Perioperative hypothermia in patients undergoing major colorectal surgery

Development and Validation of a Predictive Model for Intraoperative Hypothermia in Elderly Patients Undergoing Craniocerebral Tumor Resection: A Retrospective Cohort Study

OBJECTIVE

Timely identification of elderly patients who are at risk of developing intraoperative hypothermia (IH) is imperative to enable appropriate interventions. This study aimed to develop a nomogram for predicting the risk of IH in elderly patients undergoing resection of craniocerebral tumor, and to validate its effectiveness.

METHODS

Elderly patients who underwent craniocerebral tumor resection at a large tertiary hospital in eastern China between January 2019 and December 2022 were included (n = 988). The study population was divided into a training set and a validation set by time period. Risk factors identified through the Least Absolute Shrinkage and Selection Operator method and logistic regression analysis were used to establish the nomogram. The model was validated internally by Bootstrap method and externally by validation set through receiver operating characteristic curve analysis, Hosmer-Lemeshow test, and decision curve analysis.

RESULTS

A total of 273 (27.6%) patients developed IH. Duration of anesthesia (P < 0.001), blood loss (P < 0.001), preoperative temperature (P < 0.001), tumor location (P < 0.001), age (P < 0.05), and mean arterial pressure (P < 0.05) were identified as independent risk factors for IH. A nomogram integrating these 6 factors was constructed. The area under the curve was 0.773 (95% confidence interval: 0.735-0.811) (70.5% specificity and 75.0% sensitivity), indicating good predictive performance. The decision curve analysis demonstrated the clinical benefit of using the nomogram.

CONCLUSIONS

Our model showed good performance in identifying elderly patients who are at high risk of developing IH during craniocerebral tumor resection. The nomogram can help inform timely preventive interventions.

Knowledge and practice of nurses with respect to perioperative hypothermia prevention in the Northwest Amhara Regional State Referral Hospitals, Ethiopia: a cross-sectional study

OBJECTIVES

It has been reported that maintaining a normal body temperature among surgical patients can reduce the length of hospitalisation by up to 40%, decrease the risk of surgical site infection by 64% and reduce mortality by fourfold. Nurses are primarily responsible for preventing the occurrence of hypothermia among surgical patients. This study assessed nurses' knowledge and practices with respect to perioperative hypothermia prevention in Northwest Ethiopia, and investigated the factors associated with good knowledge and practice.

DESIGN

Cross-sectional study.

SETTING

Northwest Amhara Regional State Referral Hospitals, Northwest Ethiopia, 25 March-20 May 2021.

PARTICIPANTS

413 nurses working in the perioperative units of five referral hospitals.

OUTCOME MEASURES

Perioperative hypothermia prevention knowledge and practice among nurses.

RESULTS

Nearly three-fifths (59.1%; 95% CI: 54.7% to 63.7%) of respondents had good knowledge and about half (50.4%; 95% CI: 45.5% to 55.0%) had good practice with respect to perioperative hypothermia prevention. Factors associated with nurses' knowledge of prevention of perioperative hypothermia included male sex (adjusted OR (AOR): 1.61, 95% CI: 1.02 to 2.53), having a bachelor's degree (AOR: 2.50, 95% CI: 1.25 to 5.00), having a master's degree (AOR: 4.39, 95% CI: 1.45 to 13.20) and training participation (AOR: 3.68, 95% CI: 2.14 to 6.33). Factors associated with nurses' practice of prevention of perioperative hypothermia included working in recovery (AOR: 2.87, 95% CI: 1.08 to 7.58) and intensive care units (AOR: 2.39, 95% CI: 1.09 to 5.22), training participation (AOR: 2.64, 95% CI: 1.53 to 4.57), being satisfied with their job (AOR: 2.15, 95% CI: 1.34 to 3.43) and having good knowledge (AOR: 2.64, 95% CI: 1.63 to 4.27).

CONCLUSION

Nurses' knowledge and practice of the prevention of perioperative hypothermia were inadequate. Hospital managers need to design and strengthen training programmes and work to enhance job satisfaction.

