Predictability of Oxygen Desaturation During Sleep in Patients With Cystic Fibrosis : Clinical, Spirometric, and Exercise Parameters

摘要

Background: The purpose of this study was to determine how common sleep-related desaturationnwith preserved awake resting pulse oximetric saturation (SpO2) was in a large cohort of adultncystic fibrosis (CF) patients with variable degrees of pulmonary disease. We then determinednwhether nocturnal desaturation could reliably be predicted from standard clinical and exercisenparameters.nMethods: Seventy CF patients participated in the study (mean [SD] age, 27.3 [8.7] years; women,n54%; percent predicted FEV1 [%predFEV1], 55.7% [23.9%]). Nocturnal, resting, and exercisenSpO2 were measured. Nocturnal oximetry was measured in the patient’s home. Maximal oxygenncapacity (V ˙O2max) was determined from a graded exercise test on a stationary bicycle ergometer.nThe Shwachman-Kulczycki (S-K) illness severity score was calculated incorporating categories ofnfunctional capacity, physical examination, nutrition, and chest radiograph.nResults: Multivariate analysis reported significant differences (p < 0.0001) between pulmonaryndisease severity and overall distribution of nocturnal SpO2, with the main difference being fornpatients with severe pulmonary disease (%predFEV1 of < 50%) compared to patients with mildnor moderate disease in the SpO2 intervals of 100 to 96% (p < 0.0001) and 90 to 86% (p 5 0.0001).nPulmonary function, S-K clinical scores, V ˙O2max, and resting and maximal SpO2 correlatednsignificantly (p < 0.05) with nocturnal SpO2 levels. Stepwise discriminant analysis identifiedn%predFEV1 (or S-K scores) and resting SpO2 as the parameters that could best discriminatenpatients not likely to experience nocturnal desaturation. Specifically, our equation could predictn91% of cases less likely to nocturnally desaturate, but could only modestly predict those morenlikely to desaturate (ie, 26% of cases).nConclusions: Spirometric parameters and measurements of awake resting oxygenation are ofnlimited utility in predicting nocturnal desaturation. Nocturnal oximetry should be considered innpatients with moderate to severe lung disease even with preserved awake resting SpO .