Comparing intubation distances between direct and video laryngoscopes using motion capture: a mannequin study

There is a risk of exposure to aerosols and secretions from the patient during tracheal intubation, particularly in patients with infectious disease or during cardiopulmonary resuscitation. We hypothesized that, compared with a direct laryngoscope, the use of a videolaryngoscope would reduce this risk by increasing the intubation distance between the upper airways of the patient and the intubator during tracheal intubation.

As a cross-over design, we continuously measured the intubation distance, using a motion capture system, between a direct laryngoscope and two videolaryngoscopes (McGrath MAC (McG) and Airway Scope (AWS)), during simulated tracheal intubation in an intubation mannequin. Ten anesthesiologists participated. In Situation 1, a mannequin was placed on a table to simulate in-hospital tracheal intubation. In Situation 2, it was placed on the floor to simulate out-of-hospital tracheal intubation. The primary outcome was the shortest intubation distance.

All tracheal intubations were successful. In Situation 1, the shortest intubation distance was significantly shorter with the direct laryngoscope (20.8 cm) than with the McG (44.2 cm; P=0.007), or with the AWS (42.9 cm; P=0.005). In Situation 2, the shortest intubation distance was significantly shorter with the direct laryngoscope (18.8 cm) than with the McG (30.0 cm; P=0.007), or with the AWS (38.8 cm; P=0.013).

Using a videolaryngoscope would extend the intubation distance, in both in-hospital and out-of-hospital intubations, compared with a direct laryngoscope. Therefore, using a videolaryngoscope may reduce the risk of infection from patient to intubator.