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

Three patients with profound hypothermia were treated by rewarming on partial bypass. Two surivived and have normal mental and metabolic functions. The resuscitation of the hypothermic patient should be approached with enthusiasm since the outcome is often much better than expected from initial vital signs and neurologic examination. To avoid ventricular fibrillation the patient should be handled gently and an effort should be made to keep the patient well oxygenated and the pH normal. Blood gases should be measured often and corrected for temperature. The potassium concentration and hydration status of the patient should also be monitored closely. The rewarming of profoundly hypothermic patients can readily be accomplished with a pump oxygenator and heat exchanger. The indications for this method are not established from our small experience and the few cases reported in the literature. Certainly ventricular fibrillation is a compelling indication. Patients with frozen extremities might also benefit from this method since theoretically tissue salvage would be increased. Finally, those patients who do not respond rapidly to external rewarming may be at less risk of ventricular fibrillation if rewarmed on bypass.
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PMID:Accidental hypothermia: core rewarming with partial bypass. 0 2

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

Hind legs of dogs were amputated at the middle of the thigh and preserved in three different conditions: in ice water, in a refrigerator, and at room temperature. After 6 or 12 hours of ischemia, recirculation was established. The survival rate of the animals was observed and measurement of limb edema, potassium, pH, and lactate in the blood was performed to study the effects of hypothermia on prevention of "replantation toxemia." Cooling of the amputated limb was effective for prevention of toxemia, and the cooling effect was greater in ice water than in a refrigerator. However, when cooled in ice water, some animals died due to toxemia when the time of ischemia was prolonged to 12 hours. In the dead animals, a close relationship was observed between the developement of toxemia and metabolic acidosis due to the increase in lactate.
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PMID:An experimental study on "replantation toxemia". The effect of hypothermia on an amputated limb. 3 78

Taurine (10 and 20 micrograms) injected unilaterally into the lateral ventricle of rats caused an increase in core temperature. Bilateral injection of taurine 2.5 and 5 micrograms into the preoptic region of the anterior hypothalamus induced a dose-related hyperthermia: higher doses (10 micrograms) caused hypothermia. Intrahypothalamically taurine-induced hyperthermia was blocked by prior injection of strychnine hydrochloride (5 and 15 micrograms); doses which alone had no effect on core temperature. Of the other inhibitory amino acids injected intrahypothalamically hypotaurine also induced a hyperthermia. GABA (10 micrograms) caused hypothermia; glycine (10 micrograms) had no effect. Potassium (50 mM) stimulated release of radioactivity from superfused slices of anterior hypothalamus prelabelled with [3H]taurine in a calcium-dependent manner. A high affinity uptake mechanism with a Km of 8.5 microM was demonstrated with [3H]taurine into slices of anterior hypothalamus. Taurine may have a neurotransmitter role in the anterior hypothalamus but whether the body temperature effects represent physiological or pharmacological events remains to be established.
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PMID:Role of taurine as a possible transmitter in the thermoregulatory pathways of the rat. 3 17

Orthopaedic operations such as procedures for spinal deformity or operation for septic or loose total hip prosthesis are often associated with massive haemorrhage. Electrolyte analysis in 44 cases showed a low level of potassium. Rapid transfusion with stored blood appeared to have little effect on cardiac efficiency unless dilute calcium chloride was added. Alkaline preparations were used in patients with circulatory deficiency. Abnormalities of blood clotting were prevented by the use of fresh blood. Hypothermia and pulmonary complications also occurred and were eventually prevented by the use of assisted ventilation during the post-operative period.
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PMID:[Massive hemorrhage during major orthopedic surgery. Metabolic consequences]. 13 8

Canine kidneys were preserved under hypothermia in Collins' standard solution and the contents of sodium, potassium, and Na+ and K+-ATPase in several parts of these kidneys were followed. Hypothermic preservation in combination with single perfusion by means of Collins' solution without thermic ischemia caused loss of sodium, increase of potassium, and decrease of the total osmotic cortico-papillary gradient of the kidney. No loss of Na+ and K+-ATPase activity occurred under these conditions. The determination of Na+ and K+-ATPase level in the renal tissue turns out to be a rational method to assess the vitality of an organ to be transplanted.
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PMID:[Effect of Collins' solution the kidney concentrating gradient and the Na+ and K+-ATPase of the kidney]. 21 72

Potassium-induced cardioplegia during anoxic arrest was utilized in a study of 190 consecutive patients undergoing revascularization (average 2.8 grafts per patient) from August, 1975, through August, 1976. Surgical technique, moderate systemic hypothermia with intermittent anoxic arrest, and the surgeon were the same for all patients. One hundred thirty-five patients (KC1-treated) received a bolus (150 ml.) of potassium solution injected into the proximal aortic root whenever the aortic cross-clamp was applied; 55 others served as control subjects. The mortality rate was 2.2% (three of 135) in the KCl-treated group and one of 55 in the control group. New Q waves appeared in 5.9% (eight of 135) of the KCl-treated patients and 11% (6 of 55) of control subjects (p = N.S.). Catecholamine drips were required after bypass in 4.4% (six of 135) of patients given potassium and 18% (10 of 55) of control patients (p less than 0.05). Profound myocardial relaxation was of added technical value with potassium. It is our impression that hearts treated with potassium exhibited more prompt cardioversion, separated from cardiopulmonary bypass with less need for inotropic support, and exhibited less myocardial injury during the revascularization procedure.
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PMID:Potassium-induced cardioplegia. Additive protection against ischemic myocardial injury during coronary revascularization. 30 93

