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

In hypothermic rats with acute hypertension induced by intravenous injection of adrenalin, regional changes in blood-brain barrier permeability to macromolecules were investigated using Evans blue as indication. Evans blue albumin extravasation was determined as a macroscopic finding and a quantitative estimation with a spectrophotometer using homogenized brain to release the dye was also performed to evaluate the macroscopic findings. Five groups of rats were studied: Group I: normothermia + acute hypertension; Group II: hypothermia + acute hypertension; Group III: control hypothermia; Group IV: normothermia + hypotension; Group V: control normothermia. The rats were anaesthetized with diethyl-ether. Body temperature was lowered by submerging anaesthetized animals in an ice water bath. The colonic temperature was reduced to 20 +/- 1 degrees C. During adrenaline-induced acute hypertension the mean arterial blood pressure increased in both normothermic and hypothermic animals. Blood-brain barrier lesions were present in 40% of normothermic rats, and 60% of hypothermic rats after adrenaline-induced hypertension. Mean value for Evans blue dye in the whole brain was found to be 0.530 +/- 0.202 mg% in the normothermic rats and 0.752 +/- 0.256 mg% in the hypothermic rats during adrenaline-induced hypertension. This difference between normothermic and hypothermic rats was found to be statistically significant (P less than 0.01). Our results showed that the extravasation of Evans blue albumin was most pronounced in the brains of hypothermic rats compared to normothermic rats after adrenaline-induced acute hypertension.
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PMID:Influence of profound hypothermia on the blood-brain barrier permeability during acute arterial hypertension. 151 50

Even during adequate general anesthesia, hypertension is a common phenomenon in patients undergoing aortocoronary bypass grafting (CABG). In such cases application of vasodilators is recommended in order to decrease myocardial oxygen consumption. This study was performed to compare two commonly used substances, i.e., nitrates and nifedipine, with regard to their influence on hemodynamics, renal blood flow, kidney function, and the requirement for homologous blood transfusions. METHODS. Forty-four patients gave their informed consent to the study. They were randomly divided into 2 groups: group 1 received nitroglycerin (3.0 micrograms/kg.min), group 2 nifedipine (Adalat, 0.5 microgram/kg.min) in order to prevent hypertension in the phase before onset of cardiopulmonary bypass (CPB). Anesthesia was induced by etomidate and succinylcholine and maintained as a modified neuroleptanalgesia with fentanyl (up to 50 micrograms/kg), midazolam (0.3 mg/kg.h), and pancuronium (0.1 mg/kg). Systolic blood pressure was kept within the range of 120-160 mm Hg; in case of higher values boluses of either 0.25 mg nitroglycerin or 0.5 mg nifedipine were administered. Cardiac index, stroke volume index, rate-pressure product, intrapulmonary shunt, and pulmonary and total peripheral resistances were evaluated at five predefined points: (1) after induction of anesthesia; (2) before incision; (3) before cannulating the aorta; (4) after decannulating the aorta; and (5) at the end of operation. Creatinine and free-water clearances as well as sodium and potassium excretion were calculated for three phases of the operation: (A) induction of anesthesia--onset of CPB; (B) during CPB; and (C) end of CPB--end of operation. CPB was performed using a membrane oxygenator (Sorin 51) and a nonpulsatile blood flow of 2.5 1/min.m2, which was reduced during mild hypothermia of 30-32 degrees C to 1.7 l/min.m2. Mean arterial pressure in both groups was kept at approximately 70 mm Hg. In case of lower pressures norepinephrine (50-100 micrograms/bolus) was administered; higher pressures were treated as described above. Volume substitution was performed initially by 500 ml hydroxyethyl starch and continued, if necessary, by homologous blood or 5% human albumin in order to keep the hematocrit greater than 30 in the phases before and after CPB. RESULTS. Group 2 showed significantly higher values of cardiac index and stroke volume index at point 3 while the rate-pressure product was clearly lower, indicating better myocardial performance and lower oxygen consumption than in group 1. Creatinine and free-water clearances in all three phases did not differ. However, sodium excretion during CPB was significantly higher in the nifedipine group while potassium excretion showed no differences. The average requirement for blood and blood substitutes was lower in group 2, but the difference could not be confirmed statistically because of the large dispersion of values. Nevertheless, 4 patients in the nifedipine group but no patient in group 1 did not need homologous blood transfusion. CONCLUSION. In comparison to nitrates, nifedipine showed some advantages in the treatment of hypertension during CABG: (1) it provided better myocardial performance; (2) it had a more reliable but not too long-lasting effect on elevated total peripherial resistance, leading to better hemodynamic stability; and (3) by not affecting the capacitance vessels it may necessitate fewer homologous blood transfusions.
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PMID:[Nifedipine versus nitroglycerin in aortocoronary bypass surgery. The effect on hemodynamics, kidney function and homologous blood requirement]. 153 39

