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

We describe a case of severe hypothermia in a 32-year-old patient who fell into a crevasse. Three hours later he was rescued and flown to a district hospital. On arrival he was apparently dead, with cadaveric skin, dilated and fixed pupils, pulseless and in respiratory arrest. His rectal temperature was 26 degrees C. On the ECG monitor there was first ventricular fibrillation, then, after several unsuccessful attempts at defibrillation, the heart became asystolic. Cardiopulmonary resuscitation was begun with orotracheal intubation and external cardiac compression, which eventually lasted 4 hours and continuously required a team of 6 persons. Only at a temperature of 32.5 degrees C could the patient be defibrillated with success. In the absence of extracorporeal circulation (ECC) the victim was rewarmed by warm-air breathing and by instillation of warm saline in peritoneum, stomach and bladder. In this way the rewarming velocity was 1.8 degrees C/hour. The postacute course was characterized by severe rhabdomyolysis (CK of 100,000 U/L) with non-oliguric renal failure, which necessitated several sessions of hemodialysis. Four months later the asymptomatic patient returned to work. Our case shows that a severely hypothermic patient can successfully be treated in a primary hospital not equipped with an ECC, provided that there is a sufficiently large team. Further, uninterrupted external cardiac compression guarantees efficient circulation even over several hours. Electric defibrillation in a hypothermic patient is ineffective unless normal body temperature has been reached. Lastly, every effort to continue resuscitation must be made in the still hypothermic patient whose absence of clinical response may obscure the real possibility of complete recovery.
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PMID:[Severe accidental hypothermia with cardiopulmonary arrest: prolonged resuscitation without extracorporeal circulation]. 173 23

Of 11 patients who underwent emergency resuscitation from cardiac arrest using a system of percutaneous cardiopulmonary support (CPS), two (18%) were long-term survivors. Percutaneous cardiopulmonary support was instituted without complication in all patients, with flows ranging from 1.8 to 5.5 L/min; the average duration of support was 304.3 min. All four patients who underwent emergency surgery (two coronary revascularization, one mitral valve revascularization, one mitral valve replacement with coronary revascularization, and one primary left ventricular assist device insertion) died. One patient died while on CPS secondary to irreversible ventricular arrhythmias after a successful percutaneous transluminal coronary angioplasty (PTCA). Six patients were weaned from the support system, three of whom had undergone PTCA while on CPS. The two survivors were the youngest patients (33 and 24 years). One of them had severe hypothyroidism as the cause of cardiac arrest, and the second was a hypothermia patient who was in ventricular fibrillation for 2 hr before establishing CPS. In comparing survivors (two) to nonsurvivors (nine), a significant difference (p = 0.034) in age was found, with survivors being younger. There was also a difference in incidence of atherosclerotic cardiovascular disease (p = 0.018), with survivors having none. There was no difference in the time to CPS (p = 0.905) or time on CPS (p = 0.156). Cardiopulmonary support can be instituted, resulting in excellent stabilization in patients with cardiac arrest. Survivors tended to be young and not have atherosclerotic cardiovascular disease (ASCVD) as their primary diagnosis. Neither length of cardiac arrest before CPS nor time on support correlated with a poor outcome.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Percutaneous cardiopulmonary support in cardiac arrest. 175 Nov 50

The effects of dobutamine (DOB) on hemodynamics, critical cooling, and myocardial excitability were studied in dogs under simple deep hypothermia. Hypothermia was induced by surface cooling after the animals had been anesthetized with ether and triflupromazine (conventional method, group I). Continuous intravenous administration of DOB was combined with conventional method in group II, and surface cooling was performed with thiamylal in group III. The following results were obtained. The mean lowest temperature reached was 15.6 degrees C in group II. MAP, CO and V max of group II were maintained significantly higher than those of group I during cooling. Decrease in BE in group II was mild compared with group I. Catecholamine release during cooling was suppressed completely in group I and II, but increased markedly in group III. Myocardial threshold to artificial pacing in group II was elevated as the temperature fell, and restored during rewarming, while that of group III was unchanged during cooling. Ventricular fibrillation occurred by stimulation of pacemakers in some cases. Our results suggest that even in case of hypothermia, DOB retains a selective inotropic effect with no threat of arrhythmogenicity, and produces stable hemodynamics. These characteristics of DOB allow cooling down to 15 degrees C.
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PMID:[The effect of dobutamine on hemodynamics, critical cooling, and myocardia excitability during simple deep hypothermia]. 177 May 75

