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Query: UMLS:C0020672 (hypothermia)
 17,327 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To test the hypothesis of Rahn and Reeves that the optimal arterial pH during hypothermia follows the alpha-stat concept, we studied 50 patients during coronary artery bypass grafting or valve replacement (or both) and aortic occlusion. Intravenous anesthesia was produced by high-dose fentanyl. Thiopentone 3 mg.kg-1 body weight and pancuronium 0.1 mg.kg-1 body weight were given at the start of cardiopulmonary bypass to prevent shivering. When the temperature of venous blood reached 25 degrees C, pump flow was reduced to 1.8 L.m-2.min-1. In 17 patients (group I), arterial pH was changed in a randomized order either from high to low or from low to high by adjusting the carbon dioxide fraction of the gas flow to the bubble oxygenator. At the end of 10-minute periods with stable arterial pH, oxygen uptake was calculated by multiplying pump flow and the arteriovenous oxygen difference. In 33 other patients (group II), arterial pH was kept constant during the period of stable hypothermia at 25 degrees C, and two to five determinations of oxygen uptake were performed in each patient. The carbon dioxide fraction in the gas and arterial pH varied between the patients. In group I, oxygen uptake was 31.4 ml.m-2.min-1 at pH 7.31 and 40.3 ml.m-2.min-1 at pH 7.52-a significant difference (p less than 0.001). In group II, oxygen uptake was positively correlated to arterial pH (r = 0.52, p less than 0.01). Thus the results were in line with the alpha-stat concept of acid-base management during hypothermia.
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PMID:The effect of arterial pH on whole body oxygen uptake during hypothermic cardiopulmonary bypass in man. 281 12

Circulatory arrest during profound hypothermia is a safe technique of cardiac surgery when used in selected instances. Despite its proven safety, the degree of cerebral protection offered by this technique is still poorly defined. Ten dogs anesthetized with Pentothal (thiopental sodium) were surface cooled to 32 degrees C. They were placed on cardiopulmonary bypass, cooled to 13 degrees C (cerebral temperature), and then underwent one hour of circulatory arrest. At the end of the arrest period, the dogs were rewarmed, resuscitated, and successfully weaned from bypass. A control group of 6 dogs were subjected to the same protocol but without the one-hour period of circulatory arrest. There were no group differences in animal weight, duration of surface cooling, cardiopulmonary bypass, or rewarming, mean flow, or mean arterial pressure. After a 7-day observation period, the dogs were killed with rapid tissue fixation using formalin. No neurological deficits were noted in any of the dogs during the observation period. The fixed brains were examined by a neuropathologist. No gross or microscopic evidence of cerebral hypoxia was seen in any of the animals. We conclude that one hour of circulatory arrest under profoundly hypothermic temperatures produces no detectable neurological changes or histological evidence of cerebral hypoxia.
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PMID:The protective effect of profound hypothermia on the canine central nervous system during one hour of circulatory arrest. 395 95

Deep Hypothermia and Circulatory Arrest (DHCA) is widely used to repair complex congenital heart lesions in children. We report our experience of DHCA in seven patients of transverse aortic arch aneurysm repair. Anaesthesia consisted of Nitrous Oxide, Oxygen, morphine 1 to 1.5 mg kg-1, halothane and pancuronium. Core cooling on cardiopulmonary bypass was used. At 19 +/- 0.64 degrees C (rectal) temperature, Total Circulatory Arrest (TCA) was established. Thiopentone 30 mg.kg-1 and hydrocortisone hemisuccinate 400 mg was administered before arrest. Head was packed with ice during cooling and patients were placed in steep Trendelenberg's position before opening the aneurysm sac. Mean cardiopulmonary bypass time was 151.4 +/- 8.7 minutes. Mean duration of circulatory arrest was 38.6 +/- 6.9 minutes (range, 15 to 77 minutes). Permanent neurological deficit was found in two patients. Tracheostomy was performed in one of these patients for prolonged ventilation. Two patients died of persistent bleeding, low cardiac output and hypoxia due to right lung collapse.
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PMID:Transverse aortic arch aneurysms--a challenge ahead. 831 75

We report a case of thiopentone induced mydriasis in a 17-year-old, head injured patient. Two initial 50 mg intravenous boluses and 12 h of a 125 mg/h infusion (total of 1500 mg) of thiopentone were used to reduce intracranial pressure in this patient. The patient developed fixed dilated pupils (> 8 mm) and hypothermia (27 degrees C). Thiopentone plasma concentrations were performed giving a level of 309 mumol/1; withdrawing the thiopentone infusion resulted in the pupil diameter returning to 5 mm within 24 h. A new drug plasma concentration was performed revealing a level of 198 mumol/1. We discuss the clinical implications of such a drug response and review the relevant literature.
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PMID:Fixed dilated pupils in association with a thiopentone infusion in severe head injury. 1863 67