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

Controversy has surrounded the role of local hypothermia as a preoperative treatment in amputations of the lower extremity. A study was undertaken to determine the effectiveness of amputation under cryoanesthesia in decreasing postoperative morbidity and mortality in below-knee (BK) amputations. Of 154 BK amputations, only 91 with unreconstructable vascular disease, gangrene, or both, were included in this study. Group I consisted of 48 patients (mean age 63.9 years) who had undergone a routine BK amputation; group II consisted of 43 patients (mean age 65.7 years) who were acutely ill and too unstable to undergo a major surgical procedure. Group II patients were treated by amputation while under cryoanesthesia before any definitive operative intervention. The patients in group II were significantly (p less than 0.05) more ill preoperatively than those in group I. Group II patients had a higher prevalence of previous myocardial infarction, previous stroke, diabetes mellitus, osteomyelitis, and wet gangrene. Seventy percent of the patients in group II had three or more risk factors vs. 46% in group I. Early postoperative mortality rates did not differ significantly between groups (group I, 8%; group II, 9%); the average length of hospital stay for group I patients was 24.2 days compared with 17.7 days in group II. Group II patients sustained slightly more postoperative complications. Amputation under cryoanesthesia appears to be of value in reducing postoperative morbidity and mortality and length of hospital stay in the acutely ill patient with unreconstructable vascular disease, gangrene, or both.
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PMID:Below-knee physiologic cryoanesthesia in the critically ill patient. 334 56

Seventy-six consecutive patients, aged 80 to 89 (mean 82), underwent cardiac operations with cardiopulmonary bypass. Hypothermia (22 degrees C) and hyperkalemic cardioplegia were used in each. There were 35 men and 41 women. Thirteen patients (17%) were in New York Heart Association Functional Class III and 62 patients (81%) were in Class IV preoperatively. Coronary bypass procedures (Group I) were performed in 38 patients, of whom five had combined carotid endarterectomy. The average number of grafts was 3.7 per patient. There were two early deaths (5.2%). Single or double valve replacement, without coronary bypass (Group II), was done in 15 patients, with one early death (6.6%). Coronary bypass and valve procedures (Group III) were performed in 23 patients with seven early deaths (30%). Total early mortality was 10 deaths in 76 patients (13%). Of the 66 (87%) 30 day survivors, 19 (29.1%) had major postoperative complications, including bleeding, pericardial tamponade, sternal dehiscence, myocardial infarction, arrhythmia, and pump failure. Mean hospital stay was 23 days (9 to 117 days). Late cardiac-related deaths occurred in eight patients (9%) during the 58 (mean 28) months of follow-up. Thus combined early and late mortality was 18 deaths (24%). Mortality at any time was related to Functional Class IV status (17/18 deaths, 94% in Class IV); combined procedures (12/28 patients died, 43%); use of intra-aortic balloon pumping (8/13 patients died, 62%); and postoperative bleeding necessitating reoperation (4/6 patients died, 67%). At follow-up 84% of survivors had improved by one or more functional classes, and there was a low incidence of cardiac-related late deaths. This experience supports the concept that in octogenarians the indications for operation should be as for other patients of less advanced age, especially in those with isolated coronary artery disease and pure valve disease. Operation should not be delayed, so that these patients will not advance to higher-risk Class IV status preoperatively.
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PMID:Cardiac surgery in the octogenarian. 348 6

