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.

tramadol for post-spinal anesthesia shivering: a meta-analysis and systematic review

Background

Patients often experience shivering after spinal anesthesia. In recent years, more and more studies have compared the efficacy and side effects of intravenous butorphanol and tramadol in the treatment of shivering after spinal anesthesia. Therefore, we conducted a MATE analysis and systematic review to compare the efficacy and side effects of butorphanol vs. tramadol in the treatment of shivering after spinal anesthesia.

Methods

PubMed, Cochrane Library, and Embase databases were searched for randomized controlled trials (RCTs) from inception to 30 December 2022, comparing the effects of butorphanol vs. tramadol for the control of shivering after spinal anesthesia. Data assessment and collection were analyzed using the Review Manager 5.4 software.

Results

Five randomized controlled trials involving 302 adult patients were included in this meta-analysis. The results showed that butorphanol has a shorter time to cease shivering (standardized mean difference (SMD) = -0.53; 95% confidence interval (CI) [-0.89, -0.17], P = 0.004, I2 = 0%), a higher rate of cessation of shivering within 1 min after administering the study drugs (relative risk (RR), 1.69; 95% CI [1.15,2.48], P = 0.008, I2 = 0%), and higher incidences of sedation (RR, 2.98; 95% CI [2.11, 4.21], P <0.00001, I2 = 0%), compared with tramadol.

Conclusion

In the treatment of shivering after spinal anesthesia, butorphanol has a shorter onset time and a higher rate of cessation of shivering within 1 min after the study drugs were administered than tramadol. Therefore, butorphanol is superior to tramadol in the treatment of shivering after spinal anesthesia.

Focal hand warming for post-anaesthesia shivering control: A simple and safe non-pharmacological approach in resource limited-area

Post-anaesthesia shivering is a common complication and has multiple deleterious effects. Sometimes multiple non-pharmacological interventions applied together may not control post-anaesthesia shivering adequately, necessitating the use of drugs in some cases. Hand warming is commonly used to warm up the body since time immemorial but its role in preventing post-anaesthesia shivering has not been evaluated. This case series describes the application of this simple and safe method of focal hand warming along with other non-pharmacological measures to suppress post-anaesthesia shivering, whereby possible use of drugs could be avoided.

Effects of Active Heating Methods on Body Temperature, Shivering, Thermal Comfort, Pain, Nausea and Vomiting During General Anesthesia: A Randomized Controlled Trial

To investigate the effect of forced-air warming and heated intravenous (IV) and irrigation fluids alone and in combination on body temperature, shivering, thermal comfort, pain, nausea and vomiting in adult patients undergoing surgery under general anesthesia in a prospective, four-group, randomized controlled trial. After induction of anesthesia, 120 patients were divided into the following groups: patients warmed with forced-air warming (n = 30), patients receiving warmed IV and irrigation fluid (n = 30), patients receiving warmed IV and irrigation fluid with forced-air warming (n = 30), and the control group without any intervention (n = 30). Body temperature, shivering, thermal comfort, pain, nausea and vomiting were monitored in the first 24 hours after surgery. The general characteristics of the groups, mean body temperature, length of stay, ambient temperature, and duration of surgery in the preoperative waiting unit were similar (p > 0.05). Compared with the other groups, patients in the control group had a significant decrease in body temperature from the 30th minute during surgery (p < 0.001), lower body temperature in the first 2 hours and thermal comfort in the first three hours after surgery (p < 0.01), and higher shivering levels in the first hour after surgery (p < 0.01). There was no significant difference between the groups in terms of postoperative pain, nausea and vomiting (p > 0.05). The study findings showed that normothermia was maintained in all three intervention groups during the surgery and in the first 24 hours after surgery. Moreover, postoperative thermal comfort increased and shivering levels decreased compared with the control group, but pain, nausea and vomiting levels were not affected. The study was registered on ClinicalTrials.gov (NCT04907617).

Efficacy of intravenous nalbuphine for managing post-anaesthesia shivering: A systematic review and meta-analysis of randomised controlled trials with trial sequential analysis

Background and Aims

Post-anaesthesia shivering is distressing and is observed after spinal and general anaesthesia. Nalbuphine, a partial mu-opioid receptor antagonist with kappa-opioid receptor agonist properties, has been successfully used to manage post-anaesthesia shivering.

Methods

After registering the review with the International Prospective Register of Systematic Reviews (PROSPERO), we searched PubMed/Medline, Scopus, Ovid, Cochrane Library and clinicaltrials.gov with keywords for randomised controlled trials. The risk of bias-2 (RoB-2) scale was used to assess the quality of evidence. We also used Grading of Recommendations, Assessment, Development and Evaluations (GRADE) guidelines to evaluate the strength of evidence and trial sequential analysis to validate the conclusions.

Results

Of the 240 articles, 10 were considered eligible for review (700 patients, 350- nalbuphine, 350- control or placebo). When compared to placebo, the success rate of nalbuphine controlling shivering was significantly better (risk ratio [RR]: 2.37, 95% confidence interval [CI]:1.91, 2.94; P = 0.04, I² = 94%), but comparable to the control group drugs (opioids, dexmedetomidine, ondansetron, pethidine). Compared to placebo, shivering recurrence was significantly less with nalbuphine than with placebo (RR: 0.47, 95% CI: 0.26, 0.83; P = 0.01, I² = 61%), but comparable with the control group. The incidence of postoperative nausea/vomiting (PONV) was significantly less with nalbuphine when compared to the control group (RR: 0.67, 95% CI: 0.47, 0.95; P = 0.02, I² = 37%), but PONV in the nalbuphine group was comparable to placebo (RR: 1.20, 95% CI: 0.68, 2.12; P = 0.54, I² = 0%). Other outcomes, like the grade of shivering and hypotension, were comparable between the nalbuphine and control groups.

Conclusion

Nalbuphine successfully controls post-anaesthesia shivering and reduces the recurrence of shivering.

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.

Effects of Perioperative Hypothermia on Extubation, Recovery Time, and Postoperative Shivering in Breast Surgery

Women undergoing breast surgery seem to be under the risk for hypothermia (central body temperature <36°) due to the uncertainty caused by the preoperative preparation time and the variety of operations, leading to neglect of warming precautions. The study examines the perioperative hypothermia (PH) in breast surgery and the relationships between the depth of decrease in body temperature and individual or clinical variables. This prospective, cross-sectional, observational study includes 120 female patients 18-65 years of age who were given general anesthesia for breast surgery. The incidence of hypothermia was 68.1%. The given patients were discriminated as body temperature <36°, hypothermia was significantly related with lower weight, body mass index, American Society of Anesthesiology (ASA) score, baseline body temperatures, higher extubation, and recovery times. When patients' temperature decreases by >1 or 1.5°, lower age and longer durations of operation and anesthesia were also significant variables. The incidence of shivering is quite high at temperatures below 36°C or at 1 and 1.5°C reductions from baseline (72.7%, 84%, 94.1%, respectively). Body temperature changes of the patients had no effect on nausea-vomiting and pain scores. It turned out that the incidence of PH and shivering is high in women who underwent breast surgery. We think that the depth of decrease in body temperature should be taken into account when evaluating the predictors or clinical consequences of hypothermia, except for the 36°C limit for body temperature.

Implementing a Stepwise Shivering Protocol During Targeted Temperature Management

Background: Shivering is often encountered in patients undergoing targeted temperature management (TTM) after cardiac arrest. The most efficient, safe way to prevent shivering during TTM is not clearly defined. Objective: The purpose of this study was to evaluate the impact of shivering management using a stepwise shivering protocol on time to target temperature (TT), medication utilization and nursing confidence. Methods: Single-center, retrospective chart review of all post-cardiac arrest patients who underwent TTM between 2016 and 2021. The primary outcome is a comparison of time to TT pre- and post-protocol implementation. Secondary objectives compared nursing confidence and medication utilization pre- and post-shivering protocol implementation. Results: Fifty-seven patients were included in the pre-protocol group and thirty-seven were in the post-protocol group. The median (IQR) time to TT was 195 (250) minutes and 165 (170), respectively (p = 0.190). The average doses of acetaminophen was 285 mg pre- vs 1994 mg post- (p <0.001, buspirone 47 mg pre- vs 127 mg post- (p < 0.001), magnesium 0.9 g pre-vs 2.8 g post- (p < 0.001), and fentanyl 1564 mcg pre- vs 2286 mcg post- (p=0.023). No difference was seen for midazolam and cisatracurium. Nurses reported feeling confident with his/her ability to manage shivering during TTM 38.5% of the time pre-protocol compared to 60% post-protocol (p = 0.306). Conclusion: Implementation of a stepwise approach to prevent and treat shivering improved time to TT in our institution, although this finding was not statistically significant. The stepwise protocol supported a reduced amount of high-risk medication use and increased nursing confidence in shivering management.

