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

After a quick review of the physiopathology of extra-corporeal circulation, the value of the use of neuroplegic drugs in cardiac surgery is recalled by means of pharmacological arguments. The experimental differences existing between the combinations droperidol - phenoperidine and chlorportixene - dextromoramide, on the rate of flow and on the pressure of the perfusion, and on the esophago-rectal thermic gradients during E.C.C. is then demonstrated. Statistic calculation confirmed the superiority of chlorprotixene in the realm of tissue perfusion during E.C.C. under hypothermia.
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PMID:[Neuroplegia and extracorporeal circulation. Comparison between combinations of droperidol-phenoperidine and chlorprothixene-dextromoramide in cardiac surgery]. 1 30

During aortic clamping, drug protection of the myocardium, far from supplanting hypothermia, complements it, particularly in the case of left ventricular hypertrophy. Ultramicroscopy and new techniques of histobiological exploration of the myocite have enabled one to distinguish the lessions provoked by anoxia from those induced by reperfusion. At present, drug protection, extended to energetic solutions and electrolytes, aim at preserving energy metabolism by stocking of the substrate and at avoiding interferences which precipitate exhaustion of the adenosine triphosphate and phosphocreatinine reserves. In order to do this, hemodilution in particular is limited in subjects with decompensated cardiopathy; choice of anesthetics is orientated towards neuroleptanalgesia or fluothane, and it is attempted to neutralize the adrenergic reaction by the use of beta-blocking substances. Furthermore, it is preferred to interrupt electrogenesis at the stage of polarization: depolarizing cardioplegic solutions rich in potassium and sodium are rejected and in preference membrane stabilizers are used (procaine, magnesium, tetrodoxine...) The ultramicroscopic analysis of the structural modifications leads to sparing of the integrity of the lysosomial membrane by corticoids and alkalines. The use of calcium is deferred, anti-calcium techniques are even proposed (washing poor in calcium, verapamil). Cellular edema is prevented and treated by solution (mannitol - sorbitol) whose osmolarity must be less than 300 M osm/l. A conditioning of the biochemical and physicial structures and of cardiac work is being more and more thought of which leads to the classification of beta stimulating substances as negative, and their indications must be seriously thought of and used with reserve.
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PMID:[Drug protection of the myocardium during cardiac surgery]. 1 31

In 81 operations for correction of infants's cardiopathies, authors used, associated with E.C.C., a deep hypothermia allowing a circulatory arrest of an average duration of 52 minutes, according to the technics described by BARRAT-BOYES in 1971. From this experience, authors study the modifications brought to the organism by this hypothermia, and discuss the technical aspects in pre, per and post-operative periods. Mortality of this series is of 13,5 p. 100. It is in relation with the cardiopathy or it's correction, without anu possibility or directly charge the technique of hypothermia in its determinism. The early mortality includes a bilateral phrenic paralysis, an air embolism, three septic complications and two neurologic complications probably related to a poor thermic repartition. Advantages of this technique concern the possibility to operate in a bloodless field and a diminution of E.C.C. time.
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PMID:[Deep hypothermia on the infant: physiopathology and technics of ECC]. 1 34

Pulmonary complications after cardiac surgery under extracorporeal circulation remain frequent and sometimes grave, in spite of the great progress which has been made over the past 20 years in the methods of cardiorespiratory assistance. The authors analyse the clinical and radiological repercussions of perfusion on the lung, in 40 patients operated under ECC for coronary revascularisation. The simutaneous study of the arterial, and mixed venous blood gasses and of the alveolar gases, in 20 of these patients showed the constant occurrence of a shunt syndrome, without alveolar hypoventilation or disorders in peripheral circulatory flow. Ventilatory alcalosis, hypocapnia, hypoxemia and the rise in the alveolar arterial oxygen gradient is increased during the second post-operative day. Among the variables studied (duration of ECC, degree of hypothermia, duration of the intervention, duration of anesthesia, pleurotomy) only the latter intervened in a statistically significant manner in this study, in the increase in hypoxemia. 46 pulmonary biopsies carried out before and after ECC in 23 coronary patients were examined with the electron microscope. The initial alveolar involvement affects the septal microcirculation with signs of an increase in capillary permeability leading to an interstitial and epithelial destruction. The use of a membrane oxygenator prevents some of the alveolar lesions, as has been proved by the study of five pulmonary biopsies carried out in dogs submitted to ECC of long duration. Catherterization of the pulmonary artery carried out in 35 patients by means of a SWAN-GANZ catheter, before the intervention enabled supervision of the degree of importance and speed of the hemodynamic variations in the pulmonary circulation during the different phases of ECC (during the phase of ventricular fibrillation). The rise in the flow of left output can lead to the occurrence of negative pulmonary intravascular pressures which can be prejudicial for capillary trophicity. The syndrome of "ECC lung", a veritable "induced post-agressive lung" must be placed in the group of refractory hypoxemia of which it represents one of the most typical pictures.
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PMID:[Pulmonary complications after extracorporeal circulation. ECC lung syndrome]. 1 38

Sixty-five infants were submitted to complete repairment of a congenital cardiopathy under profound hypothermia and ECC. Description of the preparation of the young surgical patient, of the anesthesia, of the technique of ECC. The overall mortality was 35.5 p. 100. The hypothermia induced by ECC, does not introduce any supplementary risks as long as strict technical rules are respected.
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PMID:[Technics of anesthesia and hypothermia for the infant. Choice of replacement fluid for the circuit]. 1 39

