CleveMed Blogs

For most of us, when we think of carbon dioxide (CO2), we think of words like waste, danger, toxic, poison; but in reality CO₂ is not only a natural part of our existence but an essential one. We know we need to breathe oxygen to live. So many of us naturally assume that when we hold our breath, that it is the lack of oxygen that our body is reacting to and forcing us to breathe again. . . wrong. In reality, it is the accumulation of CO₂ that our body is reacting to and forcing us to breathe again, trying to reduce and remove the CO₂ from our lungs (You say: Ah ha, see, CO₂ is bad! Our body is fighting to get rid of it). Well, yes, too much of anything is a bad thing, even oxygen (Oxygen toxicity or oxygen poisoning, causes disorientation, breathing problems, and even seizures, but that’s not the point of this article). Back to CO₂, the needed concentrations of carbon dioxide we are talking about are well below the toxic levels, and most importantly without CO₂, you don’t have as much drive to breathe.

There are tens of millions of people with sleep apnea (that is, the failure to breathe while you sleep). Sleep apnea is typically further broken down into obstructive sleep apnea (OSA), where by the patient is trying to breath but air can’t get in due to an obstruction or collapse in the airway, and central sleep apnea (CSA), where by the patient just stops trying to breathe for short periods of time. The most prominent and successful treatment of OSA is using a constant positive airway pressure (CPAP) device or a variation there of. However some of these OSA patients do not get better, do not tolerate the CPAP, or even get worse. One reason is that a portion of the OSA population actually has a complex sleep apnea (CSA) condition that is masked by the OSA. In these cases the CPAP will prevent the obstructions, but then it becomes apparent that the patient is exhibiting CSA characteristics as well. The complex sleep apnea symptoms are unmasked or amplified because of a lack of respiratory drive due to insufficient levels of CO₂. Normally when we sleep, our CO₂ levels increase just slightly. Think about it, you are sleeping in a relatively stationary position creating a slight cloud of CO₂ around you. A CPAP device, however, reverses that effect since it is drawing air from an area a few feet away and pumping it into your airway. To add to that, the increased pressure and flow also acts to ‘blow off’ more of the CO₂ that is normally inside your lungs, so it is very conceivable that the CO₂ levels on CPAP can be even lower than normal (as opposed to slightly elevated in normal sleep). So this complex sleep apnea (CSA) population would appear to have a CO₂ ‘critical threshold’ right at that point between the CO₂ levels experienced with and without CPAP. There are multiple studies that have now shown that adding just a small amount of CO₂ actually treats these patients.

So yes, these patients do say, “give me CO₂ or give me bad sleep!”

Tags: Carbon dioxide, complex sleep apnea, CPAP, sleep apnea

This entry was posted on Friday, June 4th, 2010 at 2:08 pm and is filed under Sleep Disorders. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.