The impact of prophylactic intravenous lidocaine on opioid-induced cough: a meta-analysis of randomized controlled trials.

BACKGROUND

Opioids are commonly used for general anesthesia, but reflex cough can occur after an intravenous injection. We have performed a meta-analysis of randomized controlled trials (RCTs) that evaluated the effectiveness and safety of prophylactic lidocaine administered intravenously (IV) on opioid-induced cough (OIC) during induction in patients undergoing general anesthesia.

METHODS

We searched three bibliographic databases (PubMed, Embase, and the Cochrane Central Register of Controlled Trials) to identify studies meeting a priori inclusion criteria and also conducted a secondary reference review. The information used to calculate the relationship between lidocaine prophylaxis and the risk and severity of OIC was extracted by two principal investigators, respectively.

RESULTS

Six RCTs with a total of 1,740 participants were included in this meta-analysis. Overall, prophylactic lidocaine administered IV reduced both the risk of OIC [pooled risk ratio (RR) 0.471; 95 % confidence interval (CI) 0.355-0.625; P = 0.074; heterogeneity test, I (2) = 50.3 %] and its severity (weighed mean difference -0.316; 95 % CI -0.480 to -0.151; P = 0.038; heterogeneity test, I (2) = 60.5 %). Sub-group analysis indicated a significant reduction in the incidence of both fentanyl-induced cough (FIC) and remifentanil-induced cough (RIC), but it appeared that lidocaine only alleviated the severity of FIC. Further sub-group analysis indicated that the lowest effect dose of lidocaine for preventing the prevalence of OIC was 0.5 mg/kg. No severe adverse effects were reported.

CONCLUSIONS

Our meta-analysis establishes the effectiveness of prophylactic lidocaine administered IV for the prevention of OIC during induction. The lowest effective dose of lidocaine on the risk of OIC appeared to be 0.5 mg/kg.