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

Intravenous Bolus of Dexmedetomidine for Treatment of Severe Shivering After Caesarean Delivery Under Combined Spinal-Epidural Anaesthesia: A Randomized Dose-Response Study

Purpose

Shivering occurs frequently after caesarean delivery. The present study aimed to investigate the ED50 and ED95 of an intravenous (i.v.) bolus of dexmedetomidine for treating severe shivering after caesarean delivery under combined spinal-epidural anaesthesia.

Patients and methods

Seventy-five parturients with severe shivering after caesarean delivery were randomized into one of the five groups to receive an i.v. bolus of 0.2 (Group D1), 0.25 (Group D2), 0.3 (Group D3), 0.35 (Group D4) or 0.4 (Group D5) μg/kg of dexmedetomidine. Effectiveness of shivering treatment was defined as a standardized shivering score decreasing to ≤1 within 10 min of dexmedetomidine injection. The ED50 and ED95 were determined by probit regression. Adverse effects were also compared among the groups.

Results

The ED50 and ED95 of i.v. dexmedetomidine to treat severe shivering were 0.23 (95% CI, 0.16-0.26) μg/kg and 0.39 (95% CI, 0.34-0.52) μg/kg, respectively. No difference in the incidence of adverse effects was found between groups.

Conclusion

An i.v. bolus of 0.39 μg/kg of dexmedetomidine will treat 95% of parturients experiencing severe shivering after caesarean delivery.

Application of Butorphanol versus Sufentanil in Multimode Analgesia via Patient Controlled Intravenous Analgesia After Hepatobiliary Surgery: A Retrospective Cohort Study

Purpose

We investigate the efficacy and safety of butorphanol in multimodal analgesia combined with dexmedetomidine and ketorolac via patient-controlled intravenous analgesia (PCIA) after hepatobiliary surgery, as compared with sufentanil.

Patients and Methods

Postoperative follow-up data of hepatobiliary surgery patients in Henan Provincial People's Hospital from March 2018 to June 2021 were collected retrospectively and divided into butorphanol group (group B) or sufentanil group (group S) according to the postoperative intravenous controlled analgesia scheme. The baseline characteristics and surgical information of the two groups were matched through propensity score matching (PSM).

Results

A total of 3437 patients were screened, and PSM yielded 1816 patients after matching, including 908 in the butorphanol group and 908 in the sufentanil group. Compared with group S, the incidence of moderate-to-severe pain on the first postoperative day and the second postoperative day was lower in group B during rest (3.2% vs 10.9%, P<0.001; 1.2% vs 4.6%, P<0.001), and during movement (7.0% vs 18.9%, P<0.001; 2.6% vs 8.7%, P<0.001). Patients receiving butorphanol had a lower morphine consumption (50mg vs 120mg, P<0.001). The bolus attempts of an analgesic pump in group B were significantly lower than in group S (1 vs 2, P<0.001). Postoperative hospital length of stay was shortened in group B (11d vs 12d, P=0.017). The occurrence of postoperative vomiting was lower in group B (1.4% vs 3.0%, P=0.025) than in group S. However, more patients in group B experienced dizziness (0.9% vs 0.1%, P=0.019).

Conclusion

Compared with sufentanil, the application of butorphanol in multimodal analgesia combined with dexmedetomidine and ketorolac via PCIA ameliorated postoperative pain after hepatobiliary surgery, with reduced opioid consumption and shorter postoperative hospital length of stay.

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.

Efficacy and safety of intravenous dexmedetomidine as an adjuvant to general anesthesia in gynecological surgeries: A systematic review and meta-analysis of randomized controlled trials

