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

Manifestations of carbon monoxide poisoning are mostly attributable to acute hypoxic insult. In the absence of immediately available hyperbaric oxygen chamber, 100% oxygen should be delivered to the patient until carboxyhemoglobin levels in the blood are less than 5%. Presence of abnormal motor activity or prolonged abnormal consciousness are indications for proceeding with hypothermia and mechanical ventilation. Reversal of these manifestations was achieved in 3 reported cases though induction of hypothermia was delayed for as long as 24 hours. However, no beneficial effects were obtained in a fourth patient who did not receive hypothermia until 5 days after exposure. The duration of hypothermia varied between 60-70 hours in patients who showed near-complete recovery.
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PMID:Management of carbon monoxide poisoning in the absence of hyperbaric oxygenation chamber. 93 3

In investigating the stress effects of chilling (2-3 degrees C) and hypothermia (2-3 degrees C drop in body core temperature mediated by exposure to hyperbaric helium-oxygen atmosphere) on mouse resistance to "influenza," it was noted that these stresses adversely affected the course of pulmonary infection produced by aerosols of the NWS strain of influenza virus. Comparatively, respiratory LD50 values for control animals were about 25 virus plaque-forming units (PFU) with median mortality occurring on day 13. The LD50 values for mice chilled at 2-3 degrees C were about 15 PFU with median mortality on day 7, and for mice exposed to hyperbaric helium, about 12 PFU with median mortality on day 6. Cold or hyperbaric stress impaired interferon production. Impairment was observed at 24 h but not at 12 h post-challenge and persisted for several days until mice became moribund.
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PMID:Influence of cold or hyperbaric helium-oxygen environments on mouse response to a respiratory viral infection. 97 Nov 54

A description is given of a technique named "Protected Sleep", which produces a deep and residual analgesia and neurolepsia, without interfering with spontaneous respiration. A deep, stable and reliable neuroanesthesia is achieved by means of a partial pharmacodynamic blockage of the neuro-humoral reaction system. It is recognisable by the following features: 1 degree a smooth transition through pre-, per- and post-operative stages, avoiding in particular immediate awakening; 2 degrees a relative arterial hypotension, low venous pressure good peripheral circulation and tissular perfusion; 3 degrees light hypothermia; 4 degrees completely spontaneous respiration. This last factor is, to our way of thinking, of great importance: The venous return remains physiologically unchanged during inspiration in the peroperative as well as in the pre- and postoperative phases, enabling the maintenance of a constant, low venous pressure. Furthermore, should danger exist, the preservation of spontaneous respiration facilitates the immediate control of the respiratory centre. In this way we can obtain: 1. An almost perfect bloodless surgical field with good conditions for dissecting. 2. A low cerebro-spinal fluid pressure. 3. Decreased brain volume. 4. Absence of postoperative haemorrage. 5. Little of no postoperative oedema. 6. Little or no postoperative hyperthermia. "Protected sleep" is a pharmacodynamic technique realised mainly through administration of a combined and sufficient dose of pethidine, N-allyl-normorphine and levome promazine. For induction, a given dose of diazepam is combined with a single dose of succinyl-choline, to facilitate intubation, followed by a large dose of the narco-neuro-leptanalgesic mixture. For maintenance, nitrous oxide, oxygen, methoxyflurane and additional doses of the mentioned mixture are administered. Undirectional gas flow, without rebreathing, is provided, using the Ruben valve. In this paper on neuroanaesthesia, the technique of "Protected Sleep" and the pre-, per- and postoperative management and positioning of the neurosurgical patient are described in detail.
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PMID:[Anesthetic technics for surgery in otoneurology]. 98 4

Hamsters undergo hypothermia when exposed to a mixture of 80% helium and 20% oxygen at low ambient temperatures. The hypothermic hamster, rectal temperature (Tre) 7 degrees C, becomes hypoglycemic, and reversal of hypoglycemia is effected with glucose infusion. Hypothermic hamsters at Tre 7 degrees C showed a fivefold increase in survival times from 20 to 100.5 h when infused with glucose which maintained a blood level at about 45 mg/100 ml. A potential role for osmotic effects of the infusion was tested and eliminated. There was no improvement in survival of 3-O-methylglucose or dextran 40-infused animals. The fact that death eventually occurs even in the glucose-infused animal after about 4 days and that VO2 undergoes a slow decrement in that period suggests that hypothermic survival is not wholly substrate limited. Radioactive tracer, [U-14C]glucose, showed that localization of the 14C, was greatest in brain tissue and diaphragm, intermediate in heart and kidney, and lowest in skeletal muscle and liver. The significance of the label at sites important to respiration and circulation was presented.
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PMID:A role for glucose in hypothermic hamsters. 99 Jan 11

