April 2004

Sleep Talk: Diagnosing Obstructive Sleep Apnea
Patients at high risk for sleep apnea are those who exhibit loud, intermittent snoring, and have complaints of daytime sleepiness. Patients who are observed to have apneic events characterized by choking or gasping during sleep are definite candidates for further evaluation. Bed partners or family members may need to be interviewed in order to obtain accurate information about snoring and apneic events.

Role of Obesity

Obesity, particularly upper body obesity, is a risk factor for sleep apnea and has been shown to have a significant effect on its severity. Many sleep apnea patients are obese, when obesity is defined as greater than 120 percent of ideal body weight. Large neck girth in both male and female snorers is highly predictive of sleep apnea. In general, men with a neck circumference of 17 inches or greater and women with a neck circumference of 16 inches or greater are at a higher risk for sleep apnea.

Other signs and symptoms that can help identify patients at risk for sleep apnea are hypertension, excessive daytime sleepiness (especially dozing off while driving), automobile or work-related accidents, and otherwise unexplained pulmonary hypertension. The Epworth Sleepiness Scale is a simple and quick self administered method of evaluating a patient's degree of pathological sleepiness.

Ordering a Polysomnogram

If there is a high suspicion of sleep apnea after evaluating a patient, a polysomnogram is indicated to establish a diagnosis, and to differentiate sleep apnea from other possible primary organic sleep pathologies. Polysomnography, which requires an overnight stay in a sleep laboratory, is the optimum test for diagnosing sleep apnea. It includes evaluation of sleep by recording sleep stages via EEG, chin muscle tone and eye movement, airflow and ventilatory effort, EKG, body position, leg muscle activity, oxygen saturation and upper airway vibration. It is imperative that a sleep study be scored by someone with experience in polysomnography, and interpreted by someone with expertise in sleep medicine since an accurate diagnosis is critical to assuring proper treatment.

INPRACTICE

To get copies of the Epworth Sleepiness Scale for evaluation of your patients, please click on link at right.

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