Inadvertent Intraoperative Hypothermia Research Articles

Inadvertent intraoperative hypothermia during general anesthesia: current state of the problem (literature review)

Inadvertent intraoperative hypothermia is an extremely common complication of the perioperative period, which is the cause of a variety of negative effects. This may be an effect on the hemostatic system, immunity, metabolism of drugs, the occurrence of postoperative chills, which leads to a prolongation of the terms and a decrease in the quality of treatment. We analyzed publications in the databases MedLine, PubMed, Google Scholar, Web of Science, Scopus for the period 2008–2023, which contained information on the physiology of the thermoregulatory system, its functioning under general anesthesia, as well as the effect of inadvertent intraoperative hypothermia on various functional systems. We reviewed meta-analyses, systematic reviews, clinical guidelines, observational studies, and case series supplemented by a review of the literature lists in relevant publications. We demonstrated the physiology of thermoregulation system, as well as changes in its functioning under general anesthesia. We shown the impact of inadvertent intraoperative hypothermia on various functional systems. We demonstrated methods of prevention that minimize the risk of inadvertent intraoperative hypothermia.

Predicting Intraoperative Hypothermia Burden during Non-Cardiac Surgery: A Retrospective Study Comparing Regression to Six Machine Learning Algorithms

Background: Inadvertent intraoperative hypothermia is a common complication that affects patient comfort and morbidity. As the development of hypothermia is a complex phenomenon, predicting it using machine learning (ML) algorithms may be superior to logistic regression. Methods: We performed a single-center retrospective study and assembled a feature set comprised of 71 variables. The primary outcome was hypothermia burden, defined as the area under the intraoperative temperature curve below 37 °C over time. We built seven prediction models (logistic regression, extreme gradient boosting (XGBoost), random forest (RF), multi-layer perceptron neural network (MLP), linear discriminant analysis (LDA), k-nearest neighbor (KNN), and Gaussian naïve Bayes (GNB)) to predict whether patients would not develop hypothermia or would develop mild, moderate, or severe hypothermia. For each model, we assessed discrimination (F1 score, area under the receiver operating curve, precision, recall) and calibration (calibration-in-the-large, calibration intercept, calibration slope). Results: We included data from 87,116 anesthesia cases. Predicting the hypothermia burden group using logistic regression yielded a weighted F1 score of 0.397. Ranked from highest to lowest weighted F1 score, the ML algorithms performed as follows: XGBoost (0.44), RF (0.418), LDA (0.406), LDA (0.4), KNN (0.362), and GNB (0.32). Conclusions: ML is suitable for predicting intraoperative hypothermia and could be applied in clinical practice.

Risk factors and prediction model for inadvertent intraoperative hypothermia in patients undergoing robotic surgery: a retrospective analysis

This study explored the risk factors and established a prediction model for intraoperative hypothermia (IOH) in patients undergoing robotic surgery. We conducted a retrospective survey of patients undergoing elective robotic surgery at the China-Japan Union Hospital of Jilin University during June 2020–October 2021 using institutional medical records. Intraoperative core temperatures and potential influencing factors were collected, and regression analyses were used to assess the risk factors for IOH and establish a prediction model for the incidence of IOH. Overall, 833 patients who underwent robotic surgery were included in the final analysis; IOH was observed in 344 patients (incidence, 0.41; 95% confidence interval [CI] 0.38–0.45). A higher body mass index (BMI) and baseline core temperature were protective factors for IOH. A final prediction model for IOH was developed based on the determining factors with an area under the receiver operating characteristic curve of 0.85 under fivefold cross validation (95% CI 0.83–0.88). Accordingly, a lower BMI and baseline core temperature, thoracic surgeries, morning surgeries, and surgeries with longer durations were risk factors for IOH during robotic surgeries. Our prediction model has an excellent discrimination ability for predicting IOH in robotic surgeries.

Clinical Survey of Current Perioperative Body Temperature Management: What Major Factors Influence Effective Hypothermia Prevention Practice?

