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

Despite the widespread use of non-steroidal anti-inflammatory drugs (NSAIDs), the current number of reported cases of poisoning is small. However, with the introduction of 'over-the-counter' preparations of NSAIDs in some countries (e.g. ibuprofen in the UK and USA) an increased incidence of acute poisoning from this group of drugs can be expected. Conventionally, NSAIDs are divided into the following groups based on their chemical structure: arylpropionic acids, indole and indene acetic acids, heteroarylacetic acids, fenamates, phenylacetic acids, pyrazolones and oxicams. Unless NSAIDs are ingested in substantial overdose, acute poisoning with these agents does not usually result in significant morbidity or mortality. In most cases the clinical features are mild and confined to the gastrointestinal and central nervous systems, though acute renal failure, hepatic dysfunction, respiratory depression, coma, convulsions, cardiovascular collapse and cardiac arrest may complicate severe poisoning. Arylpropionic acid derivatives were thought initially to have a low order of toxicity in overdose but, in addition to anticipated gastrointestinal symptoms, headache, tinnitus, hyperventilation, sinus tachycardia, hypoprothrombinaemia, haematuria, proteinuria and acute renal failure have been described. In addition, drowsiness, coma, nystagmus, diplopia, hypothermia, hypotension, respiratory depression and cardiac arrest have been reported in severe cases of poisoning. Oxyphenbutazone and phenylbutazone are considerably more toxic in overdose. Complications of severe poisoning include coma, convulsions, hepatic dysfunction, acute renal failure, sodium and water retention, haematuria, cardiovascular collapse, respiratory alkalosis, metabolic acidosis, hypoprothrombinaemia and thrombocytopenia. In contrast, indomethacin appears to be much less toxic. In addition to gastrointestinal symptoms, indomethacin taken in overdose induces headache, tinnitus, dizziness, lethargy, drowsiness, confusion, disorientation and restlessness. Only 1 case of acute sulindac poisoning has been reported in the literature. A 16-year-old boy was admitted with hypokalaemia (2.2 mmol/L), transient granulocytosis and 'scanty' haematemesis after ingesting 12 g sulindac. No case of acute tolmetin poisoning have been reported. The fenamates (flufenamic acid, meclofenamic acid, mefenamic acid, tolfenamic acid) are, with the exception of mefenamic acid, not as widely prescribed as other groups of NSAIDs. In overdose, mefenamic acid may result in nausea, vomiting, diarrhoea, muscle twitching, convulsions and coma.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Acute poisoning due to non-steroidal anti-inflammatory drugs. Clinical features and management. 353 13

In 1975 H. Rahn put forward a new concept of hydrogen ions regulation which explains acid-base regulation in relation to body temperature and applies to all animal species. At the root of this concept is the finding that maintenance of intracellular neutrality is governed by water dissociation and regulated by imidazole-rich protein buffers. The pH of the extracellular fluid, which receives acid by-products of cell activity, is kept higher than that of the intracellular fluid (relative alkalinity). The difference between extracellular pH and neutrality is constant for each species and ranges from 0.6 to 0.8 pH units. It is unaffected by changes in temperature, and the total CO2 content of extracellular fluid remains constant. The authors were able to confirm the value of this new concept in man by experimental studies of in vitro and in vivo blood of patients undergoing aorto-coronary bypass under controlled hypothermia. They draw the following practical conclusions: (1) in subjects under moderate or deep hypothermia for surgical purposes, the acid-base status can be controlled and the extracellular pH adjusted by ensuring intracellular neutrality; this is done by keeping PCO 2 at such a level that the arterial blood pH measured at 37 degrees C remains around 7.40; (2) the problem of correcting acid-base values (pH-PCO 2) according to body temperature is solved simply by using pH and PCO 2 values measured at 37 degrees C and interpreting them, as usual, in terms of metabolic or respiratory acidosis or alkalosis.
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PMID:[Relations between acid-base equilibrium and body temperature. Physiological concepts and practical applications]. 622 30

Coronary arterial spasm observed during the course of two repeated anaesthesias in a patient having undergone aorto-femoral bypass grafting is reported by the authors. Such complications are accompanied by serious ventricular arrhythmias, though transient and healing without sequelae. Clinical and electrocardiographic characteristics of peroperative coronary arterial spasm are underlined. In patients prone to developing such spasm, peroperative alkalosis, hypothermia and parasympathetic stimuli should be avoided. Are emphasized the efficiency of preventive treatment with calcium antagonists and that of intravenous nitroglycerin in the treatment of peroperative coronary arterial spasm when it does occur.
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PMID:[Coronary spasm during repeated anesthesia]. 633 7

