Flow Limitation and Titrations

At CPAPTalk.com, I’ve posted the following to spark some discussion about the lack of attention paid to flow limitation events during titrations:

“I’m curious to know whether most PAP therapy users understand what it means to normalize airflow during your titration test. If you are under the impression that the goal is only to eliminate apneas and hypopneas, then you are missing out on a very important element that might prevent you from attaining the best sleep possible.

Years ago, it was determined that a more subtle form of breathing disturbance known as upper airway resistance (UAR) was an important component of breathing disturbances in patients with sleep apnea. Nowadays, the most common name for UAR in the sleep lab environment is flow limitation, and what’s obvious if you look for it is the need to eliminate flow limitation along with apneas and hypopneas.

At our center, www.sleeptreatment.com, we aggressively seek to find the pressures that normalize the airflow curve, which technically for most patients means that the signal looks very rounded or elliptical while you are breathing in or breathing out. As I mentioned in a previous post, we routinely use bilevel, because we find it much easier to normalize both the inhalation and exhalation airflow curves by using a higher pressure when you breathe in and lower when you breathe out. Nearly all our patients report bilevel is much more comfortable as well.

Most importantly, we have seen many patients who were titrated at other labs, where their lab reports did not mention “flow limitation.” Those labs may have only attempted to titrate out apneas and hypopneas. When we titrated these patients and sought to eliminate flow limitation events, they reported a much deeper sleep.

If you’re curious about flow limitation and whether it might be affecting your sleep, I encourage you to check out my new book, Sound Sleep, Sound Mind at www.soundsleepsoundmind.com. The book has several graphics that show flow limitations and how they differ from apneas and hypopneas. The graphics also show what normal breathing should look like, whether you happen to be a normal sleeper or whether you are getting the optimal response to PAP Therapy.”