PurposeInadvertent intraoperative hypothermia (IIH) is generally associated with several postoperative complications. Inspite of the existing guidelines, the global incidence of IIH remains unacceptably high. Understanding the conditions that influence temperature management is critical for developing future interventions to improve the postoperative patient outcomes. This study aimed to identify the major factors that hinder the implementation of IIH prevention practices.MethodsThrough a literature research, pilot small-sample investigation, and expert suggestions, 11 factors that may hinder the implementation of IIH prevention practices were identified. A questionnaire was developed, and each question was used to assess each factor. After approval by the Research Ethics Board, the questionnaires were sent to the staff anaesthesiologists at two academic hospitals via WeChat. Each answer was coded according to the degree to which the factor was affected, as anticipated. Finally, the answers were analysed based on the 80/20 rule to identify the major barriers to effective temperature management.ResultsWe included 195 participants. Knowledge, memory, attention and decision processes, beliefs about consequences, and environmental context and resources were the major factors, with cumulative composition ratios of 24%, 43.4%, 57.7%, and 70.7%, respectively. Meanwhile, behavioural regulation and social influence were the secondary factors, with cumulative composition ratios of 80.4% and 87.5%, respectively. Reinforcement, confidence in capacity, duty realisation, skills, and intention were the general factors with cumulative composition ratios of 94.3%, 99.8%, 100%, 100%, and 100%, respectively.ConclusionFour factors–knowledge, memory, attention and decision process, beliefs about consequences, and environmental context and resources–were the major factors that influence the effective hypothermia prevention practice.Relevance to Clinical PracticeThese major factors will be used in further studies as a basis to develop the corresponding solutions and improve the patient outcomes in clinical practice.

Effects of Female Reproductive Hormone Levels on Inadvertent Intraoperative Hypothermia during Laparoscopic Gynecologic Surgery: A Retrospective Study.

Background and Objectives: Female reproductive hormones may affect core body temperature. This study aimed to investigate the effects of female reproductive hormones on inadvertent intraoperative hypothermia in patients who underwent laparoscopic gynecologic surgery under general anesthesia. Materials and Methods: This retrospective study included 660 menstruating and menopausal female patients aged 19–65 years. The patients were divided into two groups according to the occurrence of inadvertent intraoperative hypothermia: non-hypothermia group (N = 472) and hypothermia group (N = 188). After propensity score matching, 312 patients (N = 156 in each group) were analyzed to investigate the association between intraoperative hypothermia and female reproductive hormones. As potential predictors of inadvertent hypothermia, the levels of female reproductive hormones were analyzed using binary logistic regression. Results: The association of estradiol (r = −0.218, p = 0.000) and progesterone (r = −0.235, p = 0.000) levels with inadvertent intraoperative hypothermia was significant but weakly negative before matching; however, it was significant and moderately negative after matching (r = −0.326, p = 0.000 and r = −0.485, p = 0.000, respectively). In a binary logistic analysis, the odds ratio for estradiol was 0.995 (p = 0.014, 0.993 < 95% confidence interval [CI] < 0.998) before matching and 0.993 (p = 0.000, 0.862 < 95% CI < 0.930) after matching, and that for progesterone was 0.895 (p = 0.000, 0.862 < 95% CI < 0.930) before matching and 0.833 (p = 0.014, 0.990 < 95% CI < 0.996) after matching. Conclusions: Estradiol and progesterone levels were associated with inadvertent intraoperative hypothermia. However, the odds ratio for female reproductive hormone levels was close to 1. Therefore, female reproductive hormones may not be a risk factor for hypothermia during gynecologic surgery under general anesthesia. However, a small sample size in this study limits the generalizability of the results.

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.

Risk factors for inadvertent intraoperative hypothermia in patients undergoing laparoscopic surgery: A prospective cohort study.

