Pilot Implementation of the Postoperative Hypothermia Management Care Bundle

Inadvertent perioperative hypothermia (IPH) is one of the common perioperative problems in patients undergoing surgery. In the literature, IPH rates in anaesthetised patients are reported to be between 50-90%. Although guidelines and guidelines for the prevention and management of IPH in surgical patients have been developed, the incidence of IPH in surgical patients is still high. In this study, it was aimed to pilot a care package developed by standardising evidence-based practices for the management of postoperative hypothermia and to evaluate its effectiveness. The research is planned as a mixed method research and will be carried out in 2 stages: pilot implementation of the care package and evaluation of its effectiveness. In the first phase of the study, the postoperative hypothermia management care bundle will be piloted, and in the second phase, the effectiveness of the care bundle will be evaluated. Within the scope of the pilot application of the care package, the care package will be applied in the Cardiovascular Surgery Intensive Care Unit of Hacettepe University Adult Hospital for a period of 6 months. The population of the study will consist of nurses working in the Cardiovascular Surgery Intensive Care Unit. All nurses working in the intensive care unit who fulfil the inclusion criteria and volunteer to participate in the study will be included in the study sample. Collection of data within the scope of the research: 'Nurse Descriptive Information Form', 'Postoperative Hypothermia Management Care Bundle Checklist', and 'Postoperative Hypothermia Management Care Bundle Compliance Assessment Form'. Will be used. In order to evaluate the effectiveness of the care bundle, 'Semi-structured Questionnaire for Interview with Nurses' will be used in qualitative interviews with nurses after the pilot application, and 'Patient Postoperative Hypothermia Follow-up Form' will be used to calculate the incidence of hypothermia and the time to reach normothermia. In the analysis of the quantitative data of the study, mean, standard deviation, median, median, quartiles, minimum, maximum values for numerical data, numbers and percentages for non-numerical data will be used. Within the scope of the research, the number of patients to whom all parameters of the care bundle are fully applied will be divided by the number of patients to whom the parameters of the care bundle should be applied and the compliance rate of nurses to the use of the care bundle will be calculated. This calculation shows that compliance with the care bundle is unsuccessful if the compliance rate is below 95%. Colaizzi's seven-step phenomenological analysis method will be used in qualitative data analysis. At the end of the research, the effectiveness of the postoperative hypothermia management care bundle developed will be revealed.

Inadvertent perioperative hypothermia is one of the most common perioperative problems in surgical patients. Inadvertent perioperative hypothermia (IPH) is defined as a decrease in body temperature below 36˚C between 1 hour before anesthesia and the first 24 hours after anesthesia \[1\]. In the literature, IPH rates in anesthetized patients are reported between 50-90% \[2-5\]. Kleimer et al. reported an IPH rate of 72.5% in orthopedic surgery patients and Bezerra et al. reported an IPH rate of 52.7% after coronary artery bypass graft surgery \[6,7\]. In a study by Senkal et al. including urology and orthopedic, thoracic and general surgery patients, the rate of IPH was reported as 35% \[8\]. The American Society of PeriAnesthesia Nurses (ASPAN) classifies a body temperature between 34-36°C as mild hypothermia, 32-34°C as moderate hypothermia and below 32°C as severe hypothermia \[9\].

There are many factors that cause the development of IPH in the perioperative period. Intraoperative factors related to the surgical process such as open body surface and use of cold drapes, opening the abdomen, intravenous fluid and blood supplementation, inhalation of irrigation fluids and anesthetic inhaler gases, long duration of surgery, cold operating room environment; patient-specific factors such as age (neonatal and advanced age), high American Society of Anesthesiologists (ASA) score, obese or low body index, female gender, heart disease, burns and diabetes mellitus are among the predisposing factors of IPH \[2,4,10-13\]. The development of IPH in surgical patients leads to many complications. Among these complications; increased blood loss, need for blood transfusion and surgical site infections, myocardial ischemia, thermal discomfort and chills, cardiac complications, impaired drug metabolism, coagulopathy and bleeding, increased mortality rate in trauma patients, impaired immune function, pain, inadequate wound healing, delayed postoperative recovery, increased postoperative nausea and vomiting and deep vein thrombosis \[2,3,7,8,10,12,14,15\]. These complications lead to prolonged post-anesthesia care or intensive care unit stay and delayed postoperative recovery \[14,16\]. Prevention of postoperative IPH and related complications depends on good management of hypothermia in the perioperative period.