To determine the ability of intraoperative hypothermia to modify changes in the plasma protein component of the acute-phase response (APR) and the plasma hormone component of the endocrine response (ER) to surgical injury, 20 patients undergoing coronary artery surgery were randomised to an intraoperative blood temperature of 28 degrees C or 20 degrees C during cardiopulmonary bypass (CPB). Serial measurements of pack-cell-volume corrected concentrations (PCVCC) of five plasma proteins (albumin, prealbumin, transferrin, caeruloplasmin, ferritin) and six plasma hormones (adrenaline, noradrenaline, cortisol, triiodothyronine, thyroxine, and thyroid-stimulating hormone) were obtained twice preoperatively, seven times during surgery, six times in the 24 hours following surgery, and a further four times until the seventh postoperative day. A more profound level of intraoperative hypothermia significantly reduced the plasma adrenaline response to CPB but not the other components of the ER or APR.
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PMID:The effects of systemic intraoperative hypothermia on the acute-phase and endocrine response to cardiac surgery. 163 76

A 62-year-old man was admitted to the hospital because of massive hemoptysis. Chest X-ray film, CT scan and IADSA demonstrated a large aneurysm of the thoracic aorta, extending from the ascending aorta to the descending aorta. Bronchoscopy revealed bleeding from left B1+2. Six days after the onset, replacement of the thoracic aorta with woven Dacron prosthetic graft, autoclaved after immersion in albumin, was performed with cardiopulmonary bypass and separate cerebral perfusion (700 ml/min) under moderate hypothermia (25 degrees C). Left upper lobe of the lung, adherent tightly to the posterior and medial wall of the aneurysm, was not dissected because bleeding from left bronchus was trivial even after systemic heparinization. Because of the cardiac dilatation, delayed chest closure was needed. Postoperative cardiac failure, necessitating much catecholamine support, was seen with gradual improvement and no neurological deficit was recognized. He was discharged from the hospital without any sequelae 2 months after the onset. Pathologic diagnosis was an atherosclerotic aneurysm.
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PMID:[Successful surgical treatment of ruptured thoracic aortic aneurysm into the lung]. 223 2

The ability of intraoperative hypothermia to modify the metabolic response to cardiopulmonary bypass (CPB) was assessed by serial alterations in iron, zinc and copper, and in their molar binding ratios to their respective transport proteins, in 20 male patients under-going elective coronary artery surgery and randomised to an operative blood temperature of 28 degrees C or 20 degrees C. Decreases in serum iron and zinc concentrations, typical of the acute phase response, were preceded by early rises. Significant alterations in the metal: protein molar binding ratios preceded significant changes in the serum concentrations of the metals and occurred earliest in the zinc: albumin binding ratio, which was apparent by the time of skin incision. An intraoperative temperature of 20 degrees C modified iron and zinc concentrations and their protein binding ratios during surgery but not in the post-operative period. These early changes in trace metals and their protein binding ratios are a simple and inexpensive method of quantitating the response to surgical injury and may be useful in assessing new interventions in cardiopulmonary bypass. An awareness of the trace element response to surgical injury is essential to avoid misdiagnoses of iron deficiency anaemia or zinc deficiency.
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PMID:The effects of intraoperative hypothermia and cardiopulmonary bypass on trace metals and their protein binding ratios. 226 37

