Effects of different forced-air warming systems on the core temperature of patients: a manikin and multi-center clinical study.

BACKGROUND: The use of forced-air warming (FAW) blankets is widely recognized for preventing shivering and hypothermia in patients under general anesthesia. Various types of products are currently available for hospitals, and we have conducted a preliminary evaluation of insulation equipment based on expert opinions and initial parameters. However, we lack real-world experiments and accurate clinical data to validate these parameters and the accuracy of our decision-making results. This study aims to confirm the effectiveness of different FAW systems by assessing the thermal protection and operational characteristics of the equipment in both experimental and clinical settings, thereby enhancing our evaluation database. METHODS: In the manikin test, we conducted six tests including heat distribution and heating rate, heater outlet temperature stability, etc. In the clinical study, patients were randomly assigned to four groups [Group A (Bair Hugger Therapy, 3 M, St. Paul, MN, USA; 63500); Group B (EQUATOR® level I, Smith Medical ASD, MN, USA; Snuggle Warm, SW-2013); Group C (Jiang Men Da Cheng Medical Devices Co., Ltd, China; IOB-006); and Group D (Shang Hai Nest Tech Medical Materials Co., Ltd, China; BH-017)], with each group comprising 30 individuals. At the start of anesthesia induction, the FAW blanket was activated and set to 43 °C until the completion of surgery. The primary endpoint was the average core body temperature during surgery. Secondary endpoints included hemodynamic and surgical variables, adverse events, and recovery metrics. RESULTS: In the manikin test, the observed results of the experimental parameters (heat distribution, air pressure difference, and hole observation test) for Group A are superior to those of the other groups. In the clinical study, although the mean perioperative core body temperature remained above 36 °C across all groups [Group A: 36.31 ± 0.04; Group B: 36.26 ± 0.06; Group C: 36.17 ± 0.03; Group D: 36.25 ± 0.05], patients in Group A maintained higher temperatures compared to the other groups (p < 0.001). CONCLUSIONS: Among patients undergoing laparoscopic radical resection of colorectal cancer with general anesthesia, all four FAW systems effectively prevented perioperative hypothermia. However, the system in Group A minimized heat loss more effectively than the others, providing superior thermal protection. TRIAL REGISTRATION: ChiCTR2200065394, 03/11/2022.

Comparison of prewarming plus intraoperative warming with intraoperative warming alone in patients undergoing minimally invasive thoracic or abdominal surgery: A systematic review and meta-analysis.

OBJECTIVE: Prewarming has been recommended to reduce intraoperative hypothermia. However, the evidence is unclear. This review examined if prewarming can prevent intraoperative hypothermia in patients undergoing thoracoscopic and laparoscopic surgeries. METHODS: PubMed, CENTRAL, Web of Science, and Embase databases were searched for randomized controlled trials (RCTs) up to 15th January 2024. The primary outcome of interest was the difference in intraoperative core temperature. The secondary outcomes were intraoperative hypothermia (<36°) and postoperative shivering. RESULTS: Seven RCTs were eligible. Meta-analysis showed that intraoperative core temperature was significantly higher at the start or within 30mins of the start of the surgery (MD: 0.32 95% CI: 0.15, 0.50 I2 = 94% p = 0.0003), 60 mins after the start of the surgery (MD: 0.37 95% CI: 0.24, 0.50 I2 = 81% p<0.00001), 120 mins after the start of the surgery (MD: 0.34 95% CI: 0.12, 0.56 I2 = 88% p = 0.003), and at the end of the surgery (MD: 0.35 95% CI: 0.25, 0.45 I2 = 61% p<0.00001). The incidence of shivering was also significantly lower in the prewarming group (OR: 0.18 95% CI: 0.08, 0.43 I2 = 0%). Prewarming was also associated with a significant reduction in the risk of hypothermia (OR: 0.20 95% CI: 0.10, 0.41 I2 = 0% p<0.0001). The certainty of the evidence assessed by GRADE was "moderate" for intraoperative core temperatures at all time points and "low" for minimal intraoperative core temperature, shivering, and hypothermia. CONCLUSION: Moderate to low-quality evidence shows that prewarming combined with intraoperative warming, as compared to intraoperative warming alone, can improve intraoperative temperature control and reduce the risk of hypothermia and shivering in patients undergoing thoracoscopic and laparoscopic procedures.

Effect of Perioperative Active Warming on Postoperative Pain and Shivering in Preschool Pediatric Patients: A Randomized Controlled Trial.

