Improvement of glottis visualization with a McCoy blade

Abstract

Difficult intubation remains one of the major risks in anaesthetic practice. Recently, as other anaesthetic societies, the French Society for Anaesthesia and Intensive Care (SFAR) has produced algorithms for the management of a difficult intubation. New laryngoscopes and blades have been marketed in recent years, however their place in these algorithms remains unclear. In this preliminary study, we compared the laryngoscopic view in 100 consecutive patients during tracheal intubation with the McCoy laryngoscope first in its normal position and after levering the distal part of the blade. All patients were included in Mallampati classes 1 and 2. Among them, 16% were classified as Cormack and Lehane grades 3 or 4 when using the blade in the normal position. These data confirm previous observations showing that the McCoy blade in normal position performs poorly as compared with the Macintosh blade. Conversely the levering of the distal part of the blade significantly decreased the incidence of Cormack and Lehane grades of 3 or 4 (2 versus 16%, P = 0.001). It is concluded that the McCoy blade is not convenient for its routine use in patients not to be at preoperatively known risk of difficult intubation. This blade significantly improves intubating conditions. Defining the exact place of this new blade in difficult intubation algorithms requires further studies.