ABSTRACT: Positive airway pressure (PAP) therapy is indicated for patients with moderate to severe obstructive sleep apnea/ hypopnea. PAP therapy is also an option for patients with mild disease, especially if they have excessive daytime sleepiness or coexisting problems such as hypertension. In addition to eliminating apneas and hypopneas, continuous PAP (CPAP) has been shown to improve daytime sleepiness, mood, vigilance, and attention and decrease the risk of motor vehicle crashes. Adverse effects, such as dry mouth and nasal and sinus symptoms, usually can be managed with humidification, intranasal corticosteroids, antihistamines, or anticholinergic spray or by changing the mask. However, adherence to CPAP therapy is a major problem. The best predictor of long-term adherence is regular use at 3 months. Interventions that may improve adherence include patient education and weekly phone calls during the first month of use.
KEY WORDS: Obstructive sleep apnea, Positive airway pressure, Continuous positive airway pressure
Obstructive sleep apnea/hypopnea (OSAH) is a common medical disorder characterized by recurrent episodes of either complete (apnea) or partial (hypopnea) upper airway collapse and obstruction during sleep. These episodes of obstruction are associated with recurrent oxyhemoglobin desaturations and arousals from sleep. When the apneas and hypopneas are associated with excessive daytime sleepiness, the term "obstructive sleep apnea/ hypopnea syndrome" (OSAHS) is generally used.
Recent literature clearly shows that OSAHS is associated with significant clinical sequelae, including excessive daytime sleepiness, cognitive impairment, and cardiovascular morbidity. Long-term cure of OSAHS is achievable only with weight loss. However, since significant weight loss is often difficult to achieve, treatment with positive airway pressure (PAP), oral appliances, or upper airway surgery should be initiated after the diagnosis of OSAHS is confirmed. In this article, we will highlight recent advances in the treatment of OSAHS with PAP modalities.
PAP is the most studied and most effective treatment for OSAHS. It works by splinting the upper airway, preventing the soft tissues from collapsing. By this mechanism, PAP effectively eliminates apneas and hypopneas, decreases recurrent arousals, and normalizes oxygen saturation.
Currently, PAP devices come in 3 forms: continuous PAP (CPAP), bilevel PAP (BiPAP), and automatic self-adjusting PAP (APAP). CPAP devices produce one fixed continuous pressure during inspiration and expiration. With BiPAP, the pressure alternates between a fixed inspiratory and lower expiratory level during the respiratory cycle. With APAP, the pressure changes throughout the night in response to changes in airflow, respiratory events, and snoring.
After the initial diagnosis of OSAHS is made, the current standard of practice involves performing full, attended polysomnography during which PAP is adjusted to determine optimal pressure for maintaining airway patency. This titration is used to find a fixed single pressure (or in the case of BiPAP, fixed inspiratory and expiratory pressures) for subsequent nightly use. (1)
While a full night of titration is considered optimal, CPAP and BiPAP can be titrated during a split-night sleep study. It is recommended that the use of titration during a split-night study be limited to patients with severe OSAHS (apnea/ hypopnea index [AHI], greater than 40/h)....