The best management for patients requiring CABG with severe calcification of the thoracic aorta has not be established. To clamp ascending aorta in such cases produce cerebral embolization, aortic dissection or mural laceration. We reported a 60-year-old male for unstable angina with LMT lesion. Emergency CABG using IABP was performed with femoral cannulation, moderate hypothermia and induced ventricular fibrillation. His postoperative course was uneventful and coronary arteriography revealed a satisfactory patent graft of the RITA to the LAD system.
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PMID:[A successful report of emergency CABG for severe calcified thoracic aorta--the porcelain aorta]. 177 87

In order to minimize heat loss cold stress induces peripheral vasoconstriction via the sympathetic nervous system. This effect is most pronounced in the extremities. Vasoconstriction does not appear in the head-neck region--a fact of great importance in emergency situations. In order to compensate for heat loss shivering is an early event, where involuntary muscle contractions increase metabolic rate 2-6 fold. Early tachycardia and elevated blood-pressure, followed by progressive bradycardia and lowered pressure are common cardiovascular effects of hypothermia. Death due to ventricular fibrillation or asystole occurs between 28 degrees-25 degrees C. Cold stress causes an osmolal diuresis with sodium and chloride as the main constituents. The natriuresis is of tubular origin and could be due to impaired autoregulation in the kidney and/or depend on the natriuretic polypeptide. The augmented urine flow decreases blood volume, lowers physical working capacity and increases blood viscosity--all negative events in a hazardous situation. Sudden immersion initiates hyperventilation for 1-2 minutes with an increasing risk of drowning. Thereafter ventilation decreases to rates consistent with metabolic requirements. In severe hypothermia carbon dioxide retention causes respiratory and metabolic acidosis. Hypothermia induces progressive depression of mental functions starting with apathy and bizarre behaviour and ending in lethargy and coma often between 30 degrees-28 degrees C. The paradoxal feeling of heat with undressing in agony could depend on cerebral receptor disturbances.
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PMID:Human physiology under cold exposure. 181 74

Alcohol is a dominant cause of death in urban hypothermia. Drinking alcohol gives a pleasant feeling of warmth. However, experimental studies on humans during relatively short exposure to moderate cold have given inconsistent results concerning heat balance. Longer exposure to colder environmental situations has, particularly with addition of strenous exercise, revealed enhanced heat loss. A warning must be given to drink alcohol beverages in connection with outdoor activities in a cold environment. It gives a feeling of bravery and influences judgement leading to ignoration of prophylactic measures. Alcohol delays the onset of shivering and reduces its duration. It augments cold diuresis thereby diminishing blood volume and physical working capacity. On the other hand, alcohol seems to protect the heart against ventricular fibrillation at low core temperatures. Furthermore ethanol also seems to have some positive properties in freezing cold injuries.
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PMID:Alcohol and cold. 181 78

During hibernation the animals decrease their body temperature down to a few degrees above 0 degree C. This means that when entering into and arousing from hibernation their body temperature passes the critical level of 20 degrees C, a temperature region where nonhibernating mammals develop circulatory arrest, usually ventricular fibrillation (VF). We found in other experiments that the hibernator heart is resistant to VF, not only induced by hypothermia, but also when induced by local application of aconitine on the epicardium, addition of 0.55 molar CaCl2 to isolated hearts perfused with a potassium free Tyrode solution, addition of procaine to isolated hearts perfused with Tyrode solution after previous administration of adrenaline, ligation of the proximal part of the left anterior descending coronary artery, and electrical stimulation in the vulnerable phase of the heart cycle. Several mechanisms are at work to explain this resistance to VF of the hibernator heart when compared to the nonhibernator heart. The factors of greatest importance seem to be the different adrenergic innervation pattern, different physico-chemical properties with a lower melting point of the lipids in the hibernator, different enzyme temperature activity curves in the hibernator and a different handling of intracellular calcium resulting in a protection against calcium overload in the hibernator heart, when compared with the nonhibernator heart.
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PMID:The hibernator heart--nature's model of resistance to ventricular fibrillation. 181 81

