Have you ever undergone any major surgery? If you have, you aren’t alone. Major surgery isn’t rare, and luckily, advanced medical technology has brought us to a point where even “major” surgeries start to become minor. However, there are still complications that may occur following surgery, such as pain, infection, and blood clots. These complications may even put you back on the surgery table. And what’s more, the number complications following surgery may be increased if sleep apnea (especially undiagnosed apnea) is present. To top it all off, because surgery may require the use of sedating pain killers or medications during recovery, sleep apnea may actually be worsened by surgery! However, is this worsening present in everyone, or only those with already present sleep apnea?
This question has been recently investigated. Using 37 subjects who had no previous diagnosis of sleep apnea and who had to spend at least 6 days in the hospital following surgery, a research team monitored the development of apnea severity for 7 nights. Monitoring began the night prior to surgery and for next 6 nights. Portable breathing-monitoring devices were used to minimize disturbances to the post-operative patients. Prior to surgery, the group average apnea hypopnea index (AHI) was only 4.6, which is technically not making the cut for sleep apnea. However, during each successive night, the AHI increased and ultimately the group had an average AHI of 22.5!
So what happened here? Why is AHI increasing with each day of recovery? The authors suggest that there may be a build-up of fluids in the airway post surgery. This build-up could cause a narrowing of the airway, which makes it more collapsible than usual. Additionally, the authors suggest that a deprivation of REM (caused by drug-induced sleep or poor sleep quality) following surgery may lead to a type of ‘REM rebound.’ Since sleep apnea is thought to be worse during REM, this rebound may increase the risk for having apneas. This issue clearly needs to be investigated further, as sleep apnea following surgery may lead to an increase in post-operative complications.
Source: Roggenbach, J., Saur, P., Hofer, S., Bruckner, T., Preusch, M., Carbone, R., & Walther, A. (2014). Incidence of perioperative sleep-disordered breathing in patients undergoing major surgery: a prospective cohort study. Patient safety in surgery, 8, 13.