Perioperative administration of dexamethasone to prevent postoperative shivering: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

To evaluate the perioperative administration of dexamethasone to prevent postoperative shivering.

METHODS

We searched PubMed, Embase, Google Scholar, Web of Science, and Cochrane Library for relevant studies of the administration of dexamethasone to prevent postoperative shivering published through 31 May 2023. The primary outcome was the incidence of postoperative shivering. Secondary outcomes comprised the incidence of postoperative nausea, vomiting, and postoperative nausea and vomiting (PONV). RevMan 5.3 software was used for the data analysis.

RESULTS

We included 12 randomized controlled trials (1276 participants). The results revealed a benefit favoring the perioperative administration of dexamethasone to prevent postoperative shivering (relative risk [RR]: 0.39; 95% confidence interval [CI]: 0.23-0.63), as well as the grade of shivering. The administration of dexamethasone also reduced the incidence of postoperative nausea (RR: 0.54; 95% CI: 0.39-0.73), postoperative vomiting (RR: 0.37; 95% CI: 0.20-0.65), and PONV (RR: 0.50; 95% CI: 0.26-0.95) compared with the control group.

CONCLUSION

This study indicated that perioperative administration of dexamethasone prevented postoperative shivering and decreased the incidence of other complications.PROSPERO registration number: CRD42020164488.

Cerebellar axonopathy in Shivers horses identified by spatial transcriptomic and proteomic analyses

BACKGROUND

Shivers in horses is characterized by abnormal hindlimb movement when walking backward and is proposed to be caused by a Purkinje cell (PC) axonopathy based on histopathology.

OBJECTIVES

Define region-specific differences in gene expression within the lateral cerebellar hemisphere and compare cerebellar protein expression between Shivers horses and controls.

ANIMALS

Case-control study of 5 Shivers and 4 control geldings ≥16.2 hands in height.

METHODS

Using spatial transcriptomics, gene expression was compared between Shivers and control horses in PC soma and lateral cerebellar hemisphere white matter, consisting primarily of axons. Tandem-mass-tag (TMT-11) proteomic analysis was performed on lateral cerebellar hemisphere homogenates.

RESULTS

Differences in gene expression between Shivers and control horses were evident in principal component analysis of axon-containing white matter but not PC soma. In white matter, there were 455/1846 differentially expressed genes (DEG; 350 ↓DEG, 105 ↑DEG) between Shivers and controls, with significant gene set enrichment of the Toll-Like Receptor 4 (TLR4) cascade, highlighting neuroinflammation. There were 50/936 differentially expressed proteins (DEP). The 27 ↓DEP highlighted loss of axonal proteins including intermediate filaments (5), myelin (3), cytoskeleton (2), neurite outgrowth (2), and Na/K ATPase (1). The 23 ↑DEP were involved in the extracellular matrix (7), cytoskeleton (7), redox balance (2), neurite outgrowth (1), signal transduction (1), and others.

CONCLUSION AND CLINICAL IMPORTANCE

Our findings support axonal degeneration as a characteristic feature of Shivers. Combined with histopathology, these findings are consistent with the known distinctive response of PC to injury where axonal changes occur without a substantial impact on PC soma.

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.

Paracetamol Versus Ondansetron for Prevention of Postoperative Shivering in Liposuction Surgeries Under Combined General Epidural Anaesthesia: A Randomized Controlled Trial

Objective

Postoperative shivering (POS) is considered one of the most common complications that is encountered by the anaesthetists worldwide. Despite using several treatment options, there has not been a clear consensus regarding this issue. This trial was conducted to investigate the efficacy and safety of paracetamol and ondansetron in preventing POS in patients undergoing liposuction procedures under combined general epidural anaesthesia.

Methods

One hundred twenty patients scheduled for liposuction were randomly allocated to one of three groups: group P (paracetamol group) which received 1 g paracetamol intravenously, group O (ondansetron group) which received 8 mg of ondansetron intravenously, and group S (saline group), which received 100 mL normal saline intravenously; all medications were given postoperatively. The primary outcome was the incidence of POS, and the secondary outcomes included shivering score, tympanic temperature, and the occurrence of side effects.

Results

The incidence of occurrence of POS was found to be lower in groups P and O compared to group S with values of 25% and 37.50% vs. 77.50%, respectively, with a P value <0.001. Additionally, the severity of POS was found to be lower in groups P and O compared to group S (P <0.001). Tympanic temperature and complications were comparable between the groups with no significant differences.

Conclusion

Prophylactic use of paracetamol or ondansetron at the end of the procedure was shown to be of great value in reducing the incidence and severity of POS, with no statistically significant difference between the paracetamol and ondansetron groups. Moreover, no significant drawbacks were reported as a result of using these medications.

Effect of intravenous tramadol versus pethidine on postspinal shivering control among mothers during cesarean section at Wolaita Sodo University Comprehensive Specialized Hospital, Southern Ethiopia: a prospective observational cohort study

Postspinal anesthesia shivering is a common complication during spinal anesthesia. It is very unpleasant and physiologically stressful for patients and challenging for healthcare providers. Shivering could be treated with tramadol or pethidine. However, the comparative effectiveness of one drug over the other drug has not been proven with a low-drug setup.

Objective

To compare the effect of intravenous tramadol versus pethidine on postspinal shivering control among obstetric mothers who underwent cesarean section.

Methods and materials

A prospective cohort study design was conducted on 180 ASA (American Society of Anesthesiology) I and II obstetric mothers. A systematic random sampling method was employed. Data were entered into EpiData version 4.6 and exported into SPSS version 25 for analysis. The independent sample t test was used to compare the difference of means between groups for normally distributed data, and the Mann-Whitney U test was used for non-normally distributed data. Categorical data were analyzed using the chi-squared test. Data were presented by mean±standard deviation for normally distributed data and median and interquartile range for non-normally distributed data. Categorical data were presented as numbers and frequencies. P values less than 0.05 were considered statistically significant.

Results

One hundred eighty participants were used for analysis. The mean time of shivering disappearance was 5.5±1.75 min and 6.6±2.08 min in tramadol and pethidine groups, respectively (P<0.001). The hemodynamic changes were all comparable between the two groups. The difference in the recurrence of shivering after treatment was significant between the groups (P<0.001). Sedation was higher in the pethidine group, 9 (10%), than in the tramadol group, 2 (2.2%). Nausea and vomiting were found to be higher in the tramadol group, 10 (11.1%), than in the pethidine group, 5 (5.6%).

Conclusions

Tramadol controlled shivering early, and recurrence of shivering and incidence of sedation were also low in the tramadol group. Therefore, tramadol is as effective as pethidine for the treatment of postspinal shivering in obstetric mothers who underwent cesarean delivery. So tramadol can be used as an alternative for postspinal shivering in obstetric mothers.

Vitality in Newborn Farm Animals: Adverse Factors, Physiological Responses, Pharmacological Therapies, and Physical Methods to Increase Neonate Vigor

Vitality is the vigor newborn animals exhibit during the first hours of life. It can be assessed by a numerical score, in which variables, such as heart rate, respiratory rate, mucous membranes' coloration, time the offspring took to stand up, and meconium staining, are monitored. Vitality can be affected by several factors, and therapies are used to increase it. This manuscript aims to review and analyze pharmacological and physical therapies used to increase vitality in newborn farm animals, as well as to understand the factors affecting this vitality, such as hypoxia, depletion of glycogen, birth weight, dystocia, neurodevelopment, hypothermia, and finally, the physiological mechanism to achieve thermostability. It has been concluded that assessing vitality immediately after birth is essential to determine the newborn's health and identify those that need medical intervention to minimize the deleterious effect of intrapartum asphyxia. Vitality assessment should be conducted by trained personnel and adequate equipment. Evaluating vitality could reduce long-term neonatal morbidity and mortality in domestic animals, even if it is sometimes difficult with the current organization of some farms. This review highlights the importance of increasing the number of stock people during the expected days of parturitions to reduce long-term neonatal morbidity and mortality, and thus, improve the farm's performance.

Intravenous versus perineural dexmedetomidine as adjuvant in adductor canal block for total knee arthroplasty

Background

Shivering following spinal anesthesia in total knee arthroplasty is challenging for anesthesiologist.

Objective

To compare two different administrative routes of dexmedetomidine firstly, as a preventive of post-neuraxial shivering and secondly, as an adjunctive analgesic and sedative agent.

