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

In cardiopulmonary bypass (CPB), despite heparin regimens in which the activated clotting time (ACT) is kept at more than 400 s, there is biochemical evidence of thrombin generation indicating activation of the coagulation system and increased fibrinolytic activity. Therefore, to reduce the coagulant activation has been one of the main issues in the improvement of CPB. The purpose of this study was to compare the heparin concentration with the ACT and to evaluate the effect of keeping higher heparin concentration on the coagulation and fibrinolytic systems during hypothermic CPB, employing moderate hypothermia (MHT) or deep hypothermic circulatory arrest (DHT). Heparin was either administered to maintain an ACT >400 s (ACT group) or to maintain a whole blood heparin concentration of 3 mg/kg (heparin group). At the lowest core temperature during CPB, the ACT and the heparinase ACT (unrelated to heparin concentration) were increased the most whereas the whole blood heparin concentration was less than half the initial concentration in both ACT groups of MHT and DHT. The thrombin-antithrombin III (TAT) content just after CPB in both MHT and DHT was significantly lower in the heparin group than in the ACT group. In conclusion, ACT does not reflect the whole blood heparin concentration during hypothermic CPB. Furthermore, maintenance of the higher heparin concentration during hypothermic CPB may suppress the activation of the coagulation system via thrombin inhibition. That effect was more remarkable in deep hypothermic CPB. Therefore, we believe that anticoagulation management during hypothermic CPB should be based on the maintenance of the higher blood heparin concentration.
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PMID:Maintenance of blood heparin concentration rather than activated clotting time better preserves the coagulation system in hypothermic cardiopulmonary bypass. 1067 57

Heparin coating of cardiopulmonary bypass (CPB) circuitry may attenuate the platelet consumption associated with CPB. We investigated the effect of temperature on the interaction between platelet and heparin coated surfaces under in vitro static conditions. Heparin coated and non coated oxygenator fibers were incubated with heparinized whole blood at 37 degrees C and 22 degrees C. The incubation time was set at 30, 60, 180, and 300 minutes. The number of platelets adhering to each fiber was assessed with enzyme immunoassay using monoclonal antibody against platelet receptor protein CD 61(GPIIbIIIa). As an index of platelet activation, plasma soluble(s) P-selectin levels were measured by enzyme-linked immunosorbent assay. Under normothermia, the number of adherent platelets on the non coated surface increased significantly after 300 min of incubation. Platelet adhesion was reduced significantly by heparin coating of the surface and was kept constant after 300 min. Under hypothermia, heparin coating was also associated with significant reduction of platelet adhesion. The levels of sP-selectin did not correlate with the extent of platelet adhesion. Our results suggest that heparin coating is effective in decreasing platelet adhesion to the synthetic surface tested regardless of the temperature under static conditions. Inhibition of platelet activation on the heparin coated surface may be masked by standard dose heparinization.
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PMID:Platelet adhesion to heparin coated oxygenator fibers under in vitro static conditions: impact of temperature. 1148 87

We wished to evaluate the safety and the advantages of using heparin-bonded extracorporeal membrane oxygenation (ECMO) to replace conventional cardiopulmonary bypass (CPB) in deep hypothermic circulation for complex cerebral aneurysm surgery.Heparin-bonded ECMO without the bridging tube and the cardiotomy reservoir was set up through the femoral vessels. Limited heparin was infused. In deep hypothermia, the ECMO blood flow was temporarily decreased as low as the neurosurgeons' request. It was applied to 4 patients with difficult intracranial aneurysms who were selected for the procedure. Clipping, wrapping, or vascular bypass was implemented to manage the aneurysms under deep hypothermia. The total heparin dosage used in the whole procedure was 9,875 +/- 1,625 U, and the mean ECMO time was 270 +/- 105 min. The blood consumption was packed red blood cell 3.0 +/- 0.5 U and fresh frozen plasma 3.8 +/- 2.3 U. Compared with our previous experiences using conventional CPB, ECMO did need less heparin and blood transfusions. Clipping was applied in 2 patients, wrapping in 1, and venous graft interposition was performed in 1. Mortality occurred in 1 patient (25%) due to brain herniation. This preliminary study suggested that the heparin-bonded ECMO without reservoir in deep hypothermia could be safe in cerebral aneurysm surgery under a low flow circuit.
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PMID:New application of heparin-bonded extracorporeal membrane oxygenation in difficult neurosurgery. 1153 14

