CPAP vs. APAP vs. BiPAP: Which One Is Best For Sleep Apnea?
May 13, 2011
Positive airway pressure (PAP) machines are the mainstay of treating obstructive sleep apnea. Over the years, with the development of different PAP models with different features, it’s getting more and more confusing to differentiate all these machine from one another, especially since various manufacturers use different names for certain models and comfort features.
As a summary, CPAP stands for continuous positive airway pressure. These machines blow a constant level of positive air pressure through a mask into your nose (or nose and mouth). Bilevel PAP refers to a machine that delivers two different levels, where a higher pressure is used during inhalation and a much lower pressure is given during exhalation. BiPAP is actually a registered brand name from Respironics. Auto-titrating PAP machines adjust your pressures as needed. There are other variations such as auto-bilevel devices and ASV units which are used for complex or central sleep apnea. For this discussion we’ll talk about CPAP, Bilevel and auto-titrating units only.
With so many different models to choose from, people continue to ask me which is the best option. If your insurance company pays for your PAP machine, you don’t have a choice—you have to start with a basic CPAP machine. Most people do well with standard CPAP models, but there will always be people who don’t do well. But before switching to a new machine, you have to first go through the standard trouble-shooting steps to make sure that there’s no leak, mouth breathing, humidity issues, mask fit, etc. It’s also important to use machines that give more objective feedback such as your AHI and leak rates, rather than just the total number of hours used. Some people then end up trying an autoPAP machine and do great, whereas for others, it makes no difference. Sometimes, continuous pressure from a CPAP machine works better than an autoPAP machine. Others do better with bilevel models.
If you look at all the published reports comparing CPAP vs. autoPAP vs. BiPAP machines, there are some differences in terms of compliance, leak rates, or tolerability, but overall, there’s no significant difference between the three in terms of subjective sleepiness, AHI measures, or quality of life scores. This is why some sleep doctors state that essentially, there’s no difference in the overall outcome between these three types of machines.
However, since research studies lump together everyone, including responders and nonresponders, it’s not a true representation of real-life outcomes. There will always be some patients that do better on autoPAP compared to a CPAP machine. Others do better on CPAP than autoPAP. Some others do much better on bilevel devices. So based on evidence based medicine, decisions are being made to downplay the potential advantages of various PAP models. I think that this is not good clinical practice. You should start with the basics first, but for patients that are frustrated and not tolerating PAP therapy, it’s worthwhile to consider other PAP options. In most cases, there are a lot of simple steps that can be taken to fully optimize the patient’s current CPAP machine, but you should never discount other options.
The same argument can be made for oral appliances and for surgery. A significant number of people do well with these options, if done properly. Unfortunately, most people who are given CPAP fall through the cracks, and are never given the opportunity to truly benefit from therapy. This is why the long-term compliance rate is so low for CPAP.
Ultimately, it’s not which model or which form of therapy is better, but start with the CPAP basics and do everything possible make sure that you’re using it properly. If it doesn’t work, talk with you doctor to discuss other PAP options. If PAP therapy doesn’t work, then consider non-PAP options.
If you’re a PAP user, did you try different models? If so, which one works best for you?