A Comparison of Haemodynamic Responses between Clinical Assessments Guided Tracheal Intubation and Neuromuscular Block Monitoring Guided Tracheal Intubation

Abstract

BACKGROUND During the induction of general anaesthesia (GA), laryngoscopy and endotracheal intubation produce significant nociceptive stimuli, which frequently results in inadvertent activation of the sympathetic nervous system. To blunt this pressor response, many drugs are successfully used. However, administration of an additional drug might cause adverse haemodynamic effects or might unnecessarily increase the depth of anaesthesia. Hence, a non-pharmacological measure to reduce the response is preferred. In this study, we wanted tocompare haemodynamic responses between clinical assessment-guided tracheal intubation and neuromuscular block monitoring-guided tracheal intubation. METHODS An observational study was conducted on 62 patients aged 18 – 60 years old belonging to American Soceity of Anaesthesiologist (ASA) I & II posted for surgeries under general anaesthesia were allotted to 2 groups of 31 each. In Group C patients, the trachea was intubated after the clinical judgment of jaw muscle relaxation. In Group M patients, the trachea was intubated after train of four counts became zero in adductor pollicis muscle. Changes in heart rate [HR], mean arterial blood pressure [MAP], Krieg’s intubation score, time between the administration of a neuromuscular blocking agent and endotracheal intubation were recorded. The collected data was analysed by mean, standard deviation, frequency, percentage, ttest and chi square test. RESULTS HR and mean arterial pressure were significantly higher in Group C as compared to Group M after laryngoscopy and tracheal intubation (P < 0.05). The mean time required for intubation was significantly shorter in Group C compared to Group M (179.52 ± 2 s vs. 358.19 ± 55 s). Excellent and good intubation conditions were observed in all Group M patients, whereas 24 out of 31 patients (77 %) in Group C showed excellent and good intubation conditions. CONCLUSIONS Haemodynamic responses to laryngoscopy and tracheal intubation can be significantly attenuated if tracheal intubation is performed following complete paralysis of laryngeal muscles, detected by neuromuscular monitoring of adductor pollicis muscle. KEY WORDS Laryngoscopy, Intubation, Haemodynamic Responses, Stress Response, Neuromuscular Monitor.