Methods

This study enrolled 56 patients who randomly allocated into two equal groups. First, the Intravenous dexmedetomidine group (IV dex) who were given 0.5 µg /kg dexmedetomidine diluted in 20 mL saline by intravenous (IV) infusion while, 20 mL of 0.25% levobupivacaine plus 1 mL saline was used for adductor canal block (ACB), and second, the adductor canal block dexmedetomidine group (ACB dex) who were given 20 mL saline by IV infusion while, 20 mL 0.25% levobupivacaine plus 1 mL of 0.5 µg /kg dexmedetomidine was used for ACB.

Results

The incidence of shivering 1 h post spinal anesthesia was equal in both groups (50%) while, the shivering grade was significantly lower in the IV dex group 1h postoperatively. The onset of sensory block was significantly higher in the IV dex group (22.14 ± 2.52 min) than in the ACB dex group (12 ± 3.31 min). Postoperative analgesic duration (hours) shows a significant increase in the ACB dex group (12.28 ± 4.47) compared to the IV dex group (9.28 ± 1.9). Sedation scores were significantly higher in the ACB dex group in the preoperative, intraoperative, and immediate postoperative recordings.

Conclusions

Perineural dexmedetomidine in ACB had a similar sedative and intraoperative anti-shivering effects compared to IV dexmedetomidine but, postoperatively it had lesser shivering control and superior analgesia after TKA under spinal anesthesia.

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.

Shivering and changes in body temperature in patients undergoing caesarean section under spinal anaesthesia with bupivacaine vs bupivacaine and fentanyl: A randomized clinical study

Background and Aims

Shivering is common after spinal anesthesia in patients undergoing cesarean section. Various drugs have been used for its prevention. The primary aim of this study was to assess the efficacy of adding a small dose of fentanyl intrathecally (12.5 μg) in reducing the occurrence of intraoperative shivering and hypothermia and note any significant side effects in this subset of patients.

Material and Methods

In this randomized controlled trial, 148 patients undergoing cesarean section under spinal anesthesia were included. In 74 patients, spinal anesthesia was administered with 1.8 mL of hyperbaric bupivacaine (0.5%), and the remaining 74 patients received 12.5 μg of intrathecal fentanyl with 1.8 mL of hyperbaric bupivacaine. Both were compared to find the incidence of shivering and change in nasopharyngeal and peripheral temperature along with the temperature at the onset of shivering and the grade of shivering.

Results

The incidence of shivering was 9.46% in the intrathecal bupivacaine plus fentanyl group, which was significantly less than the group with intrathecal bupivacaine alone (41.89%). The nasopharyngeal and peripheral temperature showed a decreasing trend in both groups but were greater in the plain bupivacaine group.

Conclusion

The addition of 12.5 μg of intrathecal fentanyl to bupivacaine in parturient undergoing cesarean section under spinal anesthesia significantly reduces the occurrence and intensity of shivering without its adverse effects such as nausea, vomiting, and pruritus, etc.

Modulation of cold-induced shivering activity by intermittent and continuous voluntary suppression

This investigation assessed the physiological effects of voluntary suppression of shivering thermogenesis in response to whole body cooling. Eleven healthy volunteers underwent passive air cooling (10°C), across three visits: NO_SUP, where participants allowed their body to freely regulate against the cold; FULL_SUP, where participants constantly suppressed shivering; INT_SUP, where participants intermittently suppressed shivering (5 min phases), interspersed with 5 min free regulation. Shivering was assessed via electromyography (EMG), mechanomyography (MMG), and whole body oxygen uptake (V̇o₂), whereas body temperature and heat exchange were assessed via skin temperature, rectal temperature, and heat flux sensors. A 29% increase was observed in shivering onset time in the FULL_SUP trial compared with NO_SUP (P = 0.032). Assessing shivering intensity, EMG activity decreased by 29% (P = 0.034), MMG activity decreased by 35% (P = 0.031), whereas no difference was observed in V̇o₂ (P = 0.091) in the FULL_SUP trial compared with NO_SUP. Partitioning the no-suppression and suppression phases of the INT_SUP trial, acute voluntary suppression significantly decreased V̇o₂ (P = 0.001), EMG (P < 0.001), and MMG (P = 0.012) activity compared with the no-suppression phases. Shivering activity was restored in the no-suppression phases, equivalent to that in the NO_SUP trial (P > 0.3). No difference was observed in thermal metrics between conditions up to 60 min (P > 0.4). Humans can both constantly and periodically suppress shivering activity, leading to a delay in shivering onset and a reduction in shivering intensity. Following suppression, regular shivering is resumed.

intravenous ketamine in the prevention of shivering during spinal anesthesia: A meta-analysis of randomized controlled trials

Background

Shivering is a common complication after subarachnoid administration of local anesthetics. Intravenous ketamine and tramadol are widely available anti-shivering drugs, especially in developing settings. This meta-analysis aimed to compare the effects of intravenous ketamine vs. tramadol for post-spinal anesthesia shivering.

Materials and methods

PubMed/MEDLINE, Web of Science, Cochrane Library, Embase, and Google Scholar databases were used to search for relevant articles for this study. Mean difference (MD) with 95% confidence interval (CI) was used to analyze continuous outcomes, and risk ratio (RR) with 95% CI to analyze categorical results. The heterogeneity of the included studies was assessed using the I2 test. We utilized Review Manager 5.4.1 to perform statistical analysis.

Results

Thirteen studies involving 1,532 patients were included in this meta-analysis. Ketamine had comparable effects in preventing post-spinal anesthetics shivering [RR = 1.06; 95% CI (0.94, 1.20), P = 0.33, I ² = 77], and onset of shivering [MD = -0.10; 95%CI (- 2.68, 2.48), P = 0.94, I ² = 0%], lower incidences of nausea and vomiting [RR = 0.51; 95%CI (0.26, 0.99), P = 0.05, I ² = 67%], and lower incidences of bradycardia [RR = 0.16; 95%CI (0.05, 0.47), P = 0.001, I ² = 33%], higher incidence of hallucinations [RR = 12; 95%CI (1.58, 91.40), P = 0.02, I ² = 0%], and comparable effects regarding the incidences of hypotension [RR = 0.60; 95%CI (0.30, 1.21), P = 0.15, I ² = 54%] as compared to tramadol.

Conclusions

Intravenous ketamine and tramadol are comparable in the prevention of post-spinal anesthetic shivering. Ketamine had a better outcome with less occurrences of nausea, vomiting, and bradycardia. However, ketamine was associated with higher incidences of hallucinations than tramadol.

Comparison of the Effect of Forced-air Warming and Warmed Intravenous Fluid on the Comfort and Prevention of Shivering After Spinal Anesthesia in Patients Undergoing Orthopedic Surgery

PURPOSE

This study aimed to compare the effect of forced-air warming and warmed intravenous fluid on the comfort and prevention of shivering after spinal anesthesia in patients undergoing orthopaedic surgery.

DESIGN

Randomized controlled clinical trial.

METHODS

A total of 120 patients were randomly divided into three groups: forced-air warming (38°C), warmed intravenous fluid (37°C), and the control group. Patients' comfort and severity of shivering were measured and recorded five times (immediately and 15 minutes after spinal anesthesia, end of the surgery, time of entrance to the recovery room, and 15 minutes after entering the recovery room), and compared with each other.

FINDINGS

There was a significant difference between the three groups in terms of comfort at all points of evaluation times (P < .001). The comfort score in the control group was significantly higher than the two intervention groups (P < .001). Moreover, the comfort score in the warmed intravenous fluid group was significantly higher than the forced-air warming group (P < .001). In addition, there was a significant difference in shivering severity between the three groups at the end of the surgery, entrance to the recovery room, and 15 minutes after surgery (P < .001). The majority of patients in the forced-air warming group (90%) had no shivering at all three times, while the warmed IV fluid and control groups was 65% and 30% respectively.

CONCLUSIONS

Non-pharmacological methods such as forced-air warming and warmed intravenous fluid can provide comfort and prevent shivering in orthopaedic patients undergoing spinal anesthesia. However, the use of forced-air warming is more effective than warmed intravenous fluid in providing comfort and preventing shivering in these patients. It is recommended that these methods be used in the operating room to provide comfort and prevent shivering in these patients.

A Systematic Review and Meta-analysis of Efficacy and Safety of Dexmedetomidine Combined With Intrathecal Bupivacaine Compared to Placebo

BACKGROUND

 Dexmedetomidine has been approved as a sedative agent in critical patients. It is also frequently used as an adjuvant with local anesthetic in spinal anesthesia. However, its use as an adjuvant has not been approved due to the paucity of data. The present systematic review and meta-analysis were undertaken to synthesize evidence for efficacy and safety when dexmedetomidine is combined with bupivacaine in spinal anesthesia.

