Effects of air versus liquid in a loss of resistance technique for identification of the epidural space:a Metaanalysis

Abstract

Objective To systematically review the effects of air or liquid in a loss of resistance technique for identification of the epidural space. Methods We searched the Cochrane Library, PubMed, EMBASE, Chinese Biomedical Database （CBM）, CNKI, VIP and ChinaInfo for studies on the effects of air versus liquid in a loss of resistance technique for identification of the epidural space. The quality of the studies was evaluated by the method recommended by Cochrane Collaboration. Meta-analysis was conducted using the Cochrane Collaboration＇s RevMan 5.0.1 software. Results Seven prospective randomized controlled trials involving 5183 patients were included in our meta-analysis. The patients were randomly allocated into 2 groups according to the technique by which the epidural space was identified： loss of resistance with air group （group air, n = 2534） and loss of resistance with liquid group （group lidocaine, n = 2649）. The results showed that the incidences of difficult catheterization, intravascular catheter insertion, incomplete block and post-operative headache were significantly lower in group liquid than in group air （P 〈 0.05）. There were no significant differences in the incidences of transient abnormal sense and accidental dural puncture between group liquid and air. Conclusion Loss of resistance with liquid can identify the epidural space more correctly than with air, with fewer complications and better analgesic efficacy. Key words: Air; Anesthesia,epidural; Meta-analysis