Emergency Department Triage in a Resource Constrained Setting: Application of the World Health Organization Triage Scale in Regional Papua New Guinea
Phase: NA
Conditions: Emergencies
Sponsor: Monash University

 
 
 
Emergency department triage in a resource constrained setting: application of the 
World Health Organization Triage Scale in regional Papua New Guinea 
 
Study protocol 
 
Version 12 
26 April 2019 
 
 
Research team 
 
Chief investigator: 
 
Peter Cameron FACEM MD 
Director of Academic Programs, Emergency & Trauma Centre, Alfred 
Health 
Professor, Department of Epidemiology & Preventive Medicine, 
Monash University 
 
Student researcher:  
Rob Mitchell FACEM 
Emergency Physician, Emergency & Trauma Centre, Alfred Health 
PhD Candidate, Department of Epidemiology & Preventive Medicine, 
Monash University 
 
 
Co-investigators: 
John Jr. McKup MMed (EM) 
 
Emergency Physician, Mount Hagen Provincial Hospital 
 
Scotty Kandelyo Med (EM) 
Emergency Physician and Regional Chief of Emergency Medicine, 
Highlands Region 
 
Gerard O’Reilly FACEM PhD 
Emergency Physician and Director of International Programs, 
Emergency & Trauma Centre, Alfred Health 
Associate Professor, Department of Epidemiology & Preventive 
Medicine, Monash University 
 
Colin Banks FACEM 
Emergency Physician, Townsville Hospital 
 
Teri Reynolds MD MS PhD 
Lead, Emergency, Trauma and Acute Care Program, World Health 
Organization 
 
 
 
 
 

 
 
Background 
 
Triage is an important component of emergency care (EC). It aims to sort patients based on the 
urgency of their condition such that the highest acuity patients are prioritised for assessment and 
treatment. Grounded in the ethical principles of equity and justice, triage is necessary whenever 
there is a mismatch between demand for EC and the availability of resources.  
 
Globally, a large number of triage scales are in use. These differ in the data required to categorise 
patients as well as the number of tiers.1 Developed settings tend to utilise five-tier systems, 
principally based on validation studies performed in Australia in the 1990s.2 The triage process is 
less efficient in these models, because triage nurses (who typically perform emergency 
department triage) take longer to assess and differentiate category three and four patients.3 
 
There have been few attempts to compare the performance of triage scales. A 2011 systematic 
review concluded that current scales were supported by limited or insufficient evidence, and 
suggested that “head-to-head comparisons are required to determine whether any of the scales 
have advantages over the others”.1  
 
Triage in developing emergency care systems  
 
Despite the established role of emergency departments (EDs) in developed countries, most of the 
world’s population does not have access to timely and effective emergency care.  This situation is 
slowly being addressed as the global health community recognises the value of EC systems.4  
 
Little is known about the prevalence of triage in low- and middle-income countries (LMICs), 
including in the Pacific region. There is also limited evidence about the utility, validity and 
reliability of triage scales in these contexts.5 While a landmark study in a paediatric ED in Malawi 
demonstrated that training staff in emergency skills, introducing triage and improving flow, 
substantially reduced case fatality rates, the mortality reduction attributable to triage is 
unknown.6  
 
A small number of triage scales have been developed for resource-limited (RL) environments. The 
most widely studied is the four-tier South African Triage Scale (SATS), which has demonstrated 
reasonable reliability and validity.5 A recent systematic review of adult triage scales in LMICs found 
that the evidence supporting any particular triage scale was moderate at best.5 
 
In the Pacific region, SATS has provided a foundation for the three-tier Solomon Islands Triage 
Scale (SITS), which has recently been piloted in Honiara.7 The World Health Organization (WHO) is 
also preparing to release a three-tier triage scale [personal communication, T Reynolds]. Neither 
of these instruments has been prospectively validated. 
 