METHODS

A literature search was done using PubMed, Google Scholar, Embase, and Cochrane Library. Search results were screened and eligible studies were included to perform a systematic review and meta-analysis using the software 'Review Manager (RevMan) version 5.4.1' using a random effect model. Cochrane's' Risk of Bias tool (RoB2)' was used for quality assessment. Mean and standard deviation was used to calculate the standardized mean difference and its forest plot for efficacy measures. For the adverse event, a number of events were used to determine the risk ratio and its forest plot using RevMan software. Publication bias is visualized using a funnel plot.

RESULTS

 A total of 21 randomized control trials evaluating the efficacy and safety of intrathecal dexmedetomidine were included in the meta-analysis. A total of 1382 participants was included in this meta-analysis. The effect estimates for efficacy parameters, i.e. duration of the sensory block having SMD 2.33; CI, 1.83-2.83, motor block with SMD 1.83, CI 1.21, 2.46, and analgesia SMD 2.81; CI, 2.11-3.51. The risk ratio for adverse effects, i.e. nausea/vomiting, bradycardia, hypotension was not significant whereas it was significant for the incidence of shivering with RR 0.38; CI 0.23-0.97. The overall risk of bias among included studies was either of 'some concern' or 'high risk.'

CONCLUSIONS

 Intrathecal dexmedetomidine when combined with bupivacaine was found to significantly increase the three efficacy parameters, i.e. duration of sensory block, motor block, and analgesia. It also appears to be safe with no increased risk of bradycardia or hypotension. It is also associated with decreased postoperative shivering.

Corrected and Republished: Impacts of intrathecal fentanyl on the incidence of postoperative nausea/vomiting: Systematic review and meta-analysis of randomized studies

Post-operative nausea and vomiting (PONV) is an event of multifactorial origin with an incidence of 30% in the general population. Opioids such as fentanyl are being used as adjuvant to local anesthetic for its antiemetic effect. In this context, with this study we aimed to evaluate the impact of spinal fentanyl as an adjuvant on the incidence of PONV compared with a placebo, and shivering. A systematic search of randomized controlled trials that evaluated the use of spinal fentanyl in the prevention of PONV and shivering was conducted in different databases, of which 32 studies met the inclusion criteria. A total of 2116 patients scheduled for various surgeries, including cesarean section, orthopedic surgery in the lower limb, hysterectomy, and transurethral resection of the prostate, were included in the final analysis. The meta-analysis estimated the relative risk of incidence of PONV in the first 24 hours after surgery and secondary outcomes included the shivering symptom. The use of intrathecal fentanyl was associated with lower incidence of PONV, but not statistically significant when compared to the placebo (RR: 0.74 CI95%: 0.55-1.01 P = 0.06). Subgroup analysis showed a statistically significant reduction in PONV incidences with lower doses between 10 and 15 μg (RR: 0.44 CI95%: 0.35-0.55 P < 0.00001, I2 = 0%) but not with higher doses 20-25 μg. Secondary outcomes showed a decrease in incidence with the use of fentanyl vs the placebo (RR: 0.49, CI95% 0.33-0.72 P = 0.0003). Current evidence shows that the use of spinal fentanyl decreases the incidence of PONV, an effect favored using low doses.

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.

Prevention of Shivering Post Subarachnoid Block: Comparison between Different Doses of Intravenous Magnesium Sulphate

Background and Objectives: Shivering is a common complication of subarachnoid block (SAB). Magnesium sulphate has been proven to be effective in preventing shivering. The aim of this study was to compare the effectiveness and adverse effects in hemodynamic parameters between 50 mg/kg and 30 mg/kg of intravenous magnesium sulphate for prevention of shivering post-subarachnoid block. Materials and Methods: Eighty-six patients scheduled for surgery under SAB, aged between 18 to 65 years old with American Society of Anesthesiologists physical status I and II were randomised into two groups. Group A received a bolus of 50 mg/kg, while Group B received 30 mg/kg of intravenous magnesium sulphate, given over a 20 min duration following SAB. Shivering grade was recorded intraoperatively according to the Crossley and Mahajan shivering scale. Mean arterial pressure (MAP), heart rate, tympanic temperature, oxygen saturation and the use of vasopressors were recorded. Results: Forty-five percent of patients in Group A and 20% of patients in Group B did not exhibit shivering (p-value < 0.01). High-grade shivering was observed in 12.5% in Group A and 40% in Group B, respectively (p-value 0.02). The MAP trend was lower in Group B (p-value < 0.01), but the incidence of hypotension was not significant in both groups. The use of vasopressors was also similar between groups. Group B showed a lower oxygen saturation trend (p-value 0.04). The trends of heart rate and tympanic temperature were not significant in both groups. No patients had episodes of bradycardia or oxygen desaturation. Conclusions: In this study, intravenous magnesium sulphate 50 mg/kg is the lowest effective dose for prevention and treatment of high-grade shivering post-SAB without significant hemodynamic adverse events.

Strategies for Hypothermia Compensation in Altricial and Precocial Newborn Mammals and Their Monitoring by Infrared Thermography

Thermoregulation in newborn mammals is an essential species-specific mechanism of the nervous system that contributes to their survival during the first hours and days of their life. When exposed to cold weather, which is a risk factor associated with mortality in neonates, pathways such as the hypothalamic–pituitary–adrenal axis (HPA) are activated to achieve temperature control, increasing the circulating levels of catecholamine and cortisol. Consequently, alterations in blood circulation and mechanisms to produce or to retain heat (e.g., vasoconstriction, piloerection, shivering, brown adipocyte tissue activation, and huddling) begin to prevent hypothermia. This study aimed to discuss the mechanisms of thermoregulation in newborn domestic mammals, highlighting the differences between altricial and precocial species. The processes that employ brown adipocyte tissue, shivering, thermoregulatory behaviors, and dermal vasomotor control will be analyzed to understand the physiology and the importance of implementing techniques to promote thermoregulation and survival in the critical post-birth period of mammals. Also, infrared thermography as a helpful method to perform thermal measurements without animal interactions does not affect these parameters.

Comparative Study of the Prophylactic Effects of Intravenous Injection of Dexmedetomidine, Ondansetron, and Pethidine on Postoperative Shivering of Abdominal Surgery under General Anesthesia: A Randomized Clinical Trial

Background

postoperative shivering is a common complication of various surgical, so far no acceptable theory has been presented on the prevention of it. The aim of this study was to compare the effect of intravenous injection of dexmedetomidine, ondansetron, and pethidine on postoperative shivering among patients under abdominal surgery.

Materials and Methods

In a double-blind clinical trial study, 128 patients undergoing abdominal surgery were selected and randomly divided into four groups of 32. In the 4 groups, 0.5 μg/kg dexmedetomidine, 0.5 mg/kg pethidine, 0.1 mg/kg ondansetron, and the same volume of normal saline were injected intravenously when anesthetics were discontinued and the incidence and severity of postoperative shivering were determined and compared in four groups.

Results

The incidence of postoperative shivering was 12.5% in the dexmedetomidine group, 31.3% in the ondansetron group, 31.3% in the pethidine group, and 50% in the control group (P = 0.015). The mean of shivering severity in the four groups was 1.33 ± 0.5, 0.17 ± 0.8, 1.09 ± 0.4, and 1.13 ± 0.39, and the difference between the four groups was significant (P = 0.005).

Conclusion

The use of all three drugs of dexmedetomidine, ondansetron, and pethidine is effective in decreasing the incidence of postoperative shivering, but the use of dexmedetomidine is associated with less postoperative shivering, better hemodynamic stability, and fewer other postoperative complications.

Pseudo-pheochromocytoma due to obstructive sleep apnea: a case report

SUMMARY

Obstructive sleep apnea (OSA) is a condition of intermittent nocturnal upper airway obstruction. OSA increases sympathetic drive which may result in clinical and biochemical features suggestive of pheochromocytoma. We present the case of a 65-year-old male with a 2.9-cm left adrenal incidentaloma on CT, hypertension, symptoms of headache, anxiety and diaphoresis, and persistently elevated 24-h urine norepinephrine (initially 818 nmol/day (89-470)) and normetanephrine (initially 11.2 µmol/day (0.6-2.7)). He was started on prazosin and underwent left adrenalectomy. Pathology revealed an adrenal corticoadenoma with no evidence of pheochromocytoma. Over the next 2 years, urine norepinephrine and normetanephrine remained significantly elevated with no MIBG avid disease. Years later, he was diagnosed with severe OSA and treated with continuous positive airway pressure. Urine testing done once OSA was well controlled revealed complete normalization of urine norepinephrine and normetanephrine with substantial symptom improvement. It was concluded that the patient never had a pheochromocytoma but rather an adrenal adenoma with biochemistry and symptoms suggestive of pheochromocytoma due to untreated severe OSA. Pseudo-pheochromocytoma is a rare presentation of OSA and should be considered on the differential of elevated urine catecholamines and metanephrines in the right clinical setting.

