A prospective controlled comparative study of haemodynamic responses, intubating conditions to laryngoscopy and tracheal intubation by using Macintosh vs. Mc Coy blade laryngoscope

Background: The invention of McCoy blade in the early 1990s is a modification of the Macintosh blade with a hinged tip. The McCoy blade reduces the amount of force applied during laryngoscopy and endotracheal intubation, thus the increased reflex haemodynamic changes in response to tracheal intubation becomes less significant. Objective: To determine the advantages of McCoy blade laryngoscope in obtunding the pressor response, better glottic visualization and ease of intubation during laryngoscopy and endotracheal intubation as compared to Macintosh blade laryngoscope. Methods: The present study was done on 60 adult patients of ASA I and II, between the age group of 20 to 50 years. We observed the haemodynamic changes, glottic view and ease of intubation by using either Macintosh or McCoy blade laryngoscope during general anesthesia at laryngoscopy and endotracheal intubation. The changes in HR, SBP, DBP, and MAP were recorded before induction, at laryngoscopy and intubation and at 1 min, 3 min and 5 min after tracheal intubation. Glottic view obtained on laryngoscope was compared as per Cormack and Lehene grading. Tracheal intubation grading was also compared between the groups. Complications during the procedure like arrhythmias, injury, and bleeding were noted. Results: In our study, a significant haemodynamic changes were observed in both the groups following laryngoscopy and endotracheal intubation. The rise in HR, SBP, DBP and MAP were more significant with Macintosh blade laryngoscope, where as better visualization of the glottis, ease of intubation and less haemodynamic changes were noted with McCoy blade laryngoscope. Conclusion: McCoy blade laryngoscope produces significantly less marked haemodynamic changes, better glottic view and ease of intubation as compared to Macintosh blade laryngoscope during laryngoscopy and tracheal intubation