BackgroundInadvertent intraoperative hypothermia is frequent during open surgeries; however, few studies on hypothermia during laparoscopic abdominal surgery have been reported. We aimed to investigate the incidence and risk factors for hypothermia in patients undergoing laparoscopic abdominal surgery.MethodsThis single-center prospective cohort observational study involved patients undergoing laparoscopic surgery between October 2018 and June 2019. Data on core body temperature and potential variables were collected. A multivariate logistic regression analysis was performed to identify the risk factors associated with hypothermia. A Cox regression analysis was used to verify the sensitivity of the results.ResultsIn total, 690 patients were included in the analysis, of whom 200 (29.0%, 95% CI: 26%−32%) had a core temperature < 36°C. The core temperature decreased over time, and the incident hypothermia increased gradually. In the multivariate logistic regression analysis, age (OR = 1.017, 95% CI: 1.000–1.034, P = 0.050), BMI (OR = 0.938, 95% CI: 0.880–1.000; P = 0.049), baseline body temperature (OR = 0.025, 95% CI: 0.010–0.060; P < 0.001), volume of irrigation fluids (OR = 1.001, 95% CI: 1.000–1.001, P = 0.001), volume of urine (OR = 1.001, 95% CI: 1.000–1.003, P = 0.070), and duration of surgery (OR = 1.010, 95% CI: 1.006–1.015, P < 0.001) were significantly associated with hypothermia. In the Cox analysis, variables in the final model were age, BMI, baseline body temperature, volume of irrigation fluids, blood loss, and duration of surgery.ConclusionsInadvertent intraoperative hypothermia is evident in patients undergoing laparoscopic surgeries. Age, BMI, baseline body temperature, volume of irrigation fluids, and duration of surgery are significantly associated with intraoperative hypothermia.

Inadvertent hypothermia and acute kidney injury (AKI) in neonates undergoing gastrointestinal surgeries: a retrospective study.

The purpose of our study was to evaluate the association between intraoperative hypothermia and AKI in neonates undergoing gastrointestinal surgeries. This retrospective study was conducted for neonates who underwent gastrointestinal surgeries from June 2018 to August 2020. Neonates with a minimum of two documented creatinine values before and after surgical procedures within 48 h were included. According to the mean intraoperative temperature, the eligible neonates were divided into three groups. The primary outcome was the incidence of AKI (as defined by the modified KDIGO criteria). The association between variables and AKI or hospital mortality was also examined. A total of 295 neonates fulfilled the eligibility criteria. AKI was more common in patients with lower intraoperative temperature compared to the normothermia group. Intraoperative mean temperature was independently associated with AKI. Patients developing AKI had a higher hospital mortality. AKI and gestational age were independently associated with hospital mortality. Inadvertent intraoperative hypothermia was associated with developing postoperative AKI.

Effectiveness of prewarming in prevention of inadvertent intraoperative hypothermia

Background: Inadvertent perioperative hypothermia (IPH), defined as a perioperative core temperature < 36 °C is attributable to redistribution of body heat from the core to peripheries during the initial phase of anaesthesia and is difficult to treat. We conducted this study to find the effectiveness of pre-warming in preventing the occurrence of hypothermia intraoperatively in adult patients undergoing elective laparotomy under general anaesthesia. Material and Methods: Forty-four adult patients undergoing elective laparotomy were randomized into two groups of 22 each. Patients in Group P were prewarmed for 60 minutes prior to induction and those in Group C did not receive prewarming. Results: Patients in Group P had a significantly higher peripheral temperature at induction compared to those in Group C (p = 0.025), whereas the core temperature at induction was found to be comparable between the 2 groups. The core to peripheral temperature gradient was found to be lower in group P when compared to group C and the difference was statistically significant (p = 0.042). The core temperature dropped to less than 35 °C in the first two hours following induction in 2 patients in Group P and in 14 patients in group C (p < 0.001). The rate of drop in the core temperature was higher in group C compared to group P (p=0.002).The mean peripheral temperature as well as the core temperature in group P was significantly higher than in group C from induction to 60th minute, and it was statistically significant. Conclusion: In the first 2 hours post induction, prewarming is effective in preventing the drop in core temperature and reduces the rate of drop in core temperature. Prewarming is effective in reducing the core to peripheral temperature gradient at induction.