This study investigated the efficacy and safety of intravenous dexmedetomidine as an adjuvant to general anesthesia in patients undergoing gynecological surgery. We systemically searched for randomized controlled trials (RCTs), and performed a meta-analysis on studies that met the inclusion criteria. The primary outcomes were postoperative nausea and vomiting (PONV), bradycardia, hypotension, and 24 h opioid consumption. The secondary outcomes include postoperative shivering, postoperative pain score, intraoperative anesthetic consumption, extubation time, postoperative sedation, and the time to first flatus. Twenty-five RCTs were included in this study. Meta-analysis showed that intravenous dexmedetomidine significantly reduced the risk of PONV (RR, 0.57 [0.47, 0.68]) and postoperative shivering (RR: 0.31 [0.22, 0.42]), 24 h opioid consumption (Mean Difference: - 4.85 mg [-8.60, -1.11]) and postoperative pain score within 24 h. However, these benefits were at the cost of increased bradycardia (RR, 3.21 [2.41, 4.28]) and hypotension (RR, 2.17 [1.50, 3.14]). Notably, no serious adverse effects were reported in any of the included studies. Thus, our study showed that intravenous dexmedetomidine provided significant antiemetic and anti-shivering effects and moderate analgesic effects in patients that underwent gynecological surgery. However, its benefits should be weighed against the significantly increased risk of bradycardia and hypotension.

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.

Effects of Dexmedetomidine on Postoperative Pain and Recovery Time in Obese Patients

Objective

The objective of this study is to investigate the effect of dexmedetomidine on postoperative pain and recovery time in obese patients.

Methods

A total of 100 obese patients with body mass index (BMI) ≥ 30 kg/m² who underwent laparoscopic sleeve gastrectomy under general anesthesia in our hospital from January 2019 to December 2021 were included and assigned into DEX group (dexmedetomidine group) and NS group (normal saline group). The bariatric surgery patients who were given normal saline pump were the NS group (n = 50), and the bariatric surgery patients who were given the dexmedetomidine pump were the DEX group (n = 50). The patients in the DEX group were given continuous intravenous infusion of dexmedetomidine before, during, and after induction of anesthesia at a dose of 0.4 μg. kg-1. h-1, 0.4 μg·kg-1. h-1, 0.2 μg·kg-1. h-1, respectively. The NS group was infused with the same volume of normal saline for the same time. The two groups of patients were treated with the same anesthesia induction and maintenance program. By comparing the operation, anesthesia, postoperative extubation, and recovery time of the two groups of patients, the effect of dexmedetomidine on the postoperative recovery time of obese patients was analyzed. Visual analogue scale (VAS) and adverse reactions were compared to analyze the effect of dexmedetomidine on postoperative pain in obese patients.

Results

The operation, anesthesia, postoperative extubation, and recovery time of the DEX group were significantly lower than those of the NS group, whereas the VAS and adverse reactions were significantly lower than those in the NS group (P < 0.05).

Conclusion

An appropriate dose of dexmedetomidine in bariatric surgery for morbidly obese patients can effectively shorten the recovery time and extubation time of patients, reduce postoperative pain and the incidence of adverse reactions, and is worthy of clinical application. Dexmedetomidine 2 μg/kg has promising anesthesia benefits in bariatric surgery of obese patients, can provide favorable analgesia and quality of recovery, help reduce the degree of stress response of patients, and does not increase the risk of adverse events. However, this study has certain limitations, so physicians should tailor the dosage according to the patient's physical condition in clinical practice.

Dexmedetomidine infusion for emergence coughing prevention in patients undergoing an endovascular interventional procedure: A randomized dose-finding trial

OBJECTIVE

Dexmedetomidine has been introduced in emergence coughing, agitation, and shivering prevention. This study aimed to investigate the optimal dose of dexmedetomidine for emergence cough prophylaxis.

METHODS

In this randomized, double-blinded, and prospective trial, 356 patients scheduled for an endovascular interventional procedure were randomly assigned to 0.3 (D 0.3), 0.4 (D 0.4), 0.5 (D 0.5), and 0.6 (D 0.6) μg·kg^-1·h^-1 dexmedetomidine rate, or saline control (C), from anesthesia induction until the end of surgery. The primary outcomes measured were cough grade and frequency. Additionally, groups were compared according to mean arterial pressure (MAP), heart rate, agitation, shivering, postoperative nausea and vomiting (PONV), extubation time, sedation scores, and postoperative first night sleep quality (secondary outcomes).