Changes in RCA activity are known to affect the acid-base balance, but a clear relationship between RCA activity and acid-base balance has not yet been established. The relationship between RCA activity and acid-base balance was studied in tonometry with 4 mixed gases for 6-9 hr, in healthy adults at rest, in halothane anesthesia and in hypothermia. RCA activity increases when pH and HCO3-/PCO2 ratio increase and PCO2 decreases in vitro. It also increases when pH and HCO3-/PCO2 ratio decrease and the range of PCO2 broadens in vivo. The relationship between RCA activity and the HCO3-/PCO2 ratio is a fan shape, because a change of the HCO3-/PCO2 ratio precedes the change of RCA activity. Some factor which increases the RCA activity may be produced secondarily in the body under the influence of high PCO2. Probably the acid-base balance is corrected by reduction of the RCA activity in the case of alkalosis, and the acid-base balance may be corrected by an increase in RCA activity in the case of acidosis.
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PMID:Management of the acid-base balance by the red blood cell carbonic anhydrase (RCA). I. Correlation of the RCA activity and acid-base balance in the in vitro and in vivo experiments. 640 61

The basic physiologic characteristics of acid-base equilibria during hypothermia were briefly reviewed. By graphic analysis, four possible clinical strategies for managing the acid-base status of the patient undergoing H-CPB were documented. The effect of hemodilution on buffer capacity was charted in a manner applicable to common current operative procedures. During hypothermia for cardiac operations as presently conducted, the perfusionist is in control of the temperature of the body and the perfusion preservation of the body and brain; the surgeon must assume responsibility for preservation of the heart. The literature pertinent to the relationship of the acid-base state to the functions and structural preservation of the heart and brain during the conditions of cooling to and rewarming from deep hypothermia associated with cardiopulmonary bypass, aortic cross clamping, cardioplegia and total circulatory arrest have been reviewed. The evidence is overwhelming that myocardial anoxia caused by aortic occlusion or total circulatory arrest at any temperature to 15 degrees C. result in progressive acidosis which, of itself, is myotoxic. In contrast, alkalinity is ionotropic. Myocardial ischemia, in both adults and infants, should be prevented and treated by alkaline perfusion cooling and by frequent coronary perfusion of a cardiopreservative solution which is extremely cold (4 to 8 degrees C.), oxygenated, has a pH of 7.8, slightly hyperosmolar and which has a hematocrit of 20 per cent (imidazole, erythrocytes and plasma protein colloid), a cardioplegic ionic pattern and energy substrates. Reperfusion of the heart should begin at a 37 pH of 7.8. Evidence is strong that the use of CO2 added to any gas mixture is harmful. It increases myocardial acidosis; it does not increase cerebral blood flow during hypothermia. Protection of the unperfused brain of an infant should emphasize prevention of circulatory arrest prolonged to more than 40 minutes. Temporary reperfusion at that time limit should be used. Probably the best general management of the body for H-CPB is alpha-stat, which preserves biologic neutrality. The uncorrected analyzer reads pH 7.4 and Pco2 at any temperature. However, the need for preservation of the hypoxic heart is overwhelming and, thus, the best acid-base management for cardiac hypothermic operations is significant respiratory alkalosis. The most appropriate sites for the collection of blood samples for gas analysis and measuring temperatures were discussed; "body temperature" is the most unreliable parameter measured. The major characteristics of an "ideal" cardiopreservative solution were described.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:The importance of acid-base management for cardiac and cerebral preservation during open heart operations. 642 51

The cardiorespiratory effects of reducing body temperature to 30 degrees C (by packing in ice) and subsequent metabolic alkalosis (by infusion of NaHCO3) were studied in six anesthetized, paralyzed, and artificially ventilated (FIO2 = 0.4) dogs. Heart rate decreased from 135 +/- 6 beats/min (mean +/- S.E.) at 37 degrees C to 84 +/- 4 at 30 degrees C; it increased to 96 +/- 4 after 2 h alkalosis. Cardiac output decreased from 1.84 +/- 0.14 to 0.66 +/- 0.08 l/min and then increased to 0.83 +/- 0.07. pHa increased, as expected on cooling, from 7.41 +/- 0.07 to 7.49 +/- 0.03; with bicarbonate it increased to 7.79 +/- 0.03. PaCO2 decreased on cooling from 32.9 +/- 1.4 to 21.7 +/- 1.2 torr, increasing with bicarbonate to 27.9 +/- 1.4 torr. VO2 decreased from 104.9 +/- 5.1 ml . min-1 . m-2 at 37 degrees C to 51.3 +/- 2.0 at 30 degrees C; with alkalosis it increased by 16.2% to 59.6 +/- 3.3 ml . ml-1 . m-2, an increase identical to that seen in normothermic alkalosis. Thus, the mechanism of the alkalosis-induced increase in oxygen consumption is not suppressed by the decrease in VO2 seen in hypothermia, and the increase in VO2 appears to be a consequence of the change in relative alkalinity rather than the increase in pH.
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PMID:Cardiorespiratory effects of hypothermia and bicarbonate alkalosis. 677 49

