Background: Surgery on fingers is a common procedure in emergency and day care surgery. Adrenaline combined with lidocaine can prolong digital nerve block and provide a bloodless operating field. Extended postoperative pain relief can reduce the need for analgesics and can facilitate hand rehabilitation. Conventionally, adrenaline is avoided at anatomical sites with end arteries such as digits, penis and pinna because of concerns about arterial spasm, ischaemia and gangrene distal to the site of drug infiltration.
Objectives: To assess the safety and efficacy of use of adrenaline (any dilution) combined with lidocaine (any dilution) for digital nerve blocks (fingers and toes).
Search methods: We searched the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 11, 2014), MEDLINE via Ovid SP (1966 to 18 November 2014) and EMBASE via Ovid SP (1980 to 18 November 2014). We also searched specific websites, such as www.indmed.nic.in; www.cochrane-sadcct.org; and www.Clinicaltrials.gov.
Selection criteria: We included randomized controlled trials (RCTs) that compared the use of adrenaline with lidocaine and plain lidocaine in patients undergoing surgery on digits (fingers and toes). Our primary outcomes were duration of anaesthesia, adverse outcomes such as ischaemia distal to the injection site and cost analysis. Our secondary outcomes were duration of postoperative pain relief and reduced bleeding during surgery.
Data collection and analysis: We used standard methodological procedures expected by The Cochrane Collaboration. Two review authors independently extracted details of trial methodology and outcome data from reports of all trials considered eligible for inclusion. We performed all analyses on an intention-to-treat basis. We used a fixed-effect model when no evidence of significant heterogeneity between studies was found and a random-effects model when heterogeneity was likely.
Main results: We included four RCTs with 167 participants. Risk of bias of the included studies was high, as none of them reported method of randomization, allocation concealment or blinding. Only one trial mentioned our primary outcome of duration of anaesthesia. The mean difference in duration of anaesthesia with use of adrenaline with lidocaine was 3.20 hours (95% confidence interval (CI) 2.48 to 3.92 hours; one RCT, 20 participants; low-quality evidence). No trial reported adverse events such as ischaemia distal to the injection site, and no trial reported cost analysis. One trial mentioned the secondary outcome of duration of postoperative pain relief, but available data were insufficient for analysis of the findings. Two trials reported the secondary outcome of reduced bleeding during surgery.Bleeding during surgery was observed in nine out of 52 participants as compared with 25 out of 51 participants in the adrenaline with lidocaine and plain lidocaine groups, respectively. The risk ratio for bleeding in the adrenaline with lidocaine group was 0.35 (95% CI 0.19 to 0.65; two RCTs, 103 participants; low-quality evidence).
Authors' conclusions: From the limited data available, evidence is insufficient to recommend use or avoidance of adrenaline in digital nerve blocks. The evidence provided in this review indicates that addition of adrenaline to lidocaine may prolong the duration of anaesthesia and reduce the risk of bleeding during surgery, although the quality of the evidence is low. We have identified the need for researchers to conduct large trials that focus on other important outcomes such as adverse events, cost analysis and duration of postoperative pain relief.