of the casualties and the medical capacity. Owing to the complex interdependence of society, infrastructure, and the natural environment, disaster processes and casualty outcomes are thus extremely difficult to predict. In the meantime, postearthquake medical rescue not only involves the study of the injuries and the process of medical rescue but also involves reducing the seismic loss of functions of the hospitals. This is undoubtedly a very challenging task, especially during earthquake relief. After many years of development, resilience theory has been applied to economics [13], engineering [14], sociology [15], environmental science [16], complex systems science [17], disaster prevention and mitigation [18], industrial engineering [19], business management [20], and other sciences and fields. Based on the practical effect of resilience theory in the above aspects, the application of resilience theory in the process of the medical rescue of a postearthquake healthcare system is also feasible.This article proposes the concept of seismic resilience of the healthcare system combining medical demands and the process of medical rescue after the earthquake, which intends to improve the efficiency of postearthquake medical rescue and reduce the waiting time of the injured. Moreover, possible challenges in the postearthquake medical rescue process were highlighted.This article is arranged as follows: Section2 provides the review methodology. Section 3 reviews the concept of resilience, healthcare systems, and healthcare system resilience. Section 4 counts the medical demand of the injured after the earthquake in the literature. Section 5 reviews the medical rescue process and points out weak components in the process. Section 6 reviews the application of resilience in the medical rescue process. Section 7 gives the conclusions and outlook.


## 2. Method

### 2.1. Data Sources and Search Strategy

Retrospective studies on the medical demand of earthquake-related injuries and the medical rescue of the resilience of hospitals after earthquakes were published in English and Chinese, irrespective of publication status and article type. The investigators conducted a systematic literature search using the following electronic databases: PubMed (from 1990 to 2022), Web of Science (from 1990 to 2022), and Scopus (from 1990 to 2022). Two parts are medical demand (“earthquakes” and “wounds and injuries”) and the medical capability of the hospital after earthquakes (“earthquakes” and “hospital” and “resilience” and “capacity” and “rescue”). We used the PubMed search, Web of Science search, and Scopus. Additionally, manual searches of references cited in all relevant original and review articles were conducted. If full texts were unavailable in the databases, we attempted to obtain information from the authors by e-mail.


### 2.2. Selection and Exclusion Criteria

For studies to be eligible for inclusion in the analysis, they had to fulfill the following criteria: For medical demand, (1) included a retrospective investigation of earthquake-related injury among inpatients after earthquakes; (2) provided a quantitative description of the types of direct physical injuries sustained in the aftermath of earthquakes; and (3) included earthquake-related injury patterns discussed in this study. The exclusion criteria were as follows: (1) described earthquake-related injury types, but did not include detailed percentages; (2) were not published in English; and (3) only reported psychological impact or indirect injuries from earthquakes. For resilience and the resilience of the healthcare system, (1) included the development of the concept of resilience; (2) the development of the concept of resilience in health systems; (3) quantitative analysis methods for resilience; and (4) the process of postearthquake medical rescue. The exclusion criteria were as follows: (1) ductile concepts and applications in materials science; (2) details of the medical rescue process (resource allocation and medical personnel efficiency); and (3) quantitative data statistics for medical system resilience analysis.


### 2.3. Search Results and Study Characteristics

#### 2.3.1. For Medical Demand

Though 1548 records were retrieved by our search strategy, we excluded 1448 articles after reading the titles and abstracts and retained 237 articles for further evaluation by reading the full texts. Finally, we selected 47 full-text articles about earthquake-related injury patterns among inpatients after earthquakes, with sample sizes of patients ranging from 33 to 37387 and the earthquake magnitude ranging from 6 to 8.


#### 2.3.2. For Resilience and the Resilience of the Healthcare System

Though 769 records were retrieved by our search strategy, we excluded 675 articles after reading the titles and abstracts and retained 245 articles for further evaluation by reading the full texts. Finally, we selected 101 full-text articles about resilience and the resilience of healthcare system, which include application of the concept of resilience in the healthcare system.


## 2.1. Data Sources and Search Strategy

Retrospective studies on the medical demand of earthquake-related injuries and the medical rescue of the resilience of hospitals after earthquakes were published in English and Chinese, irrespective of publication status and article type. The investigators conducted a systematic literature search using the following electronic databases: PubMed (from 1990 to 2022), Web of Science (from 1990 to 2022), and Scopus (from 1990 to 2022). Two parts are medical demand (“earthquakes” and “wounds and injuries”) and the medical capability of the hospital after earthquakes (“earthquakes” and “hospital” and “resilience” and “capacity” and “rescue”). We used the PubMed search, Web of Science search, and Scopus. Additionally, manual searches of references cited in all relevant original and review articles were conducted. If full texts were unavailable in the databases, we attempted to obtain information from the authors by e-mail.


## 2.2. Selection and Exclusion Criteria

For studies to be eligible for inclusion in the analysis, they had to fulfill the following criteria: For medical demand, (1) included a retrospective investigation of earthquake-related injury among inpatients after earthquakes; (2) provided a quantitative description of the types of direct physical injuries sustained in the aftermath of earthquakes; and (3) included earthquake-related injury patterns discussed in this study. The exclusion criteria were as follows: (1) described earthquake-related injury types, but did not include detailed percentages; (2) were not published in English; and (3) only reported psychological impact or indirect injuries from earthquakes. For resilience and the resilience of the healthcare system, (1) included the development of the concept of resilience; (2) the development of the concept of resilience in health systems; (3) quantitative analysis methods for resilience; and (4) the process of postearthquake medical rescue. The exclusion criteria were as follows: (1) ductile concepts and applications in materials science; (2) details of the medical rescue process (resource allocation and medical personnel efficiency); and (3) quantitative data statistics for medical system resilience analysis.


## 2.3. Search Results and Study Characteristics

### 2.3.1. For Medical Demand

Though 1548 records were retrieved by our search strategy, we excluded 1448 articles after reading the titles and abstracts and retained 237 articles for further evaluation by reading the full texts. Finally, we selected 47 full-text articles about earthquake-related injury patterns among inpatients after earthquakes, with sample sizes of patients ranging from 33 to 37387 and the earthquake magnitude ranging from 6 to 8.


### 2.3.2. For Resilience and the Resilience of the Healthcare System

Though 769 records were retrieved by our search strategy, we excluded 675 articles after reading the titles and abstracts and retained 245 articles for further evaluation by reading the full texts. Finally, we selected 101 full-text articles about resilience and the resilience of healthcare system, which include application of the concept of resilience in the healthcare system.


## 2.3.1. For Medical Demand

Though 1548 records were retrieved by our search strategy, we excluded 1448 articles after reading the titles and abstracts and retained 237 articles for further evaluation by reading the full texts. Finally, we selected 47 full-text articles about earthquake-related injury patterns among inpatients after earthquakes, with sample sizes of patients ranging from 33 to 37387 and the earthquake magnitude ranging from 6 to 8.


## 2.3.2. For Resilience and the Resilience of the Healthcare System

Though 769 records were retrieved by our search strategy, we excluded 675 articles after reading the titles and abstracts and retained 245 articles for further evaluation by reading the full texts. Finally, we selected 101 full-text articles about resilience and the resilience of healthcare system, which include application of the concept of resilience in the healthcare system.


## 3. Concepts and Quantitative Analysis Methods

### 3.1. Concept of Resilience

Resilience is derived from the Latin word, that is, resilio, which means bounce to back [21]. The concept originated in physics to characterize the resistance of materials to impact. In the 1970s, ecologist Holling [22] first used the concept of resilience to describe the multiequilibrium state of ecosystems, which is the character of the ability of ecosystems to absorb changes in response to disturbances. Resilience has been more widely used in psychology, engineering, ecology, etc. At present, there is no accepted definition of resilience in academia (Table 1). Moreover, its meaning varies within the same field of research.Table 1
Different definitions of resilience.
AuthorsDate of publicationDefinition of resilienceHolling [22]1973Resilience refers to the ability of a system to absorb, change, and perturb and to maintain a balanced state of the systemWildavsky [23]1988Resilience refers to the ability to cope with disasters after a disaster and has the characteristics of adaptation and recoveryMileti [24]1999Resilience refers to the ability of an area to undergo extreme natural events without catastrophic loss, damage, reduced productivity, and normal life and does not require a lot of outside assistanceComfort [25]1999Resilience refers to the ability and action of existing resources and capacities to adapt to new situationsAdger [26]2000Resilience refers to the resilience of public infrastructure to disaster shocksKlein et al. [16]2003Resilience is the ability to withstand the stresses of the environmentBruneau et al. [27]2003Resilience refers to the ability of a society to mitigate the impact on the city and to cope with the impact of future disasters with the least impact on societyWalker et al. [28]2004Resilience consists of four components: range, resistance, instability, and chaos. Toughness refers to the ability of a system to absorb interference and keep its key functions, structures, and characteristics functionalWalker and Slat [29]2006Resilience was originally defined as the ability of a system to respond to external disturbances in the case of maintaining its basic stateAllenby and Fink [30]2005Resilience refers to the ability of a system to maintain its functional and structural stability in the face of internal and external changes, and only when the function and structure are slowly decliningUS Department of Homeland Security [31]2006Resilience refers to the ability of the system to efficiently reduce the degree of damage to the system by disasters at a set target functional level in the event of an emergencyWamsler [32]2007Resilience refers to the ability of urban systems to survive, adapt, and develop in the face of sudden disastersUNISDR [33]2009Resilience refers to the exposure of a system, community, or society to a hazard, the ability to resist, absorb, adapt to disasters, and effectively reduce below the targetUnited Nations [34]2009Resilience is defined as the ability of systems, communities, or societies exposed to hazards, to resist, absorb, withstand, and recover from the impacts of disasters in a timely and effective manner, including the protection and restoration of essential infrastructure works and their functionsCohen et al. [35]2013Resilience is defined as the ability of a society to function properly in times of crisisResilience Alliance [36]2022Resilience is the ability of socio-ecological systems to absorb disturbances and pressures from maintaining the original characteristics, especially their original structure and functionResilience can be divided into two concepts: engineering resilience and ecological resilience. Engineering resilience is a one equilibrium state in the system. Its resilience is manifested in the fact that the system can resist disturbances and maintain its original state. System resilience can be measured by the resistance of the system to disturbances and the rate at which it returns to the original equilibrium state. Ecological resilience advocates the existence of multiple equilibrium states in the system. The resilience of the system is measured by the level of disturbances that the system needs to absorb from one equilibrium state to another. Based on previous research, Folke [37] analyzed the interaction between humans and ecosystems and further proposed socio-ecological resilience. This view holds that the system is constantly changing and maintained in a certain equilibrium that formal perturbations cause a continuous change in the system. Resilience describes not only the ability of a system to absorb disturbances to maintain its original state but also the ability of the system to self-organize and learn and adapt. Resilience which does not emphasize equilibrium is also known as evolutionary resilience.The inconsistency of the above concepts of resilience poses challenges to studying the resilience of urban systems and subsystems. How to define the resilience of urban systems and subsystems depends on the understanding of this issue. Problems were researched in two ways. One is induction, which is from individual to general. The second is the deduction, which is from general to individual. Holling [22] proposed the concept of resilience based on the observation of the development of their biological populations, which belongs to the inductive process. From the initial concept of resilience to socio-ecological resilience and resilience of urban systems and subsystems, the process of development of this concept is more analogous to the deduction. Different from the objective resilience of ecosystems, the resilience connotation of the urban system in which humans live has both subjective and objective aspects. Resilience is an objective attribute of urban systems and subsystems. Historical cases show that cities have certain resilience after encountering disturbances such as disasters. What level of resilience do cities hope to achieve? How to reach it depends on human subjective consciousness. In general, the resilience of urban systems and subsystems refers to the ability to maintain or quickly restore the core functions in the event of various disturbances such as disasters, and to adapt to future uncertainties.The performance of resilience has an obvious process. There are two main links: resistance and recovery. Resistance means that the system can withstand the negative effects of perturbations to maintain its core function. Recovery means that a system can quickly restore its functionality to the desired state after being compromised. This state may be the initial state, in which the system is considered to have a single equilibrium state. It can also be a new state, in which the system has a multiequilibrium state. In addition, adaptation is also an important connotation of resilience, which means that the system can change its structure through self-learning to prepare for future uncertain disturbances. The system adapts to improve its resistance and resilience to future disturbances. The system is constantly resisting, recovering, and adapting, leaving it in a dynamic process of constant evolution.For studying resilience, it is necessary to clarify resilience of what, to what, for what, for whom, and over what time frame. Firstly, studying resilience begins with defining systems and their boundaries. The different systems have different qualities that directly affect the understanding of resilience. Secondly, it is necessary to define the type of system disturbance, and improving the resilience of the system to one disturbance may reduce its resilience to other disturbances. It is also necessary to clarify the service targets or stakeholders of system resilience, and different stakeholders will have different requirements for the goal of resilience. Finally, the time window for observing the resilience of the system should be clarified, because the choice of time scale will affect the choice of disturbance type and the evaluation of the recovery.


