Efficacy spectrum of antishivering medications

Effect of preoperative warming on intraoperative hypothermia and postoperative functional recovery in total hip arthroplasty: a randomized clinical trial

BACKGROUND

Intraoperative hypothermia is associated with increased morbidity and impaired postoperative recovery. Direct anterior-approached total hip arthroplasty (ATHA) may lead to significant thermal loss. We aimed to assess whether preoperative warming had an impact on intraoperative hypothermia and postoperative functional recovery after ATHA.

METHODS

In this prospective randomized controlled clinical trial 40 patients scheduled for ATHA were randomly divided into two groups of 20 patients each. Group W received, prior to the induction of general anesthesia, a 30 minutes 43 °C forced-air preoperative warming. Group C did not receive any preoperative warming. A blinded observer noted the core body temperature at the time of induction and at fixed time points, i.e. every five minutes during the first hour of surgery. The evolution of postoperative patient perceived thermal comfort (TC) and functional recovery (QoR-15) was assessed 24, 48 and 72 hours after surgery. Length of stay in the post-anesthesia care unit (PACU) was noted.

RESULTS

The temperature drop was significantly faster and of higher amplitude in group C than in group W, during first hour of surgery (P<0.001). Evolution of QoR-15 and TC was significantly better in group W than in group C (P<0.001 for QoR-15 and P<0.001 for thermal comfort), with shorter length of stay (median [IQR]) in the PACU (minutes; 73 [61-79] for group C and 98 [83-129] for group W, P<0.001).

CONCLUSIONS

In ATHA, pre-warming delays and reduces intraoperative heat loss, impacting patient comfort and postoperative functional recovery.

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.

Fentanyl Versus Ondansetron for Shivering Prevention in Cesarean Section: A Comparative Study

BACKGROUND AND PURPOSE

The incidence of postoperative shivering (PS) following intrathecal anesthesia is a common complication, with potential negative impacts on patient outcomes. This study aims to evaluate the effectiveness of intrathecal fentanyl versus intravenous ondansetron in preventing post-spinal anesthesia shivering in cesarean section patients.

EXPERIMENTAL APPROACH

A randomized controlled trial was conducted from July 2021 to April 2023, involving pregnant women scheduled for cesarean section under intrathecal anesthesia. The participants were divided into three groups: group F received intrathecal fentanyl (15 μg) with spinal anesthesia, while group O received intravenous ondansetron (8 mg) added to the usual saline solution. The control group (group C) received only intravenous fluid before spinal anesthesia and intrathecal bupivacaine without fentanyl. Shivering occurrences were observed and recorded during the procedure.

KEY RESULTS

The incidence of shivering was significantly lower in the fentanyl and ondansetron groups compared to the control group (p=0.0123). Both intrathecal fentanyl and intravenous ondansetron administration showed effectiveness in reducing shivering during spinal anesthesia.

CONCLUSION

The administration of intrathecal fentanyl and intravenous ondansetron significantly reduced the occurrence of shivering during spinal anesthesia in cesarean section patients. This study contributes to advancing knowledge in the field by providing evidence of the preventative effects of these medications on post-spinal anesthesia shivering.

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.

A Comparative Evaluation of Nalbuphine and Tramadol for the Control of Post-Spinal Anaesthesia Shivering

Objectives

In this study, our primary aim was to compare the efficacy of and haemodynamic changes related to nalbuphine and tramadol when used for the control of post-spinal anaesthesia shivering, as per Wrench shivering grades. The secondary aim was to study the complications and adverse effects associated with the drugs.

Methodology

A total of 60 patients with the American Society of Anesthesiologists (ASA) physical status class I/II who were scheduled to undergo elective surgeries under spinal anaesthesia were divided into two groups of 30 each. Group N received intravenous nalbuphine 0.05 mg/kg and Group T received intravenous tramadol 1 mg/kg, two minutes after the patients started shivering after undergoing spinal anaesthesia. The anaesthesia technique was standardised for all the patients in the study. The shivering grade was measured using the Wrench shivering grade and the level of sedation was studied using the Ramsay Sedation Scale. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) were recorded. All the parameters were measured at the baseline and at one, two, five, 10, 15, and 30 minutes after administering the drug.

Results

Immediately after giving the drug, the time taken to control shivering was significantly lower in Group T: 3.633 minutes. However both the drugs controlled shivering effectively. There were no significant haemodynamic changes in both groups, probably due to the lower dosage of drugs used in our study. A different set of side effects were seen in each group. In Group N, out of 30 patients, five (16.67%) patients were sedated, four (13.33%) had hypotension, and two (6.67%) had bradycardia, whereas In Group T, out of 30 patients, five (16.67%) patients had nausea, four (13.33%) had nausea and vomiting, and two (16.67%) had dizziness following the administration of the drug. Respiratory depression or itching was not seen in any patients in either group.

Conclusion

Based on our findings, both Intravenous nalbuphine 0.05 mg/kg and intravenous tramadol 1 mg/kg are effective in treating patients with post-spinal anaesthesia shivering; however, the time taken to control shivering is lower with tramadol than nalbuphine. Both the drugs resulted in minimal haemodynamic changes and adverse effects.

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.

Association between ionized magnesium and postoperative shivering

PURPOSE

Ionized magnesium (iMg) is considered to be the biologically active fraction of circulating total serum Mg (tMg). However, only the relationship between tMg and postoperative shivering has been studied. To our knowledge, hitherto no clinical studies have investigated the association between serum ionized magnesium concentration ([iMg]) and postoperative shivering. Therefore, we aimed to retrospectively examine this association, focusing on hypomagnesemia and depletion of [iMg].

METHODS

This retrospective study involved 421 patients who underwent pancreaticoduodenectomy under general anesthesia at our center from December 2012 to September 2019. Logistic regression analysis was performed to estimate the odds ratio (OR) for the incidence of postoperative shivering.

RESULTS

Postoperative shivering developed in 111 out of 421 patients. The post-surgical concentration of [iMg] was significantly associated with postoperative shivering in the non-adjusted model, but not in the multivariable-adjusted model. In multivariable-adjusted analysis, progressive decrease of [iMg] by 0.1 mmol/L significantly increased the risk of postoperative shivering (OR: 1.64, 95% CI 1.02-2.64, p = 0.04). The multivariable-adjusted OR for postoperative shivering was 3.65 (95% CI 1.25-13.55, p = 0.02) in subjects with post-surgical [iMg] less than 0.6 mmol/L and decrease in [iMg] during surgery compared with those with post-surgical [iMg] more than 0.6 mmol/L and constant or increased of [iMg] during surgery.