Intraoperative Temperature Monitoring with Zero Heat Flux Technology (3M SpotOn Sensor) in Comparison with Tympanic and Oesophageal Temperature and Hypotermia Risk Factors: An Observational Study.

ObjectiveInadvertent hypothermia (body temperature below 35°C) is a common and avoidable challenge during surgery under anaesthesia. It is related to coagulation (clotting) disorders, an increase in blood loss, and a higher rate of wound infection. One of the methods for non-invasive monitoring of the core body temperature is the 3M SpotOn zero heat flux method. In this approach, sensors placed at the frontal region of the patient measure the skin temperature by creating an isothermic channel. The study aimed to determine the risk factors for hypothermia and compare the 3M SpotOn zero heat flux method with the tympanic membrane (eardrum) and oesophageal (food pipe) temperature measurement methods.DesignObservational.Data sourcesThe patients’ data were collected, including age, gender, weight, BMI, other illnesses, smoking history, type of anaesthesia, duration of surgery, operating room temperature, pulse rate, blood pressure, blood loss, and transfusions. Body temperature was measured by the tympanic membrane method before and after surgery, oesophageal method during surgery, and SpotOn measurements throughout all three periods were recorded.Eligibility criteriaInclusion criteria was: adult patients, both genders, who had undergone major abdominal cancer surgery at the trialists’ institution, in whom the SpotOn zero heat flux, tympanic membrane, and oesophageal temperature measurement methods had all been used. Participant exclusion criteria was the absence of recorded data.ResultsIn this study, inadvertent intraoperative hypothermia incidence was 38.1% in the recovery room. Although gender, presence of comorbidities, history of smoking, administration of epidural anaesthesia, and requirement of blood transfusion [red blood cells (RBCs) and fresh frozen plasma (FFP)] did not affect hypothermia significantly during admission to the recovery room, prewarming the patient throughout the operation prevented the occurrence of hypothermia significantly (p=0.004). Additionally, as the American Society of Anaesthesiologists (ASA) physical status score worsened, the rate of hypothermia increased significantly (Frequency: 1st degree, 29.4%; 2nd degree, 47.5%; 3rd degree, 66.7%; X2Slope- p=0.047).ConclusionThe most significant risk factor was found to be not prewarming the patient as a strict procedure, and as the ASA physical status score worsened, the rate of hypothermia increased significantly. Besides, the SpotOn method provided temperature measurements as good as the oesophageal temperature measurements. Clinical Trial registration: ISRCTN 14027708.

Guidelines of the Polish Society of Anaesthesiology and Intensive Therapy regarding prevention of inadvertent intraoperative hypothermia.

Core body temperature is strictly regulated (± 0.2 °C) and coordinated at the level of central nervous system located in the hypothalamus via several protective effector mechanisms that prevent overcooling and overheating. The central regulation permits both circadian and monthly variations of even 1°C; under normal conditions, however, the activation of effective protective mechanisms prevents even the slightest overcooling and core temperature elevation at any moment of the day.

Thermal suit connected to a forced-air warming unit for preventing intraoperative hypothermia: A randomised controlled trial.

Inadvertent intraoperative hypothermia is a common occurrence in surgical patients. A thermal suit is an option for passive insulation. However, active warming is known to be more effective. Therefore, we hypothesised that a forced-air warming (FAW) unit connected to the thermal suit is superior to a commercial FAW blanket and a warming mattress in breast cancer surgery. Forty patients were randomised to this prospective, clinical trial to wear either the thermal suit or conventional hospital clothes under general anaesthesia. The Thermal suit group had a FAW unit set to 38°C and connected to the legs of the suit. The Hospital clothes group had a lower body blanket set to 38°C and a warming mattress set to 37°C. Core temperature was measured with zero-heat-flux sensor. The primary outcome was core temperature on admission to the recovery room. There was no difference in mean core temperatures at anaesthetic induction (P=.4) or on admission to the recovery room (P=.07). One patient in the Thermal suit group (5%) vs six patients in the Hospital clothes group (32%) suffered from intraoperative hypothermia (P=.04, 95% CI 1.9%-49%). Mean skin temperatures (MSTs) were higher in the Thermal suit group during anaesthesia. No burns or skin irritations were reported. Two patients in the Thermal suit group sweated. A thermal suit connected to a FAW unit was not superior to a commercial FAW blanket, although the incidence of intraoperative hypothermia was lower in patients treated with a thermal suit.