OBJECTIVE: To evaluate the effects of perioperative active warming on the core body temperature, postoperative pain, shivering and agitation in pediatric patients. METHOD: Children aged 2-6 years undergoing elective surgery, including orthopedic soft tissue surgeries, ear nose throat surgical procedures and general surgical interventions, all performed under general anesthesia, were randomized to receive either active warming (using the forced-air warming gowns, Bair Hugger, in the pre- and postoperative period, and a carbon fiber blanket in intraoperative period; Group A), or conventional warming using green blankets pre-and post-operatively and a carbon fiber blanket intraoperatively (Group B). Children undergoing emergency surgery, surgeries involving major body cavities (abdominal, thoracic, cranial surgery), or those with endocrinological pathologies, or baseline fever, were excluded. Core body temperature (t-core), postoperative pain, shivering and agitation scores were compared between the two groups. RESULTS: Seventy children were included, with 35 in each group. No significant difference was observed between the groups in t-core values at 0 and 15 minutes preoperatively (P > 0.05). However, the value at 30 minutes preoperatively and all subsequent t-core values were higher in Group A (P < 0.001). Postoperative pain and shivering scores at 0 minutes, 30 minutes and 6 hours were significantly lower in Group A compared to Group B. No significant difference was observed in agitation scores in the immediate postoperative period, although, Group A showed reduced agitation at 30 minutes (P = 0.03). CONCLUSION: Active warming in the pre- and post-operative period significantly maintained higher core temperatures and reduced postoperative pain and shivering in children undergoing surgery compared to those receiving conventional passive warming measures in the pre- and post-operative period.

Impact of intraoperative hypothermia on the recovery period of anesthesia in elderly patients undergoing abdominal surgery.

BACKGROUND: This study aimed to investigate the impact of intraoperative hypothermia on the recovery period of anesthesia in elderly patients undergoing abdominal surgery. METHODS: A prospective observational study was conducted based on inclusion and exclusion criteria. A total of 384 elderly patients undergoing abdominal surgery under general anesthesia were enrolled in a grade A tertiary hospital in Chengdu, Sichuan Province from October 2021 and October 2022. After anesthesia induction, inflatable warming blankets were routinely used for active heat preservation, and nasopharyngeal temperature was monitored to observe the occurrence of intraoperative hypothermia. Patients were divided into hypothermia group and nonhypothermia group according to whether hypothermia occurred during the operation. Anesthesia recovery time and the incidence of adverse events or unwanted events during anesthesia recovery between the two groups were compared. RESULTS: The numbers (percentage) of 384 patients who underwent abdominal surgery developed intraoperative hypothermia occurred in 240 (62.5%) patients, all of whom had mild hypothermia. There were statistically significant differences between mild hypothermia after active warming and nonhypothermia in the occurrence of shivering (χ2 = 5.197, P = 0.023) and anesthesia recovery time (Z = -2.269, P = 0.02) in elderly patients undergoing abdominal surgery during anesthesia recovery, and there were no statistically significant differences in hypoxemia, nausea or vomiting, hypertension, hypokalemia, hypocalcemia, analgesic drug use,postoperative wound infection or postoperative hospitalization days. CONCLUSIONS: The incidence of intraoperative mild hypothermia after active warming was high in elderly patients who underwent abdominal surgery. Mild hypothermia increased the incidence of shivering and prolonged anesthesia recovery time in elderly patients undergoing abdominal surgery.

The Effect of Granisetron, Ondansetron, and Meperidine in Preventing Postoperative Shivering: Controlled Clinical Trial.

BACKGROUND: Recently, use of HT35 receptor antagonists to prevent postoperative shivering has attracted a great deal of attention. This study was conducted with the aim of investigating the effectiveness of granisetron as an HT35 antagonist when compared with ondansetron and meperidine in preventing postoperative shivering. MATERIAL AND METHODS: In this triple blind random clinical trial study, 90 patients 18-50 years of age with ASA Class I and II undergoing general anesthesia were randomly assigned into one of the three drug groups: O (4-mg ondansetron), G (40 µg/kg of granisetron), and P (25 mg meperidine), immediately before induction of anesthesia. After anesthesia induction, at the end of the surgery, after the entrance and after leaving the recovery state, central temperature, peripheral temperature, heart rate, systolic blood pressure, diastolic blood pressure, and shivering were measured and documented. Two-tailed P < 0.05 was considered significant. RESULTS: In the meperidine, ondansetron, and granisetron groups, 4 (13.3%), 3 (10%), and 10 (33.3%) of patients experienced shivering during recovery, where the difference between the ondansetron and granisetron groups was significant (p-value=0.02). The variations in the mean arterial pressure during the investigation stages only in the ondansetron group were not significant (p>0.05). At the beginning of recovery, the reduction of peripheral temperature significantly was lower in the ondansetron group (p<0.05), while reduction of the central temperature was significantly (p<0.05) higher in the granisetron group. By the end of the recovery, the variations in the peripheral temperature across the three groups were consistent with the changes at the beginning of recovery, but variations of the central temperature across the three groups was not significantly diverse. CONCLUSION: Granisetron was not found to be much effective in preventing postoperative shivering. Ondansetron and meperidine were equally effective in preventing postoperative shivering. Ondansetron also causes less hemodynamic changes compared to other drugs, while granisetron is more effective in terms of preventing nausea and vomiting.

The Effect of Clonidine Premedication on Hemodynamic Changes Following Tracheal Intubation and Co2 Gas Insufflation and Postoperative Shivering In Patients Undergoing Laparoscopic Cholecystectomy; a Randomized Clinical Trial.

