Vaddadi Sailendra 1 , V. V. L. Srividya 2
BACKGROUND Patients of COPD become hypoxic during sleep to a significant extent. Florid hypoxic episodes occur during REM sleep secondary to central diminution in respiratory output, accentuated by hypotonia of postural muscles, intercostals and accessory muscles of respiration. MATERIALS AND METHODS This is a cross-sectional study carried out prospectively in Gayathri Vidya Parishad Institute of Healthcare and Medical Technology, Visakhapatnam, AP, India, to evaluate breathing disorders during sleep in COPD patients and to correlate them with the stage of the disease. SAMPLE SIZE A total of 36 COPD patients were enrolled into the study. They are classified into Mild, Moderate and Severe COPD categories in accordance to the Indian guidelines. The study was conducted between April 2014 and May 2016. POLYSOMNOGRAPHY Overnight sleep study was conducted using Compumedics Profusion Polysomnographic Machine. A total of 20 leads were utilised for the study. The sleep data recorded by the computer was manually scored for analysing Sleep stages, Apnoeas and Hypopnoeas. Sleep scoring was done according to R and K classification. Nocturnal oxygen desaturation is defined as >30% of total recording time with a SaO2 <90% (or) nocturnal SaO2 <85% for at least 5 minutes. RESULTS Out of the 36 patients enrolled into the study, 6 were having mild COPD, 22 had moderate COPD and 8 had severe COPD. Total number of patients who had significant oxygen desaturation during sleep were 5 (13.9%). Out of these, 1 patient (16.67%) belonged to Mild COPD, 1 (4.54%) belonged to Moderate COPD and 3 (37.5%) belonged to Severe COPD. CONCLUSION We conclude that in patients with COPD, daytime SpO2 is the single most useful determinant that contributes to NOD; daytime hypercapnia being the other important factor. In Severe COPD group, daytime PaO2 contributes to NOD whereas in Mild COPD, a raised AHI might explain the occurrence of NOD.
