Factors associated to the development of hypothermia in the intraoperative period

Peri-Operative Hypothermia in Trauma Patients: A Retrospective Cohort Analysis at a Busy District General Hospital Within the National Health Service (NHS)

INTRODUCTION

 Perioperative hypothermia is defined as a patient's core body temperature of less than 36°C, which can lead to several complications. Even mild hypothermia increases the incidence of post-operative wound infection, post-operative ischaemic cardiac events and intra-operative blood loss and prolongs post-operative recovery. It is, hence, essential to maintain and provide normothermia during the perioperative phases for optimal surgical results and patient satisfaction. One of the most significant contributing factors to intra-operative hypothermia is the induction of general anaesthesia, where a significant amount of heat is shifted from the core to the peripheral circulation with consequent loss to an often-cold environment. The difference between the patient's skin and ambient temperature during the interval from entering the operating room through anaesthesia induction until draping and active warming may be significant. This study aims to look at the incidence of perioperative hypothermia in trauma and orthopaedics patients who present to a busy district general hospital in the National Health Service (NHS) and correlate this with the ambient theatre temperature and phases of surgery to draw a statistical significance.

METHODS

This retrospective observational study conducted at the North Manchester General Hospital's trauma and orthopaedics department included 300 patients listed in the trauma surgery list from 1 July 2023 to 31 August 2023. Inclusion criteria were trauma patients aged 16-85 years. Elective orthopaedic and other surgical speciality patients were excluded. The perioperative temperature measurements were collected from the anaesthesia records. Statistical calculations were conducted using the StatsDirect software (StatsDirect Ltd, Wirral, UK) from Manchester University NHS Foundation Trust, Manchester.

RESULTS

 Among the 300 patients, the overall incidence of hypothermia was 3% pre-operative, 18% pre-induction, 21% intra-operative, 21% post-operative, 3% in recovery and 0% post-recovery. Intra-operative hypothermia incidence was significant, given that active warming was applied to patients with pre-operative hypothermia. Multivariate regression analysis showed that pre-induction temperature and theatre ambient temperature were statistically significant in predicting intra-operative hypothermia.

CONCLUSION

 This study highlights the need for active interventions to recognise and prevent perioperative hypothermia in trauma and orthopaedics patients. Active pre-warming of patients and the operating rooms, regardless of surgery type and duration, is feasible and potentially beneficial. Further studies should include a randomised controlled trial comparing active and passive warming strategies to evaluate their effectiveness in improving perioperative outcomes.

Development of a perioperative thermal insulation system: Testing comfort properties for different textile sets

The poorly physical and psychological conditions of the patients make the body thermal protection crucial in the perioperative context, due to the risk of hypothermia. The lack of evidence regarding the effectiveness of textile coverings in protecting patients in the operating room, underscores the recommendation of the forced warming system using non-woven fabric for ensuring the best thermal protection in the perioperative context. This study is part of a development process of a three-layered thermal insulation system, a blanket for use in the perioperative context. After previous selection of two fabrics for the mid and outer layers, in this study three fabric samples for the inner layer with same soft tactile sensation and different textile compositions were tested to find its effect on increasing the thermal insulation of the whole set, using a thermal manikin. The serial method was used to calculate the thermal insulation properties of the sets. The best thermal insulation and thermal comfort performance was obtained by the set using an inner layer composed of polypropylene, polyamide, and elastane whose results were the highest thermal conductivity and thickness and the lowest maximum stationary heat flow density. The results indicated that this fabric influenced positively the values of the whole set once increased its thermal protection effectiveness when compared to the other tested sets. This set is more suitable for future testing in patients during their stay in the perioperative setting.

