Autonomic Function Tests in Chronic Obstructive Pulmonary Disease (COPD) and their Correlation with Disease Severity

Abstract

Background: Chronic hypoxemia in COPD patients, predispose them to cardiovascular autonomicneuropathy and cause sudden cardiorespiratory arrest. COPD patients without hypoxemia can also developcardiovascular autonomic neuropathy. Similarly, cardiovascular autonomic neuropathy, though observedmore often in patients with moderate and severe COPD, can also occur in patients with mild COPD. Thereis paucity of literature, revealing the relationship of autonomic function tests with disease severity in COPDpatients.Objective: In our study we intended to assess, autonomic function tests among different stages of COPDand also to identify the association of these autonomic function tests with disease severity.Method: It is a Cosssectional studydone on (n=130) male COPD patients (who could maintain oxygensaturation above 88%). Anthropometric parameters, autonomic function tests and Pulmonary function testwere assessed. Later, based on the GOLD stage criteria they were divided into 4 sub-groups. Data wereanalysed by SPSS 19.0 version software. One-way ANOVA was used to find Statistical difference betweenthe groups. Correlations between the variables were done using Pearson correlation test.Results: 30/15 ratio and E/I ratio levels were significantly decreased in very severe, severe and moderateCOPD patients when compared to mild COPD patients. The ?DBPIHG levels were significantly increasedduring isometric handgrip in very severe, severe and moderate COPD patients when compared to mildCOPD patients. E/I ratio (r=-0.463), 30/15 ratio (r=-0.496) negatively correlated with disease severity and?DBPIHG levels (r=0.687) positively correlated with disease severityConclusion: In our study group of COPD patients, we found increase in the sympathetic vascular BPresponse which gets increased as the disease severity is increased.30/15 ratio and E/I ratio levels negativelycorrelated with disease severity and ?DBPIHG levels positively correlated with disease severity.