This retrospective study comprises 234 cases of accidental hypothermia (core temperature less than 35 degrees C) hospitalized in 95 Swiss clinics between 1980 and 1987. The most frequent accidents were alpine (n = 78) in origin, followed by cold exposure after injuries (n = 63) and suicide attempts (n = 43). Hypothermia was induced by cold air in 129 cases and by water in 47 cases. Patients were divided evenly between the degree of hypothermia: 75 mild (32-35 degrees C), 79 moderate (28-32 degrees C) and 66 severe (less than 28 degrees C). Among the survivors the coldest patient had a core temperature of 17.5 degrees C and the longest cardiac arrest with a favourable outcome lasted 4.75 hours. Out of the 234 patients 68 died (29%). We assessed all variables relative to outcome, in particular the mechanism of the accident, the mode of cooling, temperature, circulation, age and sex, underlying diseases, rewarming methods, medication and complications during the hospital course. All variables were tested in two multiple regression analysis models (retrospective model n = 181: prospective model n = 128) with regard to significance (p less than 0.05) and survival. Results are expressed with ODD's ratios (OR). The negative survival factors are asphyxia (OR 30), invasive rewarming methods (OR 20), slow rate of cooling (OR 10), asystole on arrival (OR 9), pulmonary edema or ARDS during hospitalization (OR 8), elevated serum potassium (OR 2/mmol/l) and age (OR 1.03/year). The positive survival factors are rapid cooling rate (OR 10), presence of ventricular fibrillation in cardiac arrest patients (OR 9) and presence of narcotics and/or alcohol during hypothermia (OR 5).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Accidental hypothermia in Switzerland (1980-1987)--case reports and prognostic factors]. 188 13

The aim of the present study was to introduce a new method of external selective brain cooling in cats. By means of this device, which mainly consisted of a head-sized, closely fitting copper basin, it was possible to reduce brain temperature rapidly. The resultant difference between core and cerebral temperatures amounted to mean values of about 10 degrees C after a 20-min cooling period. Ventricular fibrillation lasting for 15 min was induced in 23 healthy adult cats by internal cardiac electrical overpacing and followed by cardiopulmonary resuscitation (CPR). In several animals (n = 8) CPR efforts failed completely or they died without any indication of sufficient spontaneous circulation. In the initial postischemic period the remaining animals stayed normothermic and served as controls (n = 7) or received external brain cooling (n = 8), which was started simultaneously with CPR and continued for 30 min. During a survival time of 4 h cardiocirculatory function was stabilized pharmacologically and artificial respiration was performed, followed by transcardiac perfusion fixation. After removal from the skull, the brains were processed for histopathological evaluation of ischemic neuronal damage by light microscopy and morphometry. The clinical data obtained indicate that the described method provides a means for efficient heat exchange from within the intracranial space. Rapid, selective brain cooling could be achieved without any critical reduction of the core temperature and therefore, cardiac arrhythmias, a usual consequence of generalized hypothermia, could be avoided. The histopathological evaluation of ischemic neuronal damage showed a significantly higher percentage of unaffected cells in some areas of the cerebral cortex in animals treated with postischemic cerebral hypothermia than in the controls.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Selective cerebral hypothermia following cardiac arrest in the cat]. 192 14

From August 1984 through November 1988, 10 of 2,658 patients undergoing coronary artery bypass grafting had ascending aortic disease that was not amenable to proximal anastomoses for coronary bypass grafting. This was due to a calcified aorta in 6 and acute aortic dissection in 4. There were 5 male and 5 female patients with a mean age of 71 years. Cannulation site was the femoral artery in 5, ascending aorta in 3, and aortic arch in 2. Profound hypothermia and ventricular fibrillation, with no cross-clamp or cardioplegia, was used in 9 patients, and circulatory arrest in 1. In 8 patients a single internal mammary artery was used as the total inflow with a saphenous vein graft brought off the internal mammary artery to one or more distal left-sided coronary vessels. Bilateral internal mammary arteries were used in 2 other patients. Operative mortality was zero. There was one perioperative myocardial infarction and one transient stroke without sequelae. All patients have done well from 1 to 6 years postoperatively. These data support the use of internal mammary arteries as single or bilateral proximal conduits for other venoarterial bypass grafts when the aorta is extensively diseased either by calcification or dissection.
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PMID:Coronary bypass grafting with totally calcified or acutely dissected ascending aorta. 198 45


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