CONCLUSION

A decrease in the [iMg] during surgery was significantly associated with postoperative shivering. Subjects who had an [iMg] lower than 0.6 mmol/L post-surgery and decreased [iMg] during surgery had a significantly higher risk of postoperative shivering. Intraoperative depletion of [iMg] was significantly associated with shivering.

Efficacy of flurbiprofen axetil for preventing postanesthetic shivering in patients undergoing gynecologic laparotomy surgeries

Background

Postanesthetic shivering is an unpleasant adverse event in surgical patients. A nonsteroidal anti-inflammatory drug has been reported to be useful in preventing postanesthetic shivering in several previous studies. The aim of this study was to evaluate the efficacy of flurbiprofen axetil being a prodrug of a nonsteroidal anti-inflammatory drug for preventing postanesthetic shivering in patients undergoing gynecologic laparotomy surgeries.

Method

This study is a retrospective observational study. I collected data from patients undergoing gynecologic laparotomy surgeries performed between October 1, 2019, and September 30, 2020, at Kumamoto City Hospital. All the patients were managed with general anesthesia with or without epidural analgesia. The administration of intravenous 50 mg flurbiprofen axetil for postoperative pain control at the end of the surgery was left to the individual anesthesiologist. The patients were divided into two groups: those who had received intravenous flurbiprofen axetil (flurbiprofen group) and those who had not received intravenous flurbiprofen axetil (non-flurbiprofen group), and I compared the frequency of postanesthetic shivering between the two groups. Additionally, the factors presumably associated with postanesthetic shivering were collected from the medical charts. Intergroup differences were assessed with the χ² test with Yates’ correlation for continuity category variables. The Student’s t test was used to test for differences in continuous variables. Furthermore, a multivariate logistic regression analysis was performed to elucidate the relationship between the administration of flurbiprofen axetil and the incidence of PAS.

Results

I retrospectively examined the cases of 141 patients aged 49 ± 13 (range 21-84) years old. The overall postanesthetic shivering rate was 21.3% (30 of the 141 patients). The frequency of postanesthetic shivering in the flurbiprofen group (n = 31) was 6.5%, which was significantly lower than that in the non-flurbiprofen group (n = 110), 25.5% (p value = 0.022). A multivariate logistic regression analysis showed that administration of flurbiprofen axetil was independently associated with a reduced incidence of postanesthetic shivering (odds ratio 0.12; 95% confidence interval, 0.02-0.66, p value = 0.015).

Conclusions

My result suggests that intraoperative 50 mg flurbiprofen axetil administration for postoperative pain control is useful to prevent postanesthetic shivering in patients undergoing gynecologic laparotomy surgeries.

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.

Dexmedetomidine for Improved Quality of Emergence From General Anesthesia: A Dose-Finding Study

BACKGROUND

Dexmedetomidine provides smooth and hemodynamically stable emergence at the expense of hypotension, delayed recovery, and sedation. We investigated the optimal dose of dexmedetomidine for prevention of cough, agitation, hypertension, tachycardia, and shivering, with minimal side effects.

METHODS

In this prospective, randomized, double-blind trial, 216 adult patients were randomly assigned to dexmedetomidine 1 µg/kg (D 1), 0.5 µg/kg (D 0.5), 0.25 µg/kg (D 0.25), or control (C). During emergence, cough, agitation, hemodynamic parameters, shivering, time to extubation, and sedation scores were recorded.

RESULTS

A total of 190 patients were analyzed. The respective incidences for the groups D 1, D 0.5, and D 0.25 versus group C were 48%, 64%, and 64% vs 84% for cough-corrected P < .003 between groups D 1 and C; 33%, 34%, and 33% vs 72% for agitation-corrected P < .003 between group C and each of the study groups; and 4%, 2%, and 7% vs 22% for shivering-corrected P = .03 and corrected P = .009 between groups D 1 and D 0.5 versus group C, respectively. The percent increase from baseline blood pressure on extubation for the 3 treatment groups was significantly lower than group C. Percent increase in heart rate was lower than control in groups D 1 and D 0.5 but not in group D 0.25. Time to extubation and sedation scores were comparable. However, more hypotension was recorded during the emergence phase in the 3 treatment groups versus group C.

CONCLUSIONS

D 1 at the end of surgery provides the best quality of emergence from general anesthesia including the control of cough, agitation, hypertension, tachycardia, and shivering. D 0.5 also controls emergence phenomena but is less effective in controlling cough. The 3 doses do not delay extubation. However, they cause dose-dependent hypotension.

Comparative study between intrathecal dexmedetomidine and intrathecal magnesium sulfate for the prevention of post-spinal anaesthesia shivering in uroscopic surgery; (RCT)

Background

Hypothermia and shivering are common complications after spinal anaesthesia, especially after uroscopic procedures in which large amounts of cold intraluminal irrigation fluids are used. Magnesium sulfate and dexmedetomidine are the most effective adjuvants with the least side effects. The aim of this study was to compare the effects of intrathecal dexmedetomidine versus intrathecal magnesium sulfate on the prevention of post-spinal anaesthesia shivering.

Methods

This prospective randomized, double-blinded controlled study included 105 patients who were scheduled for uroscopic surgery at the Kasr El-Aini Hospital. The patients were randomly allocated into three groups. Group C (n = 35) received 2.5 ml of hyperbaric bupivacaine 0.5% (12.5 mg) + 0.5 ml of normal saline, Group M (n = 35) received 2.5 ml of hyperbaric bupivacaine 0.5% (12.5 mg) + 25 mg of magnesium sulfate in 0.5 ml saline, and Group D (n = 35) received 2.5 ml of hyperbaric bupivacaine 0.5% (12.5 mg) + 5 μg of dexmedetomidine in 0.5 ml saline. The primary outcomes were the incidence and intensity of shivering. The secondary outcomes were the incidence of hypothermia, sedation, the use of meperidine to control shivering and complications.

Results

Group C had significantly higher proportions of patients who developed shivering (21), developed grade IV shivering (20) and required meperidine (21) to treat shivering than group M (8,5,5) and group D (5,3,6), which were comparable to each other.

The time between block administration and meperidine administration was similar among the three groups. Hypothermia did not occur in any of the patients.

The three groups were comparable regarding the occurrence of nausea, vomiting, bradycardia and hypotension. All the patients in group C, 32 patients in group M and 33 patients in group D had a sedation score of 2. Three patients in group M and 2 patients in group D had a sedation score of 3.

