Comparison of Oropharyngeal Oxygen Pooling and Suctioning During Intubated and Nonintubated Dental Office-Based Anesthesia
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. 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. 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. 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.Objective
Methods
Results
Conclusion
Participants Under General Anesthesia with Bilateral Nasopharygeal Airways (NPAs) in Place
Supplemental oxygen is supplied through the left NPA (red arrow), while the capnography sample line is inserted in the right NPA (yellow arrow). The oxygen analyzer probe (pink) is fixed within the silicon intraoral bite block on the left side of the mouth.
Study Protocol Schematic
The 135-second study protocol performed in all subjects after local anesthetic administration before starting any restorative dental procedures. Oxygen concentration measurements were taken every 15 seconds, and means were calculated for each of the 3 periods.
Intraoral Ambient Oxygen Concentrations: NPA vs ETT
Oropharyngeal oxygen concentrations for patients managed with NPAs vs nasal intubation with ETT. Study periods denoted by color (baseline, blue; dormant, yellow; active, green). *Difference between groups is statistically significant, P < .05. ETT, endotracheal tube; NPA, nasopharyngeal airway.
End-Tidal CO2: NPA vs ETT
Comparison of end-tidal CO2 measurements obtained throughout the study. ETT, endotracheal tube; NPA, nasopharyngeal airway.
Respiratory Rate: NPA vs ETT
Comparison of respiratory rate measurements obtained throughout the study. ETT, endotracheal tube; NPA, nasopharyngeal airway.
Contributor Notes