Vaddadi Sailendra1, V. V. L. Srividya2
The drop in oxygen saturation during sleep is more than during exercise and patients of COPD who spend more time in sleeping. Significant sleep desaturation and the sleep disturbances are greater in overlap syndrome than in OSA alone. The present study is conducted in Gayathri Vidya Parishad Institute of Healthcare and Medical Technology, Visakhapatnam, AP, India, to find the prevalence of obstructive sleep apnoea in the patients with COPD.
The present study was a cross-sectional study prospectively carried out with an aim to evaluate the breathing disorders during sleep in patients with COPD and to correlate these disorders with the stage of the disease.
SETTINGS AND DESIGN
The study Cohort was constituted by patients of COPD registered into Chest OPD or admitted in Indoor units of Gayathri Vidya Parishad Institute of Healthcare and Medical Technology, Visakhapatnam, AP, India, from July 2014 to May 2016.
A total of thirty six consecutive COPD patients who consented to be enrolled into the study were classified into Mild, Moderate and Severe stages based on the Indian Guidelines for the management of COPD.
METHODS AND MATERIAL
Spirometric evaluation and bronchial reversibility testing was conducted in all the patients. Arterial Blood Gas Analysis was done using ABL3 arterial blood gas analyser (Radiometer, Copenhagen).
Patients were hooked to Compumedics ProFusion Polysomnographic Machine (Compumedics Private Limited 2001, USA), by standard gold cups/electrodes. Thereafter, the patients were subjected to a full night sleep study (Overnight polysomnography). The electrode and sensor connection system utilises E-series EEG/PSG system in order to record the PSG study. The impedance of electrodes was checked and set to <10. A total of 20 leads were utilised for the study. The various parameters monitored included Electroencephalogram (EEG), Electro-oculogram (EOG), Electrocardiogram (ECG), chin and leg Electromyogram (EMG), nasal airflow, tracheal breath sounds, thoracic wall movements, abdominal movements, transcutaneous oxygen saturation and body position.
The sleep data recorded by the computer were manually scored for sleep stages, apnoeas and hypopnoeas. The sleep scoring was done according to R and K classification.
In the study of the 36 COPD patients, 6 patients had mild COPD, 22 had moderate COPD and 8 had severe COPD.
A Significant Correlation (p value <0.05) between Neck Circumference and RDI is found to exist. There is a small, but insignificant positive correlation between BMI and RDI. No Correlation is found to exist between Sleep Efficiency and RDI.
A significant negative correlation (p value <0.05) is found to exist between PO2 and RDI in patients with Severe COPD. None of the other parameters have any significant correlation with RDI.
RESULTS AND CONCLUSIONS
Our study which consisted of COPD in different stages of severity showed the occurrence of overlap syndrome is 13.88%. We found that neck circumference per se is responsible for the increased AHI in COPD patients (r=0.381, p<0.05).
3 patients from Mild COPD and 2 patients from Moderate COPD had OSA (overlap syndrome). None of the Severe COPD patients had OSA. Pulmonary functions did not predict the occurrence of obstructive sleep apnoea in COPD and only Neck circumference per se contributes to the raised AHI in COPD patients.