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Sleep Disorders

Dr. Mahesh Goyal, MD

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Lab Investigation

1. Hemogram – Polycythemia indicates severe disease

2. ECG and Echocardiogram – to find out evidence of PAH and ventricular hypertrophy due to systemic hypertension.

3. Arterial blood gases – to assess the level of hyposia and hypercapnea

4. Sleep Studies (clinical polysomnography)Polysomnography is defined as simultaneous recording, analysis and interpretation of large number of physiological parameters related to sleep. the various parameters recorded are: Pulse, Oxygen saturation, Respiratory volume, Snore index, Pressure, Flattening, Apnea index and apnea duration.

This is the most important investigation to diagnose OSA. The apnea – hypopnea index which is defined as the total number of apnea and hypopnea divided by total number of hours of sleep. By this score we can assess the severity of disease. In the normal individual the score is less than 5 per hour or less than 30 in whole night. AHI more than 20 per hour indicate severe disease.

The severity of OSA is also assessed by degree and duration of oxygen desaturation caused by apneas.

Sleep studies (polysomnography) is also indicated in other sleep related disorders such as:

  1. Disturbances associated with medical, psychiatric and behavioral syndromes (insomnia, periodic limb movement, affective disorders)
  2. Sleep disorders in children
  3. Detection of respiratory failure in sleep and fall in oxygen saturation in patients suffering from COPD and other chronic respiratory.

Dr. Mahesh Goyal, MD
Jaipur Allergy and Asthma Centre,
4, Park Street,
MI Road, Jaipur.

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