Study of Pulmonary Functions, Arterial Blood Gases and Autonomic Functions in Chronic Obstructive Pulmonary Disease and its Comparison Between Young and Elderly Patients

Purpose of the study: Chronic Obstructive Pulmonary Disease (COPD) is one of the most important causes of morbidity and mortality worldwide. Purpose of this study is to compare the Pulmonary functions, Autonomic functions and Arterial Blood Gases (ABG) between young and elderly COPD patients and to determine association if any between severity of the disease and autonomic dysfunctions. Methods: In this cross sectional study a total of hundred male patients attending medical OPD (Fifty young and fifty Old) who has diagnosis of COPD were included. This study was carried out in the outpatient setting in a tertiary referral Mathura Das Mathur Hospital, Jodhpur. Spirometry, arterial blood gas analysis and autonomic functions were assessed. Result: The severity of COPD was more among elderly population as compared to young patients. The risk of development of co-morbidities and acute exacerbations also was more among the elderly. The study also demonstrated a high prevalence (97%) of early and definite cardiac autonomic neuropathy among patients suffering from COPD. The autonomic dysfunction developed independent of the age of the patients suggesting that COPD is responsible for earlier onset of cardiac autonomic neuropathy. The autonomic dysfunction does not depend upon the degree of airway limitation (FEV1). The prevalence of autonomic dysfunction did not show any significant correlation with the presence of hypoxia. Introduction Currently, COPD is one of the most important causes of morbidity and mortality worldwide, causing both a significant economic impact on public health systems. Worldwide it is estimated that over 600 million patients suffer from COPD, this condition affecting about 2.5% of the population over 30 years in Europe [2, 3]. Chronic obstructive pulmonary disease (COPD) is a preventable and treatable disease, characterized by persistent respiratory airflow obstruction, usually progressive, associated with chronic inflammatory response of the airways and lungs, due to the action of noxious particles or gases. Inflammation causes a combination of inflammatory lesions in the small bronchi and lung parenchyma. It increases the destruction of alveolar septa and causes pulmonary emphysema [1]. Autonomic dysfunction leading to orthostatic hypotension has been a major cause of falls in elderly population, leading to increased morbidity. Autonomic dysfunction is common in elderly population and its incidence is increased due to various diseases and drugs. It has been recognized that chronic obstructive pulmonary disease (COPD) is a systemic disease which has been shown to negatively affect the cardiovascular and autonomic nerve system. The autonomic nervous system (ANS) innervates the entire neuraxis and influences all organ systems. It regulates blood pressure (BP), heart rate, sleep, and bladder and bowel function. Gross et al studied maximum increase in forced expiratory volume in one second (FEV1) following administration of atropine methionitrate and showed that cholinergic tone in chronic obstructive pulmonary disease (COPD) was increased in proportion to the severity of airway disease. [3] It is therefore likely that abnormal activity of autonomic nerves innervations can contribute to airway narrowing in COPD and may be relevant to the pathogenesis of COPD. The complexity of the physiologic basis by which autonomic dysfunction occurs in patients with COPD is considerable and the knowledge in this field remains elementary. In COPD patients the activity of sympathetic nerves may be affected by recurrent hypoxemia, hypercapnia, increased intrathoracic pressure swings due to airway obstruction, increased respiratory effort, systemic inflammation and the use of beta sympathomimetics. The insight into sympathovagal imbalance as a pathological phenomenon in COPD may be important in understanding the pathophysiology of COPD and may have a potential clinically importance for improving risk stratification and treatment of patients with COPD, because autonomic dysfunction has been attributed as a cause for endothelial dysfunction, increased arterial stiffness, left ventricular remodelling and supraventricular and ventricular arrhythmias. [18] . The purpose of this study is to evaluate and determine an association if any between the Arterial Blood Gas, Pulmonary function test and Autonomic function if any among the patients suffering from Chronic Obstructive Pulmonary Disease. Material and Methods This study was conducted at Department of Medicine, M.D.M. hospital, Dr SN Medical College, Jodhpur. Study Design: Cross sectional study Sample size: 100 patients (50 > 60 years and 50< 60 years) with known Chronic Obstructive Pulmonary Disease were evaluated. Mean age of 61.17 years with the youngest patient being 40 years and oldest being 85 years (Table 1). Inclusion Criteria: All known cases of Chronic Obstructive Pulmonary Disease attending Medicine outdoor. Exclusion Criteria: Patients with acute exacerbation of COPD.