Efficacy of intravenous lidocaine versus placebo on attenuating cardiovascular response to laryngoscopy and tracheal intubation: a systematic review of randomized controlled trials.

Cardiovascular response to laryngoscopy and tracheal intubation may be harmful in surgical patients with cardiovascular and cerebral diseases. The efficacy of intravenous lidocaine on attenuating the hemodynamic changes remains controversial. This systematic review aims to determine the efficacy of lidocaine versus placebo. PubMed, Embase and Cochrane Library databases were searched for relevant randomized controlled trials (RCTs). The quality of eligible RCTs was evaluated according to the modified Jadad scale. Quantitative analyses were carried out using Review Manager 5 and Stata 10. Thirty-seven trials with 1429 patients of different age groups were included in our meta-analysis. Additional lidocaine resulted in fewer changes in systolic blood pressure (SBP) (mean difference (MD) -4.32 mmHg, 95% confidence interval (CI) -6.21 to -2.43); diastolic blood pressure (DBP) (MD -4.76 mmHg, 95% CI -5.90 to -3.63); mean arterial blood pressure (MAP) (MD -2.72 mmHg, 95% CI: -3.65 to -1.80) and heart rates (HR) (MD -4.28 beats per min, 95% CI -5.83 to -2.72). Subgroup analysis showed that lidocaine was effective in both the elderly and children with the exception of failing to reduce HR in children. Exclusion of poor-quality trials did not change the favor to lidocaine. No significant publication bias across trials was found. Intravenous lidocaine helps reduce cardiovascular responses to laryngoscopy and tracheal intubation in patients of all age groups compared to placebo. Further studies are needed to clarify the effects of dosage and timing of lidocaine on hemodynamic changes.