RESULTS

A total of 351 patients were included in the analysis. The respective incidences of D 0.3, D 0.4, and D 0.5 versus C group were: 78.6%, 68.6%, 53.4% and 42.9% vs 89.7% for cough (p = 0.002, p < 0.001, and p < 0.001 between group D 0.4, D 0.5 and D 0.6 vs C, respectively); 30%, 27.1%, 20.5%, 15.7% vs 44.1% for agitation (p = 0.04, p = 0.003, and p < 0.001 between group D 0.4, D 0.5 and D 0.6 vs C, respectively); 8.6%, 7.1%, 6.8%, 5.7% vs 22.1% for shivering (p = 0.027, p = 0.013, p = 0.01, and p = 0.01 between D 0.3, D 0.4, D 0.5 and D 0.6 vs C, respectively); and 52.9%, 57.1%, 42.5%, 44.3% vs 61.8% for poor sleep quality (p = 0.02 and p = 0.04 between group D 0.5 and D 0.6 vs C, respectively). D 0.4, D 0.5 and D 0.6 showed lower MAP during extubation, compared with the C group. Also, D 0.5 and D 0.6 presented a slight delay in extubation (3.1 and 3.3 min longer than C; p = 0.002 and p < 0.001, respectively). Meanwhile, the frequency of atropine, vasopressor administration, PONV and dizziness were similar to the control.

CONCLUSIONS

Both 0.5 and 0.6 μg·kg^-1·h^-1 dexmedetomidine infusion rates effectively mitigated emergence coughing with prolonged extubation time, besides sleep disturbance. D 0.4, D 0.5, and D 0.6 reduced agitation and sustained hemodynamic stability. Finally, the four doses applied were effective in shivering attenuation.

Comparison of dexmedetomidine and meperidine for the prevention of shivering following coronary artery bypass graft: study protocol of a randomised controlled trial

INTRODUCTION

Shivering is a common complication in the postoperative period. The incidence of shivering has been reported to range from 5% to 65% under general anaesthesia and as 33% during epidural anaesthesia. Shivering can increase perioperative risk in patients. Both dexmedetomidine and meperidine are effective agents for the prevention of postanaesthetic shivering. However, few studies have compared the anti-shivering effects of different agents following coronary artery bypass graft (CABG). This study aims to compare the effects of dexmedetomidine and meperidine on the incidence of shivering in patients undergoing CABG.

METHODS AND ANALYSIS

A total of 180 patients aged 18-75 years, with an American Society of Anesthesiologists (ASA) grade of II-IV, undergoing elective CABG will be enrolled and randomly assigned to the dexmedetomidine, meperidine and control groups (placebo) in an intended 1:1:1 allocation ratio. The patients will be followed up for 7 days after surgery. The primary outcome is the incidence of shivering within 24 hours postoperatively. The secondary outcomes are the number of remedial drugs used after surgery, the incidence of postoperative hypotension and bradycardia, sedation scores, endotracheal extubation time, intensive care unit length of stay, incidence of postoperative delirium within 7 days after surgery, incidence of postoperative arrhythmias, incidence of postoperative nausea and vomiting, average hospital length of stay and mortality rate 30 days after surgery.

ETHICS AND DISSEMINATION

The study protocol was approved by the ethics committee of The First Affiliated Hospital of Shandong First Medical University on 20 January 2021 (YXLL-KY-2021(002)) and registered at ClinicalTrials.gov. The results of this study will be presented at national and international scientific meetings and conferences. We plan to publish the data in peer-reviewed international scientific journals.

TRIAL REGISTRATION NUMBER

NCT04735965.

The Impact of Optimal Dose of Ketamine on Shivering Following Elective Abdominal Hysterectomy: A Randomised Comparative Study

Background

Following surgery, patients frequently suffer from shivering, and this can lead to postoperative complications and discomfort.

Objectives

This study aimed to compare the effect of ketamine on patients’ shivering following an elective abdominal hysterectomy. Patients were given either Ketamine (0.25 mg or 0.5 mg/kg) or a placebo. The study and surgery took place in a subspecialty University Hospital for Gynecology and Obstetrics.