Inadvertent Perioperative Hypothermia in Ambulatory Surgery Patients: Incidence, Risk Factors, and Prevention Initiatives

PURPOSE

Although the number and complexity of ambulatory surgical interventions has grown considerably over the years, it has not been fully established whether hypothermia still poses a risk for these interventions. In this study, we aimed to determine the incidence, risk factors, and methods applied to prevent perioperative hypothermia in ambulatory surgery patients.

DESIGN

A descriptive research design was used.

METHODS

The study was conducted with 175 patients between May 2021 and March 2022 in the outpatient units of a training and research hospital in Mersin, Turkey. Data were collected using the Patient Information and Follow-up Form.

FINDINGS

The incidence of perioperative hypothermia was 20% in ambulatory surgery patients. Hypothermia developed in 13.7% of the patients at the 0th minute at the PACU, and 96.6% of the patients were not warmed intraoperatively. We noted a statistically significant relationship between perioperative hypothermia and advanced age (≥60 years), high American Society of Anesthesiologists' (ASA) class, and low hematocrit values. In addition, we determined that the female gender, presence of chronic diseases, general anesthesia, and a long operation time were other risk factors for hypothermia in the perioperative period.

CONCLUSIONS

The incidence of hypothermia during ambulatory surgeries is lower than that in inpatient surgeries. The warming rate of ambulatory surgery patients, which is quite low, can be improved by increasing the awareness of the perioperative team and following the guidelines.

The Effect of Postinduction Blood Glucose on Intraoperative Hypothermia

Background and Objectives: Hypothermia frequently occurs in patients undergoing surgery and is associated with adverse complications. Therefore, this study aimed to investigate the postinduction blood glucose and occurrence of intraoperative hypothermia in patients undergoing laparoscopic surgery. Materials and Methods: This retrospective observational study included 334 patients aged ≥20 years who had undergone elective laparoscopic surgery. The primary outcome of this study was the incidence of intraoperative hypothermia. Stratified analysis revealed differences between patients with and without diabetes. Results: Hypothermia occurred in 200 (59.9%) patients. In multivariate analysis, out-of-range postinduction glucose was independently associated with hypothermia (>150 mg/dL: odds ratio 2.17, 95% confidence interval (1.02, 4.61), p = 0.045; <110 mg/dL: odds ratio 2.02, 95% confidence interval (1.15, 3.55), p = 0.015), whereas preoperative HbA1c >6% was not significantly associated with hypothermia (odds ratio 1.02, 95% confidence interval (0.56, 1.84), p = 0.961). Considering only patients with diabetes, the incidence of hypothermia was lower (p = 0.002), the duration of hypothermia was shorter (p = 0.007), and the minimum temperature was higher (p = 0.006) in those with a postinduction glucose level of 110-150 mg/dL. Conclusions: The postinduction glucose level is independently associated with intraoperative hypothermia. Out-of-range postinduction glucose appeared to have an impact on the development of hypothermia in patients with diabetes, especially those with a postinduction glucose level <110 mg/dL.

A Nomogram for Predicting Unplanned Intraoperative Hypothermia in Patients With Colorectal Cancer Undergoing Laparoscopic Colorectal Procedures

Unplanned intraoperative hypothermia is a complication that can lead to a variety of negative outcomes, such as cardiovascular events. We aimed to develop and validate an intraoperative hypothermia risk prediction nomogram for patients with colorectal cancer undergoing laparoscopic colorectal procedures. We conducted a prospective cohort study with 1,091 patients (ie, 765 in the training cohort, 326 in the validation cohort) from October 2020 to November 2021. We included six predictors in the nomogram model: body mass index, diabetes diagnosis, ambient temperature, ambient humidity, duration of surgery, and use of a forced-air warmer. The model performed well, and the area under the curve was 0.855. These results, together with an external validation value, mean that health care professionals can use the nomogram to calculate the intraoperative hypothermia risk for patients undergoing laparoscopic colorectal procedures and make clinical decisions based on the results.