LEARNING POINTS

Obstructive sleep apnea (OSA) is a common condition among adults. OSA may rarely present as pseudo-pheochromocytoma with symptoms of pallor, palpitations, perspiration, headache, or anxiety. OSA should be considered on the differential of elevated urine catecholamines and metanephrines, especially in patients with negative metaiodobenzylguanidine (MIBG) scan results.

Comparison of the Occurrence of Postoperative Shivering Between Sevoflurane and Desflurane Anesthesia

General anesthetic agents can change the shivering threshold. Sevoflurane and desflurane are widely used as inhalational anesthetics and have also been reported to lower the shivering threshold in a dose-dependent manner. Although the comparison of postoperative shivering (POS) between total intravenous anesthesia and inhalational anesthesia has been reported, there have been no reports on a direct comparison between sevoflurane and desflurane anesthesia and the occurrence of POS in open abdominal surgery. After obtaining approval from the Ethics Review Committee (2020-261), 683 adult patients who underwent open radical surgery for uterine, cervical, or pancreatic cancer under general anesthesia using inhalational anesthetics at Kyushu University hospital between December 2012 and March 2020 were included in this retrospective study. The odds ratio (OR) for the occurrence of POS between the two groups (sevoflurane and desflurane) was calculated. Multivariable-adjusted analysis was performed using possible factors affecting POS. Furthermore, propensity score (PS) matching was conducted using these factors. The multivariable-adjusted OR for the occurrence of shivering in the desflurane group (62 occurrences/356 patients) was 1.06 (95% confidence interval [CI]: 0.69-1.62, p = 0.79) compared with the sevoflurane group (77/327, reference). Similarly, after PS matching, the crude OR for the occurrence of shivering in the desflurane group (47/210) was 1.09 (95% CI: 0.68-1.75, p = 0.72) compared with the sevoflurane group (44/210, reference). Similar results were obtained in the stratified analysis by sex and age. The occurrence of POS is not different between sevoflurane and desflurane anesthesia.

Impacts of intrathecal fentanyl on the incidence of postoperative nausea/vomiting: Systematic review and meta-analysis of randomized studies

Post-operative nausea and vomiting (PONV) is an event of multifactorial origin with an incidence of 30% in the general population. Opioids such as fentanyl are being used as adjuvant to local anesthetic for its antiemetic effect. In this context, with this study we aimed to evaluate the impact of spinal fentanyl as an adjuvant on the incidence of PONV compared with a placebo, and shivering. A systematic search of randomized controlled trials that evaluated the use of spinal fentanyl in the prevention of PONV and shivering was conducted in different databases, of which 32 studies met the inclusion criteria. A total of 2116 patients scheduled for various surgeries, including cesarean section, orthopedic surgery in the lower limb, hysterectomy, and transurethral resection of the prostate, were included in the final analysis. The meta-analysis estimated the relative risk of incidence of PONV in the first 24 hours after surgery and secondary outcomes included the shivering symptom. The use of intrathecal fentanyl was associated with lower incidence of PONV, but not statistically significant when compared to the placebo (RR: 0.74 CI95%: 0.55-1.01 P = 0.06). Subgroup analysis showed a statistically significant reduction in PONV incidences with lower doses between 10 and 15 μg (RR: 0.44 CI95%: 0.35-0.55 P < 0.00001, I² = 0%) but not with higher doses 20-25 μg. Secondary outcomes showed a decrease in incidence with the use of fentanyl vs the placebo (RR: 0.49, CI95% 0.33-0.72 P = 0.0003). Current evidence shows that the use of spinal fentanyl decreases the incidence of PONV, an effect favored using low doses.

The Use of Neuromuscular Blockers to Prevent Shivering in the Setting of Postcardiac Arrest Targeted Temperature Management: A Narrative Review of an Off-Label Indication

Targeted temperature management (TTM) has become a standard of care over the past two decades for the improvement in neurologic function and mortality in postcardiac arrest patients. There are various mechanisms by which hypothermia helps to improve these outcomes, one of which is by reducing oxygen requirements. Less established is the use of nondepolarizing neuromuscular blockers (NMBs) to prevent shivering during TTM. Shivering can be disadvantageous in this setting as it increases oxygen requirements, which TTM is actively trying to decrease, in an already oxygen-deprived system as well as generates heat making it difficult to maintain hypothermia. Whether NMBs can improve these outcomes is conflicting in the currently available literature and there lacks a consensus on their role in shivering management. The pharmacokinetic and pharmacodynamic responses of these agents may be altered in hypothermic patients, therefore, their standard of monitoring may be unreliable. The accurate dosing and administration of these agents also remain unclear, further complicated by the lack of a standard use protocol. Various studies have been conducted regarding the use of NMBs to prevent shivering in postcardiac arrest patients undergoing TTM; however, it remains an off-label indication requiring further investigation.

Ondansetron for Shivering after Spinal Anesthesia in Cesarean Delivery: A Systematic Review and Meta-Analysis

PURPOSE

Evaluate the efficacy of ondansetron in preventing shivering after spinal anesthesia in cesarean delivery.

DESIGN

Systematic review and meta-analysis METHODS: Following the PRISMA statement, PubMed, CINAHL, Cochrane, EMBASE, Google scholar and other grey literature databases were searched for eligible studies.

FINDINGS

The overall incidence of shivering after spinal anesthesia in cesarean delivery is 32%, with 24% in patients who received ondansetron compared to 40% in the placebo group. A total of 19 trials consisting of 1399 patients were evaluated. Compared to placebo, ondansetron is effective in reducing the incidence of shivering (RR, 0.47; 95% CI, 0.29 to 0.78; P = 0.003). The quality of evidence is low due to substantial heterogeneity, imprecision and suspected publication bias. Patients who received ondansetron are less likely to require rescue treatment for shivering (RR, 0.34; 95% CI, 0.15 to 0.76; P = 0.009). Also, ondansetron is associated with a lower incidence of hypotension necessitating vasopressor treatment, and nausea and vomiting with no effects on the incidence of bradycardia.

CONCLUSION

Ondansetron is effective in mitigating shivering after spinal anesthesia in cesarean delivery.

Development of a Resting Energy Expenditure Estimation in Patients Undergoing Targeted Temperature Management with a Surface Gel Pad Temperature Modulating Device

Targeted temperature management (TTM) directly impacts energy expenditure via temperature modulation and shivering associated with temperature modulating devices. We hypothesized that resting energy expenditure (REE) can be accurately estimated utilizing data obtained from a surface gel pad temperature modulating device (TMD) and demographic factors. Baseline demographic data, along with concurrent temperature, sedation, and shivering data, and indirect calorimetry (IDC) were collected from patients undergoing TTM. The data from the IDC and temperature modulation device (TMD) were synchronized and averaged over 60-second intervals to provide simultaneous comparisons. Heat transfer (calories) was calculated from the TMD by an equation that assessed water temperature from the TMD to the patient, water temperature returning to the TMD, water flow rates, and device mode. A linear regression model was used to determine factors associated with REE as measured by IDC. A difference in the mean between REE and estimated REE was used to assess accuracy. There were 48 assessments conducted in 40 subjects [mean (standard deviation)] age: 58 (14) years, 60% female, body surface area (BSA): 2.0 ± 0.3 who underwent simultaneous assessments. Target temperature was 36-37°C in 75%, with a median Bedside Shivering Assessment Score of 0 (range 0-2). Factors associated with REE on multivariable linear regression included older age (p < 0.001), male sex (p = 0.004), higher BSA (p < 0.001), higher patient temperature (p < 0.001), and lower heat transfer (p = 0.003). Adjusted prediction coefficients from this model were then tested against REE by a Bland-Altman analysis. The difference between difference in resting energy estimation (REEdiff) and measured REE by IDC was 6.2 calories/min (REEdiff: 95% confidence interval: -14.1 calories, 26.5 calories, p = 0.5). We believe that the heat transfer data from the TMD coupled with clinical characteristics of patients can be utilized to calculate the REE for every minute of TTM. These data can be utilized to mitigate the consequences of shivering and malnutrition during TTM.

Addition of low-dose sufentanil to ropivacaine for reducing shivering and visceral traction pain during cesarean section

Objective

To investigate the efficacy of low-dose sufentanil for preventing shivering and visceral traction pain during cesarean section under spinal anesthesia.

