Pre-hospital intubation is often required in sub-optimal conditions, such as in patients lying on the ground. Direct laryngoscopy and intubation of a patient lying supine on the ground is difficult because the intubator's head is far above the head of the patient. It is thus tricky to align the intubator's visual axis with the patient's tracheal axis. The Airway Scope is a new laryngoscope designed to facilitate intubation without requiring alignment of the oral, pharyngeal, and tracheal axes. We thus tested the hypothesis that the intubation with the Airway Scope is faster than the Macintosh laryngoscope in subjects lying on the ground.

Adult surgical patients were enrolled. Following anesthesia induction and muscle relaxation, direct laryngoscopy was performed as usual and airway characteristics noted. Patients were randomly assigned to tracheal intubation by either the Airway Scope (n=50) or the Macintosh laryngoscope (n=50). Intubation was performed from a table positioned at the height as the operating table, thus simulating intubating on the ground. Overall intubation success rate, time required for intubation, the number of attempts required for successful intubation, and airway complications related to intubation were recorded.

Inclusion Criteria:

• Patients scheduled for various surgeries requiring tracheal intubation as part of anesthesia and designated as American Society of Anesthesiologists (ASA) physical status I, II, or III.

Exclusion Criteria:

• Patients with an increased risk of pulmonary aspiration, cervical spine pathology, anticipated airway difficulties (i.e., Mallampati grade IV or thyromental distance <6 cm), and American Society of Anesthesiologists physical status >III.

Patients with anticipated airway difficulties were excluded. All intubations were performed by a single investigator.