Conclusions

Intrathecal injections of both dexmedetomidine and magnesium sulfate were effective in reducing the incidence of post-spinal anaesthesia shivering. Therefore, we encourage the use of magnesium sulfate, as it is more physiologically available, more readily available in most operating theatres and much less expensive than dexmedetomidine.

Trial registration

Clinical trial registration ID: Pan African Clinical Trial Registry (PACTR) Trial Number PACTR201801003001727; January 2018, “retrospectively registered”.

Hypothermia: Impact on plasticity following brain injury

Therapeutic hypothermia (TH) is a potent neuroprotectant against multiple forms of brain injury, but in some cases, prolonged cooling is needed. Such cooling protocols raise the risk that TH will directly or indirectly impact neuroplasticity, such as after global and focal cerebral ischemia or traumatic brain injury. TH, depending on the depth and duration, has the potential to broadly affect brain plasticity, especially given the spatial, temporal, and mechanistic overlap with the injury processes that cooling is used to treat. Here, we review the current experimental and clinical evidence to evaluate whether application of TH has any adverse or positive effects on postinjury plasticity. The limited available data suggest that mild TH does not appear to have any deleterious effect on neuroplasticity; however, we emphasize the need for additional high-quality preclinical and clinical work in this area.

Effectiveness of Magnesium in Preventing Shivering in Surgical Patients: A Systematic Review and Meta-analysis

BACKGROUND

Clinical trials regarding the antishivering effect of perioperative magnesium have produced inconsistent results. We conducted a systematic review and meta-analysis with Trial Sequential Analysis to evaluate the effect of perioperative magnesium on prevention of shivering.

METHODS

We searched PubMed, EMBASE, Web of Science, Cochrane Central Register of Controlled Trials, and 2 registry sites for randomized clinical trials that compared the administration of magnesium to a placebo or no treatment in patients undergoing surgeries. The primary outcome of this meta-analysis was the incidence of shivering. The incidence of shivering was combined as a risk ratio with 95% CI using a random-effect model. The effect of the route of administration was evaluated in a subgroup analysis, and Trial Sequential Analysis with a risk of type 1 error of 5% and power of 90% was performed. The quality of each included trial was evaluated, and the quality of evidence was assessed using the Grading of Recommendation Assessment, Development, and Evaluation approach. We also assessed adverse events.

RESULTS

Sixty-four trials and 4303 patients (2300 and 2003 patients in magnesium and control groups, respectively) were included. The overall incidence of shivering was 9.9% in the magnesium group and 23.0% in the control group (risk ratio, 0.42; 95% CI, 0.33-0.52). Subgroup analysis revealed that the incidence of shivering was lower with IV (risk ratio, 0.29; 95% CI, 0.29-0.54; Grading of Recommendation Assessment, Development, and Evaluation, moderate), epidural (risk ratio, 0.24; 95% CI, 0.13-0.43; Grading of Recommendation Assessment, Development, and Evaluation, low), and intrathecal administration (risk ratio, 0.64; 95% CI, 0.43-0.96; Grading of Recommendation Assessment, Development, and Evaluation, moderate). Only trials with low risk of bias were included for Trial Sequential Analysis. The Z-cumulative curve for IV magnesium crossed the Trial Sequential Analysis monitoring boundary for benefit even though only 34.9% of the target sample size had been reached. The Z-cumulative curve for epidural or intrathecal administration did not cross the Trial Sequential Analysis monitoring boundary for benefit. No increase in adverse events was reported.

CONCLUSIONS

Perioperative IV administration of magnesium effectively reduced shivering and Trial Sequential Analysis suggested that no more trials are required to confirm that IV magnesium effectively reduces shivering.

Effect of intrathecal dexmedetomidine on cesarean section during spinal anesthesia: a meta-analysis of randomized trials

Objective

Intrathecal dexmedetomidine has been used in spinal anesthesia during cesarean sections. The purpose of this meta-analysis was to investigate the effect of intrathecal dexmedetomidine on the adverse reactions of spinal anesthesia during cesarean section.

Methods

We searched for relevant studies using PubMed, Web of Science, and the Cochrane library. After screening studies and extracting data, we performed a meta-analysis on the effect of intrathecal dexmedetomidine during cesarean section.

Results

A total of 278 patients from 4 studies were included in this meta-analysis. The incidence of shivering in the dexmedetomidine groups was significantly lower than that in the placebo groups during cesarean section (RR=0.40, 95% CI [0.25, 0.65], P=0.0002). Intrathecal dexmedetomidine had no effect on nausea and vomiting (RR=1.08, 95% CI [0.68, 1.71], P=0.74), bradycardia (RR=1.33, 95% CI [0.31, 5.76], P=0.70), and hypotension during cesarean section (RR=0.78, 95% CI [0.59, 1.03], P=0.08).

Conclusion

Intrathecal dexmedetomidine can effectively reduce the occurrence of shivering during cesarean section, but it does not affect the occurrence of nausea and vomiting, bradycardia or hypotension.

Effect of intrathecal dexmedetomidine on preventing shivering in cesarean section after spinal anesthesia: a meta-analysis and trial sequential analysis

Objective

Intrathecal dexmedetomidine (DEX) has been used to prevent shivering in patients undergoing cesarean section. The aim of this meta-analysis was to evaluate whether intrathecal DEX could prevent shivering in cesarean section after spinal anesthesia.

Methods

We searched PubMed, Embase, Web of Science, and the Cochrane Library for randomized controlled trials (RCTs) comparing intrathecal DEX in cesarean section after spinal anesthesia with placebo and reporting on shivering, postoperative nausea and vomiting (PONV), hypotension, and bradycardia. Trial sequential analysis (TSA) was also carried out for RCTs comparing DEX with placebo. This meta-analysis has been registered on PROSPERO, and the registration number is CRD42017071640.

Results

Six randomized clinical trials comparing 360 patients were included in this study. Compared with placebo, intrathecal DEX significantly reduced the incidence of shivering (risk ratio [RR]=0.40; 95% CI [0.26, 0.62]; P<0.0001). No significant difference was found in the incidence of PONV (RR=1.34; 95% CI [0.82, 2.18]; P=0.24), hypotension (RR=1.09; 95% CI [0.84, 1.42]; P=0.50), or bradycardia (RR=1.55; 95% CI [0.54, 4.42]; P=0.42). However, no firm conclusions can be made based on the results of all outcomes according to the TSA.

Conclusion

This meta-analysis found that intrathecal DEX could prevent shivering in cesarean section after spinal anesthesia and did not induce PONV, hypotension, or bradycardia. However, firm conclusions cannot be made until more studies are conducted.

