Operating room fires: optimizing safety

This prospective study was undertaken to determine the safest means of supplemental oxygen delivery for patients undergoing facial cosmetic surgery under conscious sedation. Two common methods of oxygen delivery were used in 20 patients: (1) a nasal cannula and (2) a red rubber nasopharyngeal tube through which the cut ends of the nasal cannula were passed into the posterior pharynx.

The project was carried out in two parts. In part one, each subject was placed supine and oxygen supplementation at 3 liters/minute was applied through the nasal cannula. The oxygen concentration at 24 different set locations around the patient's face was analyzed using the random access mass spectrometer unit, starting at the right and left alar rim and then at 2-cm intervals laterally, superiorly, and inferiorly. The procedure in part one was repeated with oxygen being delivered by passing the cut cannula end through a red rubber nasopharyngeal tube into the posterior pharynx.

Statistical analysis has showed that in all sites at or above the nasal area, the difference between the nasal cannula and red rubber nasopharyngeal tube is significantly greater than 0, indicating that higher concentrations are observed with the nasal cannula than with the red rubber nasopharyngeal tube (p = 0.004).

The authors' study demonstrates a significant reduction in oxygen concentration, to levels consistent with ambient air, even at points extremely close to the oxygen source, when the nasopharyngeal tube system was used.