Prevalence and multivariable factors associated with inadvertent intraoperative hypothermia in video-assisted thoracoscopic surgery: a single-center retrospective study

BackgroundInadvertent intraoperative hypothermia increases the risk of adverse events, but its related risk factors have not been defined in video-assisted thoracoscopic surgery (VATS). This study aimed at analyzing the prevalence and factors related to inadvertent intraoperative hypothermia in adults undergoing elective VATS under general anesthesia.MethodsThis was a retrospective study using data from the Peking University People’s Hospital from January through December, 2018. Data were collected on age, sex, height, weight, American Society of Anesthesiologists physical status, the duration of preparation and surgery, timing of surgery, surgery types, anesthesia types, intraoperative core temperature and the length of stay (LOS) in the hospital from the electronic database in our center. Patients were covered with a cotton blanket preoperatively and the surgical draping during the operation. A circulation-water warming mattress set to 38 °C were placed under the body of the patients. Inadvertent intraoperative hypothermia was identified as a core temperature monitored in nasopharynx < 36 °C. Multivariate logistic regression analysis was used to identify independent risk factors of hypothermia.ResultsWe found that 72.7% (95% CI 70.5 to 75.0%) of 1467 adult patients who underwent VATS suffered hypothermia during surgery. The factors associated with inadvertent intraoperative hypothermia included age (OR = 1.23, 95% CI 1.11 to 1.36, p < 0.001), BMI (OR = 1.83, 95% CI 1.43 to 2.35, p < 0.001), the duration of preparation (OR = 1.01, 95% CI 1.00 to 1.02, p = 0.014), the duration of surgery (OR = 2.10, 95% CI 1.63 to 2.70, p < 0.001), timing of surgery (OR = 1.64, 95% CI 1.28 to 2.12, p < 0.001), ambient temperature in the operating room (OR = 0.67, 95% CI 0.53 to 0.85, p = 0.001) and general anesthesia combined with paravertebral block after induction of anesthesia (OR = 2.30, 95% CI 1.31 to 4.03, p = 0.004). The average LOS in the hospital in the hypothermia group and the normothemic group was 9 days and 8 days, respectively (p < 0.001).ConclusionsWe highlight the high prevalence of inadvertent intraoperative hypothermia during elective VATS and identify key risk factors including age, duration of surgery more than 2 h, surgery in the morning and general anesthesia combined with paravertebral block (PVB) after intubation. We also find that hypothermia did prolong the LOS in the hospital.

Too Cool? Hip Fracture Care and Maintaining Body Temperature

Introduction:Patients with hip fractures can become cold during the perioperative period despite measures applied to maintain warmth. Poor temperature control is linked with increasing complications and poorer functional outcomes. There is generic evidence for the benefits of maintaining normothermia, however this is sparse where specifically concerning hip fracture. We provide the first comprehensive review in this population.Significance:Large studies have revealed dramatic impact on wound infection, transfusion rates, increased morbidity and mortality. With very few studies relating to hip fracture patients, this review aimed to capture an overview of available literature regarding hypothermia and its impact on outcomes.Results:Increased mortality, readmission rates and surgical site infections are all associated with poor temperature control. This is more profound, and more common, in older frail patients. Increasing age and lower BMI were recognized as demographic factors that increase risk of hypothermia, which was routinely identified within modern day practice despite the use of active warming.Conclusion:There is a gap in research related to fragility fractures and how hypothermia impacts outcomes. Inadvertent intraoperative hypothermia still occurs routinely, even when active warming and cotton blankets are applied. No studies documented temperature readings postoperatively once patients had been returned to the ward. This is a point in the timeline where patients could be hypothermic. More studies need to be performed relating to this area of surgery.