BACKGROUND: Laparoscopic cholecystectomy is a proper treatment for cholecystitis but the Carbon dioxide gas which is used in surgery stimulates the sympathetic system and causes hemodynamic changes and postoperative shivering in patients undergoing operations. This study was conducted to evaluate the effects of clonidine on reducing hemodynamic changes during tracheal intubation and Carbon dioxide gas insufflation and postoperative shivering in patients undergoing laparoscopic cholecystectomy. MATERIAL AND METHODS: This prospective, randomized, triple-blind clinical trial was conducted on 60 patients between the 18-70 years-old age group, who were candidates of laparoscopic cholecystectomy surgery. The patients randomized into two groups (30 patients received 150 µg oral clonidine) and 30 patients received 100 mg oral Vitamin C). Heart rate and mean arterial pressure of patients were recorded before anesthesia, before and after laryngoscopy, before and after Carbon dioxide gas insufflation. Data were analyzed using Chi-2, student t-test, and analysis of variance by repeated measure considering at a significant level less than 0.05. RESULTS: The findings of this study showed that both heart rate and mean arterial pressure in clonidine group after tracheal intubation and Carbon dioxide gas insufflation were lower than patients in the placebo group, but there was not any statistically significant difference between the two groups (p>0.05) and also postoperative shivering was not different in groups. There was no significant statistical difference in postoperative shivering between the two groups (p>0.05). CONCLUSION: Using 150 µg oral clonidine as a cheap and affordable premedication in patients undergoing laparoscopic cholecystectomy improves hemodynamic stability during operation.

The Effect of Warmed Serum on Shivering and Recovery Period of Patients Under General and Spinal Anesthesia: A Randomized Clinical Trial.

PURPOSE: Postoperative hypothermia followed by shivering is a common phenomenon in patients undergoing surgery under anesthesia, and should be prevented and treated in postoperative patient care units. This study was conducted to investigate the effect of warmed serum injection on postoperative shivering and recovery period of patients operated under general and spinal anesthesia. DESIGN: In this clinical trial, patients to be operated on under general and spinal anesthesia were randomly assigned into two groups of test and control. In the test group, patients received warmed intravenous fluids and blood products. All patients were monitored to record vital signs, incidences of hypothermia and shivering, and recovery period. METHODS: The collected data were analyzed with repeated measures analysis of variance to detect significant differences between groups and significant changes within groups over time. FINDINGS: The incidence of nausea, vomiting, and shivering in the intervention and control groups was (4.7%, 42%), (2.8%, 16.8%), and (6.6%, 43%), respectively. Patients in the intervention group had higher body temperature than the control group (<0.001). Also, patients under spinal anesthesia had higher body temperature than patients under general anesthesia (<0.001). Blood pressure reduction was also significantly higher in the control group than in the intervention group. The patients who received warm intravenous serum, and especially those who had received spinal anesthesia spent less time in the recovery room (<0.001). CONCLUSIONS: The use of warmed intravenous serum increased the patients' core temperature, reduced their postoperative shivering, and shortened their recovery period. Considering the potential risks associated with hypothermia, using such methods for hypothermia prevention can be highly effective in preventing shivering and prolongation of the recovery period and other potential complications. Anesthesia specialists and technicians are therefore encouraged to use this method as a preventive measure.

Effects of ketamine, granisetron and dexmedetomidine on postoperative shivering and hemodynamic changes after general anesthesia: a double-blind randomized clinical trial.

Postoperative shivering is one of the most common complications of surgeries. The current research compared the effects of ketamine, granisetron, and dexmedetomidine on reducing postoperative shivering after general anesthesia. This double-blind clinical trial enrolled 148 patients (39.08 ± 5.99 years old) who had been admitted to Vali-Asr Hospital of Arak, Iran in 2019-2021. The study drugs, including dexmedetomidine, ketamine, granisetron and normal saline, were administered in corresponding groups 30 minutes before the end of surgery. The results showed that dexmedetomidine reduced mean arterial pressure and heart rate in patients. The lowest incidence of shivering was observed in the dexmedetomidine group and it increased the duration of recovery. Overall, dexmedetomidine is recommended to reduce postoperative shivering after general anesthesia, but the increase in duration of recovery should be considered.

Examining the efficacy of intravenous ibuprofen and meperidine for preventing post-operative shivering after laparoscopic cholecystectomy with general anesthesia.