To assess the effects of moderate potassium cardioplegia (37 mEq/l KCl) on the severity of myocardial ischemia during arrest and on post arrest ventricular function, 32 isolated, isovolumic feline hearts were studied before, during and 1 hour after ischemic arrest. Normothermia (37 degrees C) was maintained in the remaining 16 hearts, eight without KCl and eight with KCl. Hypothermia (27 degrees C) was maintained in the remaining 16 hearts, eight with KCl and eight without KCl. Myocardial oxygen (PmO2) and carbon dioxide tensions (PmCO2) were measured by mass spectrometry. Maximum developed intraventricular pressure (max DP) and max dP/dt were used as indices of performance. Compared with normothermic or hypothermic arrest alone, the addition of potassium cardioplegia resulted in a significant reduction in the peak PmCO2 measured during the arrest period. Hypothermia alone resulted in morphologic evidence of improved myocardial preservation and a significant reduction in peak PmCO2 compared with normothermia. Post arrest ventricular function was best with the combination of hypothermic arrest and potassium cardioplegia (max DP = 96 +/- 6% of control and max dP/dt = 99 +/- 5% of control). These data suggest that the beneficial effects of postassium cardioplegia and 27 degrees hypothermia are additive, and that reduction in myocardial ischemia as evidenced by a reduction in peak PmCO2 correlated with improvement in ventricular performance in the post arrest period and with preservation of myocardial structure.
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PMID:Effect of potassium cardioplegia on myocardial ischemia and post arrest ventricular function. 30 60

During a 7.5-year period ending in June 1977, 220 patients underwent combined aortic valve replacement and myocardial revascularization. Early (30-day) mortality was 5.4% (12 patients), and was significantly affected by the development of perioperative myocardial infarction. For 23 patients with electrocardiographic and enzymatic evidence for definite infarction, hospital mortality was 17%; for 66 patients with probable infarction mortality was 5%; and for 116 patients without evidence for infarction mortality was 3%. The difference in mortality between the definite and no infarction groups was significant (p less than 0.01). The incidence of perioperative infarction was influenced by the type of myocardial protection employed during the operative procedure. Definite infarction occurred in 24% of 41 patients who had mild (28-32 degrees C), intermittent hypothermic coronary perfusion, in 9% of 142 patients with hypothermic ischemic arrest (myocardial temperature 20 to 27 degrees C) and in none of 22 patients with hypothermic, potassium-induced cardioplegia (myocardial temperature 8--18 degrees C). The difference in the rate of infarction between the coronary perfusion and the two hypothermic ischemic arrest groups was significant (p less than 0.01). The mean duration of followup for 100% of the hospital survivors was 22.5 months. Cumulative survival was 88% at 1 year and 77% at 3 years. These figures do not differ significantly from those for patients without coronary artery disease having isolated aortic valve replacement in our institution, and are superior to those reported for patients with coronary and aortic valve disease undergoing only aortic valve replacement. We conclude that combined aortic valve replacement and myocardial revascularization should be performed in all patients in whom the lesions coexist. Hypothermic ischemic arrest, preferably in combination with potassium-induced cardioplegia, provides the most myocardial protection during operation.
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PMID:Combined aortic valve replacement and myocardial revascularization: results in 220 patients. 30 65

Both coronary perfusion and hypothermic cardioplegia are widely used methods of myocardial protection during aortic valve replacement. A theoretical objection to coronary perfusion is that it is not synchronized with cardiac contractions. Accordingly, a special pump was designed to provide perfusion at a constant range of pressure. Twenty dogs were studied during 4 hours of bypass. In six dogs no manipulations were carried out and hearts were allowed to beat in a nonworking state. Seven dogs underwent 2 hours of aortic cross-clamping and constant-pressure aortic root perfusion. Seven dogs underwent 2 hours of uninterrupted aortic occlusion with myocardial protection being maintained by cold potassium-induced arrest, Contractility did not change significantly in any of the three groups. All animals demonstrated significant hyperemia after bypass but normal endocardial/epicardial flow ratios. Although compliance deteriorated in all groups, the most striking changes were seen following 4 hours of bypass alone or constant-pressure aortic root perfusion. Hypothermic potassium arrest, in contrast, provided a slightly greater degree of myocardial protection, perhaps both by limiting the degree of ischemic injury directly and by excluding the heart from the circulating blood and the pump oxygenator system.
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PMID:Constant-pressure aortic root perfusion versus cardioplegia and hypothermia. Comparison of methods of myocardial protection. 31 94


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