Short interruptions between pre-warming and intraoperative warming are associated with low intraoperative hypothermia rates.

Prevention of inadvertent hypothermia is recommended for procedures >30minutes because hypothermia increases the risk of myocardial ischemia, intraoperative blood loss, transfusion and wound complications. Therefore, short warming interruptions between pre-warming and intraoperative warming might result in lower hypothermia rates. The aim of this retrospective investigation was to determine whether the incidence of inadvertent intraoperative hypothermia was affected by the warming interruption. The lowest intraoperative body core temperature value and the warming interruption time were taken from anaesthesia records. Body core temperature was recorded continuously, and a patient was classified to be hypothermic if the lowest recorded temperature value was <36°C. Hypothermia rates and the correlation between warming interruption times and intraoperative hypothermia rates were calculated. Five thousand eighty-four patients were analysed. The intraoperative hypothermia rate was 15.3%. Nineteen patients (0.4%) had a recorded temperature of <35.0°C. An increase in forced-air warming interruption time was significantly associated with an increase in intraoperative hypothermia rates (P<.0001). Patients with interruptions in forced-air warming >20minutes showed significantly higher hypothermia rates than those with interruptions of ≤20minutes (P<.0001). Intraoperative hypothermia rates increased significantly with longer forced-air warming interruptions between pre-warming and intraoperative warming. Short warming interruptions can preserve the effect of pre-warming and are associated with low intraoperative hypothermia rates.

Establishment and Validation of a Prediction Equation to Estimate Risk of Intraoperative Hypothermia in Patients Receiving General Anesthesia

Inadvertent intraoperative hypothermia (core temperature <36 °C) is a frequent but preventable complication of general anesthesia. Accurate risk assessment of individual patients may help physicians identify patients at risk for hypothermia and apply preventive approaches, which include active intraoperative warming. This study aimed to develop and validate a risk-prediction model for intraoperative hypothermia. Two independent observational studies in China, the Beijing Regional Survey and the China National Survey, were conducted in 2013 and 2014, respectively, to determine the incidence of hypothermia and its underlying risk factors. In this study, using data from these two studies, we first derived a risk calculation equation, estimating the predictive risk of hypothermia using National Survey data (3132 patients), then validated the equation using the Beijing Regional Survey data (830 patients). Measures of accuracy, discrimination and calibration were calculated in the validation data set. Through validation, this model, named Predictors Score, had sound overall accuracy (Brier Score = 0.211), good discrimination (C-Statistic = 0.759) and excellent calibration (Hosmer-Lemeshow, P = 0.5611). We conclude that the Predictors Score is a valid predictor of the risk of operative hypothermia and can be used in deciding whether intraoperative warming is a cost-effective measure in preventing the hypothermia.

Intraoperative hypothermia and its clinical outcomes in patients undergoing general anesthesia: National study in China.