To examine how fat might influence the metabolic effects of tumour necrosis factor alpha (TNF alpha), human recombinant TNF alpha was given intravenously to rats that had been fed for 12 weeks on diets containing (g/kg) 200 maize oil or 190 coconut oil + 10 maize oil. Rectal temperature and tissue composition measurements were made 8 and 24 h after injection. Ambient temperatures of 20 degrees and 25 degrees were employed to accentuate rectal temperature changes. Doses of 30 and 300 micrograms TNF alpha/kg body-weight were given, and brought about depression of serum zinc and albumin and elevation of copper. Muscle protein content was decreased and liver protein and Zn content enhanced by TNF alpha. Serum Zn and liver Zn content were negatively correlated 8 h after injections. Hypothermia developed within 1 h of injection. All responses except the rise in serum Cu and gain in liver Zn were more intense at the higher than at the lower dose of TNF alpha. Hypothermia was exacerbated by an environmental temperature of 20 degrees. The coconut-oil diet blunted the hypothermia and likewise the changes in serum albumin and Cu content 8 h after injections and in muscle and liver protein after 24 h. Changes in eicosanoid metabolism may be involved in the modulatory effects of the coconut-oil-enriched diet.
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PMID:Dietary fat modifies some metabolic actions of human recombinant tumour necrosis factor alpha in rats. 238 39

Twenty cases of renal carcinoma with tumor thrombus extending into the vena cava or atrium, in which cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest (DHCA) were used, are reviewed. Arterial, central venous (n = 9), or pulmonary artery catheters (n = 11), ECG, and rectal or bladder and pharyngeal temperatures were used for monitoring. The anesthetic was a high-dose narcotic supplemented with a nondepolarizing relaxant and a volatile agent. The surgery consisted of mobilization of the kidney followed by CPB via atrial and aortic cannulae, cooling via CPB, exsanguination, and removal of thrombus during DHCA. Duration of cooling was 21 +/- 7 minutes to a pharyngeal temperature of 15.8 degrees +/- 2.6 degrees C with alpha-stat pH management; DHCA lasted 26 +/- 10 minutes, and rewarming was continued to a mean pelvic temperature of 36.2 degrees C. Duration of surgery was 8.1 +/- 1.6 hours. The mean initial hematocrit was 33.5%, mean lowest Hct during CPB was 16.9%, and mean Hct at the end of surgery was 30%. Intraoperatively, 9.0 +/- 6.4 units of blood were used, and most patients received component therapy. Average crystalloid use was 7 L, and albumin or hetastarch (1.3 +/- 0.9 L) was used in 13 patients. One patient with severe cardiac disease could not be weaned from CPB. In the 19 operative survivors, there were no neurological deficits. There was one late death from pulmonary complications. The use of thiopental (n = 13), dexamethasone (n = 11), or mannitol (n = 19) was not clearly related to outcome. Hypothermia, hemodilution, alpha-stat pH management, and normoglycemia are believed to be important aspects of perioperative care.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Anesthetic management for surgical removal of renal carcinoma with caval or atrial tumor thrombus using deep hypothermic circulatory arrest. 252 Sep 37