Guidelines for the prevention and management of IPH in surgical patients have been developed \[4,7,8,17,18\]. The American Society of PeriAnesthesia Nurses (ASPAN), the Association of periOperative Registered Nurses (AORN) and the National Institute of Health and Care Excellence (NICE) have set standards for the management of IPH after surgery and evidence-based practices are included in these guidelines \[19-21\]. According to the guideline published by ASPAN (2017), in order to evaluate the hypothermia status of patients admitted to the intensive care unit after surgery, the perioperative hypothermia risk status of the patient should be evaluated, all health care members should record the risk factors found in the patient, and the signs and symptoms of hypothermia should be monitored. In the guideline, in case of hypothermia, body temperature should be measured every 15 minutes, passive heating methods (cotton-woolen blankets, socks, covering the head and open body surfaces) should be used in patients with normothermia, room temperature should be kept at 24 ˚C and above, patients with hypothermia should be heated with active heating methods (forced air-hot air blowing systems, It is recommended to ensure normal body temperature by slowly warming negative pressure heating devices, electric blankets, heat-moisture exchanger filters, intravenous fluid, blood, blood product warmers), monitoring the body temperature from the tympanic membrane or monitor with a heat probe, and measuring the body temperature every 15 minutes until the patient's normothermia is achieved in this process \[22\]. According to the hypothermia prevention and management guideline first published by NICE in 2008 and updated in 2016; Identifying risky patients before surgery, not transferring patients with a body temperature below 36 ˚C to the operating room, having the patient walk to the operating room if possible, not starting anesthesia until the patient's body temperature rises above 36 ˚C during surgery, except for emergency surgeries, It is recommended that high-risk patients should be warmed with active heating regardless of the duration of surgery and all other patients in surgeries lasting more than 30 minutes, intravenous fluids should be given by heating, respiratory gases should be humidified, the patient's body temperature should be measured every 30 minutes and actively warmed according to the situation, and patients should be comfortably warmed with blankets and covers for the first 24 hours after surgery \[21\].

Similarly, the AORN guideline recommends hypothermia management of all patients in all processes of surgery, selection of heating methods according to individual factors (such as age, gender, body mass index, heart failure, cardiovascular disease, previous cardiac surgery), and combined use of active and passive heating methods \[23\]. In the guideline of the Turkish Society of Anesthesiology and Reanimation published in 2013, recommendations regarding preoperative, intraoperative and postoperative processes for the prevention of IPH are included \[24\].

Although there are clinical practice guidelines for the management of IPH, the incidence of IPH in surgical patients is still high \[7,8,16-18\]. Reducing the incidence of IPH in surgical patients depends on good management of hypothermia in the perioperative process, and nurses have important responsibilities at every stage of the perioperative process in the management of IPH. In the study by Güclü and Karadag (2021), a care algorithm was developed to guide the decision-making of nurses for IPH care. Accordingly, nurses have important responsibilities in the management of IPH, such as risk assessment, taking measures to prevent hypothermia, diagnosing hypothermia in the perioperative process, using appropriate heating methods, and monitoring complications that may develop due to hypothermia \[11\]. Nurses, who play a key role in the multidisciplinary team in the management of IPH, still experience some problems in the management of hypothermia \[19\]. In a study conducted with AORN members, it was found that the majority of nurses defined the upper and lower limits of body temperature for hypothermia differently \[19\]. Some studies in the literature show that nurses' practices for hypothermia management are not standardized and therefore inadequate \[3,5,25,26\]. Good management of IPH, which is a preventable problem in the surgical process, may be possible with evidence-based standardization of practices in the perioperative process and systematic implementation of these practices.