Methods

This study was an interventional, randomized, controlled clinical trial. Ninety-six women who underwent elective abdominal hysterectomy were randomly assigned to three groups. Ketamine was administered to all participants 20 min prior to the end of surgery. The first group received 0.25 mg/kg of intravenous ketamine. The second group received 0.5 mg/kg intravenous ketamine. The third group received a placebo of intravenous saline. Postoperative shivering, sedation grade, hallucination, nausea, vomiting, and nystagmus were measured for each patient up to 30 minutes.

Results

The study showed that patients suffered from less shivering in the two groups that received ketamine. The reduced shivering was seen 5, 10, and 20 min following surgery in the two groups that were given two doses of 0.25 and 0.5 mg/kg ketamine compared to the control group (P value < 0.05). There was a significant difference between patients receiving normal saline and those having 0.25 and 0.5 mg/kg of ketamine in the rate of sedation grade, nausea, vomiting, and nystagmus (P value < 0.05). The main differences in patients receiving ketamine were the sedation grade at zero time and postoperative hallucination experienced by those patients who received 0.5 mg/kg of ketamine.

Conclusions

Ketamine reduced shivering in all patients following elective abdominal hysterectomy. This was regardless of dose. Patients were less likely to suffer from hallucinations and sedation grade with a lower dose of ketamine (0.25 mg/kg compared to 0.50 mg/kg).

Dexmedetomidine: What's New for Pediatrics? A Narrative Review

Over the past few years, despite the lack of approved pediatric labelling, dexmedetomidine’s (DEX) use has become more prevalent in pediatric clinical practice as well as in research trials. Its respiratory-sparing effects and bioavailability by various routes are only some of the valued features of DEX. In recent years the potential organ-protective effects of DEX, with the possibility for preserving neurocognitive function, has put it in the forefront of clinical and bench research. This comprehensive review focused on the pediatric literature but presents relevant, supporting adult and animal studies in order to detail the recent growing body of literature around the pharmacology, end-organ effects, organ-protective effects, alternative routes of administration, synergetic effects, and clinical applications, with considerations for the future.

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 Improves Cardiovascular and Ventilatory Outcomes in Critically Ill Patients: Basic and Clinical Approaches

Dexmedetomidine (DEX) is a highly selective α2-adrenergic agonist with sedative and analgesic properties, with minimal respiratory effects. It is used as a sedative in the intensive care unit and the operating room. The opioid-sparing effect and the absence of respiratory effects make dexmedetomidine an attractive adjuvant drug for anesthesia in obese patients who are at an increased risk for postoperative respiratory complications. The pharmacodynamic effects on the cardiovascular system are known; however the mechanisms that induce cardioprotection are still under study. Regarding the pharmacokinetics properties, this drug is extensively metabolized in the liver by the uridine diphosphate glucuronosyltransferases. It has a relatively high hepatic extraction ratio, and therefore, its metabolism is dependent on liver blood flow. This review shows, from a basic clinical approach, the evidence supporting the use of dexmedetomidine in different settings, from its use in animal models of ischemia-reperfusion, and cardioprotective signaling pathways. In addition, pharmacokinetics and pharmacodynamics studies in obese subjects and the management of patients subjected to mechanical ventilation are described. Moreover, the clinical efficacy of delirium incidence in patients with indication of non-invasive ventilation is shown. Finally, the available evidence from DEX is described by a group of Chilean pharmacologists and clinicians who have worked for more than 10 years on DEX.

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.

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.

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.

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.

Controlled Hypotension During Rhinoplasty: A Comparison of Dexmedetomidine with Magnesium Sulfate

Objective

The current study aimed at comparing the efficacy of dexmedetomidine and magnesium sulfate to control blood pressure (BP) during rhinoplasty and the resultant effects on the quality of surgical field in terms of bleeding and visibility.