### 3.2. Concept of Healthcare System Resilience

The World Health Organization [38] defines the health system as an organization that covers all activities aimed at promoting, restoring, and ensuring the health, including relevant public, private, and nongovernmental institutions such as hospitals, health centers, testing centers, pharmacies, and blood banks. The U.S. Department of Health and Human Services [39] defines the healthcare system as a collection of all medical organizations in the community. Chinese healthcare system [40] includes not only a collection of various medical organizations and institutions, but also a complex of many interacting and interdependent elements committed to the various resources of the health system to achieve the purpose of disease prevention and treatment and improve the health level of the population.The concept of the resilience of the healthcare system has not yet been unified (Table2). However, the studies all emphasize the resilience of the healthcare system to maintain services under shocks, or absorb the adverse effects of shocks through its adaptation and change in the process of resistance, to ensure the continuity of medical services, or restore the function as soon as possible after the function of the healthcare system has received a significant loss to ensure subsequent services. Therefore, the resilience of health systems remains a discussion of the ability of health systems to resist shocks, maintain their healthcare functions, and quickly recover from health services after being affected.Table 2
Definition of healthcare system resilience.
AuthorsDate of publicationDefinition of medical resilienceKieny and Dovlo [41]2015The resilient healthcare system absorbs the impact of emergencies while continuing to provide routine careBarasa et al. [42]2017Resilient healthcare systems need to be able to adapt and change to continue to deliver quality services and respond to emerging healthcare needsKruk et al. [43]2015The health system is defined as the ability of healthcare practitioners, institutions, and populations to prepare for and respond effectively to crises. A resilient healthcare system is perceptual and can preidentify potential risk factors affecting people’s healthBlanchet et al. [44]2017The willfulness of a health system is defined as the ability of a health system to absorb, adapt, change, and maintain control over its original structure and function when exposed to shocks, such as infectious diseases, geological disasters, and armed conflictsZhong et al. [45]2014Hospital disaster resilience is defined as the ability of a hospital to resist, absorb, and respond to disaster shocks, maintain its essential functions (such as prehospital emergency care, hospital emergency, intensive care, disinfection, and isolation), and return to its original state or a new adaptive stateCimellaro and Pique [46]2016Hospital disaster resilience is defined as the ability of a hospital system to prepare for a disaster event, absorb the effects of the disaster, recover from the disaster, and keep itself functioning wellWorld Health Organization [47]2015A resilient health system is defined as a health system that can predict, respond to, recover, and adapt to climate-related shocks or stress diseases in unstable climates to ensure the health of populations with increasing health, and considers that resilience of health systems equals reduced vulnerability plus increased adaptive capacityJacques et al. [48]2014Disaster resilience of health systems refers to a hospital’s ability to manage and continue to deliver healthcare in the event of an emergency, including the climate recovery phaseRamandi and Kashani [49]2018Disaster resilience in health systems is the ability of hospitals to respond, withstand, and absorb the effects of disasters, provide health care services, and restore basic or acceptable levels of servicesBerg and Aase [50]2019Resilience is described as a set of cognitive and behavioral strategies of individuals who enact resilience within an organizational contextWiig et al. [51]2020A resilient healthcare system might be expected to consistently deliver high quality care, withstand disruptive events, and continually adapt, learn, and improve. The capacity to adapt to challenges and changes at different system levels, to maintain high quality careLyng et al. [52]2021This study develops a new conceptual account of adaptation and innovation as a basis for resilience in healthcare. Findings emerging from this study indicate that a balance between adaptation and innovation should be sought when seeking resilience in healthcarePei et al. [53]2022This article proposes a resilience assessment framework for the interdependent transportation–healthcare system integrating physical loss and organizational management during postearthquake emergency response. Considering the earthquake-induced injured people, the seismic damage to transportation, and the quantification of the condition of the patients after being treated, a novel metric is proposed to evaluate the response effort during the first 72 h


### 3.3. Quantitative Assessment Methods for the Resilience of the Healthcare System

It is necessary to evaluate the resilience of the system under specific conditions, to the improvement of the resilience of existing systems or the design of new systems. The accuracy of the resilience evaluated greatly affects the effectiveness of the work. Resilience assessments can be both qualitative and quantitative, depending on the characteristics of the object being assessed and the analytical needs. The qualitative methods for assessing resilience mainly include questionnaires and focus group discussions [54], which are simple in principle and highly operable. However, the results are often limited by personal knowledge. The quantitative methods for assessing resilience mainly include two categories: functional curve and scorecard model (Table 3), which can obtain more objective results of the resilience. However, the calculation process is more complicated.Table 3
The quantitative approach to healthcare system resilience.
MethodQuantification of resilience in healthcare systemsFeature equationsLiterature sourcesScorecard modelIn terms of hospital geographic information, structural safety, nonstructural safety, and medical functional safety, 145 evaluation indicators were establishedN.A[55]There are 43 evaluation indicators in eight areas: hospital safety, emergency leadership and cooperation, emergency preparedness, disaster material management, emergency personnel, emergency training and drills, critical emergency response capacity, and recovery and adaptation mechanismsN.A[56]151 indicators were used to evaluate the performance of four modules, including potential hospital risk, structural safety, nonstructural safety, and disaster emergency management, to quantify the disaster resilience of the healthcare systemN.A[47]The hospital function was quantified by the scoring weighted summation results of 38 different component indicators, among which 38 indicators had different weight coefficientsN.A[57]Functional measuresHospital functions are divided into four subfunctions: structured, nonstructured, lifeline, and personnel. Then, the respective functions of different functional levels are fully arranged and combined to form a functional tree. Hospital functions are further quantified according to each combination, to quantify hospital functional resilience—[58]Define hospital functions based on fault trees, and gradually split hospital functions into multiple functional groups. Hospital resilience was finally determined by judging the functional level of the underlying group and going through a series of conduction pathsQt=∑nwi1−1−RitLit/∑nwi[48]The integral of the healthcare system function curve quantifies the disaster resilience of the healthcare system. The ratio of the number of healthy people in the disaster event to the healthy population reviewed before the disaster event was used as a quantitative indicator of the postdisaster hospital function of the health care systemQt=maxNWTcrit−NWT0−NWT,0/NWTcrit−NWT0NWT≤NWTcritNWTcrit−NWT0/maxNWTcrit,NWT−NWTcrit−NWT0NWT>NWTcrit[59]The disaster resilience of the healthcare system is divided into three types of resilience indicators (RIhPh,M) for different services: traffic resilience indicators (RIFPh,M), ambulance resilience indicators (RIAPh,M), and hospital resilience indicators (RIHPh,M)RIMph=∑hwhph,M·RIhph,M/∑hwiph,M[60]The integral of the healthcare system function curve quantifies the disaster resilience of the healthcare system. The function of individual hospitals is quantified in time by treating the woundedQt=maxWTcrit−WT0−WT,0/WTcrit−WT0WT≤WTcritWTcrit−WT0/maxWTcrit,WT−WTcrit−WT0WT>WTcrit[61]Based on the proportion of injured patients, a segmented functional index was proposed, and this was used as a functional index to calculate hospital disaster resilienceQt=A/PtA≤Pt1A≥Pt[62]A quantitative methodology that computes the capacity of hospitals to operate on injured people in the aftermath of a seismic event is presented. The model incorporates variables such as organizational and human preparedness, damage to buildings, the number of operating theatres, the amount of supplies, and the duration of a surgical treatmentHOCTOT=∑i=1nαi⋅βi⋅γiδi/ti⋅ki[63]The objective functionC1 (X) measures waiting time across the city as the average time that a patient would take since the earthquake until completing treatment in the operating roomC1X=∑t∈T∑j=i+nhi∈Γt+τi,j×xi,jt×dt/∑t∈T∑i∈Γbit[64]The probability of total functionality of the healthcare system,P (Q), can be expressed as a combination of the probability of quantity, P (QV), and the conditional probability of quality, P (QS | QV), of the offered servicePQt=PQVtαV⋅PQStαSQVtαV[65]Hospital operating capacity (HOC) should be defined as the minimum of all the availability probabilities of the departments on the hospital treatment chains for a certain type of patients, which should be a number not more than 1 (can also be set as percentage)HOCtotal=∑s=1nws⋅HOCs[66]Bruneau et al. [27] argue that resilience can be quantified by four dimensions. These four dimensions include technical, organizational, social, and economic (TOSE) (Figure 1). Different dimensions require different quantification methods. There may be different quantification methods for different engineering systems even for the same dimension. Therefore, there are several ways to quantify the resilience of healthcare systems (Table 3). Meanwhile, there are four characteristics of resilience, which are robustness, redundancy, resourcefulness, and rapidity (4R) (Figure 1). These four characteristics are coupled with each other, indicating the inconsistency of the toughness quantification method.Figure 1
Resilience analysis of four dimensions (TOSE) and four characteristics (4R).Rational assessment resilience indices are the key to quantitative healthcare system. One way to do so is through defining the service as a function of losses to different hospital departments while considering the possibility of service redistribution among the departments. Denver Health [67] based on hospital capacity or the number of staffed beds available for patients based on daily rates, defined the quantity portion of the offered medical services. Jacques et al. [48] examined the loss and redistribution of n critical clinical and support services at a hospital. Hassan and Mahmoud [68] modified the fault tree proposed by Jacques et al. [48] and regarded the available beds as the quantitative functionality. Estimating patients demand is a critical parameter for hospital functionality assessment. Zhai et al. [69] adopted the ratio of the number of patients treated to the total number of patients to measure the hospital functionality. In addition to medical service, treatment provided timely can reduce the risk of disability and death. Different time limits are given to patients, and medical resources need to be available to begin treatment as soon as possible. The time limit is known as the critical waiting time (WT), and the waiting time is defined as the time a patient is waiting before receiving assistance from medical workers, which does not include the time before entering hospitals [70]. The waiting time of patients and the number of patients treated within the critical waiting time are important index for quantitative analysis of hospital functions. The relevant indices for the quantification of hospital functions are shown in Table 3.Methods of quantitative resilience assessment are used in most of the relevant research in the field of evaluating resilience. Therefore, the scorecard model and functional curve are widely applicated. The scorecard model can be applied to different objects and multiple types of hazards. It consists of a series of indicators lists describing the resilience state and the corresponding scoring scales of the system. The indicators listed are scored sequentially according to the actual situation after the disasters. According to weighted aggregation or multiple regression of the score of each of the indicators, the score of system resilience is calculated.The functional curve quantifies resilience by analyzing the data produced in the process of recovery. Based on the random factors of the system that are directly reflected in the measure expression, the functional curve is divided into deterministic measures and random measures. The functional curve is the geometric characteristic of the recovery curve to resilience.The equation of the functional curve proposed by Bruneau et al. [27] is representative (equation (1)). This equation is proposed to achieve community seismic resilience. However, the most critical functional variable in its expression represents a broad concept. Therefore, it has good applicability and can be used to measure the resilience of different types of objects and disasters.(1)R=∫t0t0+tLCQttLCdt,where t is the time variable, R is community seismic resilience, Q (t) is community functionality standardized at moment t, and t0 and tLC represent the time when the earthquake occurred and the time when the community recovered, respectively.According to the above studies, the scorecard model is not quantitative enough, which is difficult to evaluate the improvement measures of resilience. Meanwhile, it is difficult to dynamically observe the functional performance of the resilience process of the healthcare system. The functional curves can make up for the shortcomings of the scorecard model. However, the functional curves are mostly used for single hospitals and lack the functional indicators of the hospital system and the comprehensive resilience that takes into account the postearthquake functional damage and recovery process.