Nurses' Awareness and Practices of Unintentional Perioperative Hypothermia Prevention: A Cross-Sectional Study

Unintentional perioperative hypothermia can cause potentially life-threatening complications. The aim of this study was to determine the awareness and practices of nurses regarding unintentional perioperative hypothermia prevention. The study was conducted at a teaching hospital in Gambia with descriptive cross-sectional design. A total of 53 nurses voluntarily participated in this study. The questionnaire used in this study was developed based on the American periOperative Registered Nurses (AORN) and National Institute for Health and Care Excellence perioperative hypothermia guidelines. Descriptive statistics, Pearson correlation, Student t-test, and one-way ANOVA were used in the analysis of data. The result of the study showed that nurses had high level of awareness of unintentional perioperative hypothermia prevention; however, practice levels were found to be low. Based on the results of the study, development of policies, implementation of the unintentional perioperative hypothermia prevention guidelines, and continuous education to improve nurses' knowledge and practices were recommended.

Perioperative hypothermia in open and laparoscopic colorectal surgery

BACKGROUND

The consequences of even mild inadvertent perioperative hypothermia (IPH) are significant. There is a perception laparoscopic abdominal surgery is less prone to cause hypothermia than open surgery. However, during laparoscopic surgery, the peritoneal cavity is insufflated with carbon dioxide, which has a greater evaporative capacity than ambient air. This study compared the intra-operative temperature profile of patients undergoing open and laparoscopic colorectal surgery to define the incidence and severity of hypothermia.

METHODS

All adult patients undergoing colorectal surgery between May 2005 and August 2013 were identified from an electronic database. Cases were categorized into laparoscopic and open cases. Hypothermic episodes were defined as a temperature less than 36°C lasting for more than two consecutive minutes. The incidence of hypothermic episodes, the total time under 36°C and the area under the curve (degree-minutes) were calculated.

RESULTS

A total of 1547 cases were analysed. The overall incidence of hypothermia was 67.0%. The incidence of cases with a hypothermic episode was greater in the laparoscopic group compared to the open group (71.23% versus 63.16%; chi-squared P-value 0.001). However, when other factors were considered, there was no significant difference in the relative risk of a hypothermic episode between types of surgery. There were significant differences in the severity of hypothermia.

CONCLUSION

Despite current measures to reduce the incidence, IPH remains a significant problem in colorectal surgery irrespective of the surgical approach. Further research is required to better characterize techniques that can reduce its incidence.

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

Background

Inadvertent 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.

Methods

This 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.

Results

In 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.

Conclusions

Inadvertent 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.

Effect of Forced-Air Warming Blanket on Perioperative Hypothermia in Elderly Patients Undergoing Laparoscopic Radical Resection of Colorectal Cancer

The study aimed to evaluate the effect of forced-air warming blanket combined with conventional thermal insulation measures on inadvertent perioperative hypothermia (IPH) in elderly patients undergoing laparoscopic radical resection of colorectal cancer. A total of 70 elderly patients undergoing laparoscopic radical resection of colorectal cancer with general anesthesia were included, and divided into conventional warming treatment (CT) group or forced-air warming treatment (FT) group. In the FT group, based on the conventional warming strategy, patients received prewarming with the forced-air warming blanket (38°C) for ≥20 minutes before induction of anesthesia, and received this treatment continuously during operation. The core body temperature, recovery time from anesthesia, extubating time, and length of stay in the postanesthesia care unit were recorded. The incidence of IPH and postoperative shivering was observed. The incidence of IPH was significantly lower, and average minimum body temperature during the operation was significantly higher in the FT group than that in the CT group (5.7% vs. 22.8% and 36.23°C vs. 35.89°C, respectively). The intraoperative body temperature decreased less (0.32°C vs. 0.69°C), the recovery time from anesthesia was faster (12.8 minutes vs. 17.1 minutes), and the incidence of postoperative shivering was less (2.8% vs. 28.6%) in the FT group than the CT group. In elderly patients undergoing laparoscopic radical resection of colorectal cancer, use of forced-air warming blankets combined with conventional warming measures is more effective to maintain normal body temperature during the perioperative period and reduce the incidence of IPH.

Study of risk factors for intraoperative hypothermia during pediatric burn surgery

Background

Intraoperative hypothermia (core temperature <36.0°C) is common during the perioperative period and can result in adverse consequences, especially in children. We aimed to determine the incidence of intraoperative hypothermia and its risk factors in pediatric patients during burn surgery.

