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

Continuous haemofiltration (CHF) mimics physiological glomerular filtration. Blood flows through a haemofilter, which is permeable to water and to all those substances not bound to plasma proteins, of up to about 6,000 d molecular weight. Ten to twenty liters of ultrafiltrate (UF) can be filtered daily. Solute concentration in this UF is very similar to that in plasma water. Because of the large volumes involved, the UF must be replaced continuously with an electrolyte solution. Electrolyte and acid-base disturbances can thus be easily and rapidly corrected. There are different techniques of CHF. Continuous arteriovenous haemofiltration (CAVH) avoids the use of an external blood pump, as the patient's own arterial pressure is used to drive the blood through the filter via a large-bore arterial catheter. On the other hand, continuous venovenous haemofiltration (CVVH) requires the use of a blood pump with a pressure alarm and an air bubble detector. Supplementary diffusive transport [CAVH(D),CVVH(D)] can improve the clearance of low molecular weight toxins, such as urea. In these techniques, there is a continuous flow of dialysate in the UF compartment of the haemofilter. One of the major problems with CHF is the anticoagulation of patients who are at risk of developing haemorrhagic complications. Unfractionated heparin is used most often, but other drugs have been used: low molecular weight heparin, prostacyclin, nafamostat, or sodium citrate. The neutralization of heparin has also been suggested. Because the fluid balance can be easily managed by CHF, patients in acute renal failure can be given standard intravenous feeding. Many small endogenous molecules, such as gastrin, are probably removed by CHF. However, most drugs have a molecular weight less than 6,000 d, and are not totally protein-bound. They are therefore likely to be ultrafiltered, and so, become inefficient. As a result, the drugs used should be adapted to the haemofilter, and vice versa. More than any extracorporeal circulation, CHF increases the incidence of bacterial blood contamination, because of its continuous use. Routine blood cultures should be carried out. Moreover, blood is cooled during its passage in the extracorporeal circuit, leading to hypothermia. There are some devices which prevent this. Renal function can be completely replaced with the production of 12 to 15 l UF a day. CHF must be started early on in the course of the renal failure. When the concentration of blood urea is greater than 40 mmol.l-1 diffuse transport must also be used.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[Continuous hemofiltration: an extrarenal filtration method used in intensive care]. 192 60

One hundred fifty seven consecutive octogenarians (mean age +/- standard deviation, 82.4 +/- 1.9 years) underwent coronary artery bypass grafting with hypothermia (mean temperature, 21.8 degrees +/- 1.8 degrees C), hyperkalemic cardioplegia, and cardiopulmonary bypass in a 9-year period. Sixty-six percent were male. Preoperatively, 115 patients (73%) were in New York Heart Association functional class IV, with the remainder being in either class III (23%) or class II (4%). Twenty percent of the patients had major complications including postoperative hemorrhage (15), sepsis (9), cerebrovascular accident (6), third-degree heart block (5), renal failure requiring dialysis (1), and pulmonary embolism (1). The 30-day or in-hospital mortality rate was 7.0%. Mean total hospital stay was 26.1 +/- 17.9 days. One-year and 5-year actuarial survival rates were 85% and 62%, respectively. Higher mortality was seen to be associated with New York Heart Association class IV, left ventricular ejection fraction less than 0.40, and lesser values for cardiac output and cardiac index. At the 6-month postoperative follow-up, 73% of the survivors reported that their general health had improved as compared with before operation. This experience demonstrates that for select octogenarians with unmanageable angina pectoris, coronary artery bypass grafting is an effective therapeutic option.
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PMID:Morbidity and mortality after coronary artery bypass in octogenarians. 203 31

The total number of admissions and deaths of patients with shigellosis were ascertained at the Dhaka Treatment Centre of the International Centre for Diarrhoeal Disease Research, Bangladesh, 1974-1988, and the characteristics of 67 patients who died were compared with those of 134 discharged alive. Of 9780 Shigella-infected inpatients, 889 (9.1%) died; 32.3% of deaths occurred in children less than 1 year of age. Fatality rates were highest (10.3%) in Shigella sonnei-infected patients and lowest (6.7%) in Shigella dysenteriae type 1-infected patients. Age less than 1 year, lack of breast feeding in patients 1-2 years of age, hypothermia, severe malnutrition, severe dehydration, altered consciousness, abdominal distension, thrombocytopenia, hypoproteinemia, hyponatremia, hypoglycemia, renal failure, and bacteremia were all significantly more common in case patients. In a multivariate analysis, younger age, decreased serum protein, altered consciousness, and thrombocytopenia were predictive of death. Thus in Bangladesh the fatality rate for hospitalized patients infected with any species of Shigella remains high despite relatively intensive inpatient care, and young, hypoproteinemic patients are at greatest risk of fatal illness.
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PMID:Death in shigellosis: incidence and risk factors in hospitalized patients. 231 28

