TRANSVERSE FORCES EXERTED ON THE MAXILLARY INCISORS DURING LARYNGOSCOPY

Purpose: In this study the effect of level of experience of the intuba tor on the forces applied by the Macintosh laryngoscope on the maxilla ry incisors in both the axial and transverse direction were investigat ed. Methods: Five groups of different levels of experience (15 per gro up), staff anaesthetists, residents, nurse anaesthetists, surgeons and students, performed one laryngoscopy and subsequent intubation on an intubation manikin equipped with sensors to measure these forces. Resu lts: Maximal transverse forces oriented toward the base of the skull ( Fmtpmax) were between 0 and 10 N in 46 cases (61%), between IO and 20 N in 21 (28%) and greater than or equal to 20 N (maximum 46.5 N) in ei ght cases (11%). The maximal values of the transverse forces oriented toward the intubator (Fmtnmax) were between 0 and 10 N in 69 cases (92 %), between 10 and 20 N in 3 (4%) and greater than or equal to 20 N(ma ximum 36.4 N) in 3 (4%). Level of experience was related to Fmtpmax (S pearman: P = 0.04, r = 0.24). In addition, Fmtnmax was less in experie nced intubators (anaesthetist and residents) than in inexperienced int ubators (all other groups) (Student's t test: P = 0.04). Conclusion: I n contrast to the effect on forces exerted in the axial direction, exp erience proved to have a beneficial effect on the forces in the transv erse direction.