In recent years, care packages have been used to standardize nursing practices based on evidence and to improve the quality of care \[27\]. Care bundle are defined as a set of evidence-based practices used to standardize care and treatment \[28,29\]. Care bundles are reported to have many benefits such as providing easy management of conditions requiring special care, reducing complications, shortening the length of hospital stay, reducing costs, increasing communication within the team, improving the quality of care and providing supervision \[28,29\]. In addition, it has been reported that the use of care bundles increases the satisfaction of patients and nurses and job satisfaction of nurses, reduces unnecessary applications in nursing care and improves negative patient outcomes that may result from inadequate care \[4,30\]. In the literature, there is a care bundles developed for the management of perioperative hypothermia \[31\]. The perioperative thermal care bundle developed by Duff et al. (2018) includes three elements: risk assessment, body temperature monitoring and active heating. The three elements in this care bundle are recommendations for pre-op, intra-op and postoperative processes, and it is seen that the majority of the applications are for the intraoperative phase. In the study, it was found that compliance with the care package, especially the practices in the intraoperative process, was low \[31\]. It is thought that the development and use of a care bundle specific to each stage of the perioperative process in the management of IPH will increase the applicability of the care bundle and compliance with the bundle. In the literature, there is no care bundle developed for the management of hypothermia in the postoperative period. Therefore, a care bundle specific to the postoperative process was developed in order to standardize nursing care for hypothermia in surgical patients, improve patient outcomes and increase the quality of care. This care bundle was prepared in line with the approaches recommended by the Institute for Healthcare Improvement (IHI) for the management of postoperative hypothermia . In order to create the draft form of the parameters of the care bundle, relevant studies in the literature were compiled and a comprehensive literature review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist. The parameters and sub-parameters of the draft obtained as a result of the literature review, a draft care bundle form including the parameters was prepared by the researchers in order to apply for expert opinion. Delphi method was used to evaluate expert opinions. Opinions and suggestions were received from a total of 11 experts (5 physicians, 6 nurses). The opinions and suggestions of the experts were taken into consideration and analyzed, and a consensus was reached at the end of the second round of Delphi process, thus the final version of the care bundle was determined. The postoperative hypothermia care bundle consists of three main parameters, "Diagnose hypothermia", "Maintain/maintain normothermia" and "Monitor body temperature at regular intervals", and eight sub-parameters of these parameters. For this purpose, this study evaluates the pilot implementation and effectiveness of the postoperative hypothermia management care bundle developed within the scope of the research.

1. Hypotheses and Objectives of the Study It is aimed to evaluate the pilot implementation and effectiveness of the postoperative hypothermia management care bundle.

Hypotheses and Questions of the study

Research hypotheses for the quantitative part:

H0: Nurses are not compliant with the use of the care bundle for postoperative hypothermia management.

H1: Nurses are compliant with the use of a care bundle for postoperative hypothermia management.

H0: Use of a care bundle for postoperative hypothermia management has no effect on the incidence of postoperative hypothermia.

H1: The use of a care bundle for postoperative hypothermia management has an effect on the incidence of postoperative hypothermia.

H0: The use of a care bundle for postoperative hypothermia management has no effect on the time to reach postoperative normothermia.

H1: The use of the care bundle for postoperative hypothermia management has an effect on the time to reach postoperative normothermia.

H0: Nurses are not compliant with using the care bundle for postoperative hypothermia management.

H1: The use of a care bundle for postoperative hypothermia management affects the incidence of postoperative hypothermia.

H0: The use of a care bundle for postoperative hypothermia management does not affect the incidence of postoperative hypothermia.

H1: The use of a care bundle for postoperative hypothermia management affects the incidence of postoperative hypothermia.

H0: Using the postoperative hypothermia management care bundle does not impact the time to reach postoperative normothermia.