Asystole can be the presenting ECG finding of accidental hypothermia when the core temperature is less than 28 degrees C. Even two hours of persistent asystole does not represent irreversible cardiac compromise. With cardiopulmonary support and active rewarming, resuscitation and survival without serious sequelae can be achieved. Case reports and electrophysiology studies suggest that asystole is a primary manifestation of hypothermia potentiated by carbon dioxide retention. However, ventricular fibrillation in this setting is probably a secondary complication of resuscitation efforts, being precipitated by hypocapnic alkalosis, physical manipulation of the heart, and rewarming.
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PMID:Recovery after prolonged asystolic cardiac arrest in profound hypothermia. A case report and literature review. 698 23

The charts of 16 patients with branched chain amino acidemia (MSUD) who had 48 emergency room (ER) visits, of 10 patients with propionic acidemia (PA) who had 57 ER visit, and of 13 patients with methylmalonic acidemia (MMA) who had 154 ER visits, were reviewed retrospectively for the most common clinical presentations, physical and laboratory findings. The most common clinical presentation was acute or chronic vomiting and the most common physical finding was dehydration. When hypoglycemia was found, the mental status of 55% of patients with MSUD and MMA and 20% of patients with PA, was alert. Mixed acid/base disturbance, i.e. alkalosis caused by vomiting mixed with metabolic acidosis caused by the disease, was present in 30% of MSUD, in 33% of PA, and 45% of MMA. There was no relationship between acidosis detected by the blood pH and mental status of the patients. A good correlation between base excess < -5 and serum bicarbonate < 21 mmol/l was found. Blood cultures were positive for bacteria and fungi in 15% of the visits with MSUD, in 23% with PA, and 3% with MMA. Patients with positive blood cultures did not necessarily have a temperature > 39 degrees C nor hypothermia. The results suggest that the mental status of the patients should not detract the ER physician from obtaining blood pH, gases and glucose and in all instances a blood culture should be secured, even if the patient has no fever.
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PMID:Emergency presentations of patients with methylmalonic acidemia, propionic acidemia and branched chain amino acidemia (MSUD). 772 86

Choreoathetosis developed in three patients after cardiopulmonary bypass with hypothermia. None had significant hypotension or hypoxemia; all had hypocapnia and respiratory alkalosis during the rewarming period. We postulate that hypocapnia-induced cerebral vasoconstriction may have contributed to ischemic damage in focal central nervous system areas.
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PMID:Choreoathetosis after surgery for congenital heart disease. 817 61

Acute hypothermia was surface-induced in unrestrained conscious rats at two different levels, moderate (30 degrees C TB) and severe (20 degrees C TB). Data reflecting the acid/base status were determined. The values obtained for moderate hypothermia were compared with the acid/base pattern observed during hypothermia induced by two different anaesthetics, sodium pentobarbital and urethane, at room temperature. Conscious, hypothermic animals developed an apparent respiratory alkalosis, with an increase in pHa (from 7.476 to 7.546 in moderate hypothermia and from 7.484 to 7.563 in severe hypothermia) correlated with a decrease in arterial bicarbonate levels (from 22.9 to 16.8 mmol l-1 and from 20.7 to 14.9 mmol l-1 respectively). Lactate increased slightly in conscious, severely hypothermic rats (1.02 mmol l-1). This acid/base pattern was clearly different from that seen in sodium pentobarbital (mild respiratory acidosis) and urethane-induced hypothermia (metabolic acidosis). These results suggest that conscious rats follow a pattern closer to that underlying the relative alkalinity shown by many poikilotherms than to that underlying the constant pH shown in hibernating mammals. This latter pattern, nevertheless, approaches that observed during moderate pentobarbital hypothermia and the acid/base pattern during shallow hypothermia in birds. Anaesthesia may interfere with the development of the processes that lead to the acid/base pattern observed in conscious animals.
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PMID:Comparison of acid/base status in conscious and anaesthetized rats during acute hypothermia. 825 25


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