Doctor’s Tip: Under-appreciated but serious: central sleep apnea
The information in this column can improve your quality of life and even save your life.
Apnea refers to absent breathing. Sleep apnea refers to periods of absent breathing during sleep. Obstructive sleep apnea (OSA) is the most common form of sleep apnea, affecting about 18 million Americans, 90 percent of whom are undiagnosed. Most, although not all, people with OSA snore, and often their bed partners notice several seconds of absent breathing followed by a loud snort.
Breathing effort continues during the apnea but airflow is prevented due to blockage of the upper air passages in the mouth and throat due to conditions such as enlarged tonsils and adenoids in kids, and obesity or receding chin in adults. Most people with OSA aren’t aware they have a problem, but often complain of not feeling rested when they awaken in the morning, and feeling sleepy during the day.
The second type of sleep apnea is central sleep apnea, which is caused by failure of stimulation of the respiratory center in the brain. Many of us have noticed irregular breathing when trying to sleep at high altitudes, such as on a hut trip at 11,000 feet. Lack of oxygen causes us to take a series of consecutive breaths, each deeper than the previous one, followed by several seconds of absent breathing as our bodies sense a low carbon dioxide level (as we take these deep breaths we blow out carbon dioxide).
Due to genetics, aging and other reasons, some people develop this irregular breathing at lower altitudes. According to Dr. Khilnani, the pulmonologist who directs Valley View Hospital’s Lung Center, central sleep apnea rarely occurs in people who live below 3,000 feet but is common in people who live above 3,000 feet. Unfortunately, central sleep apnea is underdiagnosed.
People with sleep apnea are in and out of a deep sleep during the night. This plus the periodic sudden drops in blood oxygen stress their bodies, particularly their cardiovascular systems. Serious problems can result, such as: daytime sleepiness, which contributes to accidents and poor job performance; high blood pressure, especially first thing in the morning; heart failure; pulmonary hypertension; heart attacks and strokes; diabetes; “thick blood” from high red blood counts as the body tries to compensate for low oxygen at night by making more red blood cells; cardiac rhythm disturbances such as atrial fibrillation; sudden death; depression; cognitive impairment; and erectile dysfunction.
If we doctors see someone with early morning or difficult-to-control hypertension, or if we see someone with heart irregularities, we should immediately screen for sleep apnea. Dr. Frank Laws, the director of VVH’s Heart and Vascular center, says he sees central and obstructive sleep apnea all the time. The screening test for sleep apnea is cheap and easy: an overnight oximetry, which involves wearing a monitor on your finger that records your oxygen during the night. If it is normal, sleep apnea is unlikely. If it is abnormal, the next step is an overnight sleep study. Home sleep studies are convenient, but unfortunately they aren’t so good for diagnosing central sleep apnea. So a sleep study done in a sleep lab is best, and VVH has one.
Dr. Khilnani feels that good sleep quality is just as important for good health as good blood pressure and cholesterol, and he thinks everyone should be screened for sleep apnea.
Treatment consists of first of all avoiding sleep aids such as Ambien, narcotics and more than minimal alcohol (these all depress respirations). Weight loss helps obstructive sleep apnea in obese people. Some dentists are trained in oral appliances, which can sometimes help OSA sufferers.
The standard treatment for obstructive and mixed sleep apnea is CPAP (continuous positive airway pressure), which involves wearing a mask over your nose at night, with a constant airflow that pushes air past upper airway obstruction. Most although not all people tolerate CPAP, and almost all who do are surprised at how much better they sleep and at how much better they feel during the day. CPAP doesn’t always work for central sleep apnea sufferers, in which case moving to a lower altitude is the answer.
Dr. Feinsinger, who retired from Glenwood Medical Associates after 42 years as a family physician, now has a nonprofit Center For Prevention and Treatment of Disease Through Nutrition. He is available for free consultations about heart attack prevention and any other medical concerns. Call 970-379-5718 for an appointment. For questions about his columns, email him at firstname.lastname@example.org.