Methods

This was a prospective, randomized, controlled study. A total of 112 full-term parturients who underwent elective caesarean delivery were randomly divided into two groups. Group R received 0.75% isobaric ropivacaine intrathecally and group RS received 0.75% isobaric ropivacaine plus 5 µg sufentanil intrathecally.

Results

There were no significant differences in the maximum sensory block time, motor block time, duration of the surgery, and heart rate, mean arterial pressure, and blood oxygen saturation before and 1, 5, and 10 minutes after spinal anesthesia, and at the end of the surgery between the two groups. Shivering was significantly more common in group R (n = 30) than in group RS (n = 8). The incidence of visceral traction pain in group R (46.43%) was significantly higher than that in group RS (14.29%). There was no significant difference in the newborns’ Apgar scores between the groups.

Conclusion

Adding low-dose sufentanil to ropivacaine can significantly reduce the incidence of shivering and visceral traction pain after spinal anesthesia.

Severe Shivering as an Adverse Effect of Regadenoson Myocardial Perfusion Imaging

Regadenoson myocardial perfusion imaging (MPI) is a widely used screening study for patients with an intermediate pretest probability of coronary artery disease (CAD). Via selective agonism of the adenosine A2A receptor, regadenoson can induce coronary steal, revealing stenotic vessel territory through transient ischemia. Common side effects of this medication include chest pain, shortness of breath, nausea, vomiting, atrioventricular block, seizure, and allergic reactions. Here we present a case of severe shivering and chest tightness after the administration of regadenoson, along with a physiologic explanation and treatment. 

Comparative evaluation of oral tramadol and gabapentin for prophylaxis of post-spinal shivering

Background and Aims:

Shivering in the peri-operative period is a common problem which is associated with various complications. Prophylaxis of shivering can thus help in reducing the cost and risk of complications. The present study was designed to compare prophylactic oral gabapentin, tramadol and placebo for prevention of post-spinal shivering.

Methods:

A total of 150 adult patients of either sex belonging to American Society of Anesthesiologists physical status I–III scheduled for elective orthopaedic surgeries were randomised to receive tramadol 100 mg (group A), gabapentin 600 mg (group B) or placebo (group C) orally 30 min before administration of spinal anaesthesia. The primary outcome was to study the incidence and severity of shivering,whereas the secondary outcome was to evaluate the incidence of adverse effects. Data were analysed by analysis of variance test, Student t-test, Mann–Whitney U test and Chi-square tests.

Results:

Incidence of shivering was comparable among groups A and B (P = 0.8) whereas it was significantly less than in group C (P = 0.00). Severity of shivering (grade 1 and 2) was comparable in all the groups (P = 0.6 and 0.36), whereas shivering grade 3 and grade 4 was significantly lesser in groups A and B as compared to group C (P = 0.01 and 0.01). The incidence of nausea and vomiting was more in group A (26%) as compared to group B (20%) (P = 0.48) but was significantly lesser than group C (48%) (P = 0.01). Incidence of sedation (sedation score ≥2) was significantly more in group B (22%) as compared to group A (4%) and group C (0%).

Conclusion:

Prophylactic oral gabapentin 600 mg and tramadol 100 mg are equally effective for prevention of post-spinal shivering.

Prevalence of aberrant blood pressure readings across two automated intraoperative blood pressure monitoring systems among patients undergoing caesarean delivery

OBJECTIVES

Aberrant automated blood pressure (BP) readings during caesarean delivery may lead to disruptions in monitoring. The present study compared the frequency of aberrant BP readings across two types of commercially available BP monitoring systems in use during caesarean delivery.

METHODS

This was a retrospective observational study using two comparable patient cohorts that resulted from simultaneous introduction of two types of monitors into a single obstetric surgical center in which similar patients were treated for the same surgical procedure by the same set of clinicians during the same year. Our primary hypothesis was that aberrant readings were significantly associated with the type of monitor being used for BP measurement, controlling for a variety of relevant covariates as specified in the analytic plan.

RESULTS

A total of 1418 cesarean delivery patients met inclusion criteria. Gaps of at least 6 min in machine-captured BP readings occurred in 159 (21.1%) of cases done in the operating room using a Datex-Ohmeda monitor vs. 183 (27.5%) of cases in the operating rooms using Phillips monitors (P = 0.005). In multivariable logistic regression analysis, the relative odds of the occurrence of monitoring gaps was 35% higher in rooms with the Phillips BP monitors as compared to the Datex-Ohmeda monitor while controlling for pre-specified covariates (odds ratio = 1.35, 95% confidence interval = 1.04-1.74, P = 0.02).

CONCLUSION

The present analysis suggests that aberrant BP readings for parturients undergoing caesarean delivery are significantly different between the two types of automated BP monitoring systems used in the operating rooms at our institution.

Extreme Postoperative Shivering: A Case Report to Remember

According to the American Society of Anesthesiologists (ASA), basic anesthetic monitoring addresses a set of parameters (oxygenation, ventilation, circulation, and temperature) that should be continually evaluated. Among these, temperature monitoring might be the most neglected by medical staff, entailing various consequences that might be undervalued and not seen as directly correlated with poor patient outcome. This clinical case depicts a postoperative patient with a state of hypothermia and severe shivering, clinically and objectively registered, that could have led to disastrous consequences, highlighting the importance of normothermia throughout the perioperative period.

Inhibition and facilitation of nociceptively evoked muscular activity by fentanyl or dexmedetomidine in isoflurane-anaesthetized pigs

OBJECTIVE

To investigate motor and cardiovascular responses to dexmedetomidine or fentanyl in isoflurane-anaesthetized pigs.

STUDY DESIGN

Experimental, balanced, block randomized, two-group design.

ANIMALS

A group of 16 crossbred pigs, 55 ± 8 days (mean ± standard deviation) old.

METHODS

Deltoid electromyography (EMG) was recorded during isoflurane anaesthesia. Electrical stimulation using 5, 10, 20 and 40 mA of the distal right thoracic limb elicited a nociceptive withdrawal reflex (NWR), quantified by the area under the curve (AUC) for the simulation intensity versus EMG amplitude response curve. Latency to movement evoked by clamping a claw for maximum 60 seconds was noted. Arterial blood pressure and pulse rate were recorded. Data were sampled at baseline and during dexmedetomidine 0.25, 0.5, 1.0, 2.0, 4.0 and 8.0 μg kg^-1 hour^-1 or fentanyl 5, 10, 20, 40, 80 and 160 μg kg^-1 hour^-1 infusions. The influence of infusion rate on NWR AUC and spontaneous EMG was analysed using a mixed model, with p < 5%.

RESULTS

NWR AUC increased at fentanyl 5 μg kg^-1 hour^-1 but decreased at fentanyl 40, 80 and 160 μg kg^-1 hour^-1 and dexmedetomidine 4.0 and 8.0 μg kg^-1 hour^-1. All pigs at fentanyl 80 μg kg^-1 hour^-1, and three pigs at dexmedetomidine 8.0 μg kg^-1 hour^-1 had mechanical latencies greater than 60 seconds. Spontaneous EMG activity increased accompanied by visually evident 'shivering' at fentanyl 5, 10 and 20 μg kg^-1 hour^-1 but decreased at dexmedetomidine 2, 4 and 8 μg kg^-1 hour^-1. Clinically relevant effects of increasing infusion rates on blood pressure or pulse rate were not observed.

CONCLUSION AND CLINICAL RELEVANCE

If anaesthetic plane or antinociception is evaluated in pigs, response to claw clamping and NWR will not necessarily give uniform results when comparing drugs. If only one method is used, results should be interpreted cautiously.

Hypoxia gradually augments metabolic and thermoperceptual responsiveness to repeated whole-body cold stress in humans

New Findings

What is the central question of this study?

In male lowlanders, does hypoxia modulate thermoregulatory effector responses during repeated whole‐body cold stress encountered in a single day?

What is the main finding and its importance?

A ∼10 h sustained exposure to hypoxia appears to mediate a gradual upregulation of endogenous heat production, preventing the progressive hypothermic response prompted by serial cold stimuli. Also, hypoxia progressively degrades mood, and compounds the perceived thermal discomfort, and sensations of fatigue and coldness.