Methods

In the present study we enrolled 197 pediatric patients with burn injury undergoing surgical debridement and skin grafting. Factors, such as total burn surface area (TBSA), were collected and analyzed to identify the potential risk factors for intraoperative hypothermia.

Results

The incidence of intraoperative hypothermia among all patients was 17.8%. Compared with patients with normothermia, children with hypothermia were associated with larger TBSA (25% vs 15%, p<0.001) and with less intraoperative active warming (34.28% vs 54.93%, p<0.05). In addition, compared with patients with moderate-degree burn, patients with severe and extremely severe burn were associated with much higher risk of intraoperative hypothermia [severe: odds ratio (OR)=3.805, 95% confidence interval (CI)=1.396-10.368, p=0.009; extremely severe: OR=6.933, 95% CI=2.604-18.462, p<0.001]. TBSA was the only independent risk factor that emerged as being strongly associated with intraoperative hypothermia (OR=1.068, p=0.001) and could be used to predict the occurrence of hypothermia when combined with other factors. TBSA for predicting intraoperative hypothermia by receiver operating characteristic (ROC) curve analysis showed a good predictive ability with an area under the ROC curve of 0.758.

Conclusion

TBSA is an important risk factor for intraoperative hypothermia in pediatric patients with burn.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Incidence of Unintentional Intraoperative Hypothermia in Pediatric Scoliosis Surgery and Associated Preoperative Risk Factors

Introduction

Intraoperative hypothermia is associated with perioperative complications such as blood loss and wound infection. Thus, perioperative heat retention methods to prevent perioperative hypothermia such as providing a warmed blanket and active patients' warming are important. Although major surgery and pediatric patient age are noted as risk factors, only a few studies focus on hypothermia as an intraoperative complication in pediatric scoliosis surgery. The aim of this study is to investigate the incidence of intraoperative hypothermia in pediatric scoliosis surgery and the associated preoperative risk factors.

Methods

We retrospectively reviewed the records of pediatric patients who underwent posterior spinal fusion at a single institution between 2015 and 2019. We recorded the background data, perioperative data, lowest recorded core temperature, and perioperative complications. Patients were divided into those whose temperature decreased below 36°C (Group H) and those who maintained a temperature of 36°C or greater (Group N) during surgery. We compared the two groups and performed multivariate analysis to identify preoperative risk factors for intraoperative hypothermia.

Results

A total of 103 patients underwent posterior spinal fusion; 56 for adolescent idiopathic scoliosis and 47 for neuromuscular scoliosis. Hypothermia was observed in 40 patients (38.8%). Group H had more non-adolescent idiopathic scoliosis (AIS) patients, lower mean body mass index, greater mean blood loss, greater number of fused vertebrae, larger preoperative Cobb angle, and lower initial core body temperature (immediately after induction of anesthesia). On multivariate analysis, a diagnosis of neuromuscular scoliosis, a lower body mass index, and a lower initial core body temperature were identified as independent risk factors for intraoperative hypothermia.

Conclusions

The incidence of hypothermia in pediatric posterior scoliosis surgery is 38.8%. Diagnosis of non-AIS, lower body mass index, and lower core body temperature at the time of anesthesia induction are preoperative risk factors for intraoperative hypothermia.

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.

Randomized clinical study comparing active heating methods for prevention of intraoperative hypothermia in gastroenterology

OBJECTIVE

to compare the efficacy of three active heating methods in the prevention of intraoperative hypothermia in open gastroenterological surgeries.

METHOD

randomized clinical trial with a sample of 75 patients, whose initial body temperature measured by a tympanic thermometer. Esophageal temperature <36ºC was considered hypothermic. Patients were divided into three groups using: thermal mattress, underbody forced-air warming blanket and heated infusion system. The tympanic and esophageal temperatures were measured at different times of the intraoperative period, but the temperature considered gold standard was the esophageal. To evaluate the homogeneity of the groups, we used chi-square test (categorical variables). In the comparison of temperature measurements over time, the analysis of variance (ANOVA) and the contrast profile test were used for the difference in temperature between the times. The non-parametric Kruskal-Wallis test was used to compare the three groups. The level of significance was 5%.

