Sleep pattern in patients with Chronic Obstructive Pulmonary Disease and correlation among gasometric, spirometric, and polysomnographic variables

ABSTRACT

OBJECTIVE: There are few studies on chronic obstructive pulmonary disease (COPD) establishing differences between the functional parameters of the disease and sleep variables. The aim of the study was to describe the sleep pattern of these patients and to correlate spirometric, gasometric and polysomnographic variables. METHODS: Transversal study using COPD patients submitted to spirometry, arterial gasometry, and polysomnography. RESULTS: 21 male patients were studied with average age = 67 ± 9; 7 ± 4 average points in the Epworth sleepiness scale, average Tiffenau's index (FEV1/FVC) = 54 ± 13.0 percent, average PaO2 = 68 ± 11 mmHg, average PaCO2 = 37 ± 6 mmHg. Sleep efficiency decreased (65 ± 16 percent) with the reduction of slow wave sleep (8 ± 9 percent) and rapid eye movement (REM) sleep (15 ± 8 percent). Average T90 was 43 ± 41 percent. Average apnea-hypopnea index (AHI) = 3 ± 5/h, where two patients (9.5 percent) presented obstructive sleep apnea. A significant correlation was observed between PaO2 and T90 (p < 0.01), PaCO2 and T90 (p < 0.05), and AHI and the cardiac rate during REM (p < 0.01). A higher number of arousals and stage change was observed. There was no linear correlation between spirometric and polysomnographic variables. CONCLUSION: Poor sleep quality of these patients was characterized by low sleep efficiency, high number of awakenings and shift of stages. There were no correlations between the spirometric and polysomnographic variables.