A Study Of The Factors Of Nocturnal Desaturation In Patients With Chronic Obstructive Pulmonary Disease

Background and objective: To study the relative factors of nocturnal desaturation in patients with chronic obstructive pulmonary disease(COPD). Methods: We studied 40 stable COPD patients. Every one performed basic investigations, physical examination , pulmonary functions, repiratory drive, arterial blood gases , and Borg scale before and after 6-minute walking test on 8-10AM. All Patients underwent overnight polysomnography (PSG) to exclude OSAS.T90>=5% was NOD,on the contrary ,was non-NOD. Results: 16 patients (40%) experienced NOD. Desaturators had lower awake Pa02, SaO2, FEV,, FEVi%, FEV1/FVC, PEF, 6-minute walking distance, higher awake PaCO2, A-aD02, Borg scale. There was negative correlation between T90 and FEV,%, PEF, PaO2, PH, PaCO2, SaO2 et al, positive correlation between MSa02 during sleep and FEV)%, PEF, PH, PaO2, SaO2, et al. The predictive formula was: T90(%)=2.787*PaCO2- 7.083 *Sa02 +554.5; MSaO2(%) = -0.404* PaCO2 -0.182 * A-aDO2 - 0.402 * R(8Hz) +117.53. The curve formula was T90(%) = 0.069*(PaCO2) 2- 4.288 * PaCO2 + 63.75. The Logistic formula was P =!/ [1+-(0.884*R (8Hz> +0.319*PaC02-0.262*SaO2+0.185*A-aD02hConclusions: The rate of occurrence of NOD in COPD was 40%. The pulmonary function, arterial blood gase, Borg scale before and after 6-minute walking test, exercise endurance of the NOD were lower than those of non-NOD. Sleep-breath disorders were severer than non-NOD. Daytime SaO2, PaCO2 , R(8Hz), A-a D02 were the predictors of NOD. Daytime PaCO2, R(8Hz), A-a DO2 were the risk factors of NOD.