CPAP Therapy Improves Heart Function, Study Says
New research points to obstructive sleep apnea (OSA) as a contributor to heart failure, but fortunately, the use of continuous positive airway pressure (CPAP) devices can help.

A randomized clinical trial, funded in part by Respironics Inc, Murrysville, Pa, showed that patients who have obstructive sleep apnea and heart failure and are treated for sleep apnea with a CPAP portable device show improvement in heart function beyond that due to drug therapy.

“Prior to this study, it had not been considered that heart failure might be adversely affected by something that goes on during sleep,” says Douglas Bradley, MD, lead investigator of the study; head of the Sleep Research Laboratories at Toronto General Hospital (TGH), Mount Sinai Hospital, and Toronto Rehabilitation Institute; and director of the University of Toronto Centre for Sleep Medicine and Circadian Biology.

Patients in the study receiving CPAP treatment in addition to medication experienced decreases in sleep apnea episodes, heart size, blood pressure, and heart rate, while heart function improved.

When OSA causes asphyxiation, the sympathetic nervous system responds, causing blood pressure and heart rate to rise at a time when the heart is supposed to be resting, according to Bradley. Compounding that is the heart oxygen starvation during sleep apnea episodes that impairs its ability to pump at a time when the load on it is being increased.

“Your heart is basically doing the same thing as if you had hypertension, which is the most common cause of heart failure,” Bradley says.

The study was conducted at TGH, University Health Network, Mount Sinai Hospital, and the Toronto Rehabilitation Institute. Researchers tested 24 patients with heart failure who also had obstructive sleep apnea. Titled “Cardiovascular Effects of Continuous Positive Airway Pressure in Patients with Heart Failure and Obstructive Sleep Apnea,” the study appeared in the March 27 issue of The New England Journal of Medicine.

FDA OKs Asthma Breath Test
In May, the US Food and Drug Administration (FDA) approved a device to help physicians monitor patients’ asthma. A first-of-a-kind, noninvasive test system, NIOX by Aerocrine AB, of Sweden, measures the concentration of nitric oxide in exhaled human breath. That concentration level indicates a patient’s response to anti-inflammatory treatment, according to the FDA.

A decrease in exhaled nitric oxide concentration suggests that the treatment may be decreasing the lung inflammation associated with asthma. According to the FDA, recent evidence shows that nitric oxide levels increase in the breath of people with asthma. Changes in nitric oxide levels may indicate whether treatment for asthma is working.

To use NIOX, patients breathe into a mouthpiece connected by a tube to a special computer that displays nitric oxide concentration.