[Evaluation of the UpsherScope laryngoscope in routine intubation with no expected difficulties]

To evaluate the new rigid, fiberoptic laryngoscope (UpsherScope) in cases with no expectation of intubation difficulty.

We studied 130 ASA I-II patients for whom no difficulty with tracheal intubation was predicted. Intubation attempts were undertaken by three staff anesthesiologists, with up to three tries permitted per patient. Causes of difficulty were recorded. A regression study of the number of tries per patient over the course of the study was used to identify a possible learning effect. Causes related to inexperience were identified by comparing their frequency of appearance between the first and second halves of the study using a chi-squared test.

Ninety-nine patients (76%) were intubated, 70 of them (54%) on the first try. A total of 223 attempts at laryngoscopy (1.71 +/- 0.85) per patient) were made. The best relation in the regression analysis was linear, with a significant slope (-0.0193, p < 0.05) and R2 = 0.103 demonstrating a learning effect. The reasons for difficulty were hitting the endotracheal tube (ETT) against the right arytenoids (18), esophageal progression of the ETT (12), blood or secretions (8), vision obstructed by the epiglottis (7), clouding (7), lateral sliding of the stylet (6), hitting the ETT against the epiglottis (4). Only ETT impingement of the right arytenoids was related to inexperience (p < 0.001). We discuss the relation of these factors to the design of the laryngoscope.

Our experience suggests that the UpsheScope does not offer advantages in routine intubations. The low success rate and the need for repeated attempts at intubation may be related to suboptimal design of the laryngoscope.