## 3.1. Concept of Resilience

Resilience is derived from the Latin word, that is, resilio, which means bounce to back [21]. The concept originated in physics to characterize the resistance of materials to impact. In the 1970s, ecologist Holling [22] first used the concept of resilience to describe the multiequilibrium state of ecosystems, which is the character of the ability of ecosystems to absorb changes in response to disturbances. Resilience has been more widely used in psychology, engineering, ecology, etc. At present, there is no accepted definition of resilience in academia (Table 1). Moreover, its meaning varies within the same field of research.Table 1
Different definitions of resilience.
AuthorsDate of publicationDefinition of resilienceHolling [22]1973Resilience refers to the ability of a system to absorb, change, and perturb and to maintain a balanced state of the systemWildavsky [23]1988Resilience refers to the ability to cope with disasters after a disaster and has the characteristics of adaptation and recoveryMileti [24]1999Resilience refers to the ability of an area to undergo extreme natural events without catastrophic loss, damage, reduced productivity, and normal life and does not require a lot of outside assistanceComfort [25]1999Resilience refers to the ability and action of existing resources and capacities to adapt to new situationsAdger [26]2000Resilience refers to the resilience of public infrastructure to disaster shocksKlein et al. [16]2003Resilience is the ability to withstand the stresses of the environmentBruneau et al. [27]2003Resilience refers to the ability of a society to mitigate the impact on the city and to cope with the impact of future disasters with the least impact on societyWalker et al. [28]2004Resilience consists of four components: range, resistance, instability, and chaos. Toughness refers to the ability of a system to absorb interference and keep its key functions, structures, and characteristics functionalWalker and Slat [29]2006Resilience was originally defined as the ability of a system to respond to external disturbances in the case of maintaining its basic stateAllenby and Fink [30]2005Resilience refers to the ability of a system to maintain its functional and structural stability in the face of internal and external changes, and only when the function and structure are slowly decliningUS Department of Homeland Security [31]2006Resilience refers to the ability of the system to efficiently reduce the degree of damage to the system by disasters at a set target functional level in the event of an emergencyWamsler [32]2007Resilience refers to the ability of urban systems to survive, adapt, and develop in the face of sudden disastersUNISDR [33]2009Resilience refers to the exposure of a system, community, or society to a hazard, the ability to resist, absorb, adapt to disasters, and effectively reduce below the targetUnited Nations [34]2009Resilience is defined as the ability of systems, communities, or societies exposed to hazards, to resist, absorb, withstand, and recover from the impacts of disasters in a timely and effective manner, including the protection and restoration of essential infrastructure works and their functionsCohen et al. [35]2013Resilience is defined as the ability of a society to function properly in times of crisisResilience Alliance [36]2022Resilience is the ability of socio-ecological systems to absorb disturbances and pressures from maintaining the original characteristics, especially their original structure and functionResilience can be divided into two concepts: engineering resilience and ecological resilience. Engineering resilience is a one equilibrium state in the system. Its resilience is manifested in the fact that the system can resist disturbances and maintain its original state. System resilience can be measured by the resistance of the system to disturbances and the rate at which it returns to the original equilibrium state. Ecological resilience advocates the existence of multiple equilibrium states in the system. The resilience of the system is measured by the level of disturbances that the system needs to absorb from one equilibrium state to another. Based on previous research, Folke [37] analyzed the interaction between humans and ecosystems and further proposed socio-ecological resilience. This view holds that the system is constantly changing and maintained in a certain equilibrium that formal perturbations cause a continuous change in the system. Resilience describes not only the ability of a system to absorb disturbances to maintain its original state but also the ability of the system to self-organize and learn and adapt. Resilience which does not emphasize equilibrium is also known as evolutionary resilience.The inconsistency of the above concepts of resilience poses challenges to studying the resilience of urban systems and subsystems. How to define the resilience of urban systems and subsystems depends on the understanding of this issue. Problems were researched in two ways. One is induction, which is from individual to general. The second is the deduction, which is from general to individual. Holling [22] proposed the concept of resilience based on the observation of the development of their biological populations, which belongs to the inductive process. From the initial concept of resilience to socio-ecological resilience and resilience of urban systems and subsystems, the process of development of this concept is more analogous to the deduction. Different from the objective resilience of ecosystems, the resilience connotation of the urban system in which humans live has both subjective and objective aspects. Resilience is an objective attribute of urban systems and subsystems. Historical cases show that cities have certain resilience after encountering disturbances such as disasters. What level of resilience do cities hope to achieve? How to reach it depends on human subjective consciousness. In general, the resilience of urban systems and subsystems refers to the ability to maintain or quickly restore the core functions in the event of various disturbances such as disasters, and to adapt to future uncertainties.The performance of resilience has an obvious process. There are two main links: resistance and recovery. Resistance means that the system can withstand the negative effects of perturbations to maintain its core function. Recovery means that a system can quickly restore its functionality to the desired state after being compromised. This state may be the initial state, in which the system is considered to have a single equilibrium state. It can also be a new state, in which the system has a multiequilibrium state. In addition, adaptation is also an important connotation of resilience, which means that the system can change its structure through self-learning to prepare for future uncertain disturbances. The system adapts to improve its resistance and resilience to future disturbances. The system is constantly resisting, recovering, and adapting, leaving it in a dynamic process of constant evolution.For studying resilience, it is necessary to clarify resilience of what, to what, for what, for whom, and over what time frame. Firstly, studying resilience begins with defining systems and their boundaries. The different systems have different qualities that directly affect the understanding of resilience. Secondly, it is necessary to define the type of system disturbance, and improving the resilience of the system to one disturbance may reduce its resilience to other disturbances. It is also necessary to clarify the service targets or stakeholders of system resilience, and different stakeholders will have different requirements for the goal of resilience. Finally, the time window for observing the resilience of the system should be clarified, because the choice of time scale will affect the choice of disturbance type and the evaluation of the recovery.


## 3.2. Concept of Healthcare System Resilience

The World Health Organization [38] defines the health system as an organization that covers all activities aimed at promoting, restoring, and ensuring the health, including relevant public, private, and nongovernmental institutions such as hospitals, health centers, testing centers, pharmacies, and blood banks. The U.S. Department of Health and Human Services [39] defines the healthcare system as a collection of all medical organizations in the community. Chinese healthcare system [40] includes not only a collection of various medical organizations and institutions, but also a complex of many interacting and interdependent elements committed to the various resources of the health system to achieve the purpose of disease prevention and treatment and improve the health level of the population.The concept of the resilience of the healthcare system has not yet been unified (Table2). However, the studies all emphasize the resilience of the healthcare system to maintain services under shocks, or absorb the adverse effects of shocks through its adaptation and change in the process of resistance, to ensure the continuity of medical services, or restore the function as soon as possible after the function of the healthcare system has received a significant loss to ensure subsequent services. Therefore, the resilience of health systems remains a discussion of the ability of health systems to resist shocks, maintain their healthcare functions, and quickly recover from health services after being affected.Table 2
Definition of healthcare system resilience.
AuthorsDate of publicationDefinition of medical resilienceKieny and Dovlo [41]2015The resilient healthcare system absorbs the impact of emergencies while continuing to provide routine careBarasa et al. [42]2017Resilient healthcare systems need to be able to adapt and change to continue to deliver quality services and respond to emerging healthcare needsKruk et al. [43]2015The health system is defined as the ability of healthcare practitioners, institutions, and populations to prepare for and respond effectively to crises. A resilient healthcare system is perceptual and can preidentify potential risk factors affecting people’s healthBlanchet et al. [44]2017The willfulness of a health system is defined as the ability of a health system to absorb, adapt, change, and maintain control over its original structure and function when exposed to shocks, such as infectious diseases, geological disasters, and armed conflictsZhong et al. [45]2014Hospital disaster resilience is defined as the ability of a hospital to resist, absorb, and respond to disaster shocks, maintain its essential functions (such as prehospital emergency care, hospital emergency, intensive care, disinfection, and isolation), and return to its original state or a new adaptive stateCimellaro and Pique [46]2016Hospital disaster resilience is defined as the ability of a hospital system to prepare for a disaster event, absorb the effects of the disaster, recover from the disaster, and keep itself functioning wellWorld Health Organization [47]2015A resilient health system is defined as a health system that can predict, respond to, recover, and adapt to climate-related shocks or stress diseases in unstable climates to ensure the health of populations with increasing health, and considers that resilience of health systems equals reduced vulnerability plus increased adaptive capacityJacques et al. [48]2014Disaster resilience of health systems refers to a hospital’s ability to manage and continue to deliver healthcare in the event of an emergency, including the climate recovery phaseRamandi and Kashani [49]2018Disaster resilience in health systems is the ability of hospitals to respond, withstand, and absorb the effects of disasters, provide health care services, and restore basic or acceptable levels of servicesBerg and Aase [50]2019Resilience is described as a set of cognitive and behavioral strategies of individuals who enact resilience within an organizational contextWiig et al. [51]2020A resilient healthcare system might be expected to consistently deliver high quality care, withstand disruptive events, and continually adapt, learn, and improve. The capacity to adapt to challenges and changes at different system levels, to maintain high quality careLyng et al. [52]2021This study develops a new conceptual account of adaptation and innovation as a basis for resilience in healthcare. Findings emerging from this study indicate that a balance between adaptation and innovation should be sought when seeking resilience in healthcarePei et al. [53]2022This article proposes a resilience assessment framework for the interdependent transportation–healthcare system integrating physical loss and organizational management during postearthquake emergency response. Considering the earthquake-induced injured people, the seismic damage to transportation, and the quantification of the condition of the patients after being treated, a novel metric is proposed to evaluate the response effort during the first 72 h