Methods

The current randomized, prospective, double-blind study was conducted on 60 patients aged 18 to 50 years classified as ASA (American Society of Anesthesiologists) physical status I who were candidates for rhinoplasty. Patients were randomly divided into 2 groups: (1) group Dex, received 1 µg/kg dexmedetomidine in 10 minutes before induction of anesthesia, followed by 0.4 - 0.6 µg/kg/hour during the maintenance of anesthesia, and (2) group Mg, received 40 mg/kg in 10 minutes before anesthesia induction followed by 10 - 15 mg/kg/hour during anesthesia maintenance. In both groups, the goal was to achieve a mean arterial pressure (MAP) of 60 - 70 mmHg. Hemodynamic variables, anesthetic, opioid, muscle relaxant requirements, and surgical field condition were recorded. Sedation score, time to reach modified Aldrete score ≥ 9, and adverse effects including nausea and vomiting (N&V) and shivering were recorded.

Results

Controlled hypotension was achieved in both groups. There was no significant difference in MAP between the groups, but heart rate (HR) was significantly lower in the Dex group (P < 0.001), compared with that of the Mg group. Bleeding score was lower (P < 0.001) and surgeon's satisfaction score was higher (P < 0.001) in the Dex group. More patients required fentanyl (P < 0.001) or nitroglycerin (P < 0.001) and the mean fentanyl (P = 0.005) or nitroglycerin (P < 0.001) required doses were higher in the Mg group. Patients in the Dex group required more frequent administration of cisatracurium (P = 0.004). Five patients in the Dex group versus no patients in the Mg group received atropine (P = 0.023). Ramsay sedation score and time to reach modified Aldrete score ≥ 9 were significantly higher in the Dex group (P < 0.001 and P < 0.001, respectively). The incidence rate of N&V and shivering were similar in both groups.

Conclusion

Dexmedetomidine was more effective than magnesium to achieve controlled hypotension, and provide a favorable surgical field condition. However, dexmedetomidine also heightened the risk of induced bradycardia and prolonged sedation. These are 2 important points to consider when applying this drug as a hypotensive agent during operation.

Dexmedetomidine as a neuraxial adjuvant for prevention of perioperative shivering: Meta-analysis of randomized controlled trials

BACKGROUND

Dexmedetomidine, a highly selective α2-adrenoceptor agonist, has been investigated for anti-shivering effects in some trials. This current meta-analysis was conducted to evaluate the effectiveness of dexmedetomidine as a neuraxial adjuvant in preventing perioperative shivering.

METHODS

This systematic review and meta-analysis was registered in PROSPERO [www.crd.york.ac.uk/PROSPERO] with the unique identification number CRD42017055991. The electronic databases PubMed, Embase, Cochrane Central Register of Controlled Trials (CENTRAL) were searched to select high-quality randomized controlled trials (RCTs) that evaluated the anti-shivering efficacy for neuraxial application dexmedetomidine as local anesthetic adjuvant. Effects were summarized using pooled risk ratios (RRs), weighed mean differences (MDs), or standardized mean differences (SMDs) and corresponding 95% confidence intervals (Cls) with random effect model. Heterogeneity assessment, sensitivity analysis, and publication bias were performed. The primary outcome was perioperative shivering.

RESULTS

A total of 1760 patients from 24 studies were included in this meta-analysis. Compared with the placebo, dexmedetomidine reduced the incidence of perioperative shivering (RR: 0.34; 95% Cl: 0.21 to 0.55; P < 0.00001), with a maximum effective dose of 5μg via subarachnoid space injection (RR: 0.55; 95% CI: 0.32 to 0.92; P = 0.02), especially in cesarean section (RR: 0.20; 95% CI: 0.09 to 0.45; P = 0.0001). Dexmedetomidine also could improve the characteristics of the block, with an increase only in the incidence of bradycardia (RR: 2.11; 95% CI: 1.23 to 3.60; P = 0.006). No significant difference could be found compared dexmedetomidine with other adjuvants, except morphine.

CONCLUSIONS

This meta-analysis shows that dexmedetomidine as a neuraxial adjuvant had statistically significant efficacy on prevention of perioperative shivering. Moreover, dexmedetomidine could improve the characteristics of the block. However, the potential induction of bradycardia should be taken seriously.

