Effects on Sleep and Wakefulness. CPAP improves both objective and subjective measures of sleep. After using CPAP regularly many patients report the following benefits:
- Restoration of normal sleep patterns.
- Greater alertness and less daytime sleepiness.
- Less anxiety and depression and better mood.
- Improvements in work productivity.
- Better concentration and memory.
- Patients' bed partners also often report improvement in their own sleep when their mates use CPAP.
If patients comply with the CPAP regimen but do not feel less sleepy after a period of time, or their sleep apnea symptoms do not improve, the airflow pressure may not be high enough. Patients may need to be retested. Likewise, if patients have started using an oral appliance or had a surgical procedure, their doctor probably needs to reevaluate them.
Autotitrating Positive Airway Pressure (APAP) Devices
Traditional CPAP devices provide a set pressure based on findings from polysomnography. This pressure does not fluctuate during the night or between nights unless it is reset. The initial settings are determined while at the sleep center, and changes are made only after another visit to the sleep center.
Autotitrating positive airway pressure (APAP) devices automatically customize air pressure for the individual patient. For some patients, APAP devices can be used to begin therapy at home without any supervision.
Patients with chronic lung disease, heart failure, obesity hypoventilation syndrome, who do not snore, or who have central sleep apnea syndrome are not considered candidates for APAP.
APAP devices usually use one of three methods:
- Overall pressure is kept low until a specific problem is detected. At that time the pressure is automatically increased rapidly.
- Pressure is low when there are no problems but is raised gradually when they are detected.
- Pressure is gradually raised and lowered in response to problems or their absence. In addition, the device can change depending on problems within single breaths.
Review Date: 06/11/2010
Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.