Intravenous magnesium sulfate <em>versus</em> intravenous meperidine to prevent shivering during spinal anesthesia

BACKGROUND Shivering is a frequent event during neuraxial anesthesia due to impaired central and peripheral thermoregulation control. Meperidine and MgSO4 are effective in lowering the shivering threshold. Hence, this study aimed to compare the efficacy of MgSO4 and meperidine to prevent shivering in patients undergoing spinal anesthesia. METHODS This was a double-blind randomized clinical trial of 100 patients divided into 2 groups. One group had MgSO4 30 mg/kg, and the other group had meperidine 0.5 mg/kg intravenously in 100 ml of 0.9% NaCl before undergoing spinal anesthesia. Participants were non-pregnant patients aged 18–65 years and had physical status I or II (based on the American Society of Anesthesiologist). Shivering was considered significant if it occurred in grade 3 or 4. Patient characteristics, shivering degree, tympanic membrane temperature, and side effects were recorded. RESULTS Shivering occurred 10% in the MgSO4 group and 19% in the meperidine group, with p = 0.23. Both groups had similar side effects of nausea, vomiting, and hypotension. CONCLUSIONS MgSO4 30 mg/kg was not superior to meperidine 0.5 mg/kg intravenously in preventing shivering in patients undergoing spinal anesthesia.

Comparison of Perioperative Active or Routine Temperature Management on Postoperative Quality of Recovery in PACU in Patients Undergoing Thoracoscopic Lobectomy: A Randomized Controlled Study

BACKGROUND

Whether intraoperative temperature management can help patients recover quickly in the postanesthesia care unit (PACU) still remains to be investigated. This study aimed to investigate the effect of intraoperative temperature management on the quality of postoperative recovery of patients who underwent pulmonary lobectomy in the PACU.

METHODS

Totally, 98 patients aged 45-60 years with a body mass index of 20-25 kg/m² who underwent elective thoracoscopic lobectomy were enrolled. Patients were categorized into two groups using a random number table: the conventional group received routine intervention to maintain normothermia (Group C, n = 49) and the aggressive group received integrated interventions (Group A, n = 49). In Group C, normothermic fluid was infused intravenously, the heating blanket was turned on when the intraoperative temperature was <35.0 °C, and the warming was stopped when the temperature reached 36.5 °C. In Group A, the fluid heated to 37 °C was infused intravenously, and the heating blanket was used intraoperatively. When the body temperature was >37 °C, the heating blanket was turned off, and when the body temperature was <36.5 °C, the heating blanket was turned on to continue heating.

RESULTS

Steward awakening scores at 1 min and 5 min after extubation and PaO₂ levels at 15 min after extubation were higher in Group A than in Group C (P < 0.05); incidence of chills, nausea, and vomiting in the PACU was lower in Group A than in Group C (P < 0.05); and length of stay in the PACU was shorter in Group A than in Group C (P < 0.05).

CONCLUSION

Aggressive intraoperative temperature management of patients undergoing thoracoscopic lobectomy can improve the quality of postoperative recovery in the PACU through a safe and smooth transition compared with routine insulation measures.

Development and internal validation of an algorithm to predict intraoperative risk of inadvertent hypothermia based on preoperative data

Intraoperative hypothermia increases perioperative morbidity and identifying patients at risk preoperatively is challenging. The aim of this study was to develop and internally validate prediction models for intraoperative hypothermia occurring despite active warming and to implement the algorithm in an online risk estimation tool. The final dataset included 36,371 surgery cases between September 2013 and May 2019 at the Vienna General Hospital. The primary outcome was minimum temperature measured during surgery. Preoperative data, initial vital signs measured before induction of anesthesia, and known comorbidities recorded in the preanesthetic clinic (PAC) were available, and the final predictors were selected by forward selection and backward elimination. Three models with different levels of information were developed and their predictive performance for minimum temperature below 36 °C and 35.5 °C was assessed using discrimination and calibration. Moderate hypothermia (below 35.5 °C) was observed in 18.2% of cases. The algorithm to predict inadvertent intraoperative hypothermia performed well with concordance statistics of 0.71 (36 °C) and 0.70 (35.5 °C) for the model including data from the preanesthetic clinic. All models were well-calibrated for 36 °C and 35.5 °C. Finally, a web-based implementation of the algorithm was programmed to facilitate the calculation of the probabilistic prediction of a patient's core temperature to fall below 35.5 °C during surgery. The results indicate that inadvertent intraoperative hypothermia still occurs frequently despite active warming. Additional thermoregulatory measures may be needed to increase the rate of perioperative normothermia. The developed prediction models can support clinical decision-makers in identifying the patients at risk for intraoperative hypothermia and help optimize allocation of additional thermoregulatory interventions.