Postoperative shivering is a common complication that can lead to increased postoperative complications. This study aimed to compare the effectiveness of intravenous ibuprofen and meperidine in preventing shivering following laparoscopic cholecystectomy. A total of 120 patients, aged 20-70 and classified as ASA I-II, were enrolled in this triple-blind clinical trial. The participants were randomly assigned to one of three groups: ibuprofen (800mg IV), meperidine (30 mg), or placebo (normal saline 2 ml), administered 30 minutes before the end of surgery. The occurrence of postoperative shivering was assessed and recorded at regular intervals (0, 5, 10, 15, 30, and 60 minutes after surgery). Additionally, postoperative pain levels were measured using a visual analog scale (VAS), sedation levels were evaluated using the Ramsay Sedation Scale (RSS), and the incidence of postoperative nausea and vomiting was documented. The prevalence and severity of postoperative shivering were not statistically significant between groups. The VAS was significantly lower in the meperidine group than the ibuprofen group throughout the study (p <0.001). The VAS was significantly lower in the ibuprofen group than the placebo group at 0 and 15 minutes after surgery. Although the incidence of nausea was slightly higher in the meperidine group, the difference was not statistically significant (p=0.75). Sedation scores were consistently lower in the ibuprofen group and higher in the meperidine group compared to the other groups (p<0.0001) The meperidine group had a significantly higher sedation score indicative of deep sleepiness (score of 4) than the other groups. Intravenous ibuprofen demonstrated comparable efficacy to meperidine in controlling shivering. Additionally, the incidence of nausea, vomiting, and sleepiness was lower in the intravenous ibuprofen group, suggesting it is a potential alternative to meperidine.

Effects of a forced-air warming system and warmed intravenous fluids on hemodynamic parameters, shivering, and time to awakening in elderly patients undergoing open cardiac surgery.

Background: As one of the most common postoperative complications, hypothermia is the main cause of numerous problems during treatment, especially in elderly patients with decreased cardiac reserves. Objectives: The aim of the present study was to compare the effects of forced-air warming system (FAWS), warmed intravenous fluids (WIVFs) and routine method on hemodynamic parameters, arterial blood gases (ABGs), shivering, and time to awakening in elderly patients undergoing open cardiac surgery (OCS). Methods: This clinical randomized controlled trial was conducted on 94 elderly patients who underwent OCS at Ayatollah Rouhani Hospital, Babol, Iran. They were divided into three groups, namely FAWS (n=31), WIVFs (n=31) and routine rewarming method (RRWM, with a blanket) (n=32). The data were then recorded in a checklist. Descriptive and inferential statistics were performed using SPSS 26 at a significance level of less than 0.05. Results: The findings demonstrated that the degree of hypothermia had a significant decreasing trend in the groups receiving FAWS and WIVFs (P=0.002). Additionally, increased respiratory rate (P=0.013), higher bicarbonate (HCO3-) levels on arrival up to 4 hours after surgery (P=0.045), reduced lactate level (P=0.005), normal base excess (BE) and accelerated time to awakening (P=0.004) were observed in patients receiving FAWS. There was no significant difference in the study groups regarding shivering. Conclusion: The results revealed that FAWS could mitigate the degree of hypothermia, increase body temperature and decrease the postoperative serum lactate levels. Moreover, BE as one of the most important parameters for ABGs, could remain at a normal level. Besides, the use of FAWS could lead to early awakening, and thus facilitate weaning and extubation of these patients.

Effect of early oral carbohydrate intake after elective Cesarean delivery on maternal body temperature and satisfaction: a randomized controlled trial.

PURPOSE: Although the Enhanced Recovery After Cesarean Delivery (ERAC) consensus statement provides recommendations for early postoperative drinking and eating, evidence from high-quality clinical research directly addressing parturients is sparse. Our objective was to assess if early oral carbohydrate intake after elective Cesarean delivery improves maternal recovery. METHODS: In this randomized controlled trial, we enrolled parturients undergoing elective Cesarean delivery under spinal anesthesia with tympanic membrane temperatures ≤ 36.5 °C immediately upon arrival at the postanesthesia care unit. Parturients were randomized to either 100 mL of oral complex carbohydrate intake (group CC) or 10 mL of water (group C). The primary outcome was maternal tympanic membrane temperature. Other outcomes included maternal thermal comfort score, degree of shivering, satisfaction, degree of thirst and hunger, and gastric emptying assessed by ultrasonography. RESULTS: We included 90 participants in the final analysis. The mean (standard deviation [SD]) maternal body temperature at 120 min after ingestion was 36.7 (0.3) °C in group CC and 36.6 (0.3) °C in group C (difference in means, 0.14 °C; 95% confidence interval, 0.02 to 0.26; P = 0.02). Furthermore, using repeated measure models, the linear trends of temperature changes over time between groups CC and C were significantly different (P = 0.04). The thermal comfort scores at 120 min after ingestion were higher in group CC than in group C (P = 0.02), and the linear trends of shivering score changes over time between groups CC and C also were different (P = 0.003). The mean (SD) visual analogue scale scores for maternal satisfaction were 84 (13) mm in group CC and 47 (20) mm in group C (P < 0.001). Nevertheless, at 90 and 120 min after ingestion, there were no differences between the two groups in the number of participants with a gastric antrum cross-sectional area > 10.3 cm2. CONCLUSIONS: Early oral carbohydrate intake after Cesarean delivery helped to restore maternal body temperature postoperatively and improve maternal satisfaction. Nevertheless, the clinical importance of these finding is unclear, given that most of the differences were small. In addition, there was no delay in maternal gastric emptying after consumption of a complex carbohydrate beverage in the early post-Cesarean period. STUDY REGISTRATION: www.chictr.org.cn (ChiCTR2000031085); first submitted 13 November 2022.