The effects of cardiopulmonary bypass (CPB) with hypothermia and systemic heparinization on ceftriaxone disposition were evaluated in seven male patients. A bolus dose of drug (14 mg/kg of body weight) was given, and blood and urine specimens were collected before, during, and after CPB for 96 h. Creatinine, albumin, and total and free ceftriaxone concentrations in plasma were measured. The ceftriaxone free fraction (ff) in vitro was estimated by equilibrium dialysis, and the in vivo ff was obtained by the ratio of renal clearance due to filtration to creatinine clearance. Pharmacokinetic parameters were based on concentrations of total drug and free drug. Albumin decreased from 3.10 +/- 0.29 g/dl presurgery to 1.42 +/- 0.17 g/dl and recovered to 2.46 +/- 0.26 g/dl on postoperative day 4. CPB markedly increased the in vitro ff, which was reversed by protamine post-CPB (ff pre-CPB, 0.15 +/- 0.01; during CPB, 0.53 +/- 0.20; post-CPB, 0.16 +/- 0.02). The in vitro ff exceeded the in vivo ff (0.53 +/- 0.20 versus 0.24 +/- 0.07), probably due to continued free fatty acid release caused by heparin during dialysis. Clearances based on free drug decreased, and the renal clearance due to filtration increased (7.6 +/- 2.8 versus 15.0 +/- 4.5 ml/min) while the creatinine clearance decreased (114 +/- 29 versus 72 +/- 28 ml/min) during CPB. Diminished binding owing to low albumin and free fatty acids explain this behavior. Lower binding also increased the volume of distribution (154 +/- 41 ml/kg) and extended the half-life (15 +/- 6 h). In summary, ceftriaxone disposition was significantly altered by CPB, resulting in marked increases in free drug concentrations, half-life, and volume of distribution and in decreased intrinsic clearance.
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PMID:Ceftriaxone disposition in open-heart surgery patients. 276 36

An aorto-coronary bypass grafting was performed in a 50 year-old man, a Jehovah's Witness, suffering from effort angina pectoris. Preoperatively, he was underwent PTCA for LAD occlusion, which failed. Single aorto-coronary bypass grafting using IMA was performed under the extracorporeal circulation primed with Ringer's Lactate and albumin. Moderate hypothermia with core temperature of 31.5 degrees C was used, and minimal level of the hematocrit was 18% during the perfusion. At the start of the operation, 800 ml of blood were withdrawn from the jugular vein to the blood bag which connected to a peripheral venous line uninterruptedly. During the operation, the autologous blood was continuously transfused very slowly and most of the autologous blood was transfused after the termination of extracorporeal circulation. The blood in the extracorporeal circuit was hemoconcentrated with ECUM (extracorporeal ultrafiltration method) from hematocrit level 22% to 35% and transfused. The postoperative course was uneventful. At the time of discharge from hospital on the 42nd postoperative day the hemoglobin level was 13.1 g/dl and hematocrit level was 42%.
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PMID:[A case of aorto-coronary bypass in Jehovah's Witness]. 278 21

The mechanisms of ischemia-reperfusion injury in skeletal muscle remain controversial. We investigated the ability of postischemic hypothermia to diminish reperfusion edema and improve skeletal muscle pH in a bilateral, in vivo isolated canine gracilis muscle model. In five anesthetized animals, both gracilis muscles were subjected to 6 hr of ischemia followed by 1 hr of reperfusion. After 5 hr of warm ischemia, one gracilis muscle was cooled to 21 degrees C (cold reperfusion, CR) while the contralateral gracilis muscle was maintained at ambient temperature (warm reperfusion, WR). Reperfusion muscle edema was quantitated by measurement of gracilis muscle weight gain. Interstitial muscle pH was monitored by glass microelectrodes. Vascular permeability was measured by analysis of albumin (125I-Alb) leak. Results are presented as the means +/- SEM. (table; see text) Postischemic hypothermia significantly increased the interstitial muscle pH and significantly reduced postreperfusion muscle edema, without changing the vascular permeability to albumin. These data suggest that hypothermia may provide a clinical method for salvaging ischemic skeletal muscle from the postreperfusion edema that can lead to compartment syndromes, reperfusion injury, and subsequent limb loss.
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PMID:Postischemic hypothermia diminishes skeletal muscle reperfusion edema. 281 55


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