## 3.3. Quantitative Assessment Methods for the Resilience of the Healthcare System

It is necessary to evaluate the resilience of the system under specific conditions, to the improvement of the resilience of existing systems or the design of new systems. The accuracy of the resilience evaluated greatly affects the effectiveness of the work. Resilience assessments can be both qualitative and quantitative, depending on the characteristics of the object being assessed and the analytical needs. The qualitative methods for assessing resilience mainly include questionnaires and focus group discussions [54], which are simple in principle and highly operable. However, the results are often limited by personal knowledge. The quantitative methods for assessing resilience mainly include two categories: functional curve and scorecard model (Table 3), which can obtain more objective results of the resilience. However, the calculation process is more complicated.Table 3
The quantitative approach to healthcare system resilience.
MethodQuantification of resilience in healthcare systemsFeature equationsLiterature sourcesScorecard modelIn terms of hospital geographic information, structural safety, nonstructural safety, and medical functional safety, 145 evaluation indicators were establishedN.A[55]There are 43 evaluation indicators in eight areas: hospital safety, emergency leadership and cooperation, emergency preparedness, disaster material management, emergency personnel, emergency training and drills, critical emergency response capacity, and recovery and adaptation mechanismsN.A[56]151 indicators were used to evaluate the performance of four modules, including potential hospital risk, structural safety, nonstructural safety, and disaster emergency management, to quantify the disaster resilience of the healthcare systemN.A[47]The hospital function was quantified by the scoring weighted summation results of 38 different component indicators, among which 38 indicators had different weight coefficientsN.A[57]Functional measuresHospital functions are divided into four subfunctions: structured, nonstructured, lifeline, and personnel. Then, the respective functions of different functional levels are fully arranged and combined to form a functional tree. Hospital functions are further quantified according to each combination, to quantify hospital functional resilience—[58]Define hospital functions based on fault trees, and gradually split hospital functions into multiple functional groups. Hospital resilience was finally determined by judging the functional level of the underlying group and going through a series of conduction pathsQt=∑nwi1−1−RitLit/∑nwi[48]The integral of the healthcare system function curve quantifies the disaster resilience of the healthcare system. The ratio of the number of healthy people in the disaster event to the healthy population reviewed before the disaster event was used as a quantitative indicator of the postdisaster hospital function of the health care systemQt=maxNWTcrit−NWT0−NWT,0/NWTcrit−NWT0NWT≤NWTcritNWTcrit−NWT0/maxNWTcrit,NWT−NWTcrit−NWT0NWT>NWTcrit[59]The disaster resilience of the healthcare system is divided into three types of resilience indicators (RIhPh,M) for different services: traffic resilience indicators (RIFPh,M), ambulance resilience indicators (RIAPh,M), and hospital resilience indicators (RIHPh,M)RIMph=∑hwhph,M·RIhph,M/∑hwiph,M[60]The integral of the healthcare system function curve quantifies the disaster resilience of the healthcare system. The function of individual hospitals is quantified in time by treating the woundedQt=maxWTcrit−WT0−WT,0/WTcrit−WT0WT≤WTcritWTcrit−WT0/maxWTcrit,WT−WTcrit−WT0WT>WTcrit[61]Based on the proportion of injured patients, a segmented functional index was proposed, and this was used as a functional index to calculate hospital disaster resilienceQt=A/PtA≤Pt1A≥Pt[62]A quantitative methodology that computes the capacity of hospitals to operate on injured people in the aftermath of a seismic event is presented. The model incorporates variables such as organizational and human preparedness, damage to buildings, the number of operating theatres, the amount of supplies, and the duration of a surgical treatmentHOCTOT=∑i=1nαi⋅βi⋅γiδi/ti⋅ki[63]The objective functionC1 (X) measures waiting time across the city as the average time that a patient would take since the earthquake until completing treatment in the operating roomC1X=∑t∈T∑j=i+nhi∈Γt+τi,j×xi,jt×dt/∑t∈T∑i∈Γbit[64]The probability of total functionality of the healthcare system,P (Q), can be expressed as a combination of the probability of quantity, P (QV), and the conditional probability of quality, P (QS | QV), of the offered servicePQt=PQVtαV⋅PQStαSQVtαV[65]Hospital operating capacity (HOC) should be defined as the minimum of all the availability probabilities of the departments on the hospital treatment chains for a certain type of patients, which should be a number not more than 1 (can also be set as percentage)HOCtotal=∑s=1nws⋅HOCs[66]Bruneau et al. [27] argue that resilience can be quantified by four dimensions. These four dimensions include technical, organizational, social, and economic (TOSE) (Figure 1). Different dimensions require different quantification methods. There may be different quantification methods for different engineering systems even for the same dimension. Therefore, there are several ways to quantify the resilience of healthcare systems (Table 3). Meanwhile, there are four characteristics of resilience, which are robustness, redundancy, resourcefulness, and rapidity (4R) (Figure 1). These four characteristics are coupled with each other, indicating the inconsistency of the toughness quantification method.Figure 1
Resilience analysis of four dimensions (TOSE) and four characteristics (4R).Rational assessment resilience indices are the key to quantitative healthcare system. One way to do so is through defining the service as a function of losses to different hospital departments while considering the possibility of service redistribution among the departments. Denver Health [67] based on hospital capacity or the number of staffed beds available for patients based on daily rates, defined the quantity portion of the offered medical services. Jacques et al. [48] examined the loss and redistribution of n critical clinical and support services at a hospital. Hassan and Mahmoud [68] modified the fault tree proposed by Jacques et al. [48] and regarded the available beds as the quantitative functionality. Estimating patients demand is a critical parameter for hospital functionality assessment. Zhai et al. [69] adopted the ratio of the number of patients treated to the total number of patients to measure the hospital functionality. In addition to medical service, treatment provided timely can reduce the risk of disability and death. Different time limits are given to patients, and medical resources need to be available to begin treatment as soon as possible. The time limit is known as the critical waiting time (WT), and the waiting time is defined as the time a patient is waiting before receiving assistance from medical workers, which does not include the time before entering hospitals [70]. The waiting time of patients and the number of patients treated within the critical waiting time are important index for quantitative analysis of hospital functions. The relevant indices for the quantification of hospital functions are shown in Table 3.Methods of quantitative resilience assessment are used in most of the relevant research in the field of evaluating resilience. Therefore, the scorecard model and functional curve are widely applicated. The scorecard model can be applied to different objects and multiple types of hazards. It consists of a series of indicators lists describing the resilience state and the corresponding scoring scales of the system. The indicators listed are scored sequentially according to the actual situation after the disasters. According to weighted aggregation or multiple regression of the score of each of the indicators, the score of system resilience is calculated.The functional curve quantifies resilience by analyzing the data produced in the process of recovery. Based on the random factors of the system that are directly reflected in the measure expression, the functional curve is divided into deterministic measures and random measures. The functional curve is the geometric characteristic of the recovery curve to resilience.The equation of the functional curve proposed by Bruneau et al. [27] is representative (equation (1)). This equation is proposed to achieve community seismic resilience. However, the most critical functional variable in its expression represents a broad concept. Therefore, it has good applicability and can be used to measure the resilience of different types of objects and disasters.(1)R=∫t0t0+tLCQttLCdt,where t is the time variable, R is community seismic resilience, Q (t) is community functionality standardized at moment t, and t0 and tLC represent the time when the earthquake occurred and the time when the community recovered, respectively.According to the above studies, the scorecard model is not quantitative enough, which is difficult to evaluate the improvement measures of resilience. Meanwhile, it is difficult to dynamically observe the functional performance of the resilience process of the healthcare system. The functional curves can make up for the shortcomings of the scorecard model. However, the functional curves are mostly used for single hospitals and lack the functional indicators of the hospital system and the comprehensive resilience that takes into account the postearthquake functional damage and recovery process.


## 4. Medical Demand after an Earthquake

A surge in medical demand that extends beyond local medical surge capacity in mass casualty incidents following major disasters is common. Shen et al. [71] elaborate the precision strategy of augmenting medical surge capacity for disaster response. Kato et al. [72] predicted under a maximal damage scenario in a future earthquake, we predicted a shortage of 2,780 beds for the treatment of severe casualties across Tokyo. Therefore, the study of the medical demand of earthquake casualties has become the key to providing medical relief for casualties in future earthquakes.


### 4.1. The Statistics of the Medical Demand

We calculated the incidence of earthquake-related injuries based on the percent published in each study. To explore the source of heterogeneity, we divided the studies by the magnitude of the earthquake. Combined with the classification and statistics of method of casualties put forward by Tang et al. [73], this article expands the casualty statistics from three aspects: injury types, injury parts, and injury factors. Casualty injuries are divided into fracture (F), soft tissue injury (ST), infection (I), nerve injury (NI), burn (B), crush (C), and amputation (A). Injury parts are divided into multiple injuries (M), internal organs (I), head/face/neck (H), trunk (TK), extremities (E), thorax (T), abdomen (AB), and spine (S). Injury factors are divided into crush/burying (C/B), slip/falling (S/F), and hit by an object (H). This article counts the number of casualties in earthquakes of magnitude 6 or higher from 1988 to 2016 (Table 4). Figure 2 shows the proportion of different casualty types.Table 4
The general characteristic of the 47 studies.
AuthorsDate of publicationEarthquake nameSampleMagnitude1Armenian et al. [74]19971988 Armenian earthquake14546.92Bai and Liu [75]20092005 Pakistan earthquake4267.83Dhar et al. [76]20072005 Pakistan earthquake4687.64Milch et al. [77]20102007 Peru earthquake9285Emami et al. [78]20052003 Iran earthquake7086.56Farfel et al. [79]20112010 Haiti earthquake3187.07Hatamizadeh et al. [80]20062003 Iran earthquake20866.88İskit et al. [81]20011999 Turkey Marmara earthquake337.49Jain et al. [82]20032001 India earthquake627.910Jian et al. [83]20102008 Wenchuan earthquake1968.011Kuwagata et al. [84]19971995 Japan earthquake27027.212Mohebbi et al. [85]20082003 Iran earthquake13326.613Mulvey et al. [86]20082005 Pakistan earthquake15027.814Parasuraman [87]19951993 Iran earthquake48036.415Peek-Asa et al. [88]20031994 California earthquake1716.716Poçan et al. [89]20021999 Turkey earthquake6307.417Pointer et al. [90]19921989 California earthquake10827.118Roces et al. [91]19921990 Philippines earthquake3637.719Roy et al. [92]20022001 India earthquake2836.920Sabzehchian et al. [93]20062003 Iran earthquake1196.521Salinas et al. [94]19981994 California earthquake3296.722Shoaf et al. [95]19981994 Northridge earthquake1496.723Tanaka et al. [96]19991995 Japan earthquake27187.224Uzun et al. [97]20051999 Turkey earthquake757.425Yang et al. [98]20092008 Wenchuan earthquake5338.026Zhang et al. [99]20092008 Wenchuan earthquake17238.027Zhao et al. [100]20112008 Wenchuan earthquake1928.028Kang et al. [101]20122010 Yushu earthquake26227.129Ding et al. [102]20152008 Wenchuan earthquake4658.0302015 Nepal earthquake718.131Wen et al. [103]20122008 Wenchuan earthquake28818.032Zhang et al. [104]20142013 Lushan earthquake20107.033Kang et al. [105]20152013 Lushan earthquake2667.034Hu et al. [106]20122008 Sichuan earthquake1018.035Li et al. [107]20122010 Yushu earthquake5827.136Doocy et al. [108]20132010 Haiti earthquake66967.037Qiu et al. [109]20102008 Sichuan earthquake34018.038Gu et al. [110]20102008 Sichuan earthquake928.039Fan et al. [111]20112008 Sichuan earthquake10388.040Lin et al. [112]20162016 Taiwan earthquake5136.441Li et al. [113]20092008 Sichuan earthquake328.042Lin et al. [114]20092008 Sichuan earthquake280088.043Johnston et al. [115]20142010/2011 Canterbury earthquakes94276.3–7.144Xu et al. [116]20132008 Sichuan earthquake373878.045Liu et al. [117]20142008 Sichuan earthquake3348.0Figure 2
Injured characteristics in the earthquake.According to the statistics of injury types of the wounded, it can be found that the number of fractured injuries accounts for the largest proportion, which is 44.83%. More than half of the wounded were fractures and soft tissue injuries. Although the proportion of wounded with crush injuries is few, the number of literatures on this type of wounded is relatively large, which is 30.The largest number of injured are extremities injuries, accounting for 47.15%. The number of trunk injuries accounted for 27.34%. Earthquake casualties also often had multiple injuries, accounting for 13.06%. The percentage of wounded in the chest, abdomen, and vertebral column is 8.76%, 5.63%, and 8.52%, respectively. The main cause of injury in the earthquake was being hit by an object, accounting for 50.81%. Crushing/falling and slipping are the other two factors that cause injuries, 25.20% and 28.35%, respectively.


