Obstructive sleep apnea (OSA) is a problem we have discussed many times.  It is a condition where the back of the throat closes at night, while sleeping, and obstructs the airway.  This wakens the patient frequently throughout the night and patients do not get the usual restful sleep needed, and then fall asleep at unusual times during the day.  Patients with this problem tend to be obese with a body mass index over 30. It has been found that 10% to 20% of OSA patients also have something called the obesity hypoventilation syndrome (OHS). 

The additional problem for patients with OHS is that they do not eliminate the usual amount of carbon dioxide when they breathe.  This elevates the carbon dioxide level in the blood and can be tested using blood gas analysis.  To do this analysis, a sample of the patient’s blood needs to be obtained from an artery, usually in the wrist. The reason to identify patients with OHS is because they often undergo surgeries sometime for weight reduction or other non-cardiac surgery reasons.  The rate of complications in this OSA/OHS group is much higher than in the group with OSA alone. 

These complications can be severe and life threatening.  Often the blood gas analysis is not checked prior to the surgery and this leaves this group of patients at risk. The obesity epidemic in America is troubling and so are its consequences. If you are considering surgery and have OSA ask to be checked for OHS with a blood gas analysis.