Home test spots breathing trouble in heart failure

Overnight home monitoring can detect sleep-related breathing disturbances in people who suffer from heart failure, according to new research. This is important said Dr. Frederic Series, because treating these breathing disorders may improve their heart condition.

However, the technique called oximetry, in which a probe attached to a finger continuously measures blood oxygen levels, cannot distinguish between Obstructive sleep apnea and central sleep apnea.

Obstructive sleep apnea occurs when the airway becomes blocked by tissue, such as the tonsils or the base of the tongue. Central apnea, in contrast, occurs when the respiratory system stops working in the absence of a blockage.

Dr. Series, from Hopital Laval Sainte Foy in Quebec, Canada, and colleagues evaluated the value of overnight oximetry for spotting breathing trouble during sleep in 50 adults with stable but symptomatic heart failure.

The technique proved highly sensitive and specific for detecting sleep-related breathing disturbances. However, the technique was unable to accurately separate patients with airway blockages from those with central respiratory events in the absence of a blockage.

Nonetheless, the researchers believe their findings should have "an important impact" in the management of heart failure patients. Breathing disturbances detected with in-home overnight oximetry, they explain, could help prioritize patients for full polysomnography, in which brain waves, eye movements, muscle activity, blood oxygen, and other functions are recorded while patients sleep in a special lab setting.

"In this way, many more (heart failure) patients may benefit from the timely diagnosis and treatment of sleep-related breathing disturbances than might otherwise be the case," Series and colleagues write in the medical journal Chest.

SOURCE: Chest May 2005.