Although the potential value of triage systems in resource-limited EDs is increasingly recognised, 
the current evidence base is limited. The impact on process indicators (eg, time to assessment) 
and clinical outcomes (eg, mortality) for time-critical conditions is largely unknown.  
 
Evaluating triage systems 
 
One of the challenges in evaluating and comparing triage systems is a lack of consistent 
methodology. Most studies have focussed on reliability and validity as markers of performance. 

 
 
 
Reliability is an essential component of a triage system, and refers to the degree to which 
repeated assessments of the same patient will deliver the same category of urgency.8 This is 
typically assessed using inter-rater agreement.  
 
The validity of a triage system refers to its ability to reflect the true urgency of the patient’s 
condition. A major challenge in validity assessment is the absence of a definitive or ‘gold standard’ 
measure of urgency.2 A range of surrogate markers have therefore been used to assess criterion 
and predictive validity, namely ED outcomes such as admission rate, mortality and length of stay. 
Some authors have suggested that a Delphi approach might also be useful for the evaluation of 
triage systems in developing settings.8  
 
Several studies have calculated under- and over-triage rates as a measure of validity.9–12 These 
typically use acceptable limits defined by the American College of Surgeons Committee on Trauma 
(ACS COT) as a reference standard.13 
 
Emergency care and triage in Papua New Guinea 
 
Papua New Guinea (PNG), a Pacific Island Country (PIC) with a population of approximately 8 
million, is faced by significant challenges in healthcare delivery. These include sunder-resourcing, a 
limited health workforce, a high burden of communicable disease (including significant rates of 
HIV/AIDS and tuberculosis) as well an increasing prevalence of non-communicable illness and 
injury.14  
 
Despite an increasing number of emergency physicians, most provinces outside of Port Moresby 
(the nation’s capital) have under-developed primary and secondary care systems to facilitate 
emergency care.15 There is little data on the epidemiology of emergency presentations, and most 
EDs are not utilising triage scales. Triage has been identified as a priority for emergency care 
development for PICs, including PNG [personal communication, G Phillips]. 
 
Aims 
 
The primary objective of this study is to measure the impact of a triage system on process 
indicators and clinical outcomes in a regional ED in PNG. 
 
The secondary objective of this study is to determine the validity and reliability of the World 
Health Organization Triage Scale in this setting. 
 
Methods 
 
Setting 
 
This study will be conducted in the ED of the Mount Hagen Provincial Hospital (MHPH) in the 
Western Highlands Province of PNG. The hospital is managed by the Western Highlands Provincial 
Health Authority (WHPHA).  
 
Mount Hagen is the third largest city in PNG, with a population of approximately 50,000. It is the 
capital of the Western Highlands Province (population approximately 400,000), and a major 
administrative centre for the Highlands region. 

 
 
 
MHPH is the city’s major health facility. There is limited primary care infrastructure within the 
province, so patients rely on MHPH for the majority of their healthcare needs. As in other parts of 
the country, there is a large burden of both communicable and non-communicable disease, 
including HIV/AIDS, tuberculosis diabetes, cardiovascular disease, chronic respiratory conditions 
and trauma. 
 
The ED receives approximately 150 presentations per day, and is staffed by one emergency 
physician, three registrars (specialists in training), five health extension officers (HEOs) and 
approximately thirty nurses. The ED has recently been redeveloped, and now includes four 
resuscitation bays, 16 acute beds and five short-stay beds. Basic pathology and radiology services 
are available. 
 
Under current arrangements, the ED has no triage system and manual data collection processes 
are leading to gross under-reporting of presentation numbers. Major challenges for the ED include 
understaffing, a large burden of primary care patients and access block.  
 
A new electronic database of ED patients has recently been implemented to capture basic 
attendance data. This system will facilitate data capture for the study. 
 
Design 
 
This study will utilise pre-post intervention methodology and will be prospectively registered as a 
clinical trial with the United States National Library of Medicine Clinical Trials Register at 
clinicaltrials.gov. 
 