### 4.2. The Analysis of the Medical Demand

The conditions of the injured after the earthquake are different. The treatment process required is far different. It is necessary to combine the hospital reception data to study the classification and proportion of the condition of the injured after the earthquake. The postearthquake casualties are mainly fracture injuries, in which multiple injuries, head injuries, and spinal cord injuries have a high fatality rate, and the probability of sequelae is relatively large.This reflects the fact that orthopedic surgery has been the means of inpatient medical relief for rescue since the earthquake. Therefore, it is crucial to prepare adequate medical equipment and personnel for medical rescue in future disasters. According to statistics of the injured at the Tribhuvan University Hospital in the 2015 Nepal earthquake, the peak of postearthquake casualty admissions occurred on the fifth day after the earthquake, and 89% of the casualties developed physical injuries, including 66% of bone injuries and received surgical treatment [118]. Postearthquake rescue data statistics showed that the change in the condition of the injured mainly presented as orthopedic and trauma-based in the early stage, and the number of medical patients gradually increased with the change of extrusion time [119, 120]. In the statistical analysis of the disease types of international rescue teams in Pakistan and Indonesia, trauma/wound diseases were predominant in the week after the earthquake, accounting for 61.46% to 79.52% and 61.48% to 72.35% in Pakistan and Indonesia, respectively. After one-week, other medical diseases increased significantly, accounting for 33.93% to 71.11% and 31.50% to 52.11% in Pakistan and Indonesia, respectively [112].The most frequently traumatized part of the body is the extremities. This may be due in part to the fact that patients with injuries to the extremities survive longer than those with chest, abdominal, or head trauma [97]. Currently, the statistics of postearthquake injury are derived from the number of injured patients accepted by medical facilities for investigation. This has resulted in some spinal, thoracic, and cranial injuries not surviving due to the severity of the injuries, resulting in these injuries not being counted, although spinal, thoracic, and cranial injuries are rare, which are often serious and life-threatening, and cannot be ignored.The statistics of crush injury casualties found that most of them were injured in multistory building structures such as brick-concrete structures, frame structures, or frame-shear structures [121]. By studying the number of crush injuries in the rural areas in Wenchuan, Lushan, and Yushu earthquakes, the proportion of crush injuries was relatively small compared to the urban areas. This is because most of the buildings in rural areas are adobe structures or brick-wood structures, which have only one floor [122]. Although buildings in rural areas have poor seismic performance and are severely damaged in earthquakes. But the rescue of the injured in this part is easier compared to multistory buildings.People are most likely to be injured by falling objects during an earthquake. During an earthquake, try to avoid taking shelter under objects that easily fall. Therefore, the spread of proper earthquake self-rescue methods is very important to reduce the number of injuries. Keep your head, abdomen, and chest protected under a solid table or bed to avoid fatal injuries during an earthquake. Meanwhile, stay away from fire sources to avoid burns. Leave the building as soon as possible after the main quake to avoid injuries caused by aftershocks.In summary, the medical rescue force with adequate health resources and equipment, especially for the extremities, is critical in the first hours after the earthquake. In addition, a detailed earthquake medical management plan should also adhere to a flexible approach to replenishing medical resources based on the distribution of different injury locations under different earthquake magnitudes.


## 4.1. The Statistics of the Medical Demand

We calculated the incidence of earthquake-related injuries based on the percent published in each study. To explore the source of heterogeneity, we divided the studies by the magnitude of the earthquake. Combined with the classification and statistics of method of casualties put forward by Tang et al. [73], this article expands the casualty statistics from three aspects: injury types, injury parts, and injury factors. Casualty injuries are divided into fracture (F), soft tissue injury (ST), infection (I), nerve injury (NI), burn (B), crush (C), and amputation (A). Injury parts are divided into multiple injuries (M), internal organs (I), head/face/neck (H), trunk (TK), extremities (E), thorax (T), abdomen (AB), and spine (S). Injury factors are divided into crush/burying (C/B), slip/falling (S/F), and hit by an object (H). This article counts the number of casualties in earthquakes of magnitude 6 or higher from 1988 to 2016 (Table 4). Figure 2 shows the proportion of different casualty types.Table 4
The general characteristic of the 47 studies.
AuthorsDate of publicationEarthquake nameSampleMagnitude1Armenian et al. [74]19971988 Armenian earthquake14546.92Bai and Liu [75]20092005 Pakistan earthquake4267.83Dhar et al. [76]20072005 Pakistan earthquake4687.64Milch et al. [77]20102007 Peru earthquake9285Emami et al. [78]20052003 Iran earthquake7086.56Farfel et al. [79]20112010 Haiti earthquake3187.07Hatamizadeh et al. [80]20062003 Iran earthquake20866.88İskit et al. [81]20011999 Turkey Marmara earthquake337.49Jain et al. [82]20032001 India earthquake627.910Jian et al. [83]20102008 Wenchuan earthquake1968.011Kuwagata et al. [84]19971995 Japan earthquake27027.212Mohebbi et al. [85]20082003 Iran earthquake13326.613Mulvey et al. [86]20082005 Pakistan earthquake15027.814Parasuraman [87]19951993 Iran earthquake48036.415Peek-Asa et al. [88]20031994 California earthquake1716.716Poçan et al. [89]20021999 Turkey earthquake6307.417Pointer et al. [90]19921989 California earthquake10827.118Roces et al. [91]19921990 Philippines earthquake3637.719Roy et al. [92]20022001 India earthquake2836.920Sabzehchian et al. [93]20062003 Iran earthquake1196.521Salinas et al. [94]19981994 California earthquake3296.722Shoaf et al. [95]19981994 Northridge earthquake1496.723Tanaka et al. [96]19991995 Japan earthquake27187.224Uzun et al. [97]20051999 Turkey earthquake757.425Yang et al. [98]20092008 Wenchuan earthquake5338.026Zhang et al. [99]20092008 Wenchuan earthquake17238.027Zhao et al. [100]20112008 Wenchuan earthquake1928.028Kang et al. [101]20122010 Yushu earthquake26227.129Ding et al. [102]20152008 Wenchuan earthquake4658.0302015 Nepal earthquake718.131Wen et al. [103]20122008 Wenchuan earthquake28818.032Zhang et al. [104]20142013 Lushan earthquake20107.033Kang et al. [105]20152013 Lushan earthquake2667.034Hu et al. [106]20122008 Sichuan earthquake1018.035Li et al. [107]20122010 Yushu earthquake5827.136Doocy et al. [108]20132010 Haiti earthquake66967.037Qiu et al. [109]20102008 Sichuan earthquake34018.038Gu et al. [110]20102008 Sichuan earthquake928.039Fan et al. [111]20112008 Sichuan earthquake10388.040Lin et al. [112]20162016 Taiwan earthquake5136.441Li et al. [113]20092008 Sichuan earthquake328.042Lin et al. [114]20092008 Sichuan earthquake280088.043Johnston et al. [115]20142010/2011 Canterbury earthquakes94276.3–7.144Xu et al. [116]20132008 Sichuan earthquake373878.045Liu et al. [117]20142008 Sichuan earthquake3348.0Figure 2
Injured characteristics in the earthquake.According to the statistics of injury types of the wounded, it can be found that the number of fractured injuries accounts for the largest proportion, which is 44.83%. More than half of the wounded were fractures and soft tissue injuries. Although the proportion of wounded with crush injuries is few, the number of literatures on this type of wounded is relatively large, which is 30.The largest number of injured are extremities injuries, accounting for 47.15%. The number of trunk injuries accounted for 27.34%. Earthquake casualties also often had multiple injuries, accounting for 13.06%. The percentage of wounded in the chest, abdomen, and vertebral column is 8.76%, 5.63%, and 8.52%, respectively. The main cause of injury in the earthquake was being hit by an object, accounting for 50.81%. Crushing/falling and slipping are the other two factors that cause injuries, 25.20% and 28.35%, respectively.


## 4.2. The Analysis of the Medical Demand

The conditions of the injured after the earthquake are different. The treatment process required is far different. It is necessary to combine the hospital reception data to study the classification and proportion of the condition of the injured after the earthquake. The postearthquake casualties are mainly fracture injuries, in which multiple injuries, head injuries, and spinal cord injuries have a high fatality rate, and the probability of sequelae is relatively large.This reflects the fact that orthopedic surgery has been the means of inpatient medical relief for rescue since the earthquake. Therefore, it is crucial to prepare adequate medical equipment and personnel for medical rescue in future disasters. According to statistics of the injured at the Tribhuvan University Hospital in the 2015 Nepal earthquake, the peak of postearthquake casualty admissions occurred on the fifth day after the earthquake, and 89% of the casualties developed physical injuries, including 66% of bone injuries and received surgical treatment [118]. Postearthquake rescue data statistics showed that the change in the condition of the injured mainly presented as orthopedic and trauma-based in the early stage, and the number of medical patients gradually increased with the change of extrusion time [119, 120]. In the statistical analysis of the disease types of international rescue teams in Pakistan and Indonesia, trauma/wound diseases were predominant in the week after the earthquake, accounting for 61.46% to 79.52% and 61.48% to 72.35% in Pakistan and Indonesia, respectively. After one-week, other medical diseases increased significantly, accounting for 33.93% to 71.11% and 31.50% to 52.11% in Pakistan and Indonesia, respectively [112].The most frequently traumatized part of the body is the extremities. This may be due in part to the fact that patients with injuries to the extremities survive longer than those with chest, abdominal, or head trauma [97]. Currently, the statistics of postearthquake injury are derived from the number of injured patients accepted by medical facilities for investigation. This has resulted in some spinal, thoracic, and cranial injuries not surviving due to the severity of the injuries, resulting in these injuries not being counted, although spinal, thoracic, and cranial injuries are rare, which are often serious and life-threatening, and cannot be ignored.The statistics of crush injury casualties found that most of them were injured in multistory building structures such as brick-concrete structures, frame structures, or frame-shear structures [121]. By studying the number of crush injuries in the rural areas in Wenchuan, Lushan, and Yushu earthquakes, the proportion of crush injuries was relatively small compared to the urban areas. This is because most of the buildings in rural areas are adobe structures or brick-wood structures, which have only one floor [122]. Although buildings in rural areas have poor seismic performance and are severely damaged in earthquakes. But the rescue of the injured in this part is easier compared to multistory buildings.People are most likely to be injured by falling objects during an earthquake. During an earthquake, try to avoid taking shelter under objects that easily fall. Therefore, the spread of proper earthquake self-rescue methods is very important to reduce the number of injuries. Keep your head, abdomen, and chest protected under a solid table or bed to avoid fatal injuries during an earthquake. Meanwhile, stay away from fire sources to avoid burns. Leave the building as soon as possible after the main quake to avoid injuries caused by aftershocks.In summary, the medical rescue force with adequate health resources and equipment, especially for the extremities, is critical in the first hours after the earthquake. In addition, a detailed earthquake medical management plan should also adhere to a flexible approach to replenishing medical resources based on the distribution of different injury locations under different earthquake magnitudes.