Cardioplegic myocardial protection has become the standard for coronary artery bypass. In contrast, we report 500 consecutive coronary artery bypass operations with intermittent aortic clamping for distal anastomoses, left ventricular venting, and 30 degrees C hypothermia. Average patient age was 62 years (range of 30 to 89 years). The number of patients who had urgent or emergency operations was 194 (39%); 251 patients had unstable angina, and 123 others had preinfarction angina (pain at rest in the hospital); 27 had evolving myocardial infarction. The average number of grafts was 3.3 per patient, and the average ischemic time was 7.65 minutes per graft. There were five hospital deaths (1%); none resulted from poor myocardial protection that caused low cardiac output. Only three survivors (0.6%) required a balloon pump to be weaned from cardiopulmonary bypass: two had acute infarctions preoperatively, and the other had an ejection fraction of 0.30 and intractable atrial arrhythmias. Only two other patients (0.4%) received any inotropic infusions postoperatively. Eighteen patients (3.6%) had a perioperative infarction. These results, particularly the virtual absence of postoperative inotropic support, in unselected patients of whom 80% had acute coronary syndromes, indicate that intermittent ischemia can provide excellent myocardial protection for coronary bypass. Brief periods of intermittent ischemia alleviate concern about cardioplegic protection via occluded coronaries or internal mammary grafts and provide a simple and safe option for myocardial protection during coronary artery bypass.
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PMID:Coronary artery bypass without cardioplegia. 349 33

The effect of two different myocardial preservation techniques on perioperative myocardial necrosis during coronary artery bypass surgery was assessed by serial myocardial creatine kinase determinations in 100 consecutive patients operated on by the same surgeon. Topical hypothermia with cold potassium cardioplegia was used randomly in 50 patients (group 1), and topical hypothermia with local interruption of the coronary circulation was used in the other 50 patients (group 2). Myocardial creatine kinase was measured by column chromatography every 6 hours for 36 hours after surgery. There was no significant difference between the two groups in terms of age, sex, functional class, extent of coronary artery disease, number of bypassed arteries, ejection fraction, or cardiopulmonary bypass time. Myocardial creatine kinase release (mean +/- standard error of the mean) was 193 +/- 33 IU/L X hours in group 1 patients operated on with cardioplegia and 210 +/- 31 IU/L X hours in group 2 patients operated on with topical hypothermia (p greater than 0.5). Myocardial creatine kinase peaks were 9.2 +/- 1.9 IU/L and 10.0 +/- 1.6 IU/L, respectively (p greater than 0.5). Perioperative myocardial infarction, as defined by serum enzyme activity and electrocardiographic criteria, occurred in 4 patients in group 1 and 3 patients in group 2. Thus, the addition of cardioplegia to topical hypothermia, although perhaps offering technical advantages, does not appear to improve myocardial protection over topical hypothermia with local interruption of the coronary circulation during coronary artery bypass surgery.
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PMID:Cold potassium cardioplegia versus topical hypothermia and intermittent aortic occlusion for myocardial protection during coronary artery surgery: a randomized clinical study. 351 46

Anaerobic metabolism in heart muscle plays a role in maintenance of myocardial preservation only during ischemia or hypoxia. In an ischemic state, such as during a heart attack or even during the induced ischemia of open heart surgery, there is impairment of blood flow to the myocardium. The major energy-yielding process in the heart is through the metabolism of glucose and lipids by oxidative reactions. Under anaerobic conditions, oxygen is not available to accept the electrons in the metabolic degradation of substrates and anaerobic glycolysis becomes important in the preservation of myocardial viability during the ischemic process. Unfortunately, the accumulated products of glycolysis, namely protons and lactate, work to inhibit glycolysis, ultimately resulting in a depression of anaerobic metabolism. Cardioplegia, as utilized during open heart surgery, has the effect of inducing instantaneous induction of myocardial mechanical and electrical arrest with a maximal inhibition of the energy utilizing metabolic processes. This effectively reduces substrate utilization and prevents the deleterious consequences of the ischemic process. Cardioplegia is most effective when combined with the additive properties of hypothermia, which plays a significant role in decreasing myocardial metabolism. However, during prolonged hypothermic cardioplegic arrest, sufficient ATP cannot be maintained for cellular integrity and anaerobic glycolysis becomes of increasing importance for maintenance of myocardial preservation. This presentation deals with the mechanics of aerobic versus anaerobic metabolism during the ischemic process of open heart surgery.
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PMID:Aerobic vs anaerobic metabolism during ischemia in heart muscle. 359 61

