Effects of Intravenous Lignocaine on Haemodynamic Responses to Laryngoscopy and Tracheal Intubation in Adults Under General Anaesthesia: A Meta-Analysis

Abstract

Background: Laryngoscopy and tracheal intubation stimulates a short-lived and sometimes very pronounced sympathetic discharge, which results in an increase of arterial pressure and tachycardia. The pressor response can lead to myocardial ischaemia, arrhythmia or an increase in ICP in patients with limited cardiovascular or cerebrovascular reserve. The use of intravenous (IV) lignocaine as a cheap, simple way to blunt this response has been in use for many years, but there has been inconsistent and sometimes conflicting evidence of its effectiveness, optimum dosage and safety. Objective: To systematically review the efficacy and safety of pre-intubation intravenous (IV) lignocaine for attenuation of the haemodynamic response to laryngoscopy and tracheal intubation in adults under general anaesthesia and provide a summary of the most recent dedicated metaanalysis on this topic.Objective: To summarise the most recent dedicated meta-analysis of the efficacy and safety of pre-intubation intravenous (IV) lignocaine for attenuation of the haemodynamic response to laryngoscopy and tracheal intubation in adults under general anaesthesia and to synthesize randomised controlled trial (RCT) evidence published between 2022 and 2026 on this topic. Methods: A structured search of the literature was performed in PubMed/MEDLINE, Embase, Scopus and the Cochrane Library for RCTs and systematic reviews published between 2022 and 2026, which included reports of IV lignocaine use and intubation-related haemodynamic parameters. The population, dosing regimen for lignocaine, comparator, and haemodynamic and safety outcomes were extracted and synthesized narratively and the most recent dedicated meta-analysis on these outcomes that was identified in the literature was used for quantitative pooling. Results: 18 articles satisfied the eligibility criteria (one dedicated meta-analysis of 18 RCTs, 1056 patients; and 17 other primary studies or related systematic reviews published since 2022). The pooled data shows that IV lignocaine 1-2 mg/kg effectively reduces the mean arterial pressure (MAP) increase observed during laryngoscopy/scope intubation, and its effect on heart rate (HR) is not consistent with dose or population characteristics. These are corroborated by individual trials 2022-2025, including obstetric, paediatric, neurosurgical and comparator-drug contexts, and an overall favourable safety profile compared to control. Conclusion: IV lignocaine 1.0-2.0 mg/kg given 1-3 minutes prior to laryngoscopy is an effective and inexpensive adjunct to help reduce the MAP response to intubation and has a more variable effect on HR. More large-scale, multi-center studies using consistent doses, dose timing and reporting of adverse events are needed to further clarify dosing recommendations for different patient populations.