## 5. The Function Capability of the Hospital

When a disaster occurs, hospitals are required to increase their receiving and treatment capacity in a very short time to meet the surge of patients. This aspect is referred to as surge response capability [123] and is conceptually defined as the combination of surge capacity and planning [124]. Medical capacity is “the ability to respond to a sudden increase in patient care demands” [125]. Achour et al. [126] optimized a reactive approach to natural hazards, which included physical and human, and increasing the resilience and flexibility of infrastructure to expand medical capacity. Therrien et al. [127] related insights from resilience research to the four “S” of surge capacity (staff, stuff, structures, and systems) and proposed a framework based on complexity theory to better understand and assess resilience factors that enable the development of surge capacity in complex health systems. A large number of medical resources and a rational medical rescue process become crucial to meet the medical demand.


### 5.1. Medical Rescue of the Wounded after the Earthquake

Based on the functional curve, the postearthquake function of the healthcare system should be clarified for evaluating the seismic resilience of the healthcare system. The literature shows that there is no uniform concept of the function of the healthcare system. The expectation of the healthcare system should be to protect human health. For this purpose, the healthcare system needs to provide a variety of medical services, including but not limited to physical examination, patient isolation, disease treatment, patient care, and disease prevention [39, 128]. It is essential to meet the medical demand of the injured in the earthquake for the medical function of the healthcare system in the disaster region.The earthquake instantly caused a large number of casualties, which easily caused a shortage of doctors and medical resources. Therefore, the medical rescue of casualties adopts a graded rescue method [129]. The medical rescue system after the earthquake learned from the treatment precept used in the war. The medical rescue process is divided into three levels, which include on-site rescue, early treatment, and specialized treatment. The first level of treatment is an on-site rescue, which mainly includes self-rescue and mutual rescue of the injured at the scene of the disaster, as well as on-sitefirst-aid activities. Diagnosis and treatment activities include hemostasis, dressing, classification of injuries, anti-infection, and some simple surgeries. After the on-site rescue, the injured were transferred to hospitals and other medical institutions for follow-up medical treatment. The second level is early treatment. Early treatment is when a patient is sent to the hospital for treatment. Hospitals in disaster-stricken areas have been damaged by earthquakes. However, those hospitals still retain certain medical rescue functions, and can still carry out early treatment of patients and surgical treatment as appropriate. However, some of the wounded with complex conditions do not recover after receiving early treatment. At this time, the casualty needs to receive the third level of medical treatment (i.e., specialized treatment). Specialist care should be performed in well-functioning medical conditions.According to the treatment site, postearthquake medical rescue can be divided into prehospital treatment and in-hospital treatment. Level 1 medical assistance is a part of the prehospital treatment. Second and tertiary-level medical assistance is considered in-hospital treatment. The key to prehospital treatment in the disaster area is to improve the survival rate of the injured after the earthquake. In-hospital treatment is to reduce the disability rate and radically treat the wounded. Therefore, it is necessary to consider the medical rescue function in the entire medical rescue process, when modeling or analyzing the postearthquake functional resilience of systems. The literature shows that the functional curves and scorecards model focuses on the comprehensive consideration of in-hospital medical function loss or recovery medical rescue process.


### 5.2. Medical Rescue Procedure in the Hospital during the Earthquake

Combined with the medical process in the evaluation of seismic resilience of healthcare systems, it helps decision-makers to formulate effective response strategies at all stages of earthquake disaster medical rescue. The key groups or weak links that have the greatest impact on the seismic performance of the system can be identified by the evaluation of seismic resilience. All aspects of medical rescues, such as injury diagnosis, surgical first aid, hospitalization, and ICU observation, should be considered when evaluating the seismic resilience of the healthcare system.The classification of the injured has become the key to the postearthquake medical rescue when facing a large number of wounded. The medical device plays an important role in medical diagnostics. The 2016 Kumamoto earthquake, which caused the interruption of medical imaging equipment in 5 out of 9 hospitals, overloaded the medical imaging diagnosis work of the other 4 hospitals, resulting in waiting times longer than normal time of the injured. Medical device auxiliary diagnosis of diseases improves the quality of medical diagnosis, and the diagnostic efficiency of medical devices is a key factor restricting the function of the hospital system (Table5).Table 5
Postearthquake application cases of medical equipment.
AuthorsMedical devicesSampleEarthquake nameZhao et al. [100]CT (computed tomography), X-ray, and color doppler18712008 Sichuan earthquakeChu et al. [130]16-slice multidetector CT scanner2212008 Sichuan earthquakeDong et al. [131]Multislice spiral CT2152008 Sichuan earthquakeDan et al. [132]Ultrasound equipment and radiological equipment33072008 Sichuan earthquakeBanaste et al. [133]CT23542010–2016 FranceYu et al. [134]Portable color doppler—2008 Sichuan earthquakeAhmad et al. [135]Ultrasound equipment872015 Pakistan earthquakeDan et al. [136]Ultrasound equipment12072008 Sichuan earthquakeIyama et al. [137]Digital radiography (DR), computed tomography (CT), and magnetic resonance imaging (MRI)3483–42252016 Kumamoto earthquakeAfter the diagnosis of the casualty, some of the wounded needed to be admitted to the emergency department for surgery. The emergency department must provide crucial medical care. Providing uninterrupted medical care in the emergency department is essential for medical rescue after the earthquake. According to the Chi-chi earthquake of 1999, 566 patients were admitted to the hospital within 3 days. In particular, the emergency department accepted 301 patients 10 hours after the earthquake [119]. Nieh et al. [138] found that emergency departments received 89.4% of casualties in the 2018 Hualien earthquake. The serious injury rate was 8.2%, indicating that moderate casualties were the majority injured in the emergency department. Emergency departments were under great pressure to treat those wounded.To alleviate the pressure of medical rescue in the emergency department, the relationship between the workload of the emergency department and the medical demands was studied. Chu and Zhong [139] studied the correlation between the dynamics of emergency workload and medical demand. According to the statistics of casualties arriving at the emergency department after the earthquake, the number of casualties in the first three days after the earthquake was 3-5 times that of the predisaster period. After 4-5 days, the number of patients gradually returns to preearthquake levels [94]. Similarly, during the 2011 East Japan Earthquake, the number of patients admitted to the emergency department increased by 23% after the earthquake based on the utilization rate of emergency department resources at the University of Tokyo tertiary hospital [140]. Lin et al. [141] compared the rapid triage approaches to the emergency department. The results showed that both rapid triage methods in the emergency department could improve the quality and speed of emergency department treatment. For the degree of dependence on medical equipment, the casualty triage strategy can greatly reduce the waiting time for the casualty in the emergency.Facing a large number of casualties after an earthquake, timely treatment and close monitoring are critical in saving lives. Huang et al. [142] discussed the treatment process of 18 patients in ICU during the Lushan earthquake and found that a reasonable ICU workflow can minimize the fatality rate of the injured. Treatment of injuries such as respiratory stress syndrome, crush syndrome, visceral injury, head injury, and bacterial infection is highly dependent on the ICU. The statistics of the casualty in the Hanshin-Awaji earthquake show that serious casualties accounted for 21% of the casualties. Takada and Otomo [143] calculated the number of casualties and hospital beds in the Nepal earthquake. Although all intensive care units and intensive care beds are provided for the seriously injured, there is a shortage of 15,053 beds for earthquake medical assistance. According to medical rescue at Christchurch Hospital Medical Rescue Clinic in the 2011 Christchurch earthquake, a generator failure caused power supplies to be cut off in important medical departments such as ICUs, which forced patients to undergo medical evacuation [144]. Due to a lot of health facilities being destroyed in the 2015 Nepal earthquake, there is a serious shortage of beds in the intensive care unit. The temporary secondary care beds have to be temporarily reconstructed for ICU. Moreover, there are still a large number of casualties that cannot get a medical rescue in the ICU, which leads the injured to become more seriously ill and even death [145].By analyzing the process of postearthquake medical rescue, it can be found that the key points of medical rescue at different stages are different. In different medical rescue stages (e.g., medical diagnosis, emergency treatment, and intensive care), there are differences in the components that affect resilience of the healthcare system. The postearthquake functional performance of the medical equipment is the key in affecting the efficiency of medical diagnosis. The key to improving emergency treatment functionality is the integrity of medical devices and system modeling strategies. The key to improving the seismic resilience of intensive care lies in the safety of building structures and system modeling strategies. Therefore, mathematical modeling also becomes the key to improve the medical rescue process.


## 5.1. Medical Rescue of the Wounded after the Earthquake

Based on the functional curve, the postearthquake function of the healthcare system should be clarified for evaluating the seismic resilience of the healthcare system. The literature shows that there is no uniform concept of the function of the healthcare system. The expectation of the healthcare system should be to protect human health. For this purpose, the healthcare system needs to provide a variety of medical services, including but not limited to physical examination, patient isolation, disease treatment, patient care, and disease prevention [39, 128]. It is essential to meet the medical demand of the injured in the earthquake for the medical function of the healthcare system in the disaster region.The earthquake instantly caused a large number of casualties, which easily caused a shortage of doctors and medical resources. Therefore, the medical rescue of casualties adopts a graded rescue method [129]. The medical rescue system after the earthquake learned from the treatment precept used in the war. The medical rescue process is divided into three levels, which include on-site rescue, early treatment, and specialized treatment. The first level of treatment is an on-site rescue, which mainly includes self-rescue and mutual rescue of the injured at the scene of the disaster, as well as on-sitefirst-aid activities. Diagnosis and treatment activities include hemostasis, dressing, classification of injuries, anti-infection, and some simple surgeries. After the on-site rescue, the injured were transferred to hospitals and other medical institutions for follow-up medical treatment. The second level is early treatment. Early treatment is when a patient is sent to the hospital for treatment. Hospitals in disaster-stricken areas have been damaged by earthquakes. However, those hospitals still retain certain medical rescue functions, and can still carry out early treatment of patients and surgical treatment as appropriate. However, some of the wounded with complex conditions do not recover after receiving early treatment. At this time, the casualty needs to receive the third level of medical treatment (i.e., specialized treatment). Specialist care should be performed in well-functioning medical conditions.According to the treatment site, postearthquake medical rescue can be divided into prehospital treatment and in-hospital treatment. Level 1 medical assistance is a part of the prehospital treatment. Second and tertiary-level medical assistance is considered in-hospital treatment. The key to prehospital treatment in the disaster area is to improve the survival rate of the injured after the earthquake. In-hospital treatment is to reduce the disability rate and radically treat the wounded. Therefore, it is necessary to consider the medical rescue function in the entire medical rescue process, when modeling or analyzing the postearthquake functional resilience of systems. The literature shows that the functional curves and scorecards model focuses on the comprehensive consideration of in-hospital medical function loss or recovery medical rescue process.


## 5.2. Medical Rescue Procedure in the Hospital during the Earthquake

Combined with the medical process in the evaluation of seismic resilience of healthcare systems, it helps decision-makers to formulate effective response strategies at all stages of earthquake disaster medical rescue. The key groups or weak links that have the greatest impact on the seismic performance of the system can be identified by the evaluation of seismic resilience. All aspects of medical rescues, such as injury diagnosis, surgical first aid, hospitalization, and ICU observation, should be considered when evaluating the seismic resilience of the healthcare system.The classification of the injured has become the key to the postearthquake medical rescue when facing a large number of wounded. The medical device plays an important role in medical diagnostics. The 2016 Kumamoto earthquake, which caused the interruption of medical imaging equipment in 5 out of 9 hospitals, overloaded the medical imaging diagnosis work of the other 4 hospitals, resulting in waiting times longer than normal time of the injured. Medical device auxiliary diagnosis of diseases improves the quality of medical diagnosis, and the diagnostic efficiency of medical devices is a key factor restricting the function of the hospital system (Table5).Table 5
Postearthquake application cases of medical equipment.
AuthorsMedical devicesSampleEarthquake nameZhao et al. [100]CT (computed tomography), X-ray, and color doppler18712008 Sichuan earthquakeChu et al. [130]16-slice multidetector CT scanner2212008 Sichuan earthquakeDong et al. [131]Multislice spiral CT2152008 Sichuan earthquakeDan et al. [132]Ultrasound equipment and radiological equipment33072008 Sichuan earthquakeBanaste et al. [133]CT23542010–2016 FranceYu et al. [134]Portable color doppler—2008 Sichuan earthquakeAhmad et al. [135]Ultrasound equipment872015 Pakistan earthquakeDan et al. [136]Ultrasound equipment12072008 Sichuan earthquakeIyama et al. [137]Digital radiography (DR), computed tomography (CT), and magnetic resonance imaging (MRI)3483–42252016 Kumamoto earthquakeAfter the diagnosis of the casualty, some of the wounded needed to be admitted to the emergency department for surgery. The emergency department must provide crucial medical care. Providing uninterrupted medical care in the emergency department is essential for medical rescue after the earthquake. According to the Chi-chi earthquake of 1999, 566 patients were admitted to the hospital within 3 days. In particular, the emergency department accepted 301 patients 10 hours after the earthquake [119]. Nieh et al. [138] found that emergency departments received 89.4% of casualties in the 2018 Hualien earthquake. The serious injury rate was 8.2%, indicating that moderate casualties were the majority injured in the emergency department. Emergency departments were under great pressure to treat those wounded.To alleviate the pressure of medical rescue in the emergency department, the relationship between the workload of the emergency department and the medical demands was studied. Chu and Zhong [139] studied the correlation between the dynamics of emergency workload and medical demand. According to the statistics of casualties arriving at the emergency department after the earthquake, the number of casualties in the first three days after the earthquake was 3-5 times that of the predisaster period. After 4-5 days, the number of patients gradually returns to preearthquake levels [94]. Similarly, during the 2011 East Japan Earthquake, the number of patients admitted to the emergency department increased by 23% after the earthquake based on the utilization rate of emergency department resources at the University of Tokyo tertiary hospital [140]. Lin et al. [141] compared the rapid triage approaches to the emergency department. The results showed that both rapid triage methods in the emergency department could improve the quality and speed of emergency department treatment. For the degree of dependence on medical equipment, the casualty triage strategy can greatly reduce the waiting time for the casualty in the emergency.Facing a large number of casualties after an earthquake, timely treatment and close monitoring are critical in saving lives. Huang et al. [142] discussed the treatment process of 18 patients in ICU during the Lushan earthquake and found that a reasonable ICU workflow can minimize the fatality rate of the injured. Treatment of injuries such as respiratory stress syndrome, crush syndrome, visceral injury, head injury, and bacterial infection is highly dependent on the ICU. The statistics of the casualty in the Hanshin-Awaji earthquake show that serious casualties accounted for 21% of the casualties. Takada and Otomo [143] calculated the number of casualties and hospital beds in the Nepal earthquake. Although all intensive care units and intensive care beds are provided for the seriously injured, there is a shortage of 15,053 beds for earthquake medical assistance. According to medical rescue at Christchurch Hospital Medical Rescue Clinic in the 2011 Christchurch earthquake, a generator failure caused power supplies to be cut off in important medical departments such as ICUs, which forced patients to undergo medical evacuation [144]. Due to a lot of health facilities being destroyed in the 2015 Nepal earthquake, there is a serious shortage of beds in the intensive care unit. The temporary secondary care beds have to be temporarily reconstructed for ICU. Moreover, there are still a large number of casualties that cannot get a medical rescue in the ICU, which leads the injured to become more seriously ill and even death [145].By analyzing the process of postearthquake medical rescue, it can be found that the key points of medical rescue at different stages are different. In different medical rescue stages (e.g., medical diagnosis, emergency treatment, and intensive care), there are differences in the components that affect resilience of the healthcare system. The postearthquake functional performance of the medical equipment is the key in affecting the efficiency of medical diagnosis. The key to improving emergency treatment functionality is the integrity of medical devices and system modeling strategies. The key to improving the seismic resilience of intensive care lies in the safety of building structures and system modeling strategies. Therefore, mathematical modeling also becomes the key to improve the medical rescue process.


## 6. The Key Points of Seismic Resilience of Healthcare

### 6.1. Seismic Performance of Medical Equipment

The seismic vulnerability of medical equipment is an indispensable part of the seismic resilience analysis of healthcare systems. However, the research standards on the seismic vulnerability of medical equipment and its dynamic response characteristics under seismic action are not uniform, which lead to large deviations in the experimental data. Seismic vulnerability data for medical devices are also not included in standards such as FEMA P58 [146] and GB/T 38591-2020 [147]. Therefore, data for medical devices come from experiments. Table 6 shows the seismic performance of the medical equipment in experiments.Table 6
Seismic performance testing of medical equipment.
AuthorsMedical equipmentTestConclusionKonstantinidis and Makris [148]Cabinet equipmentStatic testThe seismic vulnerability curve of equipment under different slip limits is given by probabilistic seismic demand model fittingCosta et al. [149]Medical medicine cabinets, medicinesShake table testThree damage states of the medicine cabinet are defined as follows: residual displacement of more than 20 mm, rocking, and overturning. Built-in drugs have two damage states: overturning and crushingKuo et al. [150]Medicine rackShake table testThe distance between the drug on the shelf falling on the ground and the medicine shelf was used to describe the mixing degree of the medicine rack after the earthquakeShang et al. [57]Infusion stents, medicine cabinets, ambulances, hospital beds, and medical shadowless lampsShake table testThe corresponding seismic fragility curves of the hospital cabinets under different damage states were developed based on experimental dataNikfar and Konstantinidis [151]Wheels/castors support medical equipmentShake table testContour plots are proposed that specify the displacement, velocity, and acceleration accuracy of vision-based measurements, which can be used in future applicationsNikfar and Konstantinidis [152]Wheels/castors support medical equipmentShake table testIt was concluded that, in base-isolated buildings, locking the wheels/casters on ECs reduces EC response. Fragility curves were developed for mobile ECs on unlocked wheels and casters in base-isolated buildingsNikfar and Konstantinidis [153]Ultrasonic equipment cart carries small equipmentShake table testAppropriate structural engineering demand parameters associated with the relative displacement and relative velocity demands of the equipment are proposed and used to develop conditional probability curves. Finally, in an effort to extend the results of this experimental study to similar equipment on wheels/casters, the performance of a simple numerical model in predicting the peak seismic demands is evaluatedThe research on medical devices using uniform standards. The seismic response and seismic damage of different types of equipment were investigated. The corresponding seismic vulnerability model was established to provide basic data for the evaluation of the seismic resilience of healthcare systems.


### 6.2. Functional Resilience Modeling Methods for Healthcare Systems

The purpose of studying the seismic resilience of the healthcare system is to improve the medical ability of the healthcare system to cope with earthquakes and ensure the effective function of the healthcare system after the earthquake. By collating the literature on postearthquake medical processes, it is found that systematic modeling and analysis of medical processes can improve the efficiency of medical functions. At present, the functional modeling methods of healthcare systems mainly include discrete event modeling, system dynamics modeling, and subject modeling.Discrete event (DE) systems are dynamic systems that evolve from asynchronous bursty event-driven states. The state of the system usually only takes a limited number of discrete values, corresponding to the quality of system components, the number of workpieces to be processed, or the situation of macro management such as planning and job scheduling. These state changes are caused by the occurrence of various events such as the appearance or disappearance of certain environmental conditions and the start or completion of system operations. Discrete event modeling in healthcare systems is primarily based on the medical process of the patient. It is a completely discrete event from the beginning of the injured entering the hospital to the end of the injured exiting the hospital. A large number of wounded people experienced the above process after the earthquake. However, the medical capacity of the hospital is limited. The wounded have to queue up for treatment. Therefore, the waiting time for the wounded will become longer. Mathematical modeling is used to calculate the visit time of patients or the use of medical resources (e.g., emergency departments and ICUs), and then propose strategies to improve hospital operation efficiency and shorten the waiting time of the injured.Agent-based models (ABMs) are a class of computational models used to simulate the behavior and interactions of autonomous agents (individual or collective entities) to assess their impact on the system. It combines elements of game theory, complex systems, emergence, computational sociology, multiagent systems, and evolutionary programming. The Monte Carlo method is used to introduce randomness. This modeling method is mostly used in the healthcare system in the transmission of diseases and the operation process of the hospital and can also be used for the simulation and analysis of the treatment process of the injured in the hospital. Doctors and the wounded are usually taken as the subjects. And the behaviors emerging from the subjects are further explored through the analysis of the interaction between the subjects.System dynamics (SD) was first proposed by Forrester [154]; different systems have unique structural systems. Moreover, according to the idea of system science, the system function is determined by the system structure. The problems of system function arise from the interaction between structural components, which is not affected by external interference or random events. Therefore, system dynamics is widely used in hospital functional modeling.Combining the therapeutic behavior and influencing factors of each component of the treatment process, the moldings study the impact of individual behavior on system behavior. Table7 shows the specific applications of the three types of modeling methods in healthcare systems. DEDs are more focused on the flow of events. ABMs are more concerned with the impact of individual attributes and behaviors on the system. The SD method focuses more on the interaction between the internal elements of the system and the change of flow. Combined with the postearthquake treatment process, appropriate modeling methods were selected to improve the resilience of all aspects of the healthcare system.Table 7
The analysis method of functional resilience of the hospital.
AuthorsCasualty classificationHealthcare resource variablesOptimizing the resultsDEsLowery [155]Classification of severely ill woundedProcedures for the presentation of critically ill patients, particularly surgery and ICUOptimizing the timing of visits for casualty patients in different types of intensive care unitsSwisher et al. [156]All the woundedNumber of caregiversThe average length of time for a casualty visit with a different number of nursing staffYi et al. [157]Patients are divided according to the type of diseaseThe time of treatment of the wounded in each departmentThe process of visits for patients with different diseases has been improved to reduce the waiting time for the casualtyCimellaro et al. [61]The severity of the wounded is divided into white, yellow, green, and white from low to highMedical resources occupied by casualty patients with different injuries (emergency rooms, ICU)The model simulates the waiting time of casualty patients with different hospital attendance rates under different seismic intensity and analyzes the difference in waiting time of casualty patients with different emergency plansBasaglia et al. [158]All the woundedEmergency, hospitalization, and doctorThe two models are defined by balancing the need to represent a complex system with sufficient accuracy, the limitations posed by data availability, and the multiplicity of outcomes of patient treatmentShahverdi et al. [159]All the wounded—Discrete modeling from patient arrival patterns, impacts on resources, and effects on unit capacities/capabilities to assess hospital system resilience to disaster events involving physical damage and demand surgeABMsKaushal et al. [160]Emergency casualtyHealthcare workers and hospital bedsThe efficiency of emergency fast-track reception has been improved, and the waiting time for the injured has been optimizedTaboada et al. [161]Emergency casualtyHealthcare workers and medical equipmentThe model optimizes the waiting time, treatment time, and number of patients treated for the injured in the emergency departmentCimellaro et al. [60]All the woundedAmbulances, hospital networks, and road networksOptimized the casualty transport processSDDiaz et al. [162]All the woundedHealthcare workersCombined with the relationship between medical supply and demand, the situation of different workloads is studied, and the doctor’s work efficiency method is optimizedCassettari et al. [163]All the woundedSickbedEffect of treatment time on bed resourcesHirsch [164]All the woundedTreatment process and infrastructureThe impact of infrastructure failures on the treatment processArboleda et al. [165]All the woundedHospital beds, doctors, medicines, and infrastructureThe impact of different casualty attendance rates or different infrastructure failures on the number of wounded waiting for treatment in each departmentKhanmohammadi et al. [62]All the woundedHealthcare buildings and infrastructureThe impact of hospital building and infrastructure repair on the proportion of wounded


## 6.1. Seismic Performance of Medical Equipment

The seismic vulnerability of medical equipment is an indispensable part of the seismic resilience analysis of healthcare systems. However, the research standards on the seismic vulnerability of medical equipment and its dynamic response characteristics under seismic action are not uniform, which lead to large deviations in the experimental data. Seismic vulnerability data for medical devices are also not included in standards such as FEMA P58 [146] and GB/T 38591-2020 [147]. Therefore, data for medical devices come from experiments. Table 6 shows the seismic performance of the medical equipment in experiments.Table 6
Seismic performance testing of medical equipment.
AuthorsMedical equipmentTestConclusionKonstantinidis and Makris [148]Cabinet equipmentStatic testThe seismic vulnerability curve of equipment under different slip limits is given by probabilistic seismic demand model fittingCosta et al. [149]Medical medicine cabinets, medicinesShake table testThree damage states of the medicine cabinet are defined as follows: residual displacement of more than 20 mm, rocking, and overturning. Built-in drugs have two damage states: overturning and crushingKuo et al. [150]Medicine rackShake table testThe distance between the drug on the shelf falling on the ground and the medicine shelf was used to describe the mixing degree of the medicine rack after the earthquakeShang et al. [57]Infusion stents, medicine cabinets, ambulances, hospital beds, and medical shadowless lampsShake table testThe corresponding seismic fragility curves of the hospital cabinets under different damage states were developed based on experimental dataNikfar and Konstantinidis [151]Wheels/castors support medical equipmentShake table testContour plots are proposed that specify the displacement, velocity, and acceleration accuracy of vision-based measurements, which can be used in future applicationsNikfar and Konstantinidis [152]Wheels/castors support medical equipmentShake table testIt was concluded that, in base-isolated buildings, locking the wheels/casters on ECs reduces EC response. Fragility curves were developed for mobile ECs on unlocked wheels and casters in base-isolated buildingsNikfar and Konstantinidis [153]Ultrasonic equipment cart carries small equipmentShake table testAppropriate structural engineering demand parameters associated with the relative displacement and relative velocity demands of the equipment are proposed and used to develop conditional probability curves. Finally, in an effort to extend the results of this experimental study to similar equipment on wheels/casters, the performance of a simple numerical model in predicting the peak seismic demands is evaluatedThe research on medical devices using uniform standards. The seismic response and seismic damage of different types of equipment were investigated. The corresponding seismic vulnerability model was established to provide basic data for the evaluation of the seismic resilience of healthcare systems.


## 6.2. Functional Resilience Modeling Methods for Healthcare Systems

The purpose of studying the seismic resilience of the healthcare system is to improve the medical ability of the healthcare system to cope with earthquakes and ensure the effective function of the healthcare system after the earthquake. By collating the literature on postearthquake medical processes, it is found that systematic modeling and analysis of medical processes can improve the efficiency of medical functions. At present, the functional modeling methods of healthcare systems mainly include discrete event modeling, system dynamics modeling, and subject modeling.Discrete event (DE) systems are dynamic systems that evolve from asynchronous bursty event-driven states. The state of the system usually only takes a limited number of discrete values, corresponding to the quality of system components, the number of workpieces to be processed, or the situation of macro management such as planning and job scheduling. These state changes are caused by the occurrence of various events such as the appearance or disappearance of certain environmental conditions and the start or completion of system operations. Discrete event modeling in healthcare systems is primarily based on the medical process of the patient. It is a completely discrete event from the beginning of the injured entering the hospital to the end of the injured exiting the hospital. A large number of wounded people experienced the above process after the earthquake. However, the medical capacity of the hospital is limited. The wounded have to queue up for treatment. Therefore, the waiting time for the wounded will become longer. Mathematical modeling is used to calculate the visit time of patients or the use of medical resources (e.g., emergency departments and ICUs), and then propose strategies to improve hospital operation efficiency and shorten the waiting time of the injured.Agent-based models (ABMs) are a class of computational models used to simulate the behavior and interactions of autonomous agents (individual or collective entities) to assess their impact on the system. It combines elements of game theory, complex systems, emergence, computational sociology, multiagent systems, and evolutionary programming. The Monte Carlo method is used to introduce randomness. This modeling method is mostly used in the healthcare system in the transmission of diseases and the operation process of the hospital and can also be used for the simulation and analysis of the treatment process of the injured in the hospital. Doctors and the wounded are usually taken as the subjects. And the behaviors emerging from the subjects are further explored through the analysis of the interaction between the subjects.System dynamics (SD) was first proposed by Forrester [154]; different systems have unique structural systems. Moreover, according to the idea of system science, the system function is determined by the system structure. The problems of system function arise from the interaction between structural components, which is not affected by external interference or random events. Therefore, system dynamics is widely used in hospital functional modeling.Combining the therapeutic behavior and influencing factors of each component of the treatment process, the moldings study the impact of individual behavior on system behavior. Table7 shows the specific applications of the three types of modeling methods in healthcare systems. DEDs are more focused on the flow of events. ABMs are more concerned with the impact of individual attributes and behaviors on the system. The SD method focuses more on the interaction between the internal elements of the system and the change of flow. Combined with the postearthquake treatment process, appropriate modeling methods were selected to improve the resilience of all aspects of the healthcare system.Table 7
The analysis method of functional resilience of the hospital.
AuthorsCasualty classificationHealthcare resource variablesOptimizing the resultsDEsLowery [155]Classification of severely ill woundedProcedures for the presentation of critically ill patients, particularly surgery and ICUOptimizing the timing of visits for casualty patients in different types of intensive care unitsSwisher et al. [156]All the woundedNumber of caregiversThe average length of time for a casualty visit with a different number of nursing staffYi et al. [157]Patients are divided according to the type of diseaseThe time of treatment of the wounded in each departmentThe process of visits for patients with different diseases has been improved to reduce the waiting time for the casualtyCimellaro et al. [61]The severity of the wounded is divided into white, yellow, green, and white from low to highMedical resources occupied by casualty patients with different injuries (emergency rooms, ICU)The model simulates the waiting time of casualty patients with different hospital attendance rates under different seismic intensity and analyzes the difference in waiting time of casualty patients with different emergency plansBasaglia et al. [158]All the woundedEmergency, hospitalization, and doctorThe two models are defined by balancing the need to represent a complex system with sufficient accuracy, the limitations posed by data availability, and the multiplicity of outcomes of patient treatmentShahverdi et al. [159]All the wounded—Discrete modeling from patient arrival patterns, impacts on resources, and effects on unit capacities/capabilities to assess hospital system resilience to disaster events involving physical damage and demand surgeABMsKaushal et al. [160]Emergency casualtyHealthcare workers and hospital bedsThe efficiency of emergency fast-track reception has been improved, and the waiting time for the injured has been optimizedTaboada et al. [161]Emergency casualtyHealthcare workers and medical equipmentThe model optimizes the waiting time, treatment time, and number of patients treated for the injured in the emergency departmentCimellaro et al. [60]All the woundedAmbulances, hospital networks, and road networksOptimized the casualty transport processSDDiaz et al. [162]All the woundedHealthcare workersCombined with the relationship between medical supply and demand, the situation of different workloads is studied, and the doctor’s work efficiency method is optimizedCassettari et al. [163]All the woundedSickbedEffect of treatment time on bed resourcesHirsch [164]All the woundedTreatment process and infrastructureThe impact of infrastructure failures on the treatment processArboleda et al. [165]All the woundedHospital beds, doctors, medicines, and infrastructureThe impact of different casualty attendance rates or different infrastructure failures on the number of wounded waiting for treatment in each departmentKhanmohammadi et al. [62]All the woundedHealthcare buildings and infrastructureThe impact of hospital building and infrastructure repair on the proportion of wounded


## 7. Conclusion

This article reviews and summarizes the concepts of resilience, healthcare systems, and the resilience of the healthcare system. The concept of resilience has shown its application prospects in many fields. And the advantages of improving system robustness, rapid recovery, and resource redundancy are obvious. The concept of resilience was introduced into the healthcare system. Its quantitative analysis methods were introduced.According to the literature review, the main findings of this study are as follows: the application effect of resilience theory in different systems clarifies the key to resilience analysis. The medical system introduces resilience theory to improve its earthquake relief performance. The quantification of the function of the medical system becomes the key to the quantitative analysis of its seismic resilience.Meanwhile, an understanding of the characteristics of medical demands due to earthquakes is fundamental for effective medical rescue and reasonable allocation of medical resources and is also beneficial for rapid injury triage and prompt treatment. Increased knowledge of the injury characteristics of patients hospitalized following seismic disasters plays an important role in summarizing experiences and lessons, improving our ability to deal with destructive disasters, and helping the effective and reasonable organization of medical rescue systems for future disasters. The profile of these injuries may also provide valuable information for injury interventions, including rehabilitation, psychological treatment, economic cost assessment, and planning for future earthquake disasters.This article reviews the postearthquake medical rescue process and explores the key points affecting the medical rescue function in the medical rescue process. Combined with the medical rescue process, the application of seismic toughness in the medical system is discussed. Numerical analysis of medical device vulnerability and system function is applied to the seismic toughness analysis of medical systems.The efficiency of postearthquake medical rescue is reflected in the efficiency of each medical link in the medical rescue process and the smoothness of the cooperation of each medical link. Therefore, the key to the seismic resilience analysis of the healthcare system lies in the key factors affecting the treatment efficiency of each medical link and the simulation analysis of the smoothness of the cooperation of each medical link. Earthquakes will continue to strike and the healthcare system must be prepared to overcome the resulting situations by anticipating consequences and planning accordingly.



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*Source: 4468383-2023-03-22.xml*