Control central de la temperatura corporal y sus alteraciones: fiebre, hipertermia e hipotermia

Introducción. En mamíferos, el control de la temperatura corporal es vital. El estado de consciencia y control motor en humanos, ocurren a una temperatura de 37°C y las desviaciones pueden alterar las propiedades celulares, generando disfunciones fisiológicas. En especies como los roedores (su relación área de superficie/volumen facilita la pérdida de calor) mantienen temperaturas basales cercanas a los 30°C. Distinto es con animales como los paquidermos, cuya temperatura es menor comparada con los humanos. El objetivo es identificar los aspectos fisiológicos de la termorregulación. Descripción de temas tratados. Revisión descriptiva de la literatura de artículos publicados en diferentes bases de datos. La termorregulación es la capacidad del cuerpo para establecer y mantener su temperatura, regulando producción y pérdida de calor para optimizar la eficiencia de procesos metabólicos. El protagonismo lo tiene el sistema nervioso central y su control neuro-hormonal en múltiples niveles. El centro regulador térmico está en el hipotálamo anterior. Este recibe información de los receptores de grandes vasos, vísceras abdominales, médula espinal y de la sangre que perfunde el hipotálamo. Cuando aumenta la temperatura central, el termorregulador activa fibras eferentes del sistema nervioso autónomo, provocando pérdida de calor por convección y evaporación. Ante el descenso de temperatura, la respuesta es disminuir la pérdida de calor (vasoconstricción y menor sudoración); además, incrementar la producción de calor, intensificando la actividad muscular. Conclusión. La termorregulación es liderada por el hipotálamo, quien regula aumento y disminución de la temperatura respondiendo a las necesidades del organismo para llegar a la homeostasis y compensación, enfrentando las alteraciones de la temperatura ambiental

Perioperative inadvertent hypothermia among urology patients who underwent transurethral resection with either TURis or transurethral resection of the prostate method

PURPOSE

The purpose of the study was to investigate the incidence of perioperative hypothermia in urology patients undergoing transurethral resection with either TURis or transurethral resection of the prostate method and to recognize the risk factors that were responsible for the occurrence of hypothermia intraoperatively in these patients.

METHODS

It was a randomized prospective study. A total of 168 patients, according to American Society of Anesthesiologists physical status I-III, were scheduled for transurethral resection either with TURis or transurethral resection of the prostate method. We measured the core body temperature before (preoperative), during (perioperative) and after (postoperative) the surgery. Age, body mass index, American Society of Anesthesiologists score, duration of surgery, preoperative prostatic volume, and vital signs were also recorded.

RESULTS

The prevalence of inadvertent hypothermia was 64.1% for the TURis group and 60% for the transurethral resection of the prostate group. Hypothermic patients in TURis group were significantly older (87.7 ± 1.7 vs 68 ± 6.7 years, p < 0.05) and had lower body mass index (26.9 ± 3.6 vs 29.2 ± 2.7, p < 0.05), while hypothermic patients in the transurethral resection of the prostate group were significantly older (86 ± 1.1 vs 70 ± 7.4 years, p < 0.05) and had notably higher duration of surgery (140.6 ± 28.9 vs 120.3 ± 14.3 min, p < 0.05) than normothermic patients.

