Lignocaine Dilemma: Is Route as Important as Dose in Attenuating Hemodynamic Stress? study finds

Recent investigation assesses the efficacy of transtracheal versus intravenous administration of 2% lignocaine in mitigating the hemodynamic stress response during general anesthesia post-induction. The study was a single-blinded, randomized controlled trial involving 138 patients, with consent obtained per ethical guidelines.

Methodology - Inclusion criteria involved patients undergoing elective procedures requiring direct laryngoscopy and endotracheal intubation, excluding those with hypersensitivity to lignocaine, pregnancy, anticipated difficult airways, or inability to consent.

Participants were divided into two groups: Group IV (intravenous) and Group TT (transtracheal) using a computer-generated randomization method.

Standard induction was performed with fentanyl, propofol, and atracurium, and lignocaine was administered post-induction. Group IV received intravenous lignocaine (1.5 mg/kg) while Group TT received a transtracheal injection (same dosage).

Vitals such as heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean blood pressure (MBP) were measured at baseline, post-induction, and at intervals of 1, 3, and 5 minutes after intubation.

Key Results - A total of 127 patients were included in the final analysis after assessing 144 for eligibility. - Patients in the TT group showed significantly less post-induction hypotension and a more stable hemodynamic profile compared to the IV group (SBP: p=0.009, MBP: p=0.019).

After intubation, the TT group had significantly lower surges in SBP, DBP, MBP, and HR at 3 and 5 minutes post-intubation compared to the IV group (e.g., SBP at 3 min: p=0.008). - The Rate-Pressure Product (a measure of cardiac workload) was consistently lower in the TT group, supporting the hematological advantages noted.

Limitations - Single-blinded design may introduce bias in data interpretation. - The study was limited to ASA I and II patients, which may reduce the generalizability of results to a broader, vulnerable patient population. - Sample size calculations suggested that while the primary outcomes were powered adequately, some secondary measures did not achieve the necessary power due to sample size constraints.

Conclusion The findings indicate that transtracheal lignocaine more effectively minimizes hemodynamic instability associated with laryngoscopy and intubation under general anesthesia over intravenous administration, particularly beneficial for high-risk patients. Future studies are recommended utilizing double-blinded designs and involving larger, diverse samples to validate findings.

Key Points

- The study involved a single-blinded, randomized controlled trial with 138 patients, aiming to evaluate the effects of 2% lignocaine administered via transtracheal and intravenous routes on hemodynamic stress during general anesthesia following induction.

- Inclusion criteria specified patients undergoing elective procedures requiring direct laryngoscopy and endotracheal intubation, excluding those with lignocaine hypersensitivity, pregnancy, anticipated difficult airways, or incapacity to consent. Ultimately, 127 patients were analyzed after screening.

- Randomization utilized a computer-generated method to form two groups: Group IV (intravenous) receiving lignocaine at 1.5 mg/kg, and Group TT (transtracheal) with identical dosing implemented post-anesthesia induction protocol which included fentanyl, propofol, and atracurium.

- Monitoring of hemodynamic parameters such as heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean blood pressure (MBP) was conducted at baseline, post-induction, and at intervals of 1, 3, and 5 minutes after intubation.

- Results demonstrated that the TT group experienced significantly reduced post-induction hypotension and maintained a more stable hemodynamic profile compared with the IV group (SBP: p=0.009; MBP: p=0.019). Additionally, lower surges in SBP, DBP, MBP, and HR at 3 and 5 minutes post-intubation were recorded for the TT group, indicating lesser stress responses.

- Potential study limitations include a single-blinded design which may introduce bias, the focus on ASA I and II patients that could limit generalizability to broader populations, and sample size constraints affecting the statistical power of some secondary measures. Findings suggest transtracheal administration of lignocaine may reduce hemodynamic instability, particularly in high-risk patients, with recommendations for future research employing double-blinded methods and larger, more diverse cohorts.

Reference –

Monotosh Pramanik et al. (2025). Comparison Between Transtracheal And Intravenous 2% Lignocaine In Attenuating Hemodynamic Stress Response Following Direct Laryngoscopy And Endotracheal Intubation: A Randomized Controlled Trial. *BMC Anesthesiology*, 25. https://doi.org/10.1186/s12871-025-03102-1.