RéSUMé: OBJECTIF: Bien que la déclaration de consensus sur la Récupération améliorée après un accouchement par césarienne (ERAC/RAAC) fournisse des recommandations pour l'ingestion postopératoire précoce de liquides et d'aliments, les données probantes issues de recherches cliniques de haute qualité portant directement sur les personnes parturientes sont rares. Notre objectif était d'évaluer si l'ingestion précoce de glucides par voie orale après une césarienne programmée améliorait la récupération maternelle. MéTHODE: Dans cette étude randomisée contrôlée, nous avons recruté des personnes parturientes bénéficiant d'une césarienne programmée sous rachianesthésie avec une température tympanique ≤ 36,5 °C immédiatement après leur arrivée en salle de réveil. Les personnes parturientes ont été randomisées à recevoir soit 100 mL de glucides complexes par voie orale (groupe GC) ou 10 mL d'eau (groupe C). Le critère d'évaluation principal était la température tympanique maternelle. Les autres critères d'évaluation comprenaient, chez la mère, le score de confort thermique, le degré de frissons, la satisfaction, le degré de soif et de faim, et la vidange gastrique évaluée par échographie. RéSULTATS: Nous avons inclus 90 personnes dans l'analyse finale. La température corporelle maternelle moyenne (écart type [ET]) à 120 minutes après l'ingestion était de 36,7 (0,3) °C dans le groupe GC et de 36,6 (0,3) °C dans le groupe C (différence dans les moyennes, 0,14 °C; intervalle de confiance à 95 %, 0,02 à 0,26; P = 0,02). De plus, à l'aide de modèles à mesures répétées, les tendances linéaires des changements de température au fil du temps entre les groupes GC et C étaient significativement différentes (P = 0,04). Les scores de confort thermique à 120 minutes après l'ingestion étaient plus élevés dans le groupe GC que dans le groupe C (P = 0,02), et les tendances linéaires des changements de score de frissons au fil du temps entre les groupes GC et C étaient également différentes (P = 0,003). Les scores moyens (ET) de l'échelle visuelle analogique concernant la satisfaction maternelle étaient de 84 (13) mm dans le groupe GC et de 47 (20) mm dans le groupe C (P < 0,001). Néanmoins, à 90 et 120 minutes après l'ingestion, il n'y avait aucune différence entre les deux groupes dans le nombre de personnes présentant une section transversale de l'antre gastrique > 10,3 cm2. CONCLUSION: L'ingestion précoce de glucides par voie orale après un accouchement par césarienne a aidé à rétablir la température corporelle maternelle postopératoire et à améliorer la satisfaction maternelle. Néanmoins, l'importance clinique de ces résultats n'est pas claire, étant donné que la plupart des différences étaient faibles. De plus, il n'y avait pas de retard dans la vidange gastrique maternelle après la consommation d'une boisson glucidique complexe au début de la période post-césarienne. ENREGISTREMENT DE L'éTUDE: www.chictr.org.cn (ChiCTR2000031085); soumis pour la première fois le 13 novembre 2022.

Pharmacologic interventions for the therapy of postanesthetic shivering in adults: a systematic review and network meta-analysis.

INTRODUCTION: Shivering is a common side effect after general anesthesia. Risk factors are hypothermia, young age and postoperative pain. Severe complications of shivering are rare but can occur due to increased oxygen consumption. Previous systematic reviews are outdated and have summarized the evidence on the topic using only pairwise comparisons. The objective of this manuscript was a quantitative synthesis of evidence on pharmacological interventions to treat postanesthetic shivering. EVIDENCE ACQUSITION: Systematic review and frequentist network meta-analysis using the R package netmeta. Endpoints were the risk ratio (RR) of persistent shivering at one, five and 10 minutes after treatment with saline/placebo as the comparator. Data were retrieved from Medline, Embase, Central and Web of Science up to January 2022. Eligibility criteria were: randomized, controlled, and blinded trials comparing pharmacological interventions to treat shivering after general anesthesia. Studies on shivering during or after any type of regional anesthesia were excluded as well as sedated patients after cardiac surgery. EVIDENCE SYNTHESIS: Thirty-two trials were eligible for data synthesis, including 28 pharmacological interventions. The largest network included 1431 patients. The network geometry was two-centered with most comparisons linked to saline/placebo or pethidine. The best interventions were after one minute: doxapram 2 mg/kg, tramadol 2 mg/kg and nefopam 10 mg, after 5 minutes: tramadol 2 mg/kg, nefopam 10 mg and clonidine 150 µg and after 10 minutes: nefopam 10 mg, methylphenidate 20 mg and tramadol 1 mg/kg, all reaching statistical significance. Pethidine 25 mg and clonidine 75 µg also performed well and with statistical significance in all networks. CONCLUSIONS: Nefopam, tramadol, pethidine and clonidine are the most effective treatments to stop postanesthetic shivering. The efficacy of doxapram is uncertain since different doses showed contradictory effects and the evidence for methylphenidate is based on a single comparison in only one network. Furthermore, both lack data on side effects. Further studies are needed to clarify the efficacy of dexmedetomidine to treat postanesthetic shivering.