Rigor prophylaxis in stage IV melanoma and renal cell carcinoma patients treated with high dose IL-2

BACKGROUND

Rigors are a significant adverse event during interleukin-2 (IL2) therapy for metastatic melanoma and renal cell carcinoma. Meperidine has been a mainstay for rigor prophylaxis but there is a paucity of data regarding possible alternatives.

METHODS

Ninety one patients receiving IL2 therapy for metastatic renal cell carcinoma and melanoma at Huntsman Cancer institute (HCI), Utah from May 2009 to October 2016 were retrospectively evaluated for rigor prophylaxis. Forty two patients received meperidine and 49 received tramadol. Rigors were tabulated using the proxy of number of doses of as needed (PRN) rigor medications and normalized by IL2 doses. Other outcomes of fever, hypotension, and renal insufficiency were noted on a binary scale and normalized by cycles. Statistical analysis was performed utilizing univariate and multivariate negative binomial models.

RESULTS

Ninety one patients were identified with metastatic melanoma or RCC who received high dose IL2 therapy. Forty two received meperidine and 49 received tramadol prophylaxis for rigors. Univariate negative binomial analysis shows incidence rate ratios (IRR): fever 0.41 (95% CI 0.28-0.62, p-value < 0.001), hypotension 1.7 (95% CI 1.11-2.61, p-value 0.015), renal insufficiency 0.58 (95% CI 0.35-0.98, p-value 0.041), rigors per all PRN meds 1.01 (95% CI 0.79-1.28, p-value 0.964), and rigors via opioid PRN meds 0.85 (95% CI 0.67-1.07, p-value 0.168). Multivariate negative binomial analysis shows IRR: fever 0.59 (95% CI 0.28-1.24, p-value 0.163), hypotension 0.93 (95% CI 0.43-2.03, p-value 0.864), renal insufficiency 1.1 (95% CI 0.52-2.32, p-value 0.807), rigors per al PRN meds 0.92 (95% CI 0.67-1.26, p-value 0.604), and rigors via opioid PRN 0.9 (95% CI 0.65-1.26, p-value 0.554).

CONCLUSION

Univariate models indicated meperidine pre-treatment was associated with significantly lower rates of fever and renal insufficiency whereas tramadol was associated with significantly lower rate of hypotension. However, when controlled for demographics and other treatment differences, these differences were no longer significant.

Comparative effectiveness of pharmacologic interventions to prevent shivering after surgery: a network meta-analysis

INTRODUCTION

Although many drugs have been studied to prevent postoperative shivering, their comparative effectiveness is unknown. We attempted to assess the comparative effectiveness of the pharmacologic strategies to prevent shivering after surgery including intravenous (IV) and intrathecal (IT) meperidine, IV and IT dexmedetomidine, IV and IT clonidine, nefopam, tramadol, ketamine, and serotonin receptor antagonists.

EVIDENCE ACQUISITION

We implemented a frequentist network meta-analysis of randomized trials. Random effect model was selected according to deviance information criteria. The incidence of moderate or severe shivering and the overall incidence of postoperative shivering were compared in all patients and subgroups of general and spinal anesthesia.

EVIDENCE SYNTHESIS

Seventy trials with 6062 participants were included. All interventions except clonidine IT and dexmedetomidine IT significantly decreased the incidence of moderate or severe shivering. All interventions except clonidine IT significantly decreased the overall incidence of shivering. Nefopam IV was ranked best regarding both the incidence of moderate or severe shivering (odds ratio [OR] 0.04, 95% confidence interval [CI] 0.04-0.25, SUCRA 86.2, moderate quality-evidence), and the overall incidence of shivering (OR 0.07, 95% CI 0.03 to 0.15, SUCRA 85.7, moderate quality-evidence), which was consistent in the subgroups of anesthesia.

CONCLUSIONS

Nefopam was ranked best regarding both severity and incidence of postoperative shivering. In addition to nefopam, tramadol, meperidine IV and IT, and dexmedetomidine IV were ranked high. However, there was significant heterogeneity regarding the individual drug regimen and surgery type, precluding firm conclusion. Further randomized trials are required to compare the efficacy of the drugs with high rank.

Postanaesthetic shivering - from pathophysiology to prevention

Postoperative shivering is a common complication of anaesthesia. Shivering is believed to increase oxygen consumption, increase the risk of hypoxemia, induce lactic acidosis, and catecholamine release. Therefore, it might increase the postoperative complications especially in high-risk patients. Moreover, shivering is one of the leading causes of discomfort for postsurgical patients. Shivering is usually triggered by hypothermia. However, it occurs even in normothermic patients during the perioperative period. The aetiology of shivering has been understood insufficiently. Another potential mechanism is pain and acute opioid withdrawal (especially with the use of short-acting narcotics). Besides that shivering is poorly understood, the gold standard for the treatment and prevention has not been defined yet. Perioperative hypothermia prevention is the first method to avoid shivering. Many therapeutic strategies for treating shivering exist and most are empiric. Unfortunately, the overall quality of the antishivering guidelines is low. Two main strategies are available: pharmacological and non-pharmacological antishivering methods. The combination of forced-air warming devices and intravenous meperidine is the most validated method. We also analysed different medications but final conclusion about the optimal antishivering medication is difficult to be drawn due to the lack of high-quality evidence. Nevertheless, control of PS is possible and clinically effective with simple pharmacological interventions combined with non pharmacological methods. However, to be consistent with the most up-to-date, evidence-based practice, future antishivering treatment protocols should optimize methodological rigor and transparency.

Introduction to surgical and perioperative clinical pharmacy for third-year pharmacy students: A pilot study of an elective course

INTRODUCTION

The objective of this study was to implement and assess an elective course that exposes pharmacy students to clinical pharmacy in the surgical and perioperative setting.

METHODS

A blended-design elective that included synchronous and asynchronous learning was developed and offered to third-year pharmacy students. Students' knowledge and perception regarding clinical topics in perioperative pharmacy was assessed using pre- and post-course assessments, online quizzes, a journal club, and course assignments. Knowledge of pharmacy operations was assessed using course assignments and reflective journal entries.

RESULTS

Pre- and post-course assessment improvement was seen in the categories of perioperative optimization of pharmacotherapy (29.1-70.1%, p=0.006), common surgical complications (45.8-91.7%, p = 0.001), and anesthetic agents (25-71.9%, p <0.001). Overall, the course was successful in increasing clinical pharmacy knowledge and was well received by students. Course evaluations were completed by 100% of students, and all rated the course as "excellent." Students demonstrated mastery of course content, though the course may not have provided optimal exposure to operating room/post-anesthesia care unit operations.