Effects on hemostasis of deep hypothermia on infant has been studied on 29 infants operated upon for a cardiopathy under deep hypothermia. Results of this study show a diminution of the coagulation factors rate, an augmentation of the fibrinolytic activity and an unforeseable variability of the residual heparin leading in all cases to a complement of the heparin neutralization by Protamine.
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PMID:[Variations in hemostasis in the infant under deep hypothermia]. 1 45

Oxygen availability during cardiopulmonary bypass was assessed in 22 patients under hypothermic and relatively normothermic conditions. The patients were divided into two groups, 17 of whom received ACD blood and 5, CPD blood. The mean P50 for all patients fell from a preoperative value of 25.9 +/- 2.4 (SD) to 15.6 +/- 2.1 during hypothermia confirming a leftward shift of the oxyhemoglobin dissociation curve. Oxygen uptake, calculated from a-v oxygen content differences (avDO2) and flow, was significantly lower during hypothermic bypass (65 +/- 27 ml/min) than during rewarming (121 +/- 41 ml/min). The increase in oxygen affinity during hypothermia was influenced also by changes in acid base and 2,3-DPG concentrations, the changes being similar in both the ACD and CPD groups of patients. During rewarming, however, oxygen availability was increased in the CPD group presumably from significantly increased 2,3-DPG concentrations. A "functional" value of hemoglobin, based upon the effects of the shift of the oxyhemoglobin dissociation curve and, therefore, reflecting the true capacity of hemoglobin to unload oxygen at the tissue level, was calculated. During the hypothermic phase of bypass, this functional hemoglobin was only 4.2 g/100 ml blood, suggesting that, in spite of reduced metabolic demands, oxygenation reserves are minimal.
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PMID:Oxygen availability during hypothermic cardiopulmonary bypass. 1 30

The total, free and unprecipitated activity of lysosomal (acid DNAase, acid RNAase, acid phosphate, acid beta-galactosidase) and peroxisomal (catalase, oxidase of D-amino acids) enzymes were studied in dog kidney cortex during storage of the tissues in solution of rheopolyglucin and under conservation of the kidney tissue by transrenal gas perfusion in hypothermia within 3 and 7 days. Labilization of lysosomal and peroxisomal membranes was observed during storage both in unperfused and in oxygenated kidney. Mechanisms of formation and functional significance of the alterations observed in structure of lysosomes and peroxisomes are discussed.
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PMID:[Labilization of lysosomal and peroxisomal membranes in the kidneys preserved by transrenal gas perfusion]. 1 22

This study tests the hypothesis that postischemic myocardial depression can be reduced by providing an initial reperfusate pH which is appropriate for myocardial temperature (i.e., metabolic systems function optimally when pH is kept slightly alkaline to the neutral point, which changes with temperature in concordance with the pK of water). Ten dogs underwent 1 hour of ischemic arrest with topical hypothermia (intramyocardial temperature 16+/-2 degrees C). The initial reperfusate (500 cc of blood from the extracorporeal circuit) was infused (100 cc/minute) into the proximal aorta just before removing the cross-clamp. Reperfusate pH was kept at 7.4 in five dogs (control) and raised to 7.8 with THAM [tris (hydroxymethyl) aminomethane] in five dogs. Measurements 30 minutes after reperfusion showed that raising reperfusate pH to 7.8 resulted in (1) higher subendocardial blood flows (109+/-20 vs 61 cc+/-8 cc/100 gm/minute), (2) redistribution of postischemic blood flow toward the subendocardium (endocardial/epicardial flow 1.25+/-0.1 vs 1.0+/-0.03), (3) higher left ventricular oxygen uptakes (0.046 vs 0.033 cc/100 gm/beat), (4) better postischemic left ventricular compliance (56+/-3% more compliant), and (5) improved left ventricular performance (88+/-7% recovery vs only 57+/-3% recovery at pH 7.4). Postischemic edema (2% water gain) was unchanged by pH modification. We conclude that initial reperfusion with the appropriate pH provides an optimal milieu for restoration of cellular metabolism, counteracts the acidosis of ischemia, and improves postischemic left ventricular blood flow, distribution, oxygen uptake, compliance, and performance.
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PMID:Studies on myocardial reperfusion injury. I. Favorable modification by adjusting reperfusate pH. 1 28

In the present study, the thermal responses induced by intraventicular administration of pyrogen prostaglandin E1, the brain monoamines norepinephrine and serotonin, and the antipyretic sodium acetylsalicylate (aspirin) were measured in conscious rabbits to assess the possible involvement of these substances in fever production. The body temperatures, metabolic rate, respiratory evaporative heat loss and vasomotor activity in response to the administration of these drugs were measured. The results showed that sodium acetylsalicylate, an inhibitor of prostaglandin synthetase, antagonizes the norepinephrine induced fever but not the prostaglandin fever. The data also showed that the serotonin induced hypothermia was reversed by prostaglandin administration. Thus, the fact strongly suggest that the prostaglandin E1 serves as a fever-prducing mediator in the central nervous system. Also, the norepinephrine fever and serotonin hpyothermia, respectively, may be associated with an increase and a decrease in prostaglandin synthesis in the brain.
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PMID:Brain monoamines act through the prostaglandin release to influence the body temperature. 1 25


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