Cardiopulmonary exercise testing in evaluation of patients of chronic obstructive pulmonary disease.

Background. Objective assessment of severity in patients with chronic obstructive pulmonary disease (COPD) is mainly limited to pulmonary function testing performed at rest. But, accurate assessment of exercise capacity in patients with COPD may be possible with cardiopulmonary exercise testing (CPET). Methods. Forty-three patients with stable COPD were included and were divided into three groups based upon the spirometry data as per the Global Initiative for Obstructive Lung Disease (GOLD) guidelines as follows: Group A: mild COPD, Group B: moderately severe COPD and Group C: severe COPD. Symptom-limited CPET was performed using treadmill on incremental continuous ramp protocol in all of them. Results. Five patients (11.6%) had mild COPD; 16 (37.2%) had moderately severe COPD and the remaining 22 (51.6%) patients had severe COPD. Anaerobic threshold was attained in all the 43 patients. The dominant symptom at peak exercise were dyspnoea (n=19) and both dyspnoea and leg fatigue (n=7). The other causes of exercise limitation included dyspnoea with significant oxygen desaturation (n=6); and dyspnoea with severe oxygen desaturation (n=2). Six patients complained only of leg fatigue at peak exercise. A significant correlation between forced expiratory volume in the first second (FEV1) percent predicted and the predicted maximum oxygen uptake (VO2 max % predicted) was observed in all the three groups (r=0.39, p=0.011) but with marked variability of peak VO2 for a given degree of airflow obstruction. Twenty-three (53.5%) patients with low anaerobic threshold (<30%) were identified as potential group likely to benefit from exercise training for pulmonary rehabilitation. Conclusions. Cardiopulmonary exercise testing is useful to determine the causes of exercise limitation and to assess the maximal exercise capacity of patients with COPD.

Spirometry and diffusion studies in patients with type-2 diabetes mellitus and their association with microvascular complications.

Background. Diabetes is a systemic disease with-well known complications involving eyes, kidneys and nerves. The presence of an extensive pulmonary microvascular circulation and abundant connective tissue raises the possibility that lung may also be a target organ in diabetes. Methods. A total of 45 subjects were included in the study. All patients were evaluated for diabetic microangiopathies: nephropathy (by 24-hour protein excretion), retinopathy (by direct ophthalmoscopy) and neuropathy (by clinical examination). The patients were divided into following three groups: Group A: patients with type-2 diabetes mellitus (DM) with evidence of microangiopathy (n=15); Group B: patients with type-2 DM without any evidence of microangiopathy (n=15); Group C: non-diabetic subjects (n=15) as controls. Glycosylated haemoglobin (HbA1C) was measured as an indicator of glycemic control. Spirometry and single-breath diffusion capacity for carbon-monoxide (DLCO) were performed on all patients using Elite Series Body Plethysmograph machine. Results. A significant reduction of diffusion capacity corrected for alveolar volume (%DL/VA) was observed in group A (p<0.001), as compared to the other groups. There were no differences among the three groups for other pulmonary functions. There was a significant correlation between DL/VA percent predicted and albuminuria (r= -0.975, p<0.001), and DL/VA percent predicted and the retinopathy (r = -0.550, p< 0.05). Conclusion. This study shows a mild reduction in diffusing capacity in patients with type-2 DM with microangiopathy.