The Effect of Prophylactic Steroids on Shivering in Adults Undergoing Surgery: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

BACKGROUND: Shivering is common following anesthesia and surgery. Corticosteroids (steroids) have been tried to reduce the risk of shivering, but the evidence in favor of their use is uncertain. The primary objective of this review was to evaluate the effect of steroids on the risk of perioperative (intra- and postoperative) shivering versus controls (placebo and active controls). Additional objectives were to assess the risk of severity of shivering, patient satisfaction with shivering prophylaxis, quality of recovery (QoR), and the risk of steroid-related adverse effects. METHODS: PubMed, Embase, Cochrane Central Registry of Trials, Google Scholar, and preprint servers were searched from inception until November 30, 2022. Randomized controlled trials (RCTs) published in the English language were retrieved, provided they reported on shivering either as a primary or secondary outcome following steroid prophylaxis in adult patients undergoing surgery under spinal or general anesthesia. RESULTS: A total of 3148 patients from 25 RCTs were included in the final analysis. The steroids used in the studies were either dexamethasone or hydrocortisone. Dexamethasone was administered intravenously or intrathecally, while hydrocortisone was administered intravenously. Prophylactic administration of steroids reduced the risk of overall shivering (risk ratio [RR], 0.65 [95% confidence interval {CI}, 0.52-0.82]; P = .0002; I2 = 77%) as well as the risk of moderate to severe shivering (RR, 0.49 [95% CI, 0.34-0.71]; P = .0002; I2 = 61%) in comparison to controls. Administration of intravenous dexamethasone (RR, 0.67 [95% CI, 0.52-0.87]; P = .002; I2 = 78%) and hydrocortisone (RR, 0.51 [95% CI, 0.32-0.80]; P = .003; I2 = 58%) were effective in shivering prophylaxis. For intrathecal dexamethasone (RR, 0.84 [95% CI, 0.34-2.08]; P = .7; I2 = 56%), the null hypothesis of no subgroup difference was not rejected ( P = .47), preventing definitive conclusions about the efficacy of this route of administration. The prediction intervals for both overall shivering risk (0.24-1.70) and risk of severity of shivering (0.23-1.0) precluded generalization of results in future studies. Meta-regression analysis was used to further explore heterogeneity. Factors like the dose and timing of administration of steroids or the type of anesthesia were not found to be significant. Patient satisfaction and QoR were higher in the dexamethasone groups versus placebo. No increased risk of adverse events of steroids was noted versus placebo or controls. CONCLUSIONS: Prophylactic steroid administration may be beneficial in reducing the risk of perioperative shivering. However, the quality of evidence in favor of steroids is very low. Further well-designed studies are needed for establishing generalization.

Comparative effects of warming systems applied to different parts of the body on hypothermia in adults undergoing abdominal surgery: A systematic review and network meta-analysis of randomized controlled trials.

STUDY OBJECTIVE: The prevention of perioperative hypothermia after anesthesia induction is a critical concern in patients undergoing abdominal surgery. The effectiveness of various warming systems for preventing hypothermia and shivering when applied to specific areas of the body remains undetermined. DESIGN: Systematic review and network meta-analysis. SETTING: Operating room. INTERVENTION: Five electronic databases were searched, including only randomized control trials (RCTs) reporting the effects of warming systems applied to specific body sites on the intraoperative core temperature and postoperative risk of shivering in adults undergoing abdominal surgery. A multivariate random-effects network meta-analysis with a frequentist framework was implemented for data analysis. MEASUREMENTS: The primary outcome was the core body temperature 60 and 120 min after anesthesia induction for abdominal surgery. The secondary outcome was the incidence of postoperative shivering. RESULTS: This review comprised a total of 24 RCTs including 1119 patients. At 60 and 120 min after anesthesia induction, a forced-air warming system applied to the upper body (0.3 °C and 95% confidence intervals = [0.3 to 0.4], 1.0 °C [0.7 to 1.3]), lower body (0.4 °C [0.3 to 0.5], 0.9 °C [0.5 to 1.2]), and underbody (0.5 °C [0.5 to 0.6], 1.2 °C [0.9 to 1.6]) was superior to passive insulation in terms of core body temperature regulation. Compared with passive insulation, the forced-air warming system applied to the lower body (odds ratio = 0.06) or underbody (0.44) and the electric heating blanket to the lower body (0.02) or the whole body (0.07) significantly reduced the risk of shivering. CONCLUSIONS: The results of this NMA revealed that forced-air warming with an underbody blanket effectively elevates core body temperatures in 60 and 120 min after induction of anesthesia and prevents shivering in patients recovering from abdominal surgery.

The Effect of Remimazolam Compared to Sevoflurane on Postoperative Shivering in Patients Undergoing Laparoscopic Gynecologic Surgery under General Anesthesia: A Prospective Randomized Controlled Trial.