RESULTS

regarding the studied variables, the groups were not homogeneous as to the categorical variable sex. All patients presented hypothermia during the intraoperative period (p> 0.05).

CONCLUSION

there was no significant difference between the heating methods in the prevention of intraoperative hypothermia. REBEC - Brazilian Registry of Clinical Trials (RBR- no. 52shjp).

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.

Clinical practice guideline. Unintentional perioperative hypothermia

The importance of the safety of our patients in the surgical theatre, has driven many projects. The majority of them aimed at better control and clinical performance; mainly of the variables that intervene or modulate the results of surgical procedures, and have a direct relationship with them. The Spanish Society of Anesthesiology, Critical Care and Therapeutic Pain (SEDAR), maintains a constant concern for a variable that clearly determines the outcomes of our clinical processes, "unintentional hypothermia" that develops in all patients undergoing an anesthetic or surgical procedure. SEDAR has promoted, in collaboration with other scientific Societies and patient Associations, the elaboration of this clinical practice guideline, which aims to answer clinical questions not yet resolved and for which, up to now, there are no documents based in the best scientific evidence available. With GRADE methodology and technical assistance from the Ibero-American Cochrane Collaboration office, this clinical practice guideline presents three recommendations (weak in favor) for active heating methods for the prevention of hypothermia (skin, fluid or gas); three for the prioritization of strategies for the prevention of hypothermia (too weak in favor and one strongly in favor); two of preheating strategies prior to anesthetic induction (both weak in favor); and two for research.

Control of body temperature and immune function in patients undergoing open surgery for gastric cancer

The influence of mild perioperative hypothermia on the immune function and incidence of postoperative wound infections has been suggested, but the specific mechanism is unclear. This study aimed to analyze the body temperature, immune function, and wound infection rates in patients receiving open surgery for gastric cancer. Body temperature was controlled in each patient using one of four different methods: wrapping limbs, head and neck; insulated blankets; warming infusion fluids and insulated blankets; and warming fluids without insulated blankets. One hundred patients were randomly divided into four groups of 25 patients each, and every group received a different intraoperative treatment for maintaining normal body temperature. Nasopharyngeal and rectal temperatures, transforming growth factor beta (TGF-β), interleukin 10 (IL-10) levels, and cluster of differentiation (CD)3+T and CD4+/CD25+ regulatory T cell (Treg) counts were measured before surgery and at 2 and 4 hours postoperatively. Patients were evaluated at one week after surgery for signs of infection. Intraoperative body temperature and measures of immune function varied significantly between the four groups, with the largest temperature changes observed in the group in which only the limbs were wrapped in cotton pads to control the body temperature. The lowest temperature change (i.e., close to normal temperature) and cytokine response after surgery were observed in the group in which infusion fluids and transfused blood (if needed) were heated to 37℃, peritoneal irrigation fluid was heated to 37℃, and an insulation blanket was heated to 39℃ and placed under the patient. No intergroup differences were found in the infection rates at one week after surgery. In conclusion, body temperature variation during surgery affects the immune function of patients, and maintaining body temperature close to normal results in the least variation of immune function.

Effect of "An Innovative Technology" Active Warming and Passive Warming on Unplanned Hypothermia During Perioperative Period: A Clinical Trial

Patients are at risk for unplanned hypothermia during the perioperative period due to many reasons, including anesthesia, low room temperature, cold intravenous fluid, and blood transfusion. This study was conducted to examine the effect of active and passive warming methods applied in patients during the perioperative period on unplanned hypothermia. This study is a case-control type study. The population of this study is composed of the patients hospitalized in surgical clinic and undergone abdominal region-related operations. Ninety patients were accidentally included in the study. The first group of patients were actively warmed during the perioperative period (carbon fiber resistive system - W-500D + 190 × 50 cm), the second group was passively warmed at least for 20 minutes during preoperative period (with blanket, socks etc.), and the third group was followed up as the control group. It was established that body temperature average of the active warming group has significantly increased during perioperative period (p < 0.001), and this temperature was significantly higher than the other groups until the third hour. It was found that the body temperature average of all groups was equal to 36.2 ± 0.26, 35.4 ± 0.49, and 35.2 ± 0.47, respectively, at the end of operation, and the difference among them was statistically significant (p ≤ 0.001). The active warming method applied with carbon fiber resistive system during the perioperative period is an effective method.

