June 16, 2000
While the most effective treatment for severe, obstructive sleep apnea is a tracheotomy, many people decline to have the operation because they loathe the idea of having a quarter sized opening in their neck. Now, a study in the June issue of American Journal of Respiratory and Critical Care Medicine, proves that a tiny 2 millimeter opening can work as well when combined with a new technology to monitor the flow of air. The finding may lead to new treatments in the future.
"This study gives us a new approach to supporting ventilation in patients with sleep apnea and other kinds of breathing disorders," says Alan Schwartz, M.D., associate professor of pulmonary medicine at Johns Hopkins and lead author of the study. "This approach is potentially far more tolerable."
Obstructive sleep apnea, a common condition, occurs when air cannot flow properly through a person's nose or mouth. Triggered by problems such as excess tissue in the airway, the condition seriously disturbs normal sleep and causes fatigue. Oral devices and surgeries can remedy the problem, but the most common therapy is continuous positive airway pressure (CPAP). CPAP, used during sleep, provides a stream of air to the throat via a mask and pump. It keeps structures from blocking the air passage. But when a person with severe apnea cannot tolerate the mask or other treatments fail, doctors recommend tracheotomies. Many patients, however, refuse the operation, aghast at the size of the necessary opening surgeons must leave in the neck.
For the past 10 or 15 years, the so called "mini tracheotomy" has been available for emphysema patients and others who need extra oxygen. To see if this therapy could also be used for sleep apnea, Schwartz's team enlisted five apneic patients who had undergone large tube tracheotomies. The researchers placed caps over the existing holes and slid skinny tubing through the caps to simulate mini tracheotomies. The doctors then monitored the patients breathing patterns during sleep.
The researchers discovered that a greater flow of air is needed to avoid apnea than merely to provide extra oxygen. A higher flow rate, however, sometimes closed patients' vocal chords and increased tracheal pressure. To avoid this problem, doctors developed a computer-controlled flow delivery device that monitored tracheal pressure and varied the flow of air appropriately. Patients hooked up to a computer running the newly designed program were able to successfully avoid apnea.
"Based on our clinical experience, we know that many people cannot use the CPAP mask but refuse to have a tracheotomy because they cannot stand the thought of having a big hole in their neck," says Schwartz. "We need other options for treating severely affected patients and this study shows a new, potentially more tolerable approach."
In the future, the doctors hope to make this device available to the public by fitting their program onto a tiny microchip. This microchip will be attached to the tracheotomy itself, making a separate computer unnecessary.
According to statistics from the National Institutes of Health, obstructive sleep apnea afflicts an estimated 18 million Americans. In a given night, a person can have as many as 100 or more involuntary breathing pauses per hour. The frequent interruptions of deep sleep often lead to early morning headaches and grogginess during the day. Consequences of the condition include depression, irritability, sexual dysfunction, and difficulties with learning and memory. It can also cause a person to fall asleep randomly, while at work or driving a car for example, and is associated with irregular heartbeat, high blood pressure, heart attack, and stroke.
Other authors of the study include Daniel J. O'Hearn, Karen LeBlanc, Philip L. Smith, Christopher P. O'Donnell, and David W. Eisele from Johns Hopkins; and Hartmut Schneider and J. H. Peter from Philipps-Universitat Marburg in Marburg, Germany.