To the Editor
I want to remind colleagues about the possibility of an “adulterated” oxygen supply during construction when it involves main oxygen supplies to a facility. I think it is important to get the word out.
The facility in which I work has been undergoing major renovation and construction. There have been projects off and on nearly every year. One day last week around noon time several MDs and CRNAs noted a drop in the oxygen concentration during their cases. It happened rapidly within minutes, in 8-9 operating rooms. The inspired oxygen concentration dropped to 2-3%. The reactions of personnel varied and no one knew immediately that it was happening in any other room except their room. Most turned on the oxygen tank on the back of the machine. Some placed the patient on an Ambu bag and tank oxygen, and some, on an Ambu and wall oxygen.
The oxygen line pressure coming in was normal. It was soon evident that this oxygen inflow concentration problem was system wide. There were no patient’s adversely affected although oxygen saturations fell into the 70s for 1-2 minutes in some instances.
The root of the problem was discovered as the day progressed. The construction project had the possibility of interfering with the main oxygen line from the large storage tank. In anticipation of that problem, a new line was run to work around the construction. As is the case with any such line, after it is completed and before it is turned on, it is tested with nitrogen for leaks. After this, it is purged with the gas that is supposed to run in that line. This was done, but obviously not satisfactorily.
What we learned/relearned was the best reaction by the anesthesia personnel (when line pressure was normal and oxygen inflow concentration was not normal) was to take the patient off of machine oxygen and use independent tank oxygen.
In addition since oxygen line pressure never dropped because it was pressurized with nitrogen gas, turning the oxygen tanks on that are attached to the machine did not solve the problem. The normal line pressure did not allow the tank oxygen to flow adequately.
A great note of thanks to the many anesthesiologists (scientists) that came before us, mandating safety alarms for inspired oxygen concentration and line pressure monitoring. These alarms saved our patients from significant harm.
One final thought, as is done most of the time, whenever construction might interfere with operating room functions, all personnel are notified to be alert. When possible, any potential interference should be done outside of OR operating times although this would not have solved this problem.
If this can be of use, please pass it on.
Name and state withheld by request.