Pre-intervention 
 
A new MHPH ED Patient Registration and Triage Form (PRTF) will be created to facilitate the new 
system and capture relevant data items, such as demographics and initial vital signs (Appendix 1). 
This form will be based on an existing MHPH ED discharge form, as well as a triage form 
successfully implemented in another Pacific setting.7 
 
Data from the PRTF will be entered by ward clerks into the ED’s electronic patient registration 
system (recently implemented as part of a hospital-wide data improvement project).  This system 
forms part of the MHPH medical records database.  
 
After a trial period of staff testing the new form, the PRTF will be implemented and baseline data 
captured in the database. During this period, the PRTF will not include any triage information 
(Appendix 1A). Based on a power calculation (see below), two months of pre-intervention data will 
be collected. 
 
In order to identify patients who meet inclusion criteria, as defined below, the PRTF will require 
the treating clinician to indicate whether the patient had one of the ten sentinel conditions (listed 
below).    
 
 
 
 

 
 
Intervention 
 
The intervention will comprise implementation of a new triage and patient flow system facilitated 
through staff training and clinical redesign.  
 
The three-tier World Health Organization Triage Scale (WHOTS) will be used as the triage 
instrument. This tool, developed collaboratively by the WHO, International Committee of the Red 
Cross (ICRC) and Médecins Sans Frontières (MSF), incorporates features of the SATS but has been 
modified for application in a wide variety of RL settings. WHOTS documents are provided in 
Appendix 2. 
 
At the end of the baseline data collection period, MHPH ED staff will be trained in the new system. 
A variety of ED clinicians (who will subsequently take on the triage role) will be the focus of this 
training program. This will include nurses, community health workers and health extension officers 
in order to provide flexibility in the staffing model. Triage training will be delivered by an 
experienced Australasian volunteer nurse(s) and comprise workshops on triage principles, paper-
based scenarios and simulation exercises. 
 
Signage will be introduced to facilitate the new system of flow, and the ED will begin utilising the 
version of the PRTF that incorporates triage data (Appendix 1B). The triage instrument will be 
piloted over a one-month period (approximately). Modifications will be made based on real-time 
feedback as well as observations by the visiting team.  
 
Post-intervention 
 
After completion of the trial period, the new triage and flow system will be implemented under 
the leadership of local clinicians. The ED registration database will be updated to capture triage 
category data. 
 
For admitted patients, hospital length-of-stay (LOS) and inpatient mortality data will be obtained 
from the WHPHA medical records database. These patients will be identified by the patient’s 
unique hospital identification number. 
 
Outcomes 
 
Primary objective 
 
The primary outcome will be time-to-assessment (TTA) by an ED clinician for ten time-critical 
conditions: 
• Severe trauma 
• Major burns 
• Severe head injury 
• Ruptured ectopic pregnancy 
• Septic shock 
• Myocardial infarction 
• Severe asthma/COPD 
• Severe pneumonia 
• Meningitis 
• Appendicitis 

 
 
 
Pragmatic definitions for these conditions are provided at Appendix 3. 
 
The primary outcome will also be analysed by the proportion of patients with these clinical 
syndromes that are seen within a clinically appropriate timeframe (defined as 15 minutes, as 
discussed below).  
 
Secondary outcomes will include: 
• Length of hospital stay 
• ED mortality 
• Inpatient mortality 
 
These are also defined in Appendix 3. 
 
Secondary objectives 
 
Validity of the WHOTS will be assessed through its ability to predict ED outcomes. This will include 
the relationship between triage category and admission rates and ED mortality. 
 
Under- or over-triage rates will also be calculated using disposition as a reference standard. This 
approach has limitations (see below) but is widely used in triage research.  
 