H1: Using the postoperative hypothermia management care bundle impacts the time to reach postoperative normothermia.

Research questions for the qualitative section:

1. What are the experiences of nurses regarding the use of the postoperative care bundle?
2. What are the nurses' suggestions for the use of the postoperative care bundle
3. What are the nurses' experiences for the use of the postoperative hypothermia management care bundle?
4. What are the nurses' suggesstions for the use of the postoperative hypothermia management care bundle?

3. Research Plan and Methods Method of the Study: This study was planned as a mixed method research in which qualitative and quantitative research methods were used together in order to pilot the care bundle for the management of postoperative hypothermia and to evaluate its effectiveness.

Place and Characteristics of the Study: The study was planned to be conducted in the Cardiovascular Surgery Intensive Care Unit of Hacettepe University Adult Hospital. The Cardiovascular Surgery Intensive Care Unit has a capacity of 13 adult and 9 pediatric beds and provides care for patients undergoing cardiovascular and thoracic surgery. In the intensive care unit, 17 nurses work in shifts of 08-20 and 20-08 hours. A general hospital orientation program is applied for a new nurse starting to work in the intensive care unit. There is no standardized protocol for hypothermia management in the intensive care unit. In patients admitted to the intensive care unit after surgery, body temperature is monitored half-hourly and hourly, and one of the passive or active heating methods is used according to the needs of the patient. Nurses working in the intensive care unit receive training on hypothermia management as part of in-service training. In-service trainings are carried out annually within the scope of subjects determined according to the needs of nurses.

Research Time: The research will be conducted between March 1, 2025 and December 31, 2025 following the approval of Hacettepe University Clinical Research Ethics Committee

Population and Sample of the Study: The population of the study will consist of nurses working in the Cardiovascular Surgery Intensive Care Unit. All nurses working in the intensive care unit who meet the inclusion criteria and volunteer to participate in the study will be included in the research sample.

Patient sample: The population of the study will consist of patients cared for in the cardiovascular surgery intensive care unit. All patients hospitalized in the intensive care unit who meet the inclusion criteria and volunteer to participate in the study will be included in the study sample.

Inclusion criteria For nurses

* Working as a nurse in Cardiovascular Surgery Intensive Care Unit for at least 6 months
* Volunteering to participate in the study

For patients to be cared for during the piloting of the care package:

* 18 years of age or older
* Being in the first 24 hours of postoperative follow-up in the Cardiovascular Surgery Intensive Care Unit
* He/she or his/her legal representative has given consent to participate in the study Exclusion criteria For nurses
* Leaving the Cardiovascular Surgery Intensive Care Unit before the completion of the study period
* Unwillingness to continue working

For patients to be cared for during the piloting of the care package:

• Emergency surgical operations, patients with abnormal thermoregulation such as malignant hyperthermia and neuroleptic malignant syndrome, and patients with ASA IV-V

Data Collection Tools The data were collected using 5 forms: "Nurse Introductory Information Form", "Care Package for Postoperative Hypothermia Management Checklist", "Care Package for Postoperative Hypothermia Management Compliance Assessment Form", "Semi-structured Questionnaire for Interview with Nurses" and "Patient Postoperative Hypothermia Follow-up Form".

Nurse descriptive information form: This form was developed by the researchers and consisted of a total of 7 questions including the nurse's age, gender, educational status, working time, working time in intensive care unit, hypothermia training status and the guidelines or protocols followed for hypothermia.

Care bundle checklist for postoperative hypothermia management: It is a form developed by the researchers to be used in the pilot implementation of the care bundle for postoperative hypothermia and includes the parameters that make up the care bundle. In the control list, there is a field for marking the care package parameters, implementation date and hours, realized and unrealized applications. Once in each shift in which the patient receives care, the performed and unperformed practices from the parameters that make up the care bundle will be marked on this checklist by the nurses. Practices performed will be marked on the checklist as (+) and practices not performed will be marked as (-). The form will be filled in by the nurses.