The central nervous system (CNS) sensitivity to the hypnotic (general anesthetic) action of phenobarbital and to the neurotoxic (convulsive) action of theophylline is greater in rats with acute renal failure than in normal animals, consistent with clinical observations. In the case of phenobarbital, this increased sensitivity can be produced in normal rats by infusion of a solution of the lyophilized dialysate of serum from rats with renal failure. It was hypothesized that the relevant constituent(s) of this dialysate may circulate between the blood and the intestinal lumen and that it (they) can be adsorbed by orally administered activated charcoal and thereby removed from the body. If so, treatment of renal failure rats with activated charcoal should partly reverse the increased CNS sensitivity to phenobarbital and to other drugs similarly affected. Accordingly, rats with renal failure produced by bilateral ligation of ureters were given an aqueous suspension of activated charcoal, about 1 g per kg body weight, orally every 8 hr for six doses. Uremic controls received equal volumes of water. About 2 hr after the last dose, the animals were infused i.v. with phenobarbital to onset of loss of righting reflex or with theophylline to onset of maximal seizures. In the phenobarbital study, charcoal treatment partly reversed the hypothermia associated with renal failure and caused a reduction of creatinine and total bilirubin concentrations in serum. The cerebrospinal fluid (CSF) concentration of phenobarbital at onset of loss of the righting reflex was significantly higher in charcoal treated rats than in their controls.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Kinetics of drug action in disease states. XXXIX. Effect of orally administered activated charcoal on the hypnotic activity of phenobarbital and the neurotoxicity of theophylline administered intravenously to rats with renal failure. 233 96

An imbalance of excitatory and inhibitory amino acid-ergic neurotransmission has been suggested to play a role in the pathogenesis of hepatic encephalopathy. For further evaluation of this hypothesis, several parameters of amino acid-ergic neurotransmission were studied in rats with acute liver failure induced by the administration of 300 mg per kg thioacetamide by gavage on two consecutive days. By appropriate supportive care, hypoglycemia, renal failure and hypothermia were avoided. Rats were monitored clinically and neurologically. Hepatic encephalopathy evolved in four distinct, easily recognizable stages. Light and electron microscopic examination of brains of rats with hepatic encephalopathy revealed only a slight swelling of nuclei of neurons and astrocytes without signs of neuronal degeneration or brain edema. In rats with hepatic encephalopathy, the concentrations of GABA, glutamate and taurine were decreased in the cerebral cortex, the hippocampus and the striatum, whereas those of aspartate and glycine were unchanged or increased. GABAA and benzodiazepine receptors were studied as parameters for the postsynaptic GABAA-benzodiazepine receptor complex, glutamic acid decarboxylase as parameter for presynaptic GABA-ergic neurons and stimulation of benzodiazepine binding by GABA as a parameter for a GABA-mediated postsynaptic event. None of these parameters was different in hepatic encephalopathy as compared to controls. Similarly, Ca++/Cl(-)-dependent and -independent glutamate receptors as parameters for glutamatergic neurons were unchanged in rats with hepatic encephalopathy. Thus, in rats with thioacetamide-induced liver failure and hepatic encephalopathy, changes of the concentrations of neurotransmitter amino acids occur in the brain. Other neurochemical parameters, however, failed to identify alterations of GABA-ergic or glutamatergic neurotransmission in hepatic encephalopathy.
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PMID:Hepatic encephalopathy in thioacetamide-induced acute liver failure in rats: characterization of an improved model and study of amino acid-ergic neurotransmission. 256 68

The keys to a better outcome in the management of ruptured aneurysm are early diagnosis, aggressive resuscitation, and early operation, with prompt achievement of proximal control. Having achieved these goals, there is a tendency to let down one's guard and relax; indeed, the principles of aneurysm repair beyond this point are similar to those of elective surgery. However, it should be remembered that nearly every complication is more likely in emergency than in elective operations. Therefore, even more care needs to be taken with the technical details at this point to avoid the complications discussed in the following article. The perioperative management must continue at the same heightened level to combat acidosis, hypothermia, coagulation disorders, cardiac dysfunction, fluid overload with pulmonary edema, renal failure, and other common sequelae of this challenging undertaking.
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PMID:Ruptured abdominal aortic aneurysms. Special considerations. 266 51

To improve the surgical results of aneurysms of the transverse aortic arch, it is essential to select the optimal support technique to protect the cerebral ischemia during the aortic arch occlusion. In the four year period between 1983 and 1987, 21 consecutive patients had surgical correction of aneurysms of the transverse aortic arch at our institution. The causes of aneurysms were dissection (type A) in 16 patients and arteriosclerosis in 5 patients. Seven patients had emergency operation for frank or impending rupture. Two method for cerebral protection were employed during the period of arch exclusion. In Group I, 11 patients underwent selective cerebral perfusion both to innominate and left common carotid arteries via one roller pump at a rate of 600 ml/min (25 degrees C). The average cerebral perfusion time was 70.4 +/- 20.5 minutes. In Group II, 10 patients underwent deep hypothermia (15 degrees C to 20 degrees C) and total circulatory arrest to allow repair of the transverse aortic arch. The concomitant AVR was performed in two patients and CABG in one patient. The average cerebral arrest time was 35.2 +/- 3.4 minutes. Two out of 10 patients had additional cerebral perfusion because cerebral ischemic time exceeded over 45 minutes. There were three early deaths (14.3%) in this series. The causes of early death were bleeding in two patients and renal failure in one patient. There were no cerebral complications in both groups. The duration of extracorporeal bypass necessary for cooling and rewarming phase in Group II was longer than that in Group I.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Clinical study on surgical treatment of aortic arch aneurysm using selective cerebral perfusion or hypothermic circulatory arrest]. 273 49

