European journal of applied physiology and occupational physiology
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Eur J Appl Physiol Occup Physiol · Jan 1987
Comparative StudyTympanic temperatures during hemiface cooling.
In adult men the left half of the head was covered with thick heat insulation, and the right hemiface was cooled by spraying a mist of water, and vigorous fanning. The subjects were immersed up to the waist in warm water (42 degrees) to achieve hyperthermia. In control sessions the subjects were rendered slightly hypothermic by preliminary exposure to cold. ⋯ This latter result cannot be explained by conductive cooling from the skin to the tympanic membrane and implies a vascular cooling of the left Tty originating from the other side of the head. It is concluded that selective cooling of the brain takes place during hyperthermia. The main mechanism is forced vascular convection, but conductive cooling also occurs.
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Eur J Appl Physiol Occup Physiol · Jan 1985
Extracorporeal CO2-removal: pulmonary and extracorporeal equilibria in dogs and sheep.
Extracorporeal CO2-removal promises to be an efficient alternative to the conservative treatment of advanced lung diseases. Extracorporeal CO2-removal is achieved in a veno-venous bypass in combination with low frequency ventilation. Positive clinical results in the treatment of adult respiratory distress syndrome (ARDS) are encouraging. ⋯ We report here on experiments with dogs and sheep undergoing a veno-venous bypass employing a CO2-eliminator. The experimental results are compared with theoretical values which predict the important relationships between blood flow rate of the extracorporeal circulation (ECC), the CO2-elimination capacity of the CO2-eliminator and the low ventilation rate (down to apnea for 5 h) of the natural lung. It was shown that the blood gas data as well as acid base status could be maintained within physiological ranges.
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Eur J Appl Physiol Occup Physiol · Jan 1984
Comparative StudyVaried and repeated atropine dosages and exercise-heat stress.
Comparisons of physiological responses to 0, 0.5, 1, and 2 mg atropine (IM) were made in seven males (X +/- SD: age, 24 +/- 3 years; ht, 174 +/- 12 cm; wt, 76 +/- 3 kg) while they exercised (approximately 390 W) in a hot-dry (40 degrees C, 20% rh) environment. Responses to 4 mg, as well as repeatability of responses to 2 mg, were studied in two and six of these subjects, respectively. On 8 test days an intramuscular injection of atropine or saline control was administered 20 min before subjects walked on a treadmill for two 50-min bouts. ⋯ Mean weighted skin temperature (Tsk) was relatively constant during exercise and was warmer (P less than 0.05) with increasing atropine dosage. In a repeat 2 mg trial, HR was 6 bt . min-1 lower (P less than 0.05) on the second exposure but Tre was the same (P greater than 0.05) on both days. For subjects walking in the heat, three new observations were: 1) 0.5 mg of atropine resulted in increased HR and Tsk compared to control values; 2) HR was elevated but the magnitude of change decreased with increasing dosage, while the elevation in Tre was consistent with increasing dosage; and 3) rectal temperatures (in trials with and without atropine) were unaffected by previous days of atropine administration.