Abstract

We examined whether hypoxia would modulate thermoeffector responses during repeated cold stress encountered in a single day. Eleven men completed two ∼10 h sessions, while breathing, in normobaria, either normoxia or hypoxia (PO2: 12 kPa). During each session, subjects underwent sequentially three 120 min immersions to the chest in 20°C water (CWI), interspersed by 120 min rewarming. In normoxia, the final drop in rectal temperature (T_rec) was greater in the third (∼1.2°C) than in the first and second (∼0.9°C) CWIs (P < 0.05). The first hypoxic CWI augmented the T_rec fall (∼1.2°C; P = 0.002), but the drop in T_rec did not vary between the three hypoxic CWIs (P = 0.99). In normoxia, the metabolic heat production (M˙) was greater during the first half of the third CWI than during the corresponding part of the first CWI (P = 0.02); yet the difference was blunted during the second half of the CWIs (P = 0.89). In hypoxia, by contrast, the increase in M˙ was augmented by ∼25% throughout the third CWI (P < 0.01). Regardless of the breathing condition, the cold‐induced elevation in mean arterial pressure was blunted in the second and third CWI (P < 0.05). Hypoxia aggravated the sensation of coldness (P = 0.05) and thermal discomfort (P = 0.04) during the second half of the third CWI. The present findings therefore demonstrate that prolonged hypoxia mediates, in a gradual manner, metabolic and thermoperceptual sensitization to repeated cold stress.

Improvement of the clinical signs of gait abnormality after treatment with levothyroxine in a horse with shivering and hypothyroidism

An 11-year-old Hanoverian gelding used for jumping was evaluated for gait abnormalities and hoof problems in the hindlimbs. Clinical examinations revealed signs consistent with shivers. A thyroid gland enlargement was noticed, baseline serum thyroid hormone (TH) concentrations were low, and a low response to thyrotropin-releasing hormone administration was observed. Hypothyroidism was suspected. The horse was treated with levothyroxine for 1 year. TH concentrations returned to the normal range by week 4 of treatment. Thirty weeks after the initiation of levothyroxine therapy, the gait abnormality improved. Our findings suggest that the assessment of thyroid status and especially of the subclinical thyroid gland disorders in horses affected with shivering, as well as evaluation of the effects of levothyroxine on the improvement of clinical signs could be promising in establishing the aetiopathogenesis and/or treatment of shivering in horses.

Prophylactic low dose ketamine infusion for prevention of shivering during spinal anesthesia: A randomized double blind clinical trial

BACKGROUND AND AIMS

Regional anesthesia is known to produce perioperative hypothermia and shivering. We aimed to evaluate if prophylactic low dose ketamine bolus followed by infusion would prevent intraoperative and postoperative shivering under spinal anesthesia.

MATERIAL AND METHODS

Sixty patients belonging to American Society of Anaesthesiologists (ASA) 1 and 2 undergoing abdominal and lower limb surgery were randomized to receive either 0.2 mg/kg iv of ketamine bolus followed by infusion 0.1 mg/kg/hr (Group K) or5 ml of saline followed by 0.1 ml/kg/hr solution (Group S) as an infusion throughout the period of surgery. The incidence of shivering was the primary outcome of the study with degree of sedation and the hemodynamic profile between the two groups being the secondary outcomes. Hemodynamics (Heart rate, Mean Blood Pressure and temperature), Grade of shivering and grade of sedation were assessed intraoperatively and for grade of shivering and sedation two hours postoperatively. Repeated measures Analysis of Variance (ANOVA) was used to compare the hemodynamic variables and Chisquare test/Fisher's exact test to compare the grades of shivering and sedation between the two groups.

RESULTS

Intraoperative shivering was seen in eighteen patients in saline group (58.06%) and only with four patients (13.79%) with ketamine group (P < 0.001). Post operative shivering was also significantly less in ketamine group compared to saline (P = 0.01). Also, patients who received ketamine had significant sedation in the intraoperative period (P < 0.001).

CONCLUSION

Prophylactic low dose ketamine administered as a small bolus followed by an infusion was effective in preventing both intraoperative and postoperative shivering.

Acute basilar artery occlusion with recurrent shivering: A case report

RATIONALE

Shivering is an important physiological response of the body that causes muscle tremors to maintain temperature homeostasis. Traumatic brain injuries that affect the hypothalamus cause hypothermia, and physical removal of suprasellar tumors causes thermoregulation imbalance. However, no study has reported shivering due to ischemic stroke.

PATIENT CONCERNS

A 58-year-old male patient was admitted to our emergency department to evaluate severe stenosis of the basilar artery. While waiting for further examination, he exhibited coarse shivering and severe dysarthria.

DIAGNOSIS

Brain computed tomography angiography revealed occlusion of the entire basilar artery, and cerebral hypoperfusion was diagnosed in that area.

INTERVENTIONS

Transfemoral cerebral angiography (TFCA) was immediately performed, followed by thrombectomy of the basilar artery.

OUTCOMES

Neurological deficits, including shivering, were rapidly reversed. The same symptom reoccurred 5 hours later, and TFCA was performed for thrombectomy and stenting, and neurological symptoms immediately reversed. The patient's neurological symptoms did not worsen during hospitalization.

LESSONS

Patients with acute basilar artery occlusion need prompt management because they have a higher mortality rate than those with other intracranial artery occlusions. When a patient exhibits neurological deficits accompanied by abrupt shivering for no specific reason, basilar artery occlusion must be considered.

The effect of combination of warm intravenous fluid infusion and forced air warming versus forced air warming alone on maternal temperature and shivering during cesarian delivery under spinal anesthesia

Objective

Administration of warm intravenous (IV) fluid infusion and use of forced air warmers is the most easy and physiologically viable method for maintaining normothermia during surgery and postsurgical periods This study was conducted to assess the effect of combination of active warming (AW) methods namely warm IV fluid infusion and forced air warming versus forced air warming only (WA) on maternal temperature during elective C-delivery under spinal anesthesia.

Materials and Methods

A total of 100 patients scheduled for elective c-section were grouped into those who received both warmed IV fluid infusion and forced air warmer (Combination of active warming WI= 50) and those who received only forced air warmer (WA = 50). Core body temperature and shivering incidence were recorded using a tympanic thermometer from prespinal till the end of surgery every 10 min and in postanesthesia care unit (PACU) at 0, 15, and 30 min.

Results

Core temperature showed statistically significant difference in 15, 35, 45, and 55 min between air warmer and warm infusion groups and in PACU at 0, 15, and 30 min, it was statistically significant (P = 0.000) among WI group (mean temperature = 36.79°C) when compared to WA group (mean temperature = 35.96°C). There was a lower incidence of shivering in WI compared to WA group, which is statistically significant.

Conclusion

Combination of warm Intravenous fluid infusion and Forced air warming is better than forced air warming alone. In maintaining near normal maternal core body temperature during elective cesarean section following spinal anesthesia. Combined warming method also reduces shivering incidence.

Intravenous dexmedetomidine versus intravenous clonidine for post spinal anesthesia shivering: a meta-analysis of randomized controlled trials

BACKGROUND

Dexmedetomidine and clonidine are the most extensively studied drugs for shivering treatment, because α₂-adrenergic agonists can reduce the shivering threshold. The objective of this meta-analysis was to compare the efficacy and complications of dexmedetomidine with those of clonidine, when used for control of post spinal anesthesia shivering.

METHODS

Electronic databases were searched for randomized controlled trials (RCT) comparing the effect of dexmedetomidine versus clonidine for control of post spinal anesthesia shivering. The endpoints were effective rate of shivering treatment, time to cease shivering, recurrent rate of shivering and complications.

RESULTS

Six studies comprising 340 adult patients were included in this meta-analysis. Dexmedetomidine had higher effective rate of shivering treatment (odds ratio [OR]: 4.11, 95% confidence interval (CI): [1.53, 11.07], P = 0.005), shorter time to cease shivering (Mean differences (MD)=-1.91; 95% CI [-3.66, -0.15], P = 0.03), lower recurrent rate of shivering (OR = 0.30; 95% CI [0.12, 0.75], P = 0.01), compared to clonidine. Dexmedetomidine had a lower rate of hypotension and higher incidence of sedation than clonidine.

CONCLUSIONS

Dexmedetomidine is superior to clonidine when used for shivering treatment after spinal anesthesia, because of higher incidence of effective rate and sedation, faster control of shivering, lower incidence of recurrent rate and hypotention.

Prevention of postanesthetic shivering under subarachnoid block for cesarean section: A randomized, controlled study comparing tramadol versus ondansetron

Background

Shivering is a frequent undesirable event in patients undergoing cesarean delivery under spinal anesthesia. Postanesthetic shivering has a multitude of deleterious effects and different methods have been used to prevent it. We therefore compare the efficacy of ondansetron to that of tramadol in preventing postanesthetic shivering in women undergoing cesarean section under subarachnoid block.

Aim

Comparison of the efficacy of ondansetron to that of tramadol in preventing postanesthetic shivering in women undergoing cesarean section under subarachnoid block.

Subject and Methods

This is a prospective, double-blind, placebo-controlled, randomized study. The patients (n = 109) were randomly allocated to three groups according to the study drugs, namely tramadol 50 mg group (Group T), ondansetron 4 mg group (Group O), and saline 4 ml group (Group S) using envelope randomization. Statistical analyses were done using Statistical Package for Social Sciences 20.0.

