The cricothyroid versus the spray-as-you-go method for topical anesthesia during flexible bronchoscopy: A systematic review and meta-analysis of randomized controlled trials.

Background Lignocaine can be administered during bronchoscopy using either a direct injection through the cricothyroid membrane (the cricothyroid method) or a spray of lignocaine solution through the bronchoscope working channel (the spray-as-you-go method). In this meta-analysis of randomized controlled trials (RCTs), we compared the efficacy of these two methods for topical anesthesia during flexible bronchoscopy. Methods We performed a systematic search to extract the relevant RCTs comparing the two techniques. Results Five RCTs meeting the inclusion criteria (747 subjects) were identified. The cricothyroid method was associated with significantly less cough (standardized mean difference [SMD] = -1.18, 95% confidence interval [CI] [-1.75, -0.62], P < 0.001, significant heterogeneity I2 = 86%, P < 0.001). On analysis of secondary outcomes, the cricothyroid method was associated with a greater operator-rated procedure satisfaction (SMD = 1.00, 95% CI [0.74, 1.25], P < 0.001), less time for upper airway negotiation (mean difference, MD = -0.99, 95% CI [-1.37, -0.6], P < 0.001), and a significantly less cumulative dose of lignocaine administered (MD = -68.12, 95% CI [-130.18, -6.06], P = 0.03). The overall procedure duration (MD = 0.08, 95% CI [-0.09, 0.24], P = 0.36) and patient discomfort (MD = -0.08, 95% CI [-0.38, 0.22], P = 0.59) were not different between the two methods. There was no significant publication bias (P = 0.94). Conclusions The cricothyroid method is associated with less cough during flexible bronchoscopy. Other advantages are a greater operator-rated procedure satisfaction at a less cumulative lignocaine dose. These findings highlight the superior performance characteristics of the cricothyroid method for lignocaine administration for flexible bronchoscopy.