CPAP: Continuous Positive Airway Pressure
CPAP is first-line treatment for obstructive sleep apnea (Phillips 1990; Elshaug 2008; Almeida 2013). Numerous studies show that this method of applying constant mild air pressure to the airway during sleep reduces apneic (paused) and hypopneic (light) breathing and helps relieve signs and symptoms of sleep loss like fatigue, drowsiness, and cognitive and mood changes (Weaver 2012; Engleman 1993; Sanchez 2009; Kushida 2012; Ferini-Strambi 2003; Tomfohr 2011; Lau 2013). A 2013 review indicates that the more hours per night the device is used, the greater the benefit (Wickwire 2013).
Several studies have found that treatment of sleep apnea with CPAP can improve cardiac function and insulin sensitivity; and reduce heart rate, blood pressure, and cardiovascular mortality (Hassaballa 2005; Fava 2014; Aggarwal 2014; Ge 2013; Cordero-Guevara 2011; Marin 2005). An analysis of prior research found a trend for CPAP use to reduce the risk of death due to cardiovascular events in people with sleep apnea (Ge 2013).
There have been mixed results in studies looking at the effect of CPAP on blood glucose control, but it appears that people with severe sleep apnea are the most likely to experience a benefit in blood glucose management with CPAP (Bonsignore 2013). A rigorous review of studies examining CPAP and glycemic control concluded that most studies show that CPAP improves insulin sensitivity and markers of long-term glucose control in people with sleep apnea and type 2 diabetes or pre-diabetes. The best effect was seen after three months of nightly use for four or more hours per night (Gallegos 2014).
One barrier to consistent CPAP use is comfort (Beecroft 2003; Ballard 2007; Weaver 2010). It is estimated that only 70% of people to whom CPAP is recommended actually begin treatment with it, and of those who do, only 50% continue long term. Furthermore, many people are unsuccessful at using CPAP for the recommended number of hours during sleep. Fortunately, technological advances intended to improve patient comfort are under development (Wickwire 2013).
People who tolerate the CPAP mask and straps but find the constant air pressure uncomfortable may prefer one of two other options for positive airway pressure. The first is called bilevel positive airway pressure, or BiPAP. With BiPAP therapy, a lower level of air pressure is used during expiration, and a higher level during inspiration. This may improve comfort, especially for people who use higher pressure settings with CPAP and have trouble exhaling against the pressure. The second is called automatic positive airway pressure, or APAP. With APAP therapy, the device automatically adjusts its pressure output to the pressures it senses during the breathing cycle. APAP may be more comfortable for people whose apnea occurs mainly in certain sleep positions (Stasche 2006).
Other Oral Appliances
Oral appliances, or dental devices, are used during sleep to physically keep the upper airway open by either holding the lower jaw forward or moving the tongue forward (Hoffstein 2007; Chan 2007). These devices are usually custom-fitted by a dentist and are more likely to be helpful in people who have mild-to-moderate sleep apnea, are younger, less overweight, and have a smaller neck circumference (Remmers 2013; Hoffstein 2007). Although less effective than CPAP, oral appliances are sometimes used in those who are unable to tolerate CPAP (Gutierrez 2013; Freedman 2014).
A rigorous literature review published in 2013 concluded that there was not adequate evidence to support the recommendation of any specific drug for the treatment of obstructive sleep apnea, though many trials have attempted to study medications for this purpose (Mason 2013). However, central sleep apnea may respond to medications that stimulate breathing or promote sedation. Evidence in support of pharmacological treatment of central sleep apnea is sparse. Modafinil (Provigil) has been approved for daytime sleepiness in patients with sleep apnea. Other medications that are sometimes prescribed, but are not FDA-approved for sleep apnea, include acetazolamide (Diamox) and theophylline, to stimulate breathing, as well as the sedatives temazepam (Restoril) and zolpidem (Ambien) (Becker 2014; Mayo Clinic 2013; Seda 2014; Eckert 2014; Dopp 2010; Launois 2013; Kielb 2012).
Some people with obstructive sleep apnea continue to suffer with excessive daytime sleepiness in spite of CPAP therapy or other treatments. Modafinil is a wakefulness-promoting medication that is effective in relieving daytime sleepiness in people with obstructive sleep apnea (Inoue 2013; Bittencourt 2008; Black 2005). Common side effects of modafinil include anxiety, headache, nausea, and nervousness (NLM 2015a).
Surgery can be an important part of the treatment approach to sleep apnea when the obstruction is due to an obvious anatomical problem, such as enlarged tonsils or adenoids, or a deviated septum. There is considerable variability in the success rate of sleep apnea surgery, with estimates of benefit ranging from as low as 35% to as high as 92% (Li 2008; Camacho 2013; Kotecha 2014; Tien 2014; Khirani 2012). Surgical techniques can attempt to open the airway and decrease collapsibility. A combination of surgical methods may be recommended in some cases (Handler 2014; Tien 2014).