Determination of the appropriate oropharyngeal airway size in adults: Assessment using ventilation and an endoscopic view

Introduction: Size 9 and 8 airways for men and women, respectively, have been proposed as most appropriate based on endoscopy. However, a limitation of this guideline is that ventilation was not assessed.

Methods: In this retrospective review of prospectively collected data, 149 patients requiring tracheal intubation for general anesthesia were included. The adequacy for manual and pressure-controlled mechanical ventilation and views at the distal end of each airway was assessed using a fiber-optic bronchoscope with various airway sizes (7, 8, 9, 10, and 11).

Results: For men, size 9, 10, and 11 airways permitted clear manual and adequate mechanical ventilation; size 7 and 8 airways caused partially obstructed manual and inadequate mechanical ventilation. On endoscopy, size 7 and 8 airways caused complete obstruction by the tongue; size 10 and 11 airways either touched or passed beyond the tip of the epiglottis. For women, the size 7 airway caused partially obstructed manual and inadequate mechanical ventilation; size 9 and 10 airways provided clear manual and adequate mechanical ventilation. The size 8 airway permitted clear manual ventilation, though mechanical ventilation was inadequate in one patient. On endoscopy, the size 7 airway caused complete obstruction in >50% of women; size 9, 10, and 11 airways either touched or passed beyond the tip of the epiglottis.

Conclusions: With respect to adequate ventilation in conjunction with an acceptable endoscopic view, size 9 and size 8 oropharyngeal airways appear to be the most appropriate sizes for clinical use in men and women, respectively.