Background/ObjectiveInadvertent intraoperative hypothermia (core temperature <36°C) is a frequently preventable complication with several adverse consequences. Our study aimed to determine the overall incidence of inadvertent intraoperative hypothermia and its risk factors associated with clinical outcomes in this national survey in China.MethodsWe conducted a national cross-sectional study with 30 days postoperative follow-up from November 2014 through August 2015. A total of 3132 eligible patients underwent general anesthesia were randomly selected from 28 hospitals in the nationwide of China.ResultsThe overall incidence of intraoperative hypothermia was as high as 44.3%, in which cumulative incidence rates of hypothermia being 17.8%, 36.2%, 42.5% and 44.1% within 1 h, 2 h, 3 h and 4 h respectively following induction of anesthesia. All patients were warmed passively by covering of surgical draping, sheets or cotton blankets, whereas only 14.2% of patients received active warming with space heaters or electric heater or electronic blankets. Compared to normothermic patients, patients with hypothermia is associated with more postoperative ICU admit, longer PACU and more postoperative hospital days, but no difference in surgical site infection (SSI) rates or 30-day mortality. Several factors were shown to be associated with decreased risk of hypothermia. They are active warming (OR = 0.46, 95% CI 0.26–0.81), BMI ≥ 25 (OR = 0.54, 95% CI 0.45–0.65), higher baseline core temperature (OR = 0.04, 95% CI 0.03–0.06), and higher ambient temperature (OR = 0.83, 95% CI 0.78–0.88). Risk factors associated with an increased risk of hypothermia included major-plus surgery (OR = 1.49, 95% CI 1.23–1.79), and long anesthesia (>2 h) (OR = 2.60, 95% CI 2.09–3.24).ConclusionsThe incidence of intraoperative hypothermia in China is high, and the rate of active warming of patients during operation is low. Hypothermia is associated with more postoperative shivering, increased ICU admissions, and longer postoperative hospital days.

Incidence of Inadvertent Intraoperative Hypothermia with Continuous Air Forced Active Warming. Single Center, Retrospective Study

Incidence of Inadvertent Intraoperative Hypothermia with Continuous Air Forced Active Warming. Single Center, Retrospective Study

Incidence of Inadvertent Intraoperative Hypothermia and Its Risk Factors in Patients Undergoing General Anesthesia in Beijing: A Prospective Regional Survey.

Background/ObjectiveInadvertent intraoperative hypothermia (core temperature <360 C) is a recognized risk in surgery and has adverse consequences. However, no data about this complication in China are available. Our study aimed to determine the incidence of inadvertent intraoperative hypothermia and its associated risk factors in a sample of Chinese patients.MethodsWe conducted a regional cross-sectional survey in Beijing from August through December, 2013. Eight hundred thirty patients who underwent various operations under general anesthesia were randomly selected from 24 hospitals through a multistage probability sampling. Multivariate logistic regression analyses were applied to explore the risk factors of developing hypothermia.ResultsThe overall incidence of intraoperative hypothermia was high, 39.9%. All patients were warmed passively with surgical sheets or cotton blankets, whereas only 10.7% of patients received active warming with space heaters or electric blankets. Pre-warmed intravenous fluid were administered to 16.9% of patients, and 34.6% of patients had irrigation of wounds with pre-warmed fluid. Active warming (OR = 0.46, 95% CI 0.26–0.81), overweight or obesity (OR = 0.39, 95% CI 0.28–0.56), high baseline core temperature before anesthesia (OR = 0.08, 95% CI 0.04–0.13), and high ambient temperature (OR = 0.89, 95% CI 0.79–0.98) were significant protective factors for hypothermia. In contrast, major-plus operations (OR = 2.00, 95% CI 1.32–3.04), duration of anesthesia (1–2 h) (OR = 3.23, 95% CI 2.19–4.78) and >2 h (OR = 3.44, 95% CI 1.90–6.22,), and intravenous un-warmed fluid (OR = 2.45, 95% CI 1.45–4.12) significantly increased the risk of hypothermia.ConclusionsThe incidence of inadvertent intraoperative hypothermia in Beijing is high, and the rate of active warming of patients during operation is low. Concern for the development of intraoperative hypothermia should be especially high in patients undergoing major operations, requiring long periods of anesthesia, and receiving un-warmed intravenous fluids.

Methods to prevent intraoperative hypothermia.

Inadvertent intraoperative hypothermia is by far the most commonly occurring anaesthesia-related complication. It can increase the risk of unfavourable events perioperatively. Higher rates of surgical site infections and blood transfusions, coagulation and drug metabolism disturbances are said to be the most relevant issues linked to this phenomenon. Although they have been available for several years now, dedicated systems designed to prevent it are still not part of routine anaesthesia conducted in Poland. This review aims to discuss the factors which may potentially increase the risk of hypothermia, and to present tools that are readily available and effective in perioperative temperature management.