Background and objectives: Anesthesia maintenance agents affect the incidence of postoperative shivering (PS) after general anesthesia. This study compared the effects of remimazolam with sevoflurane on PS in patients undergoing laparoscopic gynecologic surgery under general anesthesia. Materials and methods: Seventy-four patients were allocated into one of two groups. In anesthesia maintenance, group S received sevoflurane and remifentanil, and group R received remimazolam and remifentanil. Results: The incidence and severity of postoperative shivering, mean arterial pressure (MAP), heart rate (HR), core body temperature, and the association of PS with hypothermia, MAP, or HR in the post-anesthesia care unit (PACU) were measured. Group R had significantly lower rates of perioperative hypothermia (58.8 vs. 27.8%, p = 0.009) and postoperative shivering (41.2 vs. 19.4%, p = 0.047). The severity of PS was also lower in group R than in group S (p = 0.034). Core body temperature was significantly higher in group R than in group S from 10 min after induction (p = 0.047) to the PACU (p = 0.009). MAP and HR were significantly higher in group R than in group S from 20 min after induction (p = 0.047) to the PACU (p = 0.009). In group S, the correlation between the severity of PS and the incidence of hypothermia (φc = 0.414, p = 0.121) was moderate but not significant. In group R, the correlation between PS severity and hypothermia (φc = 0.418, p = 0.043) was moderate and significant. Conclusions: Remimazolam showed better results than sevoflurane in anesthesia maintenance regarding hypothermia and PS.

Incidence of postoperative hypothermia and shivering and risk factors in patients undergoing malignant tumor surgery: a retrospective study.

BACKGROUND: Perioperative hypothermia and shivering are common and can cause adverse outcomes. The aim of this study was to investigate the incidence of postoperative hypothermia and shivering and their risk factors in patients undergoing malignant tumor surgery. METHODS: This retrospective study collected data from patients with American Society of Anesthesiologists physical status (ASA) I or II who underwent scheduled surgery from November 2020 to March 2021 at Fudan University Shanghai Cancer Center. Each patient's core body temperature was measured at three time points: time point 1 (arrival at the postanesthesia care unit (PACU)), time point 2 (after 30-min care in the PACU), and time point 3 (at discharge from the PACU). At time point 1, if the patient's body temperature was below 36 ℃, we provided an active forced-air warmer. At time point 2, if it was still below 36 ℃, the forced-air warmer was still applied until the patient was discharged from the PACU. If it reached 36 ℃, the forced-air warmer would be switched off. Univariate and multivariate logistic regression combined with stepwise methods and linear regression were used to explore risk factors for postoperative hypothermia and shivering. RESULTS: The numbers (percentage) of 202 patients who developed postoperative hypothermia at the different time points were 52 (25.7%), 37 (18.3%) and 28 (13.9%). Eight patients (4.0%) experienced shivering. Multivariate logistic regression showed that high weight (OR = 0.923, 95% CI: 0.884 to 0.964, P = 0.0003) and low estimated blood loss (OR = 0.252, 95% CI: 0.115 to 0.550, P = 0.0005) were protective factors against hypothermia, while long surgical duration (OR = 3.339, 95% CI: 1.675 to 6.655, P = 0.0006) was an independent risk factor for hypothermia at time point 1. There was no risk factor associated with the occurrence of shivering (P > 0.05). There was a significant difference between the hypothermia and normothermia groups in the median length of stay in the PACU (59.0 vs. 49.0 min, P = 0.0123). CONCLUSIONS: Postoperative hypothermia occurred frequently. Weight, estimated blood loss and surgical duration were significantly associated with hypothermia on arrival at the PACU.

Evaluation of Postoperative Warming Care Protocol for Thermal Comfort and Temperature Management Immediately After Surgery: Nonrandomized Controlled Trial.

PURPOSE: This study aimed to determine the effects of a warming care protocol (WCM) on temperature control and thermal comfort perception in hypothermia following major abdominal surgery. DESIGN: A prospective nonrandomized controlled trial. METHODS: A total of 54 patients undergoing major abdominal surgery were assigned to receive routine care (control group, 27 patients) or the WCM (intervention group, 27 patients). The body temperature (core and peripheral) was measured, and physical symptoms were monitored every hour for 4 hours after arriving at the ward and then every 4 hours for up to 12 hours. FINDINGS: The temperature gap, calculated as the difference between the core and skin temperatures, was similar between the control and intervention groups at the end of surgery. However, the temperature gap in the intervention group decreased within 3 hours after arrival at the ward and remained lower than that in the control group. The visual analog scale score for postoperative thermal discomfort was significantly lower in the intervention group than in the control group, indicating achievement of higher comfort with the warming intervention. CONCLUSIONS: Patients were warmed using active warming methods under the WCM, which in turn increased the thermal comfort perception with the body temperature. Postoperative patients often require warming care for thermal comfort, which may be improved by proper observation and management within 1 to 2 hours postoperatively. Our results indicate that nurses could effectively warm the patient to maintain normal body temperature following surgery not only to improve thermal comfort, but also to prevent shivering and possibly various postoperative complications.

A Novel Device for Intraoperative Hypothermia Prevention in Patients with Lower Abdominal Surgery: A Prospective Randomized Single-Center Study.

