Upper airway resistance syndrome.

Many clinicians are familiar with the clinical symptoms and signs of obstructive sleep apnea (OSA). In its most blatant form, OSA is complete airway obstruction with repetitive, prolonged pauses in breathing, arterial oxyhemoglobin desaturation; followed by arousal with resumption of breathing. Daytime symptoms of this disorder include excessive daytime somnolence, intellectual dysfunction, and cardiovascular effects such as systemic hypertension, angina, myocardial infarction, and stroke. It has been recently recognized that increased pharyngeal resistance with incomplete obstruction can lead to a constellation of symptoms identical to OSA called "upper airway resistance syndrome" (UARS). The typical findings of UARS on sleep study are: (1) repetitive arousals from EEG sleep coinciding with a (2) waxing and waning of the respiratory airflow pattern and (3) increased respiratory effort as measured by esophageal pressure monitoring. There may be few, if any, obvious apneas or hypopneas with desaturation, but snoring may be a very prominent finding. Treatment with nasal positive airway pressure (NCPAP) eliminates the symptoms and confirms the diagnosis. Herein we describe two typical cases of UARS.