New borns and babies with congenital heart disease in poor condition have been shown to have a higher risk of developing hypoglycaemia. Blood sugar levels (BSL), acid-base balance and oxygen saturation have been studies in 10 babies from 7.5 to 15 months of age, weighing less than 9kg, before, during and after open-heart surgery. Preoperative mean BSL in the anaesthetized patient was 76mg per cent. It rose slightly after the onset of surgery and further increased to an average of 205mg per cent during cardio-pulmonary bypass with the temperature stablized at 28-29 degrees C. In the early postoperative phase BSL normalized but slowly, reaching a mean value of 107mg per cent 20-24h after the end of surgery. These results demonstrate that, at least under the usual conditions of extracorporeal circulation and hypothermia at our clinic, hypoglycaemia is not a threat in babies undergoing open-heart surgery for total correction of congenital lesions. The possible mechanisms leading to the observed hyperglycaemia are discussed and the results compared with similar studies in adult patients.
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PMID:[Blood sugar levels and acid-base balance in babies before, during and after open-heart surgery with hypothermia and extracorporeal circulation (author's transl)]. 100 46

Severe catheter-related thromboatheromatous lesions were found at necropsy in 33 of 56 infants who had umbilical arterial catheters passed during life. In infants dying within 8 days of insertion of the catheter, varying degrees of thrombosis of the aorta and its major branches were seen. With increasing thrombosis and aging of the thrombus, fatty deposits were seen first within the thrombus, and then in the intima and media. In addition there was evidence of proliferation of medial smooth muscle cells and of disruption of the medial architecture below the thrombus, characterized by the presence of abundant mucopolysaccharide. In infants who survived longer, varying degrees of organization of the thrombus could be traced, leading eventually to raised fibrous plaques with lipid and occasionally calcification. The lesions in the older infants were similar in many respects to experimental thromboatheromatous lesions produced in rabbits, and to some lesions of artheroma occurring spontaneously in humans. A wide variety of embolic phenomena were found, with features suggesting asynchrony of embolic episodes. The presence of thrombotic lesions could not be related to birthweight, Apgar scores at 1 and 5 minutes, age at catheterization, duration of catheterization, underlying disease process, age at death or the presence of hypothermia, acidosis, or anomalies in coagulation tests. There is a need for less hazardous methods of monitoring arterial oxygen tension.
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PMID:Thromboatheromatous complications of umbilical arterial catheterization in the newborn period. Clinicopathological study. 100 79

Acute hypoxic hypoxia ("height" 7000 m) did not cause distinct alterations in content of adenyl and guanyl nucleotides from brain tissue. Negative alterations in the pool of macroergic phosphates occurred in a deficit of oxygen ("height" 8000 m). Short-term training with hypoxia prevented the alterations in nucleotide pool even if the extreme hypoxia was applied ("height" 9000 m). Pre-cooling of animals promoted the maintenance of nucleotide pool at the "height" of 8000 and 9000 m. Hypothermia did not protect against the distinct alterations in content of both adenyl and guanyl nucleotides under conditions of oxygen deficit ("height" 9500 m and 1100 m).
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PMID:[Macroergic phosphates in the brain under hypoxia]. 102 35

In surface-induced deep hypothermia, metabolic acidosis resulting from lactacidemia was observed. In the hypothermic heart, the rate of reduction in the coronary arteriovenous (A-V) difference ratio of lactate, pyruvate, and nonesterified fatty acids (NEFA) was proportionately less than that of coronary flow and myocardial oxygen consumption, suggesting that lactate, pyruvate, and NEFA play important roles as energy fuels in the hypothermic heart. Myocardial metabolism of glucose was reduced; exogenous corticosteroids and ATP do not influence the myocardial metabolism of carbohydrates and lipids in the hypothermic heart.
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PMID:Experimental studies on myocardial metabolism of carbohydrates and lipids in surface-induced deep hypothermia. 103 4

Thirty-six dog kidneys were perfused with different perfusion pressures (between 15 and 60 mm. Hg) for 72 hours and then transplanted. Hypothermic human albumin was the perfusion fluid. Enzyme release, kidney weight, and renal oxygen consumption were measured during perfusion. Kidneys perfused with a flow rate of 0.8 ml. per gram per minute (21 mm. Hg mean perfusion pressure) showed the smallest increase in kidney weight and the best function after transplantation. Renal vascular resistance was independent of the level of the perfusion pressure and renal oxygen consumption was independent of the applied flow rate. It is concluded that the perfusion pressure applied with hypothermic perfusion should be as low as possible because in this way kidney damage caused by perfusion can be avoided most easily.
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PMID:Analysis of the optimal perfusion pressure and flow rate of the renal vascular resistance and oxygen consumption in the hypothermic perfused kidney. 109 16

At the present time, simple hypothermia or regional or total body perfusion probably afford the best means of myocardial protection of the donor heart. However, the potential of either technique is extremely limited, and a combination of hypothermia with some form of perfusion system will probably enable considerably longer periods of storage of the donor organ. Such a perfusion system has not yet been conclusively developed, though considerable advances have been made. It is doubtful whether or not the addition of hyperbaric oxygen to hypothermia greatly prolongs the storage period. Metabolic inhibition by a chemical agent is an attractive method of preservation, possibly associated with hypothermia, but the search for the perfect agent continues. Actual freezing of the organ may prove feasible in the future, but recent work in the field of cryobiology has proved almost uniformly disappointing. The use of the autoperfusing heart-lung preparation as a short term storage system deserves further study, but its value as a really long term system of storage of the heart seems unlikely at the present time. Xenobanking has been encouragingly successful in experimental situations, but its clinical application will prove to be expensive and difficult.
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PMID:Donor heart resuscitation and storage. 109 70


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