The purpose of this study was to evaluate the safety of profound hypothermic circulatory arrest with heparin-coated circuits and low dose systemic heparinization in the treatment of cerebral aneurysms. Surgery for giant intracranial aneurysms not operable using standard neurosurgical techniques was performed in 8 patients. All patients were placed on cardiopulmonary bypass using the closed-chest technique, except for the first patient who underwent open-chest bypass. Heparin was administered systemically (3,000 IU) and into the circuit (1,500 IU). Total circulatory arrest was begun at 20 degrees C. The D-dimer, alpha2 plasmin inhibitor-plasmin complex, thrombin-antithrombin III, and beta-thromboglobulin concentrations were measured to evaluate the changes in the coagulation and fibrinolytic systems during bypass. There were no neurologic or cardiac complications. None of the indicators of platelet activation, coagulation, or fibrinolysis were elevated. Hypothermic circulatory arrest combined with heparin-coated circuits and low dose systemic heparinization is safe for use in neurosurgery.
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PMID:Hypothermia with heparin-coated circuits and low dose systemic heparinization in neurosurgery. 1207 14

Extravasation of a chemotherapeutic agent is one of the most frequent complications in cancer patients. Full-thickness skin necrosis often occurs after extravasation. Alternative approaches to treatment are local wound care, elevation, and hypothermia. It was shown that heparin prevents skin necrosis. In this experimental study, the effects of heparin fractions on the prevention of skin necrosis were compared by applying an extravasation model of Adriamycin in rats. Forty Sprague-Dawley male rats weighing 250 to 300 g were used. A total of 0.3 ml doxorubicin hydrochloride was administered subcutaneously to all rats. Ten minutes later, in the control group (group I), 1 ml normal saline was administered subcutaneously. In the first experimental group (group II), 100 U per day heparin sodium was administered in a volume of 1 ml subcutaneously. In the second experimental group (group III), nadroparin calcium (5 anti-Xa U per kilogram per day) was administered. In the third and last experimental group (group IV), dalteparin sodium (5 anti-Xa U per kilogram per day) was administered. All drugs were administered for 2 weeks. Necrotic areas were measured 4 weeks later. Statistical analysis was performed using the Kruskal-Wallis analysis of variance and the Mann-Whitney test. Heparin fractions caused a decreased ulcer rate and size than controls ( < 0.05). There was no superiority among heparin fractions. The authors think that low-molecular weight heparins are preferred, considering the higher risk of bleeding with unfractionated heparin.
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PMID:Effects of heparin fractions on the prevention of skin necrosis resulting from adriamycin extravasation: an experimental study. 1235 79

Mild hypothermia has been shown to provide protective effects in patients with ischemia (e.g. acute stroke and heart attack), but traditional methods for inducing, maintaining, and reversing hypothermia are slow, difficult to administer and control, and uncomfortable for patients. An innovative method produces mild, wholebody hypothermia (32 degrees C to 34 degrees C) by use of an endovascular heat exchanger placed into the inferior vena cava. A closed-loop system accurately changes core body temperature with average cool-down rates of 4.8 degrees C per hour, tight-target temperature control of +/- 0.1 degree C, and average rewarm rates of 1.9 degrees C per hour. By enhancing the mixing of blood in the vicinity of the heat exchanger, the disposable, small-diameter catheter efficiently exchanges heat between the closed-loop circulating fluid and the blood stream in response to body temperature. A control algorithm adapts to body physiology and thermal mass to mitigate temperature excursions. Flexible, bellow-shaped segments along the length of the catheter allow precise maneuvering within blood vessels. Heparin, covalently bonded to the catheter, helps control thrombogenicity. This novel design has potential clinical applications in cerebrovascular surgery, acute stroke, acute myocardial infarction, cardiac arrest, and fever control.
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PMID:A novel system for mild hypothermia. 1517 68

