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Biomedical subjects

K V Kumar

Publications and source records attributed to K V Kumar.

40 records · Page 3Linked to original sources
PubMedDate not supplied

Efficacy of Doppler ultrasound [correction of utrasound] for screening symptoms of decompression sickness during simulated extravehicular activities.

Doppler ultrasound is frequently used for monitoring circulating microbubbles during decompression to assess the symptoms of Decompression Sickness (DCS). This analysis was carried out to evaluate its effectiveness for screening symptoms of DCS during simulated extravehicular activities (EVA). The information from various hypobaric chamber studies carried out at the NASA Johnson Space Center, Houston, TX was used in this analysis (n=516). The circulating microbubbles were detected in the precordial area in 42% (218/516), and symptoms were reported in 16% (81/516) of these exposures. The accuracy of Doppler-detectable bubbles (Spencer grades) on all symptoms of DCS was examined by calculating measures of sensitivity and specificity. The efficacy of Doppler as a screening device was examined by calculating their positive predictive value (PPV) and negative predictive value (NPV). The results of these analyses indicated that the sensitivity of Doppler decreased, and the PPV increased with higher Spencer grades. However, the likelihood of detecting true negative cases (NPV) was consistently higher with all bubble grades. Due to the high false-positive rate and low prior probabilities of the risk of DCS, Doppler was found to be more useful to identify those who did not develop DCS, than to detect positive cases of DCS in the simulated EVA exposures.

Decompression Sickness↗
PubMedDate not supplied

Energy utilization rates during shuttle extravehicular activities.

The work rates or energy utilization rates during EVA are major factors in sizing of life support systems. These rates also provide a measure of ease of EVA and its cost in crew fatigue. From the first Shuttle EVA on the STS-6 mission in 1983, we have conducted 59 man-EVA and 341 man-hours of EVA. Energy utilization rates have been measured on each of these EVA. Metabolic rate was measured during each EVA using oxygen utilization corrected for suit leakage. From 1981-1987, these data were available for average data over the EVA or over large segments of the EVA. Since 1987, EVA oxygen utilization data were available at 2-minute intervals. The average metabolic rate on Shuttle EVA (194 kcal/hr.) has been significantly lower than metabolic rates during Apollo and Skylab missions. Peak rates have been below design levels, infrequent, and of short duration. The data suggest that the energy cost of tasks may be inversely related to the degree of training for the task. The data provide insight on the safety margins provided by life support designs and on the energy cost of Station construction EVA.

Aerospace Medicine↗
PubMedDate not supplied

A study on clinical profile of falciparum malaria in a tertiary care hospital in south India.

Malaria continues to be a major problem in tropical countries. To study the clinical features and complications of malaria in a tertiary care hospital in south India, records of 183 patients were analysed. Among 86 patients with P. falciparum and mixed infection, 24 (28 per cent) had cerebral malaria and 32 (37 per cent) had hyperbilirubinemia. Twenty-three out of 32 (72 per cent) patients with jaundice had direct hyperbilirubinemia and elevated liver enzymes suggesting hepatocellular damage. Mortality of the order of 10 per cent was seen only in P. falciparum malaria. High incidence of hepatic involvement and hepatorenal failure were the unusual features observed in the study.

Adolescent↗