Effect of Selective and Nonselective Cyclooxygenase Enzyme Inhibition on Arterial Blood Pressure and Cerebral Blood Flow with Exposure to Intermittent Hypoxia in Humans

Background: Intermittent hypoxia (IH) simulating obstructive sleep apnea raises blood pressure (BP) and impairs cerebral blood flow response. The pathophysiology of intermittent hypoxia-mediated increase in BP involves multiple mechanisms but the role of cyclooxygenase (COX) catalyzed vasoactive prostaglandins (PG) is unclear. Methods: A placebo controlled double-blind randomized cross-over trial was designed using nonselective COX inhibitor indomethacin (50 mg tid/po), selectively COX-2 inhibitor celecoxib (200 mg bid/po) comparing with placebo. Healthy males ingested either of drugs for 4 days and physiological measurements were taken on 5th day with an acute isocapnic-hypoxia challenge pre- and post 6 hrs of IH exposure. Urinary PGs were assayed pre- and post- IH exposure. Results: After 4 days of drug, INDO increased BP compared to PLBO and CLBX; and lowered CBF compared to PLBO (air and baseline breathing). Mean arterial pressure gain with INDO increased followed by CLBX in response to acute isocapnic hypoxia and it was driven by increased gains in both systolic BP and diastolic BP (statistically not significant). CBF gain was blunted with CLBX while it was similar between INDO and PLBO although they were not statistically significant. With 6 hrs of IH (post-IH), CBF gain remained blunted with CLBX but was augmented with INDO (statistically not significant). CVC gain was lower with CLBX (statistically not significant). Both drugs lowered vasodilator and vasoconstrictor PGs compared to PLBO. Pre-IH PGI2:TxA2 was higher with INDO compared to PLBO (p < 0.001) and CLBX (p < 0.001). Conclusion: Indomethacin perturbs cardio- and cerebrovascular homeostasis in more robust manner as compared to placebo and celecoxib after 4 days of ingestion

Side-effect of acetazolamide in prevention of acute mountain sickness

The scientific letter by Firth et al. (S Afr Med J 2011;101:462) about the side-effect of acetazolamide on a hiker on Mt Kilimanjaro makes a rather hasty conclusion about the recommendation of acetazolamide to prevent acute mountain sickness (AMS), especially in a rapid ascent climb such as Kilimanjaro. It is difficult to disagree about the pathophysiology of acetazolamide causing corneal oedema, but we must note that it is a drug used for glaucoma treatment, and the dosage regimen is usually higher than that prescribed for the prevention of AMS. Interestingly, the authors did not mention the dose and duration of acetazolamide in the article. The cause-effect relationship is difficult to establish from this case report without knowing the dosage regimen and control. Based on the rare side-effect (if indeed it is) in this report, it would not be justifiable to advise against using acetazolamide as a prophylactic of AMS; this could rather invite other serious acute altitude illnesses that would be far more probable were it not used. Major trials with large numbers of participants have reported a fairly safe outcome of acetazolamide. Hence, we should continue using acetazolamide with caution for preventing AMS where there is rapid ascent profile. Reply by P G Firth, C Gray and C Novis

Estimation of Physiological Cost Index as an Energy Expenditure Index using MacGregor’s Equation

Introduction: Physical activity and energy expenditure can be quantified by measuring heart rate, oxygen uptake and respiratory quotient. The Physiological Cost Index (PCI) proposed by MacGregor is a simple and straightforward method to estimate the energy expenditure index. Here, we aim to estimate the energy expenditure among young Asian population using MacGregor’s equation. &#13; Methods: A total of 50 young randomly selected healthy females performed 50m, 100m and 150m walking test at their self-selected preferred speed. The physiological cost index values for 100 m walk at speeds slower and faster than the preferred speed were also obtained. The physiological cost index during exercise was calculated using MacGregor’s equation considering heart rate and speed of walking over the varying distances. &#13; Results: The PCI values on three different distances are consistent during self selected preferred speed. The PCI estimation on second and third tests for all three distances walked consistently reproducible. However for each distance walked, the first test the PCI was significantly higher than the second and third test values. The PCI values increased significantly when subjects walked either slower (p = 0.02) or faster (p = 0.001) than their normal preferred speed. &#13; Conclusion: The physiological cost index values were similar for varying distances walks. The PCI was the least at the preferred speed of walking and increased when the subjects either walked slower or faster than the preferred speed. The first estimation was higher than subsequent estimations. &#13; Keywords: energy expenditure index; exercise; physiological cost index. | PubMe

Pulmonary Functions are Impaired among Carpet Factory Workers: A Spirometric Evaluation

