A Comparison Of Circulatory Response To Laryngoscopy And Intubation With MacIntosh And McCoy Blade

Background: It has been observed that laryngoscopy and intubation leads to profound cardiovascular effects along with an increase in catecholamine concentrations. Multiple studies have been conducted to attenuate the same. McCoy blade has been found to decrease this pressor response as compared to the Macintosh blade used routinely. Therefore, a comparative study of heart rate (HR) and mean arterial pressure (MAP) changes during laryngoscopy and intubation using these two blades was conducted to establish the same. Methods: The study included 200 patients divided into two groups of 100 each. Laryngoscopy and intubation was performed either with Macintosh or McCoy blade. The HR and MAP were recorded at every 1 minute interval during laryngoscopy and intubation for 5 minutes. Apart from above observations, Mallampatti classification (MPC), Cormack and Lehane classification (C& L) and time required for intubation were noted. Results: There was no difference in baseline HR and MAP in both the groups i.e. Macintosh (MK) and McCoy (MY) . The percentage rise from baseline HR and MAP in MK group was highly significant during laryngoscopy and intubation and 1 minute after that as compared to MY group. Similarly, comparison of HR and MAP changes between both the groups revealed highly significant decrease in the parameters in MY group, during laryngoscopy and intubation and 1 minute after the procedure. No other complications of laryngoscopy & intubation were observed in our study. Conclusion: McCoy blade, primarily devised for difficult intubation has additional benefit of alleviating the pressor response to laryngoscopy and intubation. We recommend its use in patients with cardiovascular compromise, raised intracranial tension (ICT), apart from its established indications. Abbreviations: HRHeart Rate, MAPMean Arterial Pressure, ICT – Intracranial tension