This paper analyzes the results of the use of enoxaparin for anticoagulant therapy in reconstructions on the ascending aorta (AA) as compared to unfractionated heparin applied previously in the control group. Between 1986 and 2003 a total of 30 patients with AA aneurysms were operated on at the clinic. Insufficiency of the aortic valve with degree II-III regurgitation was present in 25 (83.3%) cases. Chronic dissection of the AA was identified in 10 (33.3%) cases. The patient's age varied from 24 to 52 years (mean 39 years). The etiological factors of AA aneurysm were: Marfan's syndrome (46.7% of cases), Erdheim's syndrome (26.7%), atherosclerosis (10.0% of cases); previous chest traumas were recognized in 16.6% of patients. All the patients were operated on under extra-corporeal circulation and moderate hypothermia. The patients were distributed into two groups. In the control group, eighteen patients were operated on. Anticoagulant therapy was carried out using unfractionated heparin i. v. in a daily dose 10-15 thousand units. Heparin injection was initiated on the first postoperative day and continued for 6.5 days on the average, with a progressive change over to the use of indirect anticoagulants. In the basic group, twelve operated patients were administered the anticoagulant enoxaparin s.c. in a daily dose 0.7-1.0 mg/kg bw. Enoxaparin therapy was initiated from the first postoperative day and continued for 8.9 days on the average, with a progressive change over to indirect anticoagulants. The postoperative lethality in the control group accounted for 22.2% (4 patients). In two cases, it was induced by heart failure and in two cases, by hemorrhagic complications. In the basic group, the beneficial results were achieved in 91.7%; no hemorrhagic complications were recorded. The data obtained allow the conclusion that the use of enoxaparin significantly facilitates the postoperative management of patients with AA aneurysms, providing for a controllable and safe anticoagulant effect.
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PMID:[The use of low-molecular heparins in reconstructive surgery of ascending aortic aneurysms]. 1562 90

Fifty-four year-old man with recent history of myocardial infarction and a percutaneous coronary intervention who suffered a ventricular fibrillation arrest at home. He was resuscitated in the field. His heart rhythm was in atrial fibrillation. The cardiac catheterization showed a patent stent from his previous myocardial infarction and no new occlusions. He subsequently underwent hypothermia protocol using the Alsius CoolGard 3000 Temperature Control System and Icy Catheter. Heparin drip was started for atrial fibrillation 36 hours after catheter insertion and became therapeutic 2 hours before the end of cooling maintenance phase. Heparin drip was stopped 4 hours into the rewarming phase because of spontaneous conversion to sinus rhythm. Subcutaneous heparin was resumed for deep venous thrombosis prophylaxis. He was extubated to room air after hypothermia protocol. The cooling catheter was removed 88 hours after insertion. Within 1 minute of catheter removal, his oxygen saturation dropped to 80%. Transthoracic echocardiogram showed a mobile thrombus in the right atrium prolapsing into the right ventricle. Computer tomography angiography of the chest confirmed a large saddle embolus. Ninety minutes later, patient went into cardiac arrest with pulseless electrical activity while he was being considered for surgical embolectomy, but he could not be resuscitated. The temporal relationship of the catheter removal and his acute clinical decompensation led to believe that this was an intravascular cooling catheter (ICC)-related event. Providers should be cognizant of the complications of central venous catheters such as thrombosis formation, as it could lead to fatal pulmonary embolism. Physicians should promote frequent assessment of the access site(s) during routine physical examinations and potentially use point of care vascular ultrasound in high-risk cases to rule out a catheter-associated thrombus before catheter removal.
Ther Hypothermia Temp Manag 2018 Jun
PMID:Intravascular Cooling Catheter-Related Venous Thromboembolism After Hypothermia: A Case Report and Review of the Literature. 2957 Apr 28


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