Foetal responses to dexmedetomidine in parturients undergoing caesarean section: a systematic review and meta-analysis

Objective This current meta-analysis was conducted to evaluate effects of dexmedetomidine on neonatal maternal factors. Methods The electronic databases of PubMed, Embase, and Cochrane Central Register of Controlled Trials were searched. The primary outcomes were neonatal parameters, including umbilical blood gases and Apgar scores. The secondary outcomes were maternal parameters. Results We identified six randomized controlled trials (RCTs). No differences in neonatal umbilical blood gases, and Apgar scores at 1 min (WMD: -0.09; 95% CI: -0.21 to 0.04; I²= 0%) and 5 min (weighted mean difference (WMD): 0.03; 95% CI: -0.05 to 0.11; I²= 37%) were observed with dexmedetomidine. For maternal parameters, characteristics of motor and sensory block and postoperative analgesia (standard mean difference (SMD): 3.99; 95% CI: 2.85 to 5.12; I²= 78%) were significantly improved after dexmedetomidine treatment. Adverse events, including nausea/vomiting and shivering (risk ratio (RR): 0.26; 95% CI: 0.11 to 0.60; I²= 0%), were lower after dexmedetomidine treatment. Conclusion This meta-analysis shows that dexmedetomidine is safe for neonates who are delivered by caesarean section. Moreover, dexmedetomidine used in neuraxial anaesthesia can improve the characteristics of motor and sensory block and prolong the maternal pain-free period. Dexmedetomidine can also reduce the maternal incidence of postoperative adverse effects.

Intrathecal Dexmedetomidine Alleviates Shivering during Cesarean Delivery under Spinal Anesthesia

Shivering associated with spinal anesthesia during Cesarean delivery is an uncomfortable experience for the parturient, which may also cause adverse effects. In this prospective, randomized, double-blind, placebo-controlled study, we sought to evaluate the effect of intrathecal dexmedetomidine, administered as an adjunct to hyperbaric bupivacaine for Cesarean delivery, on the incidence and severity of shivering associated with spinal anesthesia. Patients undergoing Cesarean delivery were randomly allocated to three groups of 30 patients each. Experimental treatments were added to hyperbaric bupivacaine as follows: Patients in group I (control) were administered isotonic saline. Patients in groups II and III received dexmedetomidine (2.5, 5 µg, respectively), mixed with isotonic saline. Shivering was observed in 11, 10 and 2 patients in groups I, II and III, respectively. The incidence of shivering in group III was significantly lower than that in groups I (p=0.005) and II (p=0.01). The severity of shivering was significantly different between the three groups (p=0.01). There were no significant inter-group differences with respect to mean arterial pressure and heart rate at any time point after administration of intrathecal local anesthesia (p>0.05). Intrathecal dexmedetomidine (5 µg) administered as an adjunct to hyperbaric bupivacaine during Cesarean delivery significantly reduced the incidence and intensity of shivering associated with spinal anesthesia.

Effect of Dexmedetomidine in Preventing Postoperative Side Effects for Laparoscopic Surgery: A Meta-Analysis of Randomized Controlled Trials and Trial Sequential Analysis (PRISMA)