DISCUSSION AND CONCLUSIONS

Students agreed that the course was valuable and helped them develop new skills otherwise not developed by the curriculum; this conclusion was supported by objective assessment data. A team-teaching model allowed for minimal resources to operate the course. Moving forward, an early lecture addressing perioperative operations may supplement an area the course was lacking. Additionally, a longer duration of operating room shadowing may provide requested opportunities for observation of direct patient care.

A prospective, randomized, double-blinded control study on comparison of tramadol, clonidine and dexmedetomidine for post spinal anesthesia shivering

Introduction

Shivering, a common intraoperative problem under spinal anesthesia increases the oxygen consumption considerably and is uncomfortable and distressing to the patient, anesthesiologist as well as surgeon. The present study was designed to explore the effectiveness of tramadol, clonidine and dexmedetomidine in the treatment of post spinal anesthesia shivering and to look for their adverse effects.

Methods

This prospective, randomized, double blinded control study was done on 90 patients who developed shivering under spinal anesthesia. They were randomly allocated into three groups with Group T receiving tramadol 1 mg.kg⁻¹, Group C getting clonidine 1 mcg.kg⁻¹ and Group D patients receiving dexmedetomidine 0.5 mcg.kg⁻¹. The time taken to control shivering, recurrence rate, hemodynamic variables, sedation score and adverse effects were observed.

Results

Dexmedetomidine was faster in the control of shivering in 5.7 ± 0.79 minutes (min) whereas tramadol took 6.76 ± 0.93 min and clonidine was slower with 9.43 ± 0.93 min. The recurrence rate was much lower in the dexmedetomidine group with 3.3% than for clonidine (10%) and tramadol (23.3%) group. The sedation achieved with dexmedetomidine was better than clonidine and tramadol. The tramadol group had more cases of vomiting (four) and dexmedetomidine group had six cases of hypotension and two cases of bradycardia. Two of the clonidine patients encountered bradycardia and hypotension.

Conclusion

Dexmedetomidine is better than tramadol and clonidine in the control of shivering because of its faster onset and less recurrence rate. Though complications are encountered in the dexmedetomidine group, they are treatable.

Preventing shivering with adjuvant low dose intrathecal meperidine: A meta-analysis of randomized controlled trials with trial sequential analysis

The aim of this systematic review and meta-analysis is to evaluate the pros and cons of adjuvant low dose intrathecal meperidine for spinal anaesthesia. We searched electronic databases for randomized controlled trials using trial sequential analysis (TSA) to evaluate the incidence of reduced rescue analgesics, shivering, pruritus, nausea and vomiting when applying adjuvant intrathecal meperidine. Twenty-eight trials with 2216 patients were included. Adjuvant intrathecal meperidine, 0.05-0.5 mg kg-1, significantly reduced incidence of shivering (relative risk, RR, 0.31, 95% confidence interval, CI, 0.24 to 0.40; TSA-adjusted RR, 0.32, 95% CI, 0.25 to 0.41). Intrathecal meperidine also effectively reduced need for intraoperative rescue analgesics (RR, 0.27, 95% CI, 0.12 to 0.64; TSA-adjusted RR, 0.27, 95% CI, 0.08 to 0.91) and the incidence of pruritus was unaffected (RR, 2.31, 95% CI, 0.94 to 5.70; TSA-adjusted RR, 1.42, 95% CI, 0.87 to 2.34). However, nausea and vomiting increased (RR, 1.84, 95% CI, 1.29 to 2.64; TSA-adjusted RR, 1.72, 95% CI, 1.33 to 2.23; RR, 2.23, 95% CI, 1.23 to 4.02; TSA-adjusted RR,1.96, 95% CI, 1.20 to 3.21). Under TSA, these results provided a sufficient level of evidence. In conclusion, adjuvant low dose intrathecal meperidine effectively attenuates spinal anaesthesia-associated shivering and reduces rescue analgesics with residual concerns for the nausea and vomiting.

Systematic Quality Assessment of Published Antishivering Protocols

Shivering is a common side effect of targeted temperature modulation and general anesthesia. Antishivering strategies often employ a stepwise approach involving both pharmacological and physical interventions. However, approaches to treat shivering are often empiric and vary widely across care environments. We evaluated the quality of published antishivering protocols and guidelines with respect to methodological rigor, reliability, and consistency of recommendations.Using 4 medical databases, we identified 4027 publications that addressed shivering therapy, and excluded 3354 due to lack of relevance. After applying predefined eligibility criteria with respect to minimal protocol standards, 18 protocols/guidelines remained. Each was assessed using a modified Appraisal of Guidelines for Research and Evaluation II (mAGREE II) instrument containing 23 quality items within 6 domains (maximal score 23). Among 18 protocols/guidelines, only 3 incorporated systematically reviewed recommendations, whereas 15 merely targeted practice standardization. Fifteen of 18 protocols/guidelines addressed shivering during therapeutic cooling in which skin counterwarming and meperidine were most commonly cited. However, their mAGREE II scores were within the lowest tertile (1 to 7 points) and the median for all 18 protocols was 5. The quality domains most commonly absent were stakeholder involvement, rigor of development, and editorial independence. Three of 18 protocols/guidelines addressed postanesthetic antishivering. Of these, the American Society of Anesthesiologists guidelines recommending forced-air warming and meperidine received the highest mAGREE II score (14 points), whereas the remaining 2 recommendations had low scores (<5 points).Current published antishivering protocols/guidelines lack methodological rigor, reliability, and strength, and even the highest scoring of the 18 protocols/guidelines fulfilled only 60% of quality items. To be consistent with evidence-based protocol/guideline development processes, future antishivering treatment algorithms should increase methodological rigor and transparency.

[A prospective, randomized, double-blinded control study on comparison of tramadol, clonidine and dexmedetomidine for post spinal anesthesia shivering]

INTRODUCTION

Shivering, a common intraoperative problem under spinal anesthesia increases the oxygen consumption considerably and is uncomfortable and distressing to the patient, anesthesiologist as well as surgeon. The present study was designed to explore the effectiveness of tramadol, clonidine and dexmedetomidine in the treatment of post spinal anesthesia shivering and to look for their adverse effects.

METHODS

This prospective, randomized, double blinded control study was done on 90 patients who developed shivering under spinal anesthesia. They were randomly allocated into three groups with Group T receiving tramadol 1mg.kg^-1, Group C getting clonidine 1mcg.kg^-1 and Group D patients receiving dexmedetomidine 0.5mcg.kg^-1. The time taken to control shivering, recurrence rate, hemodynamic variables, sedation score and adverse effects were observed.