Warming of Irrigation Fluids for Prevention of Perioperative Hypothermia During Arthroscopy: A Systematic Review and Meta-analysis

PURPOSE

To determine whether warming of irrigation fluids (32°C-40°C) compared with using room-temperature irrigation fluids (20°C-22°C) decreases the risk of perioperative hypothermia (<36°C) for patients undergoing shoulder, hip, or knee arthroscopy.

METHODS

One reviewer, with the assistance of a medical librarian, searched the following databases: PubMed, Embase, Cochrane Central, SPORTDiscus, Web of Science, and CINAHL (Cumulative Index to Nursing and Allied Health Literature). Level I and II studies involving shoulder, hip, or knee arthroscopy were included. Two reviewers screened the abstracts and titles. Two reviewers assessed the risk of bias of selected studies using The Cochrane Collaboration tool. Meta-analyses were conducted on the following outcomes: hypothermia, lowest temperature, maximum temperature drop, and shivering.

RESULTS

Seven studies of patients undergoing arthroscopy were included in the qualitative synthesis (5 shoulder studies, 1 hip study, and 1 knee study; 501 patients). The study involving knee arthroscopy was excluded from the meta-analyses because of insufficient data and high clinical heterogeneity (surgical site distal to the core, not involving extravasation of large amounts of fluid). The remaining 6 studies were included in 1 or more meta-analyses: hypothermia (5 shoulder and 1 hip study), lowest temperature (3 shoulder and 1 hip study), maximum temperature drop (2 shoulder and 1 hip study), and shivering (5 shoulder and 1 hip study). Warming of irrigation fluids for shoulder or hip arthroscopy significantly decreased the risk of hypothermia (odds ratio, 0.15; 95% confidence interval [CI], 0.06-0.40; P = .0001), increased the lowest mean temperature (mean difference, 0.46°C; 95% CI, 0.11°C-0.81°C; P = .01), decreased the maximum temperature drop (mean difference, -0.64°C; 95% CI, -0.94°C to -0.35°C; P < .0001), and decreased the risk of shivering (odds ratio, 0.25; 95% CI, 0.07-0.86; P = .03).

CONCLUSIONS

When irrigation fluids are warmed for shoulder and hip arthroscopy, the risk of hypothermia is less, the drop in intraoperative temperature is less, the lowest body temperature is higher, and the risk of postoperative shivering is reduced.

LEVEL OF EVIDENCE

Level II, systematic review of Level I and II studies.

Effect of preoperative combined warming strategy on body temperature and recovery quality in patients undergoing major abdominal surgeries

AIM

To explore the effects of preoperative combined warming strategy on body temperature and recovery quality in patients undergoing major abdominal surgeries.

METHODS

Sixty patients scheduled for elective major abdominal surgeries under general anesthesia were randomly divided into either a control group (n = 30) or an observation group (n = 30). The preoperative combined warming strategy consisting of warming blanket and infusion warming was applied in the observation group, while quilt warming was applied in the control group. All patients stayed in the preoperative preparation room for at least 30 min. Data recorded and compared between the two groups included general clinical information, the total time of operation, total fluid infusion and output volume, the change of body temperature at various time points, and the adverse events related to recovery period.

RESULTS

There was no significant difference in operative time, total fluid infusion and output volume, anesthesia extubation time, amount of drainage, incidence of restlessness, or body temperature at T0 between the two groups. Compared with baseline body temperature at T0, the temperatures at T2-T6 were significantly lower in the control group, while the temperature at T1-T2 was significantly higher in the observation group. Compared with body temperature at T1, the temperatures at T2-T6 in the control group and those at T3-T6 in the observation group were significantly lower (P < 0.05). Compared with the observation group, the temperatures at T1-T6 in the control group were significantly lower, and the incidence rates of intraoperative hypothermia and postoperative shivering were significantly increased (P < 0.05).

CONCLUSION

Preoperative combined warming strategy can significantly prevent the occurrence of hypothermia and improve the quality of recovery in patients undergoing major abdominal surgery.

