Diagnosis of Obstructive Sleep Apnea (OSA)
Identification of obstructive sleep apnea syndrome based solely on history and symptoms is not possible. Several studies have attempted to predict the syndrome using clinical symptoms. Even in high-risk patients using trained personnel, obstructive sleep apnea syndrome was correctly identified with only 60% of the patients.
When a history includes all major symptoms, neck circumference, obesity, and physical examination findings, obstructive sleep apnea is very likely. Sleep studies confirm the diagnosis, establish severity, and may help start treatment.
Traditionally, diagnostic sleep studies are performed for one night followed by a second night of therapeutic study for nasal continuous positive airway pressure (CPAP) titration (determination of the amount to be used for a given result).
A "split night" diagnostic and therapeutic sleep study may diagnose obstructive sleep apnea and apply nasal continuous positive airway pressure (CPAP) in a single night of testing. This approach is successful in titrating nasal CPAP in 70 - 80% of patients. Split studies save resources, expense, and patient time, but may under-estimate necessary CPAP pressure in some patients.
PDF on Froedtert Hospital Sleep Study
The diagnosis of the syndrome may not routinely require traditional measures of sleep. A wide variety of devices have been employed to diagnose obstructive sleep apnea without measures of sleep. These devices may be less expensive, more convenient, and better tolerated by patients. Most monitor single or multiple cardiorespiratory variables.
In high-risk patients with severe obstructive sleep apnea syndrome, devices that measure multiple variables including heart rate, respiratory effort, airflow, and oxyhemoglobin desaturation are likely to have more acceptable sensitivity.