CONCLUSION

Perioperative inadvertent hypothermia among urology patients who underwent transurethral resection with both TURis and transurethral resection of the prostate method is of high incidence. We recommend monitoring of the temperature of core body of all these patients, especially those with advanced age and lower body mass index.

Investigation of inadvertent hypothermia incidence and risk factors

OBJECTIVE

This study was conducted to determine the incidence of inadvertent hypothermia in operative patients and the risk factors that are involved in the development of hypothermia.

MATERIAL AND METHODS

This prospective, descriptive, cross-sectional study was conducted from January 2016to August 2016 with 144 patients who over the age of 18 years, underwent general surgery, orthopedic surgery, urologic surgery, neurosurgery, and plastic and reconstructive surgery. Data was collected with the "Hypothermia Data Collection Form." Body temperature was measured by the tympanic membrane in the waiting room, operating room, and PACU.

RESULTS

Overall, 89% of the patients (n=129) were normothermic in the preoperative phase; 74.30% of the patients (n=107) in intraoperative phase and 75.70% of the patients (n=109) in postoperative phase were hypothermic. American Society of Anesthesiologist (ASA) score, preoperative body temperature, operating room temperature, and using heating method at operation were found to be effective in the development of inadvertent hypothermia during the operating period. It was determined that premedication, preoperative and postoperative body temperature, and the operating room temperature were effective for inadvertent hypothermia in the postoperative period.

CONCLUSION

As a result of the study, it was determined the rate of inadvertent hypothermia was high during and after surgery. Preoperative and intraoperative patient body temperature and operating room temperature were found to be effective in preventing inadvertent hypothermia.

Risk factors for hypothermia during major abdominal surgery

AIM

To identify the risk factors for hypothermia during major abdominal surgery.

METHODS

Sixty patients aged between 33 and 82 years who underwent elective major abdominal surgeries were selected and divided into either a hypothermia or a non-hypothermia group according to occurrence of hypothermia or not. Data recorded and compared between the two groups included general clinical information, anesthesia method and time taken, total fluid infusion, blood transfusion, blood loss and intraoperative warming strategy. Logistic regression analysis was used to analyze the factors that were found to have a statistic difference between the two groups, in order to identify the risk factors affecting the occurrence of intraoperative hypothermia.

RESULTS

Thirty-seven (61.7%) patients were found to have hypothermia during surgeries. Age, body mass index (BMI), anesthesia time taken, and total fluid infusion were found to have statistic differences between the two groups (P < 0.05). Logistic regression analysis showed that BMI < 24 kg/m² (OR = 0.103, P < 0.05) and anesthesia time taken (OR = 1.645, P < 0.05) were independent risk factors for intraoperative hypothermia in patients undergoing major abdominal surgeries.

CONCLUSION

BMI < 24 kg/m² and anesthesia time taken ≥ 3 h are independent risk factors for intraoperative hypothermia in patients undergoing major abdominal surgeries.

Guideline Implementation: Preventing Hypothermia

The updated AORN "Guideline for prevention of unplanned patient hypothermia" provides guidance for identifying factors associated with intraoperative hypothermia, preventing hypothermia, educating perioperative personnel on this topic, and developing relevant policies and procedures. This article focuses on key points of the guideline, which addresses performing a preoperative assessment for factors that may contribute to hypothermia, measuring and monitoring the patient's temperature in all phases of perioperative care, and implementing interventions to prevent hypothermia. Perioperative RNs should review the complete guideline for additional information and for guidance when writing and updating policies and procedures.

Warmed intravenous infusion for controlling intraoperative hypothermia

OBJECTIVE

to verify the effectiveness of warmed intravenous infusion for hypothermia prevention in patients during the intraoperative period.

METHOD

experimental, comparative, field, prospective and quantitative study undertaken at a federal public hospital. The sample was composed of 60 adults, included based on the criteria of axillary temperature between 36ºC and 37.1ºC and surgical abdominal access, divided into control and experimental groups, using the systematic probability sampling technique.