Care bundle for postoperative hypothermia management compliance assessment form: This form is a form developed by the researchers to be used in the pilot implementation of the care bundle for postoperative hypothermia management, including the parameters that make up the care bundle and the descriptive characteristics of the patient (age, gender, diagnosis, surgery). The compliance assessment form will be completed by the researcher to evaluate the nurses' compliance with the care bundle. The researcher will fill out the form by visiting the intensive care unit at any time of the day when the intensive care nurses are not aware of it. The researcher will evaluate the implementation of the care package parameters by the nurses for each patient for whom the care bundle is used and whether the applications are marked on the checklist with this form. If the care bundle parameters were applied and marked on the checklist, the box in the "applied" section of the compliance assessment form will be checked, if not, the box in the "not applied" section will be checked, and if the control form was not marked, the box in the "not filled" section will be checked. In the explanation section, the reasons for not applying the parameters that are not applied will be stated. Within the scope of this form, the compliance rate of the care bundle will be calculated. The rate found with this calculation will show the success of compliance with the care package. In the calculation, the compliance rate will be calculated by dividing the number of patients to whom all parameters of the care bundle are fully implemented by the number of patients to whom the care bundle parameters should be implemented. In this calculation, a compliance rate below 95% means that compliance with the care bundle is unsuccessful \[29\].

Semi-structured questionnaire for interview with nurses: This form consists of 6 semi-structured questions created by the researchers in a phenomenological design in order to examine the thoughts of the nurses in depth. The questionnaire will be used in face-to-face individual interviews with the nurses included in the study after the pilot study is completed.

Patient postoperative hypothermia follow-up form: This form was developed by the researchers to determine the incidence of hypothermia and the time to reach normothermia in patients who received care using the care bundle during the pilot study. In this form, starting from the admission of the patient to the intensive care unit, body temperature will be recorded every 15 minutes for the first 1 hour and then every hour for the first 24 hours. The form will be completed for each patient only for the first 24 hours postoperatively.

Implementation of Research The research will be carried out in 2 stages: pilot implementation of the care bundle and evaluation of its effectiveness (obtaining the experiences of the nurses, determining the incidence of hypothermia and the time to reach normothermia during the use of the care bundle).

Phase 1: Pilot Implementation of the Care bundle Informing nurses about the care bundle and its use: The pilot implementation of the care bundle will be carried out in the cardiovascular surgery intensive care unit. At this stage, firstly, all nurses working in the intensive care unit will be informed about the study and informed consent forms will be obtained from the nurses who volunteered to participate in the study. A meeting will be organized with the nurses who volunteered to participate to inform them about the introduction and use of the postoperative hypothermia management care bundle. In this meeting, the "Nurse Introductory Information Questionnaire", which includes the introductory information of the nurses, will be filled in. A presentation will be made on the content of the care bundle, how the elements are determined and how to use the care bundle in the intensive care unit. The information meeting will be repeated in the same week for nurses who cannot attend the meeting. After the information meeting, the postoperative hypothermia care bundle will be used by the nurses caring for the patients followed up in the cardiovascular surgery intensive care unit.

Use of the care bundle: The pilot implementation of the care bundle will last for 6 months. During this period, patients who meet the inclusion criteria in the cardiovascular surgery intensive care unit will be cared for using the care bundle. The "Care bundle Checklist for Postoperative Hypothermia Management", which includes the elements of the care package for postoperative hypothermia management, will be completed by the nurse for each patient cared for during this period. Care bundle checklists will be completed by the nurse providing care for each patient in the first 24 hours postoperatively, once in each work shift. The checklists will be reproduced by the researcher and kept in a cabinet accessible by each nurse in the intensive care unit. This form will be placed in the patient's file by the nurse providing care and will be used throughout the period of care. The nurse will put a (+) sign meaning yes in the box opposite the parameter in the control form during the shift in which the care bundle element was applied, if the care bundle element was applied during the period of care, and a (-) sign meaning no if the care bundle element was not applied. The checklist of the patient whose 24-hour follow-up in the intensive care unit was completed or who was discharged from the intensive care unit will be collected by the investigators during daily visits.