The purpose of this study was to assess the degree, time sequence, and biochemical correlates of hypothermic protection against ischemic acute renal failure. Rats subjected to 40 minutes of bilateral renal artery occlusion (RAO) were made mildly hypothermic (32 degrees-33 degrees C, by cold saline peritoneal lavage) during the following time periods: 1) RAO only, 2) reperfusion only (beginning at 0, 15, 30, or 60 minutes after RAO and maintained for 45 minutes), or 3) during and after (0-45 minutes) RAO. Continuously normothermic (37 degrees C) RAO rats served as controls. The control rats developed severe acute renal failure (blood urea nitrogen [BUN], 95 +/- 4 mg/dl; creatinine, 2.2 +/- 0.1 mg/dl; and extensive tubular necrosis at 24 hours). Hypothermia confined to RAO was highly protective (BUN, 33 +/- 5 mg/dl; creatinine, 0.62 +/- 0.07 mg/dl; and minimal necrosis). Hypothermia partially preserved ischemic renal adenylate high-energy phosphate (ATP and ADP), increased AMP and inosine monophosphate concentrations, and lessened hypoxanthine/xanthine buildup (assessed at end of RAO). Hypothermia confined to the reflow period (beginning at 0, 15, and 30 minutes) was only mildly protective (e.g., BUN, 58-63 mg/dl); the degree of protection did not differ according to the time of hypothermic onset. Lowering reflow temperature to 26 degrees C had no added benefit. Hypothermia that started at 60 minutes after RAO conferred no protection. Combining ischemic and postischemic hypothermia abolished all renal failure (assessed at 24 hours). This study offers the following conclusions: Mild hypothermia can totally prevent experimental ischemic acute renal failure. Hypothermia is highly effective during ischemia, and it is mildly protective during early reflow; these benefits are additive. During early reflow, hypothermic protection is not critically time dependent. By 60 minutes of reflow, no effect is elicited; this absence of effect possibly signals completion of the reperfusion injury process. Hypothermia's protective effects may be mediated, in part, by improvements in renal adenine nucleotide content and, possibly, by decreasing postischemic oxidant stress.
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PMID:Degree and time sequence of hypothermic protection against experimental ischemic acute renal failure. 280 43

The authors relate their experience concerning the surgical correction of congenital coronary fistula. Between May 1971 and June 1986, 9 patients (4 boys and 5 girls) aged from 17 days to 49 years were operated upon at the Division of Cardiac Surgery of Bergamo (Ospedali Riuniti). All the patients, except three who were asymptomatic, showed early cardiac failure or dyspnoea on effort and angina in the elderly. At the physical examination a continuous murmur was heard in 8 cases; the chest x-ray showed significant cardiomegaly and on the electrocardiogram a right/left ventricular hypertrophy pattern was detected in 5 patients. All the patients underwent cardiac catheterization and a coronary angiography. The left-to-right shunt ranged from 60% to 250% of the cardiac output. The anomalous communication affected the right coronary artery in 7 cases and the left in 2, opening into the right atrium in 4 patients, into the right ventricle in 3 and into the pulmonary artery in 2. All patients but one, in whom division and suture were the only necessary procedures, underwent correction by means conventional cardiopulmonary by-pass with moderate hypothermia. In 3 cases closure through the coronary artery was preferred, in 1 through the right ventricle and in 2 transpulmonary. There was only 1 late death which occurred in a 3 year-old patient due to renal failure. After a mean follow-up of 6 years, 7 patients are to be asymptomatic while 1 patient had to be reoperated for a significant residual shunt.
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PMID:[Congenital coronary fistulae. Comments on 9 surgical cases]. 297 Apr 13

Patients undergoing cardiac surgery are mildly hypothermic by the completion of the surgical procedure. They need to return to a normothermic state if enzymatic functions are to proceed in their normal manner. The body can produce heat by elevating metabolic rate or by activating the shivering mechanism. Metabolic rate peaks shortly after separation of the patient from cardiopulmonary bypass, and therefore contributes to heat production. Because of the effects of neuromuscular blockage administered both during and after surgery; these patients may be unable to generate heat by shivering, and shivering is usually undesirable. This eliminates the major heat production mechanism available to the body. Therefore, heat must be transferred down its gradient by means of convection and conduction. External and internal methods accomplish these goals. External methods, which minimize additional heat loss, include the use of warming lights, elevation of room temperature, and the use of blankets. Internal methods, which transfer heat by convection, may be used to help actively reverse hypothermia. Such techniques include warmed inhalation gases and intravenous fluids, warmed nasogastric lavage fluid, and warmed peritoneal dialysis fluid for patients with end-stage renal failure with severe electrolyte disorders after surgery.
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PMID:Rewarming and cardiac surgery: a review. 304 84


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