LAUSR

OBJECTIVE The risk of a spontaneous surgical fire increases as oxygen concentrations surrounding the surgical site rise above the normal atmospheric level of 21%. Previously published in vitro findings imply this phenomenon (termed oxygen pooling) occurs during dental procedures under sedation and general anesthesia; however, it has not been clinically documented. METHODS Thirty-one children classified as American Society of Anesthesiologists I and II between 2 and 6 years of age undergoing office-based general anesthesia for complete dental rehabilitation were monitored for intraoral ambient oxygen concentration, end-tidal CO2, and respiratory rate changes immediately following nasotracheal intubation or insertion of nasopharyngeal airways, followed by high-speed suctioning of the oral cavity during simulated dental treatment. RESULTS Mean ambient intraoral oxygen concentrations ranging from 46.9% to 72.1%, levels consistent with oxygen pooling, occurred in the nasopharyngeal airway group prior to the introduction of high-speed oral suctioning. However, 1 minute of suctioning reversed the oxygen pooling to 31.2%. Oropharyngeal ambient oxygen concentrations in patients with uncuffed endotracheal tubes ranged from 24.1% to 26.6% prior to high-speed suctioning, which reversed the pooling to 21.1% after 1 minute. CONCLUSION This study demonstrated significant oxygen pooling with nasopharyngeal airway use before and after high-speed suctioning. Uncuffed endotracheal intubation showed minimal pooling, which was reversed to room air ambient oxygen concentrations after 1 minute of suctioning.