RESULTS

Dexmedetomidine was faster in the control of shivering in 5.7±0.79minutes (min) whereas tramadol took 6.76±0.93min and clonidine was slower with 9.43±0.93min. The recurrence rate was much lower in the dexmedetomidine group with 3.3% than for clonidine (10%) and tramadol (23.3%) group. The sedation achieved with dexmedetomidine was better than clonidine and tramadol. The tramadol group had more cases of vomiting (four) and dexmedetomidine group had six cases of hypotension and two cases of bradycardia. Two of the clonidine patients encountered bradycardia and hypotension.

CONCLUSION

Dexmedetomidine is better than tramadol and clonidine in the control of shivering because of its faster onset and less recurrence rate. Though complications are encountered in the dexmedetomidine group, they are treatable.

Effects of intrathecal dexmedetomidine on shivering after spinal anesthesia for cesarean section: a double-blind randomized clinical trial

Background

Shivering is among the common troublesome complications of spinal anesthesia (SA), and causes discomfort and discontentment in parturients undergoing cesarean sections (CSs). The aim of this study was to investigate the effects of intrathecal dexmedetomidine in the prevention of shivering in those who underwent CS under SA.

Subjects and methods

Fifty parturients planned for elective CSs under SA were enrolled in this prospective, double-blinded, controlled study and randomly divided into two equal groups. Spinal block was achieved with 12.5 mg 0.5% heavy bupivacaine plus 5 μg dexmedetomidine (BD group) or 0.5 mL 0.9% normal saline (BN group). The incidence and intensity of shivering, peripheral and core body temperature, hemodynamic parameters, and adverse events was recorded.

Results

The incidence of shivering was significantly higher in the BN group (52%) than the BD group (24%) (P=0.04). Likewise, the intensity of shivering was significantly higher in the BN group than the BD group (P=0.04). The incidence of adverse events, such as hypotension, nausea/vomiting, and bradycardia, was not significantly different between the two groups, although the grade of sedation was higher in the BD group than the BN group (P=0.004).

Conclusion

We conclude that intrathecal dexmedetomidine is effective in lowering the incidence and intensity of shivering in parturients undergoing CSs under SA without major adverse effects.

Analgesia, sedation, and neuromuscular blockade during targeted temperature management after cardiac arrest

The approach to sedation, analgesia, and neuromuscular blockade during targeted temperature management (TTM) remains largely unstudied, forcing clinicians to adapt previous research from other patient environments. During TTM, very little data guide drug selection, doses, and specific therapeutic goals. Sedation should be deep enough to prevent awareness during neuromuscular blockade, but titration is complex as metabolism and clearance are delayed for almost all drugs during hypothermia. Deeper sedation is associated with prolonged intensive care unit (ICU) and ventilator therapy, increased delirium and infection, and delayed wakening which can confound early critical neurological assessments, potentially resulting in erroneous prognostication and inappropriate withdrawal of life support. We review the potential therapeutic goals for sedation, analgesia, and neuromuscular blockade during TTM; the adverse events associated with that treatment; data suggesting that TTM and organ dysfunction impair drug metabolism; and controversies and potential benefits of specific monitoring. We also highlight the areas needing better research to guide our therapy.

The Preventive Role of Low-Dose Intravenous Ketamine on Postoperative Shivering in Children: A Placebo Randomized Controlled Trial

Background

Postoperative shivering is a major problem in children undergoing general anesthesia.

Objectives

The aim of the present study was to investigate the role of low-dose intravenous ketamine for prevention of shivering after induction of general anesthesia in children who had undergone tonsillectomy.

Patients and Methods

This was a randomized, double-blinded, placebo-controlled trial including 80 children, of American society of anesthesiologists (ASA) physical status I or II, scheduled for tonsillectomy under general anesthesia who were randomly assigned to an intravenous ketamine (0.5 mg/kg, n = 40; group K) group or matched dose placebo (n = 40; group N) group. Surgical and demographic data, unexpected side effects, and the occurrence of shivering for each child were assessed by a blinded observer at the following time points: T0, in the recovery room; T10, at 10 minutes; T20, at 20 minutes; T30, and at 30 minutes.

Results

With regards to the demographic and surgical data, no significant differences between the two study groups were observed (P ≥ 0.05). Shivering intensity in children who had received ketamine was significantly lower than children who had not received ketamine, at T0, T10, T20, and T30 after arrival (P < 0.05). There were no significant differences in hallucination, nausea, vomiting, hemodynamic dysfunction, blurred vision, and seizure in the K group compared with the N group (P ≥ 0.05).

Conclusions

Administration of intravenous ketamine at a dosage of 0.5 mg/kg immediately after anesthesia induction had a preventive effect on shivering intensity without hemodynamic alterations in children undergoing general anesthesia for tonsillectomy.

Perioperative thermoregulation and heat balance

Core body temperature is normally tightly regulated to within a few tenths of a degree. The major thermoregulatory defences in humans are sweating, arteriovenous shunt vasoconstriction, and shivering. The core temperature triggering each response defines its activation threshold. General anaesthetics greatly impair thermoregulation, synchronously reducing the thresholds for vasoconstriction and shivering. Neuraxial anaesthesia also impairs central thermoregulatory control, and prevents vasoconstriction and shivering in blocked areas. Consequently, unwarmed anaesthetised patients become hypothermic, typically by 1-2°C. Hypothermia results initially from an internal redistribution of body heat from the core to the periphery, followed by heat loss exceeding metabolic heat production. Complications of perioperative hypothermia include coagulopathy and increased transfusion requirement, surgical site infection, delayed drug metabolism, prolonged recovery, shivering, and thermal discomfort. Body temperature can be reliably measured in the oesophagus, nasopharynx, mouth, and bladder. The standard-of-care is to monitor core temperature and to maintain normothermia during general and neuraxial anaesthesia.

A comparison of prophylactic use of meperidine, meperidine plus dexamethasone, and ketamine plus midazolam for preventing of shivering during spinal anesthesia: a randomized, double-blind, placebo-controlled study

STUDY OBJECTIVES

The aim of this study is to compare the efficacy of combination of meperidine and dexamethasone with that of placebo, meperidine alone, and the combination of ketamine and midazolam in preventing shivering during spinal anesthesia.

DESIGN

This is a prospective, placebo-controlled study.

SETTING

The setting is at an operating room of a university-based teaching hospital.

PATIENTS

Two hundred American Society of Anesthesiologists I and II patients undergoing orthopedic and urologic surgery under spinal anesthesia were included.