Results

A total of 100 patients completed the study (33 in Group S, 33 in Group T, and 34 in Group O). The three groups were comparable with respect to demographic characteristics. Shivering was observed in 16 (48.5%) of the patients in Group S; 13 (39.4%) patients in Group T, and in only 2 (5.9%) patients in Group O. The differences in incidence of shivering were statistically significant between Groups O and S (P = 0.000) and Groups O and T (P = 0.001) but not between Groups T and S (P = 0.460). The differences across the groups were not statistically significant in terms of incidence of intraoperative hypotension, bradycardia, and the cumulative amount of ephedrine consumed.

Conclusion

This study demonstrated that ondansetron is superior to tramadol in preventing shivering under spinal anesthesia in women undergoing cesarean section.

Body temperature control in rats by muscle tone during rest or sleep

AIM

To explore the role of tonic motor unit activity in body temperature control.

METHODS

Motor unit activity in soleus and several other skeletal muscles was recorded electromyographically from adult rats placed in a climate chamber on a load sensitive floor, which, together with video monitoring, allowed detection of every successive period of movement and no movement.

RESULTS

In the absence of movements during rest or sleep, motor unit activity was exclusively tonic and therefore equivalent to muscle tone as defined here. The amount of tonic activity increased linearly in the soleus as the ambient temperature decreased from 32°C to below 7°C, owing to progressive recruitment and increased firing rate of individual units. Brief movements occurred randomly and frequently during rest or sleep in association with brief facilitation or inhibition of motor neurons that turned tonic motor unit activity on or off, partitioning the tonic activity among the available motor units. Shivering first appeared when a falling ambient temperature reached ≤7°C in several muscles except soleus, which was as active between shivering bursts as during them.

CONCLUSION

Muscle tone and overt shivering are strikingly different phenomena. Tonic motor unit activity in the absence of movements evokes isometric contractions and, therefore, generates heat. Accordingly, when the amount of tonic activity increases with falling ambient temperature, so must heat production. Consequently, graded muscle tone appears as an important and independent mechanism for thermogenesis during rest or sleep at ambient temperatures ranging from <7°C to at least 32°C.

Room Temperature Versus Warm Irrigation Fluid Used for Patients Undergoing Arthroscopic Shoulder Surgery: A Systematic Review and Meta Analysis

PURPOSE

The aim of this study was to analyze whether warm irrigation fluid could reduce postoperative adverse effects in patients undergoing arthroscopic shoulder surgery compared with room temperature irrigation fluid.

DESIGN

A systematic review and meta-analysis of clinical trials was performed.

METHODS

A computerized search of electronic databases was performed. The inclusion criteria were studies comparing the clinical effects of room temperature and warm irrigation fluid on patients undergoing arthroscopic shoulder surgery.

FINDINGS

Warm irrigation fluid reduced the degree of core body temperature drop and the incidence of hypothermia. A statistically lower incidence of shivering also occurred in the warm irrigation fluid group.

CONCLUSIONS

The use of warm irrigation fluid better maintains core body temperature and reduces incidence of shivering than room temperature irrigation fluid. Therefore, warm irrigation fluid is a better choice for arthroscopic shoulder surgery.

Cannabinoid Receptor Agonist WIN55, 212-2 Adjusts Lipid Metabolism in a Rat Model of Cardiac Arrest

The objective of this study was to investigate the effects of pharmacologically induced hypothermia with WIN55, 212-2 (WIN)on postresuscitation myocardial function, microcirculation, and metabolism-specific lipids in a rat cardiac arrest (CA) model. Ventricular fibrillation was electrically induced and untreated for 6 minutes in 24 Sprague-Dawley rats weighing 450-550 g. Cardiopulmonary resuscitation including chest compression and mechanical ventilation was then initiated and continued for 8 minutes, followed by defibrillation. At 5 minutes after restoration of spontaneous circulation (ROSC), animals were randomized into four groups: (1) normothermia with vehicle (NT); (2) physical hypothermia with vehicle (PH); (3) WIN55, 212-2 with normothermia (WN); and (4) WIN55, 212-2 with hypothermia (WH). For groups of WN and WH, WIN was administered by continuous intravenous infusion with a syringe pump for 4 hours. PH started at 5 minutes after resuscitation. NT maintained core temperature at 37°C ± 0.2°C with the aid of a heating blanket. Hypothermia groups maintained temperature at 33°C ± 0.5°C for 4 hours after ROSC. There was a significant improvement in myocardial function as measured by ejection fraction, cardiac output, and myocardial performance index in animals treated with WH and PH beginning at 1 hour after start of infusion. In the WH and PH groups, buccal microcirculation was significantly improved compared with NT and WN. Plasma at pre-CA and ROSC 4 hours was harvested for lipid metabolism. The WH group appeared to be closer to baseline than the other groups in lipid metabolism. lysophosphatidylcholine (LPC) 18:2, free fatty acid (FFA) 22:6, and ceramide (CER) (24:0) changed significantly among the lipidomic data compared with NT (p < 0.05). Postresuscitation hypothermia improved myocardial function and microcirculation. WH-mediated lipid metabolism had the best metabolic outcome to bring back the animals to normal metabolism, which may be protective to improve outcomes of CA. LPC 18:2, FFA 22:6, and CER (24:0) may be important predictors of outcomes of CA.

A prospective observational study

BACKGROUND

Shivering during caesarean section (CS) under spinal anaesthesia is a common phenomenon. It could not only alter patient's physiology by increasing oxygen consumption but also affect the parturient's experience of childbirth. Shivering is thought to be associated with intraoperative hypothermia, but the risk factors and exact mechanism remain unclear.

METHODS

We conducted a prospective, observational study to examine the potential risk factors for intraoperative shivering, including anxiety levels. Two hundred patients undergoing elective CS under spinal anaesthesia were recruited. Parturient anxiety levels were evaluated using the State-Trait Anxiety Inventory (STAI) questionnaire. Age, weight, height, BMI, anxiety level, number of previous deliveries, sensory block level, level of education, temperature difference during surgery and American Society of Anesthesiologists score were investigated as potential risk factors. Stepwise logistic regression was used to assess the predictors for shivering.

RESULTS

Data from 155 parturients were analysed. Shivering incidence was 21.9% (34 parturients). The statistical model predicted 8.5% of a shivering incidence variability (R-square Nagelkerke = 0.085). Out of all measured variables, only the number of previous deliveries [(W) = 4.295 Exp(B) = 0.562 P < .05] and STAI-X1 [(W) = 4.127 Exp(B) = 1.052 P < .05] were significant. In our model, the risk of shivering decreased by 44% with every previous delivery and increased by 5.2% with each 1-point increase in STAI-X1.

CONCLUSION

We failed to prove a strong correlation between the measured variables and shivering. Our findings, however, support the hypothesis, that to a limited extent, anxiety promotes shivering during CS.

Subarachnoid and epidural dexmedetomidine for the prevention of post-anesthetic shivering: a meta-analysis and systematic review

Background

Post-anesthetic shivering incurs discomfort to patients or even exacerbates their condition. However, no ideal drug has been well established for preventing post-anesthetic shivering. Currently, subarachnoid and epidural dexmedetomidine have demonstrated to have an anti-shivering effect.

Methods

An electronic search was conducted to identify randomized placebo-controlled trials reporting shivering and then compared subarachnoid and epidural dexmedetomidine with placebo in adults undergoing selective surgery. Data assessment and pooling were analyzed by Review Manager 5.3, STATA 15.0 and GRADE-pro 3.6 software.

Results

Twenty-two studies (1389 patients) were subjected to this meta-analysis. The incidence of post-anesthetic shivering decreased from 20.10% in the placebo group to 10.30% in the dexmedetomidine group (RR, 0.48; 95% CI, 0.39–0.59; Z=6.86, P<0.00001, I²=32%). Non-Indian, epidural-space route and cesarean subgroups indicated a better anti-shivering effect. In the subarachnoid-space route subgroup, a dosage of >5 μg showed significantly superior anti-shivering effects than that of ≤5 μg. Subarachnoid and epidural dexmedetomidine increased the incidence of bradycardia, had no impact on nausea and vomiting, shortened the onset of block and lengthened the duration of block and analgesia. However, its effect on hypotension and sedation remained uncertain. The overall risk of bias was relatively low. The level of evidence was high, and the recommendation of voting results was strong.

Conclusion

Dexmedetomidine as a subarachnoid and epidural adjunct drug could decrease the incidence of post-anesthetic shivering in a dose-dependent manner. However, caution should be taken in patients with original bradycardia.