Introduction: Carpet factory produces various types of dusts and workers occupationally get exposed to them continuously. It has adverse health effects and most notably to the pulmonary functions. Nepal is one of the carpet exporter developing countries and still does have many factories within Kathmandu valley. However, the health hazards especially the status of pulmonary function of carpet factory workers from Nepal has not been studied. Methods: A cross-sectional comparative study was designed to recruit carpet factory workers and healthy controls to assess their pulmonary functions. A total of 118 subjects (59 males and 59 females) were recruited (60 carpet factory workers and 58 controls). Pulmonary function tests were carried out using Medical International Research Spirolab II portable spirometer. Results: The carpet factory workers had significantly less FEV1 (90.37 ±16.6 % vs. 103.89±9.79%, p<0.001), FVC (87.78 ± 15.48 % vs. 102.81 ± 8.41 %, p < 0.001) and PEFR (66.19 ± 20.29 % vs. 102.81 ± 11.09 %, p < 0.001) as compared to control group. Similarly the carpet factory workers had significantly higher FEV1/FVC ratio (89.96 ± 6.42 % vs. 87.12 ± 4.58 %, p = 0.007) as compared to control. Conclusions: Carpet industry dusts exposure adversely affects pulmonary functions among its workers. The findings significant increase in the FEV1/FVC ratio and decrease in FEV1, FVC, and PEFR suggest that the effects are both restrictive and obstructive patterns of lung disease. Keywords: carpet industry; lung function; occupational health; pollution; spirometry. | PubMe

Pulmonary Functions are Impaired among Carpet Factory Workers: A Spirometric Evaluation

Introduction: Carpet factory produces various types of dusts and workers occupationally get exposed to them continuously. It has adverse health effects and most notably to the pulmonary functions. Nepal is one of the carpet exporter developing countries and still does have many factories within Kathmandu valley. However, the health hazards especially the status of pulmonary function of carpet factory workers from Nepal has not been studied. Methods: A cross-sectional comparative study was designed to recruit carpet factory workers and healthy controls to assess their pulmonary functions. A total of 118 subjects (59 males and 59 females) were recruited (60 carpet factory workers and 58 controls). Pulmonary function tests were carried out using Medical International Research Spirolab II portable spirometer. Results: The carpet factory workers had significantly less FEV1 (90.37 ±16.6 % vs. 103.89±9.79%, p&lt;0.001), FVC (87.78 ± 15.48 % vs. 102.81 ± 8.41 %, p &lt; 0.001) and PEFR (66.19 ± 20.29 % vs. 102.81 ± 11.09 %, p &lt; 0.001) as compared to control group. Similarly the carpet factory workers had significantly higher FEV1/FVC ratio (89.96 ± 6.42 % vs. 87.12 ± 4.58 %, p = 0.007) as compared to control. Conclusions: Carpet industry dusts exposure adversely affects pulmonary functions among its workers. The findings significant increase in the FEV1/FVC ratio and decrease in FEV1, FVC, and PEFR suggest that the effects are both restrictive and obstructive patterns of lung disease. Keywords: carpet industry; lung function; occupational health; pollution; spirometry. | PubMe

Pulmonary Functions are Impaired among Carpet Factory Workers: A Spirometric Evaluation

Introduction: Carpet factory produces various types of dusts and workers occupationally get exposed to them continuously. It has adverse health effects and most notably to the pulmonary functions. Nepal is one of the carpet exporter developing countries and still does have many factories within Kathmandu valley. However, the health hazards especially the status of pulmonary function of carpet factory workers from Nepal has not been studied. Methods: A cross-sectional comparative study was designed to recruit carpet factory workers and healthy controls to assess their pulmonary functions. A total of 118 subjects (59 males and 59 females) were recruited (60 carpet factory workers and 58 controls). Pulmonary function tests were carried out using Medical International Research Spirolab II portable spirometer.  Results: The carpet factory workers had signi cantly less FEV1 (90.37 ±16.6 % vs. 103.89±9.79%, p<0.001), FVC (87.78 ± 15.48 % vs. 102.81 ± 8.41 %, p < 0.001) and PEFR (66.19 ± 20.29 % vs. 102.81 ± 11.09 %, p < 0.001) as compared to control group. Similarly the carpet factory workers had signi cantly higher FEV1/FVC ratio (89.96 ± 6.42 % vs. 87.12 ± 4.58 %, p = 0.007) as compared to control.  Conclusions: Carpet industry dusts exposure adversely affects pulmonary functions among its workers. The  ndings signi cant increase in the FEV1/FVC ratio and decrease in FEV1, FVC, and PEFR suggest that the effects are both restrictive and obstructive patterns of lung disease. Keywords: carpet industry; lung function; occupational health; pollution; spirometry