Local cooling in wheelchair athletes during exercise-heat stress.

Wheelchair athletes with spinal cord injuries (WA) face challenges to thermal homeostasis, including reduced cutaneous vasoaction and sweat production. The purpose of this study was to evaluate the efficacy of local cooling to reduce heat strain in WA. Six elite, endurance-trained male WA (33 +/- 3 yr, 64 +/- 4 kg) performed three strenuous exercise tests in a hot-humid environment (32.9 +/- 0.1 degrees C, 75 +/- 3% RH) by pushing a racing chair on a stationary roller (30 min, 16.5 km.h-1, 704-766 W metabolic heat) while wearing shorts and socks. The three treatments involved an ice-packet vest (V) (0.14 m2 of skin surface), a refrigerated headpiece (H) (0.16 m2), or no cooling (C) (control). The vest and headpiece offered potential cooling of 388 W and 266 W. Mean body heat storage for trials V (117 +/- 26 W), H (117 +/- 22 W), and C (164 +/- 40 W) were statistically similar, partly because V (117 +/- 47 W) and H (75 +/- 59 W) cooled inefficiently (30 and 28%, respectively). Repeated measure ANOVA indicated no significant between-treatment differences (P > 0.05) for any variable in trials V, H, and C. We concluded that local cooling during V and H was ineffective because heat storage decreased, but was not prevented.

Differences in pulmonary function tests among whites, blacks, and American Indians in a textile company.

Normal standards for pulmonary function in nonwhite populations are not presently available to occupational health workers. The present study examined differences in %FVC, FVC, FEV1/FVC, FEF 200-1200 and FEF 25-75% among whites, blacks, and American Indians. The sample consisted of 4209 job applicants to a textile company in southeastern United States. Multiple regression and analyses of covariance were employed to control differences in age, height, weight, and smoking status. Blacks were significantly lower in five of the six comparisons but higher in FEV1/FVC%. The pulmonary function measures of Indians fell generally between those of whites and blacks. Differences were observed between blacks and whites of both sexes regarding the effects of cigarette smoking. The need for race specific stardards was confirmed and the question of using smokers in the acquisition of normative data was raised.

Hypoxemia and hypocarbia following intermittent positive-pressure breathing.

The authors determined the effects of short-term, vigorous intermittent positive-pressure breathing (IPPB) on arterial blood O2 tension (Pao2) in 10 unmedicated preoperative adult patients (ASA class I). Arterial blood was analyzed before and 0.5, 5, 15, and 40 minutes after 12 minutes of IPPB with nebulized 0.9% HaCl and room air. Pao2 increased from 89.1 +/- 11 torr (mean +/- SD) to 102.1 +/- 13.9 torr, and arterial CO2 tension decreased from 29.5 +/- 4 torr to 18.4 +/- 3 torr, causing significant respiratory alkalosis (pHa 7.62 +/- 0.05). Five minutes after IPPB, Pao2 decreased to 69.2 +/- 8 torr; alveolar-arterial Po2 difference, breathing 21% O2, increased significantly; and serum K+ concentration decreased significantly. All these values returned to baseline levels within 40 minutes. The authors, acknowledging the value of IPPB when specifically indicated, counsel caution in patients with borderline pulmonary reserve and arterial oxygenation.