In order to evaluate the nurses' compliance with the use of the care bundle, the researcher will visit the intensive care unit at different times every day and evaluate the descriptive characteristics of the patients receiving care with the "Care bundle Compliance Assessment Form for Postoperative Hypothermia Management" and the status of the application of the care package parameters by the nurses and whether the applications are marked on the checklist. The researcher will check the box in the "applied" section of the compliance assessment form if the care bundle parameters were applied and marked on the checklist, the box in the "not applied" section if not applied, and the box in the "not filled" section if the control form was not marked. In the explanation section, they will determine the reasons for the non-application of the parameters with the responsible clinical nurse. During the pilot implementation period, printed posters of the care package will be hung in different areas of the clinic where nurses can see them.

Phase 2: Evaluating the Effectiveness of the Care bundle Determining the experiences of nurses towards the care bundle: In order to examine the experiences of nurses regarding the developed care bundle, in-depth individual interviews will be conducted with nurses in a phenomenological design. Interviews will be conducted face-to-face, in an environment and time suitable for interviewing in the hospital, using a "Semi-Structured Questionnaire". The interviews are expected to last approximately 20-30 minutes Determination of the incidence of postoperative hypothermia and the time to reach normothermia: At this stage, the data collected using the "Patient Postoperative Hypothermia Follow-up Form" during the pilot implementation will be analyzed and the incidence of postoperative hypothermia and the average time to reach normothermia in the 6-month period will be determined. During body temperature monitoring, the development of hypothermia at any time during the first 24 hours postoperatively will be considered as postoperative hypothermia \[6\]. The time to reach normothermia will be determined by calculating the time in minutes until the patients admitted to the intensive care unit reach normothermia. The mean time to reach normothermia will be calculated for patients who hypothermia at any time during the first 24 hours of intensive care unit stay. The results will be compared with the incidence of hypothermia and time to normothermia in the period before the implementation of the postoperative hypothermia management care bundle in the ICU.

2. Data Evaluation Statistical analysis of the quantitative data of the study will be conducted using the SPSS 23 package program, and qualitative data analysis will be conducted using the MAXQDA program.

Mean, standard deviation, median, median, quartiles, minimum, maximum values will be used for quantitative numerical data, and numbers and percentages will be used for non-numerical data.

In qualitative data analysis, Colaizzi's \[77\] seven-step phenomenological analysis method (identification, defining important statements, shaping meanings, clusters of themes, developing detailed descriptions, creating the basic structure, seeking verification of the basic structure) will be used \[78\].

Nurses' compliance with the care bundle will be calculated according to the formula below. If any of the care bundle parameters are not implemented, the care package will be considered as not realized for that application. The rate found with this calculation will show the success of compliance with the care bundle. In the calculation, the compliance rate will be calculated by dividing the number of patients in whom all parameters of the care bundle were fully implemented within the scope of the study by the number of patients in whom the care bundle parameters should be implemented. In this calculation, a compliance rate below 95% means that compliance with the care bundle is unsuccessful\[29\].

Eligibility Criteria:
Inclusion Criteria:

For Nurses

* Working as a nurse in Cardiovascular Surgery Intensive Care Unit for at least 6 months
* Volunteering to participate in the study

For patients to be cared for during the pilot implementation of the care bundle:

* 18 years of age or older
* Being in the first 24 hours of postoperative follow-up in the Cardiovascular Surgery Intensive Care Unit
* He/she or his/her legal representative has given consent to participate in the study

Exclusion Criteria:

For nurses

* Leaving the Cardiovascular Surgery Intensive Care Unit before the completion of the study period
* Unwillingness to continue working

For patients to be cared for during the piloting of the care package:

- Emergency surgical operations, patients with abnormal thermoregulation such as malignant hyperthermia and neuroleptic malignant syndrome and patients with ASA IV-V