This study aims to explore the value of lithotomy position thermal sleeve application during lower abdominal surgery in patients with hypothermia. A total of 100 patients who underwent urinary, gastrointestinal, or gynecological operations were included in this study. The patients were randomly divided into two groups: the test group (n = 50) and the control group (n = 50). In the control group, the environment, fluid, patient upper abdomen, and pasted 3 L stone-cut pants were heated. In the test group, the lithotomy position surgical warmer was used based on environment, fluid, and upper abdomen warming. The various indicators present in the two groups were compared and analyzed using the Statistical Package for Social Sciences 19.0. Before the operation, the body temperature was 36.73°C ± 0.28°C in the test group and 36.74°C ± 0.29°C in the control group; the difference between the two groups was not statistically significant (p > 0.05). In the test group, the entry temperature was 36.83°C ± 0.04°C; after 2 hours of operation, it became 37.21°C ± 0.03°C. There were no significant changes in body temperature after 4 hours of operation, basic body temperature was maintained (36.80°C ± 0.02°C). In the control group, the entry temperature was 36.54°C ± 0.05°C; however, it became 35.94°C ± 0.07°C after 2 hours of operation, making the patient prone to developing hypothermia. The differences between the two groups were statistically significant (p < 0.05). In patients undergoing urinary, anorectal, or gynecological operations, the use of a warming intervention during surgery in the lithotomy position can effectively stabilize body temperature and reduce the occurrence of postoperative shivering. ClinicalTrials.gov ID: ChiCTR2100046522.

Redistributional Hypothermia Prevention by Prewarming with Forced-Air: Exploratory, Open, Randomized, Clinical Trial of Efficacy.

Avoiding redistributional hypothermia that decreases core temperature by 0.5-1.5°C within the 1st hour of surgery is difficult. The efficacy of prewarming using a forced-air warming (FAW) device with a lower-body blanket on redistribution hypothermia during epidural procedures have not been investigated. After ethics approval, 113 patients undergoing laparoscopic surgery under general anesthesia combined with epidural anesthesia were enrolled. Intervention (prewarming) group patients who were warmed from operating room entry, including during epidural anesthesia, was compared with the control group that was warmed from just before surgery started. In total, 104 patients (52, control; 52, prewarming) were analyzed. In the prewarming group, compared to the control group, the core temperature 20 minutes after anesthesia induction (36.9 ± 0.4 vs. 37.1 ± 0.4°C, p < 0.02) was significantly higher. The core temperature was higher in the prewarming group than in the control group until 3 hours after the surgery. In the prewarming group, compared to the control group, the core temperature-time integral below baseline till 180 minutes after surgery start (65.1 ± 64.0 vs. 8.1 ± 18.6°C/min, p < 0.0001) or 30 minutes after anesthesia induction (5.3 ± 6.2 vs. 2.0 ± 4.7°C/min, p < 0.0001) were significantly smaller. Postoperative shivering was comparable between the groups. Prewarming during epidural catheter insertion with a FAW device could safely prevent a core temperature decrease induced by redistribution or heat loss without additional preparation, effort, space, or time requirements.

Combined Forced Air Warming and Warm Intravenous Fluid Strategy for Perioperative Hypothermia in Cesarean Delivery: A Systematic Review and Meta-Analysis.

PURPOSE: Evaluate the effect of a combined forced-air warming (FAW) and warm intravenous fluid (IVF) modality on maternal and neonatal outcomes in cesarean delivery under neuraxial anesthesia. DESIGN: Systematic Review and Meta-analysis. METHODS: An extensive search was conducted using PubMed, Cochrane Library, MEDLINE, CINAHL, Google Scholar, and other grey literature. Only randomized controlled trials examining the combined modality on maternal temperatures were included. Risk ratio (RR), mean difference (MD), and standardized mean difference (SMD) were used to estimate outcomes with suitable effect models. Quality of evidence was assessed using the Risk of Bias and GRADE system. FINDINGS: Nine trials involving 595 patients were included. Combined strategy showed a smaller change in maternal temperature from baseline by 0.42°C (MD, -0.42; 95% CI, -0.62 to -0.22; P < .0001), higher temperature on PACU arrival (MD, 0.46; 95% CI, 0.11-0.82; P = .01), 15 minutes (MD, 0.43; 95% CI, 0.19-0.67; P = .0004) and 30 minutes after surgery (MD, 0.38; 95% CI, 0.12-0.64; P = .005). Combined strategy also reduced the incidence of hypothermia (RR, 0.55; 95% CI, 0.31-0.95; P = .03), and shivering (RR, 0.40; 95% CI, 0.28-0.58; P < .00001) with improvement in maternal comfort score (SMD; 0.38; 95% CI, 0.08-0.69; P = .01). However, there were no differences in clinical indicators of adverse neonatal outcomes. Lack of participants blinding, and substantial heterogeneity were limitations of this review. CONCLUSION: The use of combined FAW and warm IVF is an effective strategy in mitigating perioperative hypothermia in cesarean delivery under neuraxial anesthesia.