Dexmedetomidine (DEX) has been used extensively for patients during surgery. Some studies found that DEX could reduce the incidence of postoperative side effects in laparoscopic surgical patients. However, no firm conclusions were made about it.The authors searched for randomized controlled trials (RCTs) in PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials testing DEX administrated in laparoscopic surgical patients and reporting on postoperative nausea, vomiting, shivering, heart rate, mean arterial pressure (MAP), or extubation time after surgery or within 1 hour in postoperative care unit. Trial sequential analysis (TSA) was used for RCTs comparing DEX with placebo or no treatment in laparoscopic surgery patients. A protocol for this meta-analysis has been registered on PROSPERO (http://www.crd.york.ac.uk/prospero) and the registration number is CRD42015020226.Fifteen studies (899 patients) were included. DEX could significantly reduce the incidence of postoperative nausea (risk ratio [RR] and 95% confidence interval [CI], 0.43 [0.28, 0.66], P < 0.0001), vomiting (RR and 95% CI, 0.36 [0.18, 0.72], P = 0.004), shivering (RR and 95% CI, 0.19 [0.11, 0.35], P < 0.00001), rescue antiemetic (RR and 95% CI, 0.18 [0.07, 0.47], P = 0.0006), and increase the incidence of dry mouth (RR and 95% CI, 7.40 [2.07, 26.48], P = 0.002) comparing with the control group. In addition, firm conclusions can be made on the results of postoperative nausea according to the TSA. Meta-analysis showed that DEX group had a significantly lower heart rate (mean difference [MD] and 95% CI, -14.21 [-18.85, -9.57], P < 0.00001) and MAP (MD and 95% CI, -12.35 [-15.28, -9.42], P < 0.00001) than the control group, and firm conclusions can be made according to the TSA. No significance was observed on extubation time between 2 groups (MD and 95% CI, 0.70 [-0.89, 2.28], P = 0.39).The results from this meta-analysis indicated that perioperative DEX decreased postoperative nausea and shivering in laparoscopic surgical patients. However, common adverse effects were lower heart rate and MAP. Firm conclusions cannot be made on postoperative shivering, rescue antiemetic, and dry mouth until more RCTs were included.

Effectiveness of dexmedetomidine use in general anesthesia to prevent postoperative shivering: a systematic review

BACKGROUND

Postanesthetic shivering remains a significant source of distress following general anesthesia. Despite numerous studies investigating pharmacologic prophylaxis for postanesthetic shivering, no gold standard medication has been identified. Prophylactic dexmedetomidine administration has been examined as a possible preventative treatment modality for postanesthetic shivering; however its effectiveness has not been established.

OBJECTIVES

The objective of this review was to evaluate the effectiveness of intravenous prophylactic dexmedetomidine for reduction of postanesthetic shivering during the first two hours after general anesthesia.

INCLUSION CRITERIA

TYPES OF PARTICIPANTS

 The participants included in this study were adults between 18 and 68 years of age receiving general anesthesia for any surgical procedure. Only participants with American Society of Anesthesiologist physical status I or II were included. Types of intervention(s): This review evaluated the effectiveness of intravenous dexmedetomidine in preventing postanesthetic shivering. Studies that compared preoperative or intraoperative administration of dexmedetomidine to placebo were included. Types of studies: The studies included in this review were all randomized controlled trials. Types of outcomes: This review assessed all studies that included the following outcome measure: presence of postanesthetic shivering observed in the post-anesthesia care unit during the first two hours after the completion of surgery.

SEARCH STRATEGY

A three-step search strategy was utilized in this review to find published and unpublished studies. Only studies published in English between 1999 and 2015 were included in this review.

METHODOLOGICAL QUALITY

Quantitative papers selected for retrieval were assessed by two independent reviewers for methodological validity prior to inclusion in the review using standardized critical appraisal instruments from the Joanna Briggs Institute Meta-Analysis of Statistics Assessment and Review Instrument.

DATA EXTRACTION

Data was extracted from papers included in the review using the standardized data extraction tool from Joanna Briggs Institute Meta-Analysis of Statistics Assessment and Review Instrument. The data extracted included specific details about the interventions, populations, study methods and outcomes of significance to the review question and specific objectives.

DATA SYNTHESIS

Quantitative data was pooled in statistical meta-analysis using Joanna Briggs Institute Meta-Analysis of Statistics Assessment and Review Instrument. All results were subject to double data entry. Effect sizes were expressed as odds ratio and the 95% confidence intervals were calculated for analysis. Heterogeneity was assessed statistically using the standard Chi-square test.

RESULTS

This review included eight randomized controlled trials with 625 participants. The results of the meta-analysis revealed a statistically significant decrease in postanesthetic shivering for the dexmedetomidine group. The Mantel-Haenszel overall relative risk ratio was 0.27 in favor of the dexmedetomidine group [relative risk 0.27, at 95% confidence interval 0.19, 0.36, P < 0.0001]. A relative risk reduction value was calculated as 0.73.

CONCLUSIONS

The prophylactic administration of intravenous dexmedetomidine reduces the incidence of postanesthetic shivering in patients undergoing general anesthesia.