Predictive factors of maternal hypothermia during Cesarean delivery: a prospective cohort study

PURPOSE

Although perioperative hypothermia may increase maternal morbidity, active warming is infrequently performed to maintain normothermia during Cesarean delivery (CD). The aim of this prospective observational study was to determine the factors associated with maternal hypothermia in this setting.

METHODS

Women scheduled for elective or emergency CD were consecutively included in this study from November 2014 to October 2015. Maternal temperature was measured using an infrared tympanic thermometer on the patient's arrival in the operating room, at skin incision, and at the end of skin suture. Maternal hypothermia was defined by tympanic temperature < 36°C at the end of skin suture. Univariate analysis was performed, followed by multivariate logistic regression analysis, in order to determine the factors associated with maternal hypothermia at the end of the surgery.

RESULTS

Three hundred fifty-nine women were included and analyzed during this study. The incidence of hypothermia was 23% (95% confidence interval, 18 to 27) among the total population included. According to multivariate analysis, obesity, oxytocin augmentation of labour, and use of active forced-air warming were associated with a decreased risk of maternal hypothermia, while maternal temperature < 37.1°C on arrival in the operating room, maternal temperature < 36.6°C at skin incision, and an infused volume of fluids > 650 mL were significantly associated with maternal hypothermia. Both goodness of fit and predictive value of multivariate analysis were high.

CONCLUSION

Several predictive factors for maternal hypothermia during CD were identified. These factors should be taken into account to help prevent maternal hypothermia during CD.

Forced-Air Warming for Rewarming and Comfort Following Laparoscopy: A Randomized Controlled Trail

We investigated the efficacy of a forced-air warming (FAW) system on postoperative rewarming and comfort in patients undergoing laparoscopic surgery. In this randomized controlled trial, a total of 127 participants were randomly divided into the FAW group ( n = 64) and control group ( n = 63). The esophageal temperature was measured every 30 min during surgery, and the tympanic temperature and comfort levels were measured preoperatively and in the postanesthesia care unit (PACU). Data analysis used the generalized estimating equation. We found that there was a lower incidence of postoperative hypothermia in the FAW group compared with the control group, as well as a higher body temperature between 30 and 180 min in the PACU, a shorter time for rewarming, and a higher comfort level. Taken together, these results suggest that FAW is an effective rewarming technique for laparoscopic patients during surgery and in the PACU that improves comfort levels.

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.

Intraoperative modifiable risk factors of colorectal anastomotic leakage: Why surgeons and anesthesiologists should act together

BACKGROUND

Colorectal anastomotic leakage (CAL) is a major surgical complication in intestinal surgery. Despite many optimizations in patient care, the incidence of CAL is stable (3-19%) [1]. Previous research mainly focused on determining patient and surgery related risk factors. Intraoperative non-surgery related risk factors for anastomotic healing also contribute to surgical outcome. This review offers an overview of potential modifiable risk factors that may play a role during the operation.

METHODS

Two independent literature searches were performed using EMBASE, Pubmed and Cochrane databases. Both clinical and experimental studies published in English from 1985 to August 2015 were included. The main outcome measure was the risk of anastomotic leakage and other postoperative complications during colorectal surgery. Determined risk factors of CAL were stated as strong evidence (level I and II high quality studies), and potential risk factors as either moderate evidence (experimental studies level III), or weak evidence (level IV or V studies).

RESULTS

The final analysis included 117 articles. Independent factors of CAL are diabetes mellitus, hyperglycemia and a high HbA1c, anemia, blood loss, blood transfusions, prolonged operating time, intraoperative events and contamination and a lack of antibiotics. Unequivocal are data on blood pressure, the use of inotropes/vasopressors, oxygen suppletion, type of analgesia and goal directed fluid therapy. No studies could be found identifying the impact of body core temperature or mean arterial pressure on CAL. Subjective factors such as the surgeons' own assessment of local perfusion and visibility of the operating field have not been the subject of relevant studies for occurrence in patients with CAL.

CONCLUSION

Both surgery related and non-surgery related risk factors that can be modified must be identified to improve colorectal care. Surgeons and anesthesiologists should cooperate on these items in their continuous effort to reduce the number of CAL. A registration study determining individual intraoperative risk factors of CAL is currently performed as a multicenter cohort study in the Netherlands.

