Abstract
Purpose :
Despite standard protocols and best practices, operating room fires remain a rare but significant risk during surgery. To better stratify risk for operating room fires as they relate to enriched oxygen environments, we performed an experiment to measure local oxygen concentrations at common surgical sites with a model patient breathing supplemental oxygen at 1-5L/min with a nasal cannula, and 6-10L/min with a basic respiration mask.
Methods :
A model was draped laying in the supine position using an open-faced under chin drape, and a Salter style nasal O2 cannula was placed into position. Local oxygen concentrations were measured at the lateral canthi, upper eyelids, medial canthi, lower eyelids, along the hairline, mid-cheeks, philtrum, oral commissures, jaw lines, and under the drapes with an OxyCheq-X O2 Analyzer under supplemental oxygen flow rates of 1-5L/min. This procedure was then repeated using an AirLife Adult Oxygen Mask with the same points measured at flow rates of 6-10L/min.
Results :
At flow rates of 1-5L/min with the nasal cannula, the local oxygen concentration around the canthi, upper eyelids, lower eyelids, and forehead never surpassed that of ambient room air at 21%. At 6-10L/min with the basic mask the local oxygen concentrations at the forehead increased from 21% to 23%. At the eyelids under 6-10L/min the local oxygen concentrations at the lateral canthi increased from 32% to 49%, at the upper lids from 25% to 45%, at the medial canthi from 24% to 35%, and at the lower lids from 30% to 58%.
Conclusions :
Administering supplemental oxygen at flow rates of 1-5L/min with a nasal cannula, the local oxygen concentrations around the eyelids and the forehead never exceed that of ambient room air, suggesting there is minimal increased of fires in eyelid and forehead surgery due to supplemental oxygen with this setup. At flow rates of 6-10L/min with a basic mask, the flow pattern of oxygen is directed out of the mask at any point without a perfect seal, leading to the largest oxygen enriched environments over the eyelids, oral commissures, and cheeks. Surgery over the eyelid and midface would be at a significantly increased risk of operating room fires, while forehead surgery with this setup is only minimally increased.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.