Monday, December 5, 2011

Difficulty Breathing During Anesthesia and Obstructive Sleep Apnea

I'm not an anesthesiologist, but I always learn cool things about sleep from them - after all they are always putting people to sleep. Apparently, there is an association between patients that are difficult to intubate and obstructive sleep apnea (OSA). Now there is a study that was done to determine if patients that are difficult to ventilate with an anesthesia gas mask are at risk for OSA. If so, then anesthesiologists would be able to identify potential patients and refer them on to a sleep center for diagnosis and treatment.

I can see the connection between difficulty using a mask to ventilate (abbreviated DMV) and OSA because the two conditions share similar risk factors - elevated weight, older age, male gender, increased upper airway crowding, and a history of snoring. When a patient is under general anesthesia, their throat is more relaxed and could collapse more easily. This could contribute to difficulty ventilating with a gas mask.

In this study, ten patients had sleep studies after full recovery from surgery and a minimum of 30 days after their operation. The sleep studies showed that all ten subjects had some degree of OSA, with 80% having moderate to severe OSA. The more difficult to ventilate with a mask, the more severe the OSA. The results are interesting but there are limitations to this study. The average time between surgery and the sleep study was 7 months and 2 days with a maximum time of 21 months. Therefore, keep in mind that patients could have gained weight during the time from their surgery to the sleep study, and that weight gain could have increased their risk of OSA. Also, all of the study subjects had similar characteristics known to be associated with OSA - elevated weight, large collar size, more snoring, more high blood pressure, and more daytime sleepiness than the general population. Therefore, these characteristics could be responsible for the high amounts of OSA, not the DMV. Finally, there was no control group, so it's not known how many patients without DMV would also be diagnosed with OSA.

No comments:

Post a Comment