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

Background/Objective

Inadvertent 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.

Methods

We 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.

Results

The 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.

Conclusions

The 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.

TRPA1 mediates the effects of hypothermia on the monocyte inflammatory response

INTRODUCTION

Hypothermia is a well-known risk factor for postoperative complications because it prolongs the monocyte inflammatory response. The purpose of this study was to investigate whether temperature-activated ion channels (transient receptor protein channels [TRP] A1 and V1) mediate the effects of temperature on monocytes.

METHODS

Primary human monocytes were isolated and stimulated with lipopolysaccharide at 32°C or 39°C. RNA was isolated for analysis of microRNA (miR)-155 expression, and cytokines in the supernatant were measured with an enzyme-linked immunosorbent assay. Specific inhibitors of TRPA1 (HC- 030031) and a specific activator of TRPV1 (capsaicin) were used to block or activate TRPA1 and TRPV1, respectively. Statistical analysis was performed using the Wilcoxon signed-rank test.

RESULTS

TRPM8 mRNA was not expressed in primary human monocytes, whereas TRPA1 and TRPV1 were expressed. TRPV1 mRNA expression was suppressed at 32°C but not at 39°C. TRPA1 was induced strongly at 32°C and 39°C. Immunofluorescence microscopy confirmed that monocytes express TRPA1 and TRPV1 on their cell surface. Interleukin-10 secretion was increased by blocking TRPA1 (77.8 ± 3 2.8 pg/mL) and activating TRPA1 (79.4 ± 16.1 pg/mL) after 24 hours at 32°C (control 37.4 ± 17.1 pg/mL, P < .05). At 36 hours, tumor necrosis factor secretion was decreased after TRPA1 blockade (2,321 ± 439 pg/mL) and TRPV1 activation (2,137 ± 411 pg/mL) compared with control (2,567 ± 495 pg/mL, P < .05). Furthermore, miR-155 expression also was suppressed at 24 hours by TRPA1 blockade and TRPV1 activation (both P < .05). Silencing of TRPA1 normalized monocyte IL-10 secretion at 32°C.

CONCLUSION

These results demonstrate that hypothermia mediates its effects on monocytes through TRPA1. Blockade of TRPA1 or activation of TRPV1 may be used to modify the effects of hypothermia on the monocyte inflammatory response.

Unintentional perioperative hypothermia is associated with severe complications and high mortality in elective operations

INTRODUCTION

Hypothermia occurs in as many as 7% of elective colorectal operations and is an underestimated risk factor for complications and death. Rewarming of hypothermic patients alone is not sufficient to prevent such adverse events. We investigated the outcomes of patients who became hypothermic (<35°C) after elective operations and compared them with closely matched, nonhypothermic operative patients to better define the impact of hypothermia on surgical outcomes, as well as to identify independent risk factors for hypothermia.

METHODS

We queried the University HealthSystem Consortium (UHC) database for elective operative patients who became unintentionally hypothermic from October 2008 to March 2012, and identified 707 patients. Exclusion criteria were deliberate hypothermia, age <18 years, or death on day of admission. Separately, to validate the accuracy of hypothermia coding, we reviewed the hospital charts of all University of Louisville Hospital patients with hypothermia whose data were submitted to UHC.

RESULTS

All patients from UHC with a code for hypothermia were indeed unintentionally hypothermic. Hypothermic patients undergoing elective operations experienced a 4-fold increase in mortality (17.0% vs 4.0%; P < .001) and a doubled complication rate (26.3% vs 13.9%; P < .001), in which sepsis and stroke increased the most. Several independent risk factors for hypothermia were amenable to preoperative improvement: anemia, chronic renal impairment, and unintended weight loss. Severity of illness on admission, age >65 years, male sex, and neurologic disorders also were risk factors.

CONCLUSION

Hypothermia is associated with an increased rate of mortality and complications. Preventive treatment of these risk factors before operation and aggressive warming measures in the "at risk" population may decrease hypothermia-related morbidity and mortality in elective operations. Randomized-controlled trials should be conducted to evaluate the impact of aggressive warming measures in the at-risk population.