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.

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SEARCH STRATEGY: A three-step search strategy was utilized in this review to find published and unpublished studies.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.