INTERVENTIONS

Subarachnoid anesthesia was performed by using 15mg of 0.5% hyperbaric bupivacaine. Patients were randomly allocated to receive saline (placebo, group C), meperidine 0.4mg/kg (group Me), ketamine 0.25mg/kg plus midazolam 37.5μg/kg (group KMi), and meperidine 0.2mg/kg plus dexamethasone 0.1mg/kg (group MeD). All drugs were given as an intravenous bolus immediately after intrathecal injection.

MEASUREMENTS

During surgery and stay in the recovery room, shivering score, blood pressure, and some other adverse effects were recorded at 5-minute intervals. Axillary and tympanic temperatures were recorded at 15-minute intervals during the perioperative period.

MAIN RESULTS

The incidence of shivering after 30minutes of spinal anesthesia in groups C, Me, KMi, and MeD was 64%, 20%, 20%, and 4%, respectively, which was significantly higher in group C compared with other groups (P<.0001). Regarding adverse effects, there was no significant difference between groups (P≥.2). Axillary temperature significantly increased in the 15th-120th-minute interval in groups Me, KMi, and MeD (P<.0001) and in group MeD was higher than that in other groups. Core temperature decreased in the 15th-120th-minute interval in group MeD, lower than that in other groups (P<.0001).

CONCLUSIONS

Prophylactic use of meperidine 0.2mg/kg plus dexamethasone 0.1mg/kg was more effective than meperidine 0.4mg/kg as a sole agent or the combination of ketamine 0.25mg/kg and midazolam 37.5μg/kg in preventing shivering resulting from spinal anesthesia.

Implications of palonosetron in elderly patients undergoing laparoscopic cholecystectomy with respect to its anti-shivering effect

BACKGROUND

The elderly are vulnerable to hypothermia and have a higher risk of cardiovascular events induced by marked increases in oxygen consumption due to shivering. Five-hydroxytryptamine-3 (5-HT3) receptor antagonists have been previously reported to reduce post-anesthesia shivering.

AIM

In the present study, the authors investigated the effects of palonosetron, a new-generation 5-HT3 antagonist, on core hypothermia and the incidence of shivering after laparoscopic cholecystectomy in elderly patients.

METHODS

Forty-eight patients (65-80 years) were randomly assigned to one of two groups and administered palonosetron 0.075 mg (palonosetron group, n = 24) or the same volume of normal saline (control group, n = 24) before anesthesia induction. Core body temperatures and hemodynamic variables were monitored during and after operation. Post-anesthetic shivering (PAS) and pain scores were obtained in a post-anesthetic care unit.

RESULTS

Intraoperative esophageal temperature changed significantly over time (P = 0.010), but significant intergroup difference in change was not observed (P = 0.706). Furthermore, shivering frequencies were similar in the two groups (P = 0.610). However, postoperative pain scores at 30 min after entering the post-anesthesia care unit were significantly lower in the palonosetron group (P = 0.002).

DISCUSSION

Regardless of the previously reported anti-shivering effect of 5-HT3 receptor antagonists, pre-operative palonosetron 0.075 mg did not influence perioperative hypothermia or PAS in this study. This discrepancy might be due to the dose responsiveness of palonosetron to PAS and relatively low incidence of PAS in the elderly.

CONCLUSIONS

Pre-operative administration of palonosetron 0.075 mg did not influence perioperative hypothermia or post-anesthesia shivering in elderly patients undergoing laparoscopic cholecystectomy. However, palonosetron might be beneficial for reducing early postoperative pain in elderly patients with opioid-based patient-controlled analgesia.

Alpha-2 adrenergic agonists for the prevention of shivering following general anaesthesia

BACKGROUND

Shivering after general anaesthesia is common. It is unpleasant but can also have adverse physiological effects. Alpha-2 (α-2) adrenergic agonist receptors, which can lead to reduced sympathetic activity and central regulation of vasoconstrictor tone, are a group of drugs that have been used to try to prevent postoperative shivering.

OBJECTIVES

To assess the following: the effects of α-2 agonists on the prevention of shivering and subsequent complications after general anaesthesia in people undergoing surgery; the effects of α-2 agonists on the risk of inadvertent perioperative hypothermia; and whether any adverse effects are associated with these interventions.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and EMBASE on 13 June 2014. Our search terms were relevant to the review question and limited to studies that assessed shivering or hypothermia. We also carried out searches of clinical trials registers, and forward and backward citation tracking.

SELECTION CRITERIA

We considered all randomized controlled trials, quasi-randomized studies, and cluster-randomized studies with adult participants undergoing surgery with general anaesthesia in which an α-2 agonist was compared with another α-2 agonist or a placebo for the prevention of shivering.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data, consulting a third review author in the case of disagreements. We used standard Cochrane methodological procedures, including an assessment of risk of bias and use of GRADEpro software to interpret findings.

MAIN RESULTS

We included 20 studies with 1401 surgical participants comparing an α-2 agonist against a control. Thirteen studies compared clonidine with a control, whilst seven compared dexmedetomidine with a control. The doses, methods, and time of administration varied between studies: three studies gave the drug orally or as an intravenous bolus preoperatively and nine intraoperatively; one study gave the drug as an infusion starting preoperatively and seven started at varying points from anaesthetic induction to the end of surgery. Whilst all the studies were described as randomized, many provided insufficient detail on methods used. We had anticipated that attempts would be made to reduce performance bias by blinding of personnel and participants, however this was detailed in only six of the papers. Similarly, in some studies detail was lacking on methods to reduce the risk of detection bias. We therefore downgraded the quality of evidence in our 'Summary of findings' table by one level for risk of bias using the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) approach.All 20 included studies presented outcome data for postoperative shivering, and in meta-analysis α-2 agonists were shown to significantly reduce the risk of shivering (Mantel-Haenszel risk ratio 0.28, 95% confidence interval 0.18 to 0.43, P value < 0.0001). We found significant evidence of heterogeneity (I(2) = 80%) for this result that was not explained by sensitivity or subgroup analysis; we therefore downgraded the inconsistency of the evidence by one level. Although we did not feel that there were concerns with imprecision or indirectness of the data, we downgraded the quality of the evidence for the risk of publication bias following visual analysis of a funnel plot. Using GRADEpro, we rated the overall quality of the data for shivering as very low. Only one study reported the incidence of core hypothermia, whilst 12 studies measured core temperature. However, as the results for core temperature were reported in different styles, pooling the results was inappropriate. We found no studies with participant-reported outcomes such as experience of shivering or participant satisfaction. We found limited data for the outcomes of length of stay in the postanaesthetic care unit (three studies, 200 participants) and the following adverse effects: sedation (nine studies, 875 participants), bradycardia (eight studies, 716 participants), and hypotension (seven studies, 688 participants). Unpooled analysis suggested that sedation and bradycardia were significantly more common with dexmedetomidine than placebo, with all seven dexmedetomidine studies and none of the clonidine studies reporting statistically significantly higher levels of sedation as an adverse effect.

