Sildenafil improves six-minute walk distance in chronic obstructive pulmonary disease: A randomised, double-blind, placebo-controlled trial.

Background. Sildenafil has been found to improve exercise capacity and haemodynamic parameters in patients with various pulmonary disorders. This study was undertaken to evaluate its efficacy in severe chronic obstructive pulmonary disease (COPD). Methods. In this double-blind, randomised, placebo-controlled study, 37 patients with severe COPD received either sildenafil or placebo for 12 weeks. Distance covered in six-minute walk test (6MWD) was taken as primary end-point. Pulmonary artery pressure (PAP) was measured as secondary end point. Results. Thirty-three patients (15 in sildenafil arm and 18 in placebo arm) completed the study. Non-parametric tests were used for comparison. There was significant increase in 6MWD from baseline after three months of follow-up in sildenafil users (median change in distance covered in six-minute walk test (Δ6MWD)=190m) as compared to placebo users (Δ6MWD=0m, p< 0.05). The PAP decreased significantly (χ2=14.94, p<0.05) in sildenafil group after three months, while it did not change significantly among placebo group (χ 2=3.84, p>0.05). Conclusion. Sildenafil improved 6MWD and PAP in patients with severe COPD. This trial has been registered with Indian Council of Medical Research (ICMR) Trial Registry. [CTRI Registry Number: CTRI/ 2009/091/000017]

Breath carbon monoxide levels in different forms of smoking.

Background and Objectives. Bidi, cigarette, hookah and chillum are common modes of tobacco smoking in India. Many people consider hookah and chillum smoking less toxic because smoke is filtered through water or wet cloth. We evaluated the toxicity of tobacco smoking by measuring end-tidal carbon monoxide (eCO) levels after various modes of smoking. Methods. Eighteen healthy smokers who smoked bidi, cigarette, hookah and chillum on six days were studied. They smoked one bidi, one cigarette, five minutes hookah, one serve (15 minutes) hookah, five minutes chillum and one serve (15 minutes) chillum on six days randomly. The eCO values were measured before initiation of smoking and for a period of one hour after the smoking session. Increase in eCO values in comparison to baseline after different modes of smoking was compared. Results. In comparison to baseline, mean eCO levels were raised by 4.94 (0.96) parts per million (ppm) immediately and 4.17 (1.07) ppm 60 minutes after cigarette smoking. Bidi smoking caused slightly less increase in mean eCO levels (3.17 [0.82]). One serve of hookah and chillum smoking caused elevation of mean eCO values by almost eight-folds higher than that of cigarette smoking. Five minutes of smoking with hookah (22.18 [5.29]) and one serve of hookah (33.0 [8.76]) and chillum (40.14 [12.73]) caused significantly higher values of mean increase in eCO in comparison to cigarette smoking (p<0.001). Conclusion. With regard to eCO levels, hookah and chillum smoking are much more toxic than cigarette smoking.