Abstract
Purpose :
Over 650 surgical fires occur annually in the United States. Open supplemental oxygen (O2) delivery makes the periocular area particularly vulnerable to operative fires. Due to the increased fire risk with higher O2 percentages, the Joint Commission and the Emergency Care Research Institute recommend O2 supplementation of 30% or less during open delivery. However, 100% O2 is often given via nasal cannula during ophthalmology procedures, and little is known regarding the periocular O2 concentrations. We create a model to replicate an open-system delivery of O2 and concurrently measure O2 levels in the periocular region to assess the fire risk of ophthalmology procedures.
Methods :
This is an experimental study using an adult-size mannequin head (MH) to simulate a surgical setting. A nasal cannula is placed in the “nostrils” and connected to the O2 tank. An O2 sensor was secured in the periocular area. O2 delivery was controlled by adjusting the flow rate. The highest O2 level was recorded after turning on 100% O2 at the corresponding flow rate. The O2 was then turned off, and levels were recorded every 5 seconds. The time needed for O2 levels to reach 25% was recorded. This was repeated at flow rates of 1 liter (L), 2L, 3L, 4L, and 6L. The effect of surgical draping was evaluated by repeating the experiment on the MH with surgical towels (Figure 1).
Results :
Without draping, 100% O2 supplemented at 1, 2, 3, 4, and 6 L per minute reached 38.2%, 42.8%, 44.6%, 46.5%, and 48.7% O2, respectively. (Figure 2A) Higher initial O2 levels were seen with surgical drapes at 59.8%, 65.7%, 66.5%, 66.9%, and 71.4%, respectively. (Figure 2B) All initial O2 level measures were above the safety threshold of 30%. All flow rates in both draping techniques reached an O2 level of 25% or lower after 20 seconds.
Conclusions :
Our results showed that periocular O2 levels can increase significantly with the use of supplemental O2 via an open system. Due to the proximity of the ocular region to the area of O2 delivery, higher than recommended levels of O2 were recorded regardless of draping. In both settings, the time it took for O2 levels to drop to 25% was 20 seconds, suggesting that timely intraoperative cessation of O2 delivery is crucial in preventing surgical fires.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.