AUTHORS' CONCLUSIONS

There is evidence that clonidine and dexmedetomidine can reduce postoperative shivering, but patients given dexmedetomidine may be more sedated. However, our assessment of the quality of this evidence is very low.

Nefopam for the prevention of perioperative shivering: a meta-analysis of randomized controlled trials

BACKGROUND

Shivering is a frequent complication following surgery and anaesthesia. A large variety of studies have been reported that nefopam may be efficacious for the prevention and treatment of perioperative shivering. Regrettably, there is still no conclusion of the efficacy and safety of nefopam for the prevention of perioperative shivering. The aim of this analysis is to evaluate the efficacy of nefopam for the prevention of perioperative shivering in patients undergoing different types of anaesthesia compared with placebo group and other active interventions.

METHODS

PubMed, EMBASE, Cochrane Central Register of Control Trials were systematically searched for potentially relevant trials. Trial quality and extracted data were evaluated by two authors independently. Dichotomous data on the absence of shivering was extracted and analysed by using relative risk (RR) with 95% confidence interval (CI). Continuous outcome was abstracted and analysed by using weighted mean difference (WMD) with 95% confidence interval (CI). Outcome data was analysed by using random effect model or fixed effect model in accordance with heterogeneity.

RESULTS

Compared with placebo, prophylactic administration of nefopam significantly reduced the risk of perioperative shivering not only in the patients under general anaesthesia but also neuraxial anaesthesia (RR 0.08; 95% CI 0.05-0.13). As compared with clonidine, nefopam was more efficacious in the prevention of perioperative shivering (RR 0.34; 95% CI 0.17-0.70). Nefopam has no influence on the extubation time (WMD 0.92; 95% CI -0.15-1.99).

CONCLUSION

Our analysis has demonstrated that nefopam is associated with the decrease of risk of perioperative shivering following anaesthesia without influencing the extubation time.

Efficacy of dexmedetomidine on postoperative shivering: a meta-analysis of clinical trials

PURPOSE

Shivering is a frequent complication in the postoperative period. The aim of the current meta-analysis was to assess the efficacy of dexmedetomidine on postoperative shivering.

METHODS

Two researchers independently searched PubMed, EMBASE and the Cochrane Central Register of Controlled Trials for controlled clinical trials. The meta-analysis was performed by Review Manager.

RESULTS

Thirty-nine trials with 2,478 patients were included in this meta-analysis. Dexmedetomidine reduced postoperative shivering compared with placebo (risk ratio [RR] = 0.26; 95% confidence interval [CI]: 0.20 to 0.34), with a minimum effective dose of 0.5 µg·kg(-1) (RR = 0.36; 95% CI: 0.21 to 0.60). The anti-shivering effect can be achieved both intravenously and epidurally when administered within two hours prior to the end of surgery. The efficacy of dexmedetomidine was similar to widely used anti-shivering agents, such as fentanyl, meperidine, tramadol, clonidine and so on; however, dexmedetomidine may increase the incidence of sedation, hypotension, bradycardia and dry mouth.

CONCLUSIONS

The present meta-analysis indicates that dexmedetomidine shows superiority over placebo, but not over other anti-shivering agents. Therefore, considering its high price and potential adverse events, dexmedetomidine may not be appropriate solely for the purpose of the prevention of postoperative shivering.

Complete resolution of myoclonus-like involuntary movements under subarachnoid block after midazolam administration in a patient undergoing cesarean section: a case report

Involuntary movement during and after neuraxial anesthesia, such as spinal and epidural anesthesia, is rarely observed. In this report, we describe a case of myoclonus-like involuntary movement of the upper extremities in a patient undergoing a planned repeat cesarean section under spinal anesthesia with bupivacaine that completely subsided after administration of 2 mg of midazolam. The myoclonus-like movement did not recur or cause any apparent neurological side effects.

Anesthetic premedication: new horizons of an old practice

The practice of anesthetic premedication embarked upon soon after ether and chloroform were introduced as general anesthetics in the middle of the 19(th) century. By applying opioids and anticholinergics before surgery, the surgical patients could achieve a less anxious state, and more importantly, they would acquire a smoother course during the tedious and dangerous induction stage. Premedication with opioids and anticholinergics was not a routine practice in the 20(th) century when intravenous anesthetics were primarily used as induction agents that significantly shorten the induction time. The current practice of anesthetic premedication has evolved into a generalized scheme that incorporates several aspects of patient care: decreasing preoperative anxiety, dampening intraoperative noxious stimulus and its associated neuroendocrinological changes, and minimizing postoperative adverse effects of anesthesia and surgery. Rational use of premedication in modern anesthesia practice should be justified by individual needs, the types of surgery, and the anesthetic agents and techniques used. In this article, we will provide our readers with updated information about premedication of surgical patients with a focus on the recent application of second generation serotonin type 3 antagonist, antidepressants, and anticonvulsants.

Randomised double-blind comparative study of dexmedetomidine and tramadol for post-spinal anaesthesia shivering

Background and Aims:

Dexmedetomidine (α₂ adrenergic agonist) has been used for prevention of post anaesthesia shivering. Its use for the treatment of post-spinal anaesthesia shivering has not been evaluated. The aim of this study was to evaluate and compare the efficacy, haemodynamic and adverse effects of dexmedetomidine with those of tramadol, when used for control of post-spinal anaesthesia shivering.

Methods:

A prospective, randomised, and double-blind study was conducted in 50 American Society of Anaesthesiologists Grade I and II patients of either gender, aged between 18 and 65 years, scheduled for various surgical procedures under spinal anaesthesia. The patients were randomised in two groups of 25 patients each to receive either dexmedetomidine 0.5 μg/kg or tramadol 0.5 mg/kg as a slow intravenous bolus. Grade of shivering, onset of shivering, time for cessation of shivering, recurrence, response rate, and adverse effects were observed at scheduled intervals. Unpaired t-test was used for analysing the data.

Results:

Time taken for cessation of shivering was significantly less with dexmedetomidine when compared to tramadol. Nausea and vomiting was observed only in tramadol group (28% and; 20% respectively). There was not much difference in the sedation profile of both the drugs.

Conclusion:

We conclude that although both drugs are effective, the time taken for cessation of shivering is less with dexmedetomidine when compared to tramadol. Moreover, dexmedetomidine has negligible adverse effects, whereas tramadol is associated with significant nausea and vomiting.