Predictors of Nocturnal Oxygen Desaturation in Normoxemic Patients with Moderate to Very Severe Chronic Obstructive Pulmonary Disease.

ABSTRACT

Introduction: COPD is associated with complications suchas reduced oxygen saturation and hypoventilation duringsleep and is underdiagnosed among normoxemic patients. Toidentify the daytime parameters to predict nocturnal oxygendesaturation in normoxemic patients with moderate to verysevere chronic obstructive pulmonary disease. To correlate thepresence of nocturnal oxygen desaturation with pulmonaryhypertension.Material and methods: A cross-sectional study wasperformed at ACS medical college Chennai for 14 monthsfrom May 2017 to June 2018. The study population included103 participants. Data on variables such as 6-minute walk test,spirometry, nocturnal oximetry, partial pressures of O2 andCO2 were assessed.Results: A total of 103 patients were included in the analysiswith 93.2% males and 3.9% current smokers and 87.4%ex-smokers. 52.4% had a normal chest X-ray. Around45.6% had hyperinflated lungs. In the 6 minutes-walktest, 32% participants had desaturation. 50.5% had positiveC-reactive protein levels indicating the presence of systemicinflammation. Right atrial/right ventricular dilatation wasnoted among 34% participants. Nocturnal desaturation with3 to 4 episodes/hour was present among 39% participants.Univariate analysis results show that post FEV 1, partialpressure of oxygen and carbon dioxide, presence ofdesaturation and RA/RV dilatation on echocardiography wereall statistically significant predictors of nocturnal oxygendesaturation in normoxemic patients with moderate to verysevere Chronic Obstructive Lung Disease.Conclusion: Screening the COPD patients for these daytimepredictors will enable in identifying the patients who havenocturnal desaturation. This in turn will aid in early initiationof home oxygen therapy.