Over-triage will be defined as the proportion of emergency (category 1) patients who are 
discharged. Under-triage will be defined as the proportion of non-urgent (category 3) patients who 
are admitted. Rates will be compared with the acceptable under- and over-triage rates 
recommended by ACS COT13 (and widely referenced in triage research) and then benchmarked 
against other published data.  This approach has limitations (given that not all category 1 patients 
will required admission, and many category 3 patients could reasonably be expected to; 
recommendations for triage in trauma do not necessarily apply to other disease categories; and 
the performance targets provided by an American society do not necessarily apply to other 
contexts) but will be undertaken to enable comparison with other triage research from LMICs.   
 
Reliability will be assessed through inter-rater agreement between two local triage nurses as well 
as a local nurse and independent expert triage nurse.  
 
Analysis 
 
All data will be obtained from the MHPH medical records database. Hospital medical records staff 
will export de-identified into an Excel document, which will be provided to researchers and stored 
on a secure, password protected Monash University drive. All data will be analysed using Stata. No 
identifiable data will be available to the researchers. 
 
Primary objectives 
 
For the primary outcomes, Student’s t-test will be used to compare the difference in TTA for the 
ten sentinel conditions (assuming parametric data). Chi-Square will be used to determine the 
difference in proportions of patients seen within 15 minutes. 
 

 
 
For the secondary outcomes of ED mortality, hospital mortality and hospital LOS, Student’s t-test 
or Chi-Square will be used as appropriate. 
 
Secondary objectives 
 
For predictive validity, Chi-Square and correlation coefficient derived by Cramer’s V will be used to 
investigate the relationship between triage category and admission rates & ED mortality.  
 
Under- and over-triage rates will be calculated using the definitions above. Acceptable limits set by 
the American College of Surgeons Committee on Trauma (an under-triage rate of less than 10% 
and an over-triage rate of 30–50%) will be used as the reference standard.13 This approach is 
consistent with that used in other triage research, despite the limitations discussed above.9–12 
 
For reliability, the modified Kappa statistic will be used to test inter-rater agreement between 
triage nurses. 
 
Sample size 
 
It is estimated that approximately 15 patients per day present with one of the ten sentinel 
syndromes and wait an average of 20 minutes to be seen. A clinically significant improvement in 
the TTA for these patients is thought be five minutes. Although Australasian guidelines 
recommend that high acuity presentations (equivalent to categories one and two in the 
Australasian Triage Scale) are seen within 10 minutes of arrival,16 a target of 15 minutes is thought 
to be acceptable in the resource limited context of MHPH.  
 
Based on these figures, a sample size of 34 (17 per group) will be required to demonstrate a 
clinically significant decrease in TTA for the selected time-critical conditions at an alpha of 0.05 
and beta of 0.8.  
 
The primary outcome will also be analysed by the proportion of patients seen within 15 minutes of 
arrival. Assuming baseline performance is 45%, an absolute improvement of 10% (to 55%) will 
require a sample size of 784 (392 per group) at an alpha of 0.05 and beta of 0.8. 
 
The secondary outcome of mortality will require a larger sample. In order to demonstrate an 
absolute reduction in mortality of 5% (from an estimated baseline mortality rate of 15%), a sample 
size of 1372 (686 per group) is required at an alpha of 0.05 and beta of 0.8. 
 
To ensure a satisfactory sample size to demonstrate all outcomes, pre- and post-intervention 
periods of 8 weeks will be utilised. This is based on a total sample size of 1372 for the secondary 
outcome of mortality (with a buffer of 10%) at an estimated presentation rate of 15 per day. This 
requires pre- and post-intervention periods of at least 50 days. 
 
Ethics 
 
Ethics approval, including a waiver of consent, will be sought from Monash University. Consistent 
with local processes, approval to conduct this research will then be sought from the Medical 
Research Advisory Committee within the Papua New Guinean National Department of Health. 
 
 

 
 
 
 
Limitations 
 
This study has been designed to ensure it is methodologically robust. There are, however, several 
limitations that will be need to be considered when interpreting the results. 
 
The pre-post nature of the design means that the study may be subject to confounding. A 
particular risk is that a new and efficient triage system may prompt an increase in ED 
presentations, and a change in the overall acuity of the patient cohort. For this reason, the primary 
outcome will focus on ten clearly-defined time critical conditions. 
 
