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

Femoral artery perfusion for cardiopulmonary bypass is still employed for reoperation, procedures involving the thoracic aorta, and partial bypass in critical patients. Retrograde aortic dissection is the most significant complication of femoral perfusion. The reported incidence is from 0.6% to 14% with a mortality of 66%. Most of the deaths occurred in patients in whom the dissection was not recognized , or in whom the dissection was recognized but not treated appropriately. Our experience with retrograde dissection totals six patients of 640 (0.9%) in whom femoral inflow was used. Four of the six patients survived the dissection. Sudden increase in extracorporeal line pressure shortly after beginning cardiopulmonary bypass associated with decreased venous return, dampened radial arterial pressure, and the abrupt appearance of a bluish, bulging ascending aorta establishes the diagnosis. Survival is enhanced if cardiopulmonary bypass is promptly discontinued, aortic cannulation established, and bypass reinstituted with the induction of profound hypothermia. Circulatory arrest may then be employed to repair the false passage. In this series the proposed operation was completed in all six patients.
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PMID:Retrograde aortic dissection during cardiopulmonary bypass. 697 67

Pulmonary thromboendarterectomy for chronic pulmonary emboli was performed on ten patients, ages 20 to 67 years, between July 1977 and June 1981. Five patients each were assigned to New York Heart Association functional classes III and IV. All patients had pulmonary hypertension and increased pulmonary vascular resistance. Obstruction beginning in the lobar arteries and involving more