RESULTS

22 patients (73.4%) from both groups left the operating room with hypothermia, that is, with temperatures below 36ºC (p=1.0000). The operating room temperature when patients arrived and patients' temperature when they arrived at the operating room were statistically significant to affect the occurrence of hypothermia.

CONCLUSION

the planning and implementation of nursing interventions carried out by baccalaureate nurses are essential for preventing hypothermia and maintaining perioperative normothermia.

Hypothermia Prevention During Surgery: Comparison Between Thermal Mattress And Thermal Blanket


This study aimed to compare the efficiency of the thermal blanket and thermal mattress in the prevention of hypothermia during surgery. Thirty-eight randomized patients were divided into two groups (G1 – thermal blanket and G2 - thermal mattress). The variables studied were: length of surgery, length of stay in the post-anesthetic care unit, period without using the device after thermal induction, transport time from the operating room to post-anesthetic care unit, intraoperative fluid infusion, surgery size, anesthetic technique, age, body mass index, esophageal, axillary and operating room temperature. In G2, length of surgery and starch infusion longer was higher (both p=0.03), but no hypothermia occurred. During the surgical anesthetic procedure, the axillary temperature was higher at 120 minutes (p=0.04), and esophageal temperature was higher at 120 (p=0.002) and 180 minutes (p=0.03) and at the end of the procedure (p=0.002). The thermal mattress was more effective in preventing hypothermia during surgery.

Active cutaneous warming systems to prevent intraoperative hypothermia: a systematic review

This study analyzed the evidence available in the literature concerning the effectiveness of different active cutaneous warming systems to prevent intraoperative hypothermia. This is a systematic review with primary studies found in the following databases: CINAHL, EMBASE, Cochrane Register of Controlled Trials and Medline. The sample comprised 23 randomized controlled trials. There is evidence in the literature indicating that the circulating water garment system is the most effective in maintaining patient body temperature. These results can support nurses in the decision-making process concerning the implementation of effective measures to maintain normothermia, though the decision of health services concerning which system to choose should also take into account its cost-benefit status given the cost related to the acquisition of such systems.

Management of hypothermia: impact of lecture-based interactive workshops on training of pediatric nurses

This study aimed to determine the efficacy of interactive workshop on the management of hypothermia and its impact on pediatric nurses' training. This is a pretest-to-posttest quasi-experimental descriptive study. Thirty pediatric nurses attended an interactive lecture-based interactive workshop on the management of hypothermia. Participants had to accept an invitation to the presentation before the training event. They completed the lecture, and a multiple-choice question test before and after the lecture was given. There was a significant improvement in mean test scores after the lecture when compared with those before the lecture (mean [SD], 15.5 [1.3] vs 5.0 [1.7], P < 0.001). The information gained in this study will be valuable as a baseline for further research and help guide improvements in the management of hypothermia with the ultimate goal of enhancing safe and quality patient care.

Prewarming operating rooms for prevention of intraoperative hypothermia during total knee and hip arthroplasties

Prewarming operating rooms has been shown to limit hypothermia in pediatric surgical patients but may be associated with extreme discomfort for surgeons. We examined the effect of prewarming operating rooms on core temperatures during knee and hip arthroplasties. Sixty-six patients were randomized to the prewarmed group at 24 °C or control group at 17 °C. The prewarmed group core temperature (mean, 36.14 °C) before active warming was significantly higher (P = .018) than that of the control group (mean, 35.83 °C). By the start of surgery, the difference was 36.01 °C prewarmed vs 35.83 °C control, P = .038. There was no significant difference in the last recorded mean temperatures between groups: 36.35°C (prewarmed) vs 36.16 °C (control). A prewarmed operating room for adults undergoing knee or hip arthroplasty had minimal effect on preventing intraoperative hypothermia.