A 74-year-old man with myxedema and hypothermia had increased activities in plasma of creatine kinase (CK; EC 2.7.3.2), aspartate aminotransferase (AST; EC 2.6.1.1), and lactate dehydrogenase (LD; EC 1.1.1.27) and increased proportions of CK-MB (up to 20% of total CK) and LD1 isoenzymes, but no clinical or investigational evidence of associated myocardial infarction. This case illustrates that plasma enzyme activity and isoenzyme profiles in such clinical settings should be interpreted with caution, because increases in CK-MB and LD1 may relate to myxedema coma or hypothermia (or both) rather than to myocardial infarction.
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PMID:Cardiac enzyme changes in myxedema coma. 382 11

The efficacy of moderate hypothermia with rewarming in attenuating the myocardial and circulatory consequences of acute coronary ligation was studied in open-chest, anesthetized dogs. Thirty minutes after ligation of the proximal left anterior descending coronary artery, 14 dogs were surface-cooled to 27 degrees C, maintained at this temperature for 2 hr, rewarmed to normothermic levels, and monitored for an additional hour. Fifteen dogs were maintained for a corresponding time period after coronary ligation at normothermic levels. Dogs maintained normothermic demonstrated significant depression (from preligation values) of dP/dt, cardiac output (CO), stroke volume (SV), and left ventricular stroke work and power (LVSW, LVSP) at elevated levels of left ventricular end-diastolic pressure (LVEDP). Dogs subjected to the hypothermic procedure demonstrated decreased inotropic status during hypothermia, but with rewarming, exhibited significantly greater values of left ventricular pressure, dP/dt, CO, SV, LVSW, and LVSP at lower values of LVEDP than observed in dogs maintained normothermic. Increased dysrhythmic activity was not observed during hypothermia. Hearts from dogs subjected to the hypothermic protocol demonstrated qualitatively greater dehydrogenase activity both at the periphery and in the center of the nonperfused region. The results suggest that moderate hypothermia during evolving myocardial infarction may preserve left ventricular cardio- and hemodynamics and thus may be useful in delaying morphological and functional deterioration until definitive treatment can be instituted.
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PMID:Salutary effects of moderate hypothermia on the circulatory and myocardial consequences of acute coronary occlusion in dogs. 407 11

One hundred twenty-four patients had 155 carotid endarterectomies for the relief of stroke symptoms. General hypercarbia anesthesia and arterial pco2 monitoring were used, without resort to internal bypass shunt or hypothermia. Significant permanent post-operative complications developed in three patients (1.9 percent) and there were two postoperative deaths, one of which was caused by a massive myocardial infarction.
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PMID:A safe approach to carotid endarterectomy. 513 26

AMP deaminase, 5'-nucleotidase and adenosine deaminase have been estimated in skeletal muscle and myocardial tissue in normal rats and in rats subjected to experimental myocardial infarction or hypothermia. A difference in the enzyme distribution was found between the right and left ventricles in the normal rat. A decrease in the activity of 5'-nucleotidase and an increase in the activity of adenosine deaminase were observed in infarcted myocardial tissue. The activity of all 3 enzymes was found to be depressed in the myocardium in rats subjected to hypothermia. These results are discussed in relation to adenosine production and its beneficial effects.
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PMID:AMP deaminase, 5'-nucleotidase and adenosine deaminase in rat myocardial tissue in myocardial infarction and hypothermia. 628 39

One hundred patients with severe coronary artery disease, and impaired left ventricular function were studied. Thirteen of these required valve replacements. Eight required repair of a left ventricular aneurysm. In addition, all these patients had three or more coronary artery diseases. The patients underwent aortocoronary bypass using saphenous vein grafts. For myocardial protection, general and topical hypothermia was used during the procedure, along with perfusion of the root of the aorta, with a cardioplegic solution. Additional cardioplegic perfusion was achieved by perfusing the vein graft anastomosed to the left anterior descending coronary artery below the obstruction, or other vein grafts anastomosed to the circumflex artery or the right coronary artery (or its branches if dominant), during total aortic clamping. No mortality occurred in these patients. Only two patients developed perioperative myocardial infarction, but they recovered. The authors believe that this method can offer further myocardial protection during ischemic arrest.
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PMID:Perioperative myocardial protection in severe coronary artery and valvular heart diseases with impaired ventricular function. 633 62


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