Other factors may also influence the primary outcome, such as changes in staffing levels and acute 
fluctuations in demand for emergency care (for instance, in the setting of disaster or outbreak). 
Within the influence of the researchers, attempts will be made to control these factors and 
minimise variation across the study period. 
 
There is a risk that the study will be subject to the Hawthorne effect. Although treating clinicians 
will be blinded to the primary outcome, they will have knowledge of the ten sentinel conditions by 
virtue of their inclusion on the PTRF. It is therefore possible that patients presenting with these 
syndromes will be prioritised for care. 
 
These limitations reflect the real-world challenges of conducting research in developing settings. 
The proposed study design is an attempt to balance methodological rigour with the practical 
considerations of emergency care delivery and research at MHPH. 
 
Conclusion 
 
Triage is an essential component of EC systems, especially in developing settings where demand 
for care typically exceeds the available resources. This study, using pre-post intervention 
methodology, will determine whether the introduction of a triage system leads to a clinically 
significant decrease in TTA for selected time-critical syndromes. It will also describe the impact on 
ED mortality, hospital mortality and total LOS. 
 
A secondary objective of this study is to assess the validity and reliability of the WHO triage scale. 
There is currently no published data on the performance of this system. 
 
This study will provide important data on the impact of triage on clinical and process outcomes for 
patients presenting with time-critical conditions to a resource-limited ED. It will help inform the 
future development and application of triage systems in other developing settings, and allow 
comparison of the WHOTS with other triage instruments.  
 
References 
 
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Farrokhnia N, Castren M, Ehrenberg A, et al. Emergency Department Triage Scales and Their 
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3.  
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Appendix 1 
 
Appendix 1A – Pre-intervention Patient Registration and Triage Form 
Appendix 1B – Post-intervention Patient Registration and Triage Form 
 
See attached. 
 
Appendix 2 
 
World Health Organization Triage Scale – user guidance 
 
See attached. 
 
Appendix 3 
 
Definitions for primary and secondary outcomes 
 
Definitions related to primary outcomes 
 
• Major trauma – any injury requiring blood transfusion or an intercostal catheter in the ED, 
or transfer direct to the operating theatre 
• Severe head injury – any patient with objective evidence of a head injury and a Glasgow 
Coma Scale less than nine 
• Major burns – any burn of greater than 15% total body surface area, as estimated by the 
treating clinician 
• Myocardial infarction – an ECG positive for ST-elevation myocardial infarction, or raised 
troponin based on the threshold defined by the local laboratory 
• Septic shock - fever (temperature >37.5°C) and hypotension (systolic BP £90mmHg) 
• Ruptured ectopic pregnancy – objective evidence of pregnancy (extra-uterine gestational 
sac on ultrasound or positive urine bHCG) and free fluid on ultrasound 
• Severe asthma/COPD – any patient with an oxygen requirement where the most likely 
diagnosis is an exacerbation of asthma or chronic obstructive pulmonary disease 
• Severe pneumonia – any patient with an oxygen requirement where the most likely 
diagnosis is pneumonia 
• Meningitis – any patient where the most likely clinical diagnosis is meningitis 
• Appendicitis - any patient where the most likely clinical diagnosis is appendicitis 
 
Time to assessment - the time interval in minutes between patient arrival at ED reception and the 
time of first assessment by the treating clinician 
 
Definitions related to secondary outcomes 
 
• Length of hospital stay – the number of days from presentation to discharge 
• ED mortality –any death that occurs while the patient was physically in the ED, excluding 
patients who meet criteria for ‘deceased on arrival’ 
• Inpatient mortality - any death that occurs while the patient was admitted to hospitals, 
excluding any deaths that occur in the ED 
 

 
 
Deceased on arrival is defined as any patient who is obviously deceased on arrival, as determined 
by the treating clinician.