Effects of intravenous lignocaine on haemodynamic responses to laryngoscopy and tracheal intubation in adults under general anaesthesia: A systematic review and meta-analysis.

Abstract

Background and aims: Haemodynamic fluctuations during laryngoscopy and tracheal intubation remain a key concern in anaesthetic practice, with cardiovascular stress responses posing risks of serious complications. This meta-analysis aims to assess the benefits and risks of pre-intubation intravenous (IV) lignocaine, focusing on enhancing haemodynamic stability and developing evidence-based dosing guidelines.

Methods: Searches were performed in PubMed, Embase, the Cochrane Library, Web of Science, ClinicalTrials.gov, and key references up to 16 February 2025 to identify randomised controlled trials (RCTs) comparing adult patients who received or did not receive IV lignocaine prior to tracheal intubation. Data from eligible studies were pooled to calculate the combined risk ratio (RR) or mean difference (MD).

Results: Eighteen studies (1056 participants) were included. A single IV injection of lignocaine at 40 mg fixed-dose and 0.5-2 mg/kg was studied for preventing haemodynamic fluctuations induced by laryngoscopy and tracheal intubation. Relative to non-lignocaine, IV lignocaine suppressed the increases in mean arterial pressure (MAP) [MD: -3.85; 95% confidence interval (CI): -6.61, -1.09; P = 0.006; I ² = 84%] and heart rate (HR) (MD: -4.72; 95% CI: -7.55, -1.90; P = 0.001; I ² = 86%) caused by laryngoscopy and tracheal intubation. The lignocaine group had fewer complications compared with the non-lignocaine group.

Conclusions: IV lignocaine 1-2 mg/kg can effectively suppress the increase in MAP caused by laryngoscopy and tracheal intubation. However, the effectiveness of lignocaine regarding HR seems to require optimisation based on both dosage and ethnicity.