Written by Dr. Anitha Paderla, MBBS | 
Medically Reviewed by Dr. Sunil Shroff, MBBS, MS, FRCS (UK), D. Urol (Lond) on Feb 07, 2020

Diagnosis of Obstructive Sleep Apnea

Objective testing method is employed to make an initial diagnosis of some patients who complain of snoring and excessive day time sleepiness.

  • Epworth sleepiness scale is used to gauge the extent of day time sleepiness with the help of a questionnaire answered by the patient.
  • Nocturnal polysomnography is considered the best evaluation tool for diagnosing obstructive sleep apnea. This tool helps in assessing the patient in a sleep laboratory by applying several physiological parameters when the patient is asleep.

Apneic events can then be documented based on chest wall movement with no air flow and low oxygen levels in the blood (measured by oxy-hemoglobin desaturations).

A respiratory disturbance index (RDI) is then calculated and expressed as the number of abnormal respiratory events per hour of sleep. The cut-off point adopted by a few sleep laboratories, in the case of continuous positive airway pressure, is RDI of 20 episodes per hour.

A multiple sleep latency test (MSLT) measures the extent of daytime sleepiness. The time required by an average adult to fall asleep during the day is 10 minutes; therefore it is considered abnormal if the mean sleep latency is below 5 minutes.


sunny1 Tuesday, June 3, 2008

See this recent publication that indicates that obstructive Sleep Apnea - Obstructive sleep apnea (OSA) is associated with coronary artery disease (CAD). We hypothesized that OSA is independently related to the risk of CAD or death from any cause. In this observational cohort study, patients referred for OSA underwent polysomnography, and subsequent CAD events (myocardial infarction, coronary angiography or bypass graft surgery) or death were recorded. Patients were divided into exposure (AHI 15) and comparison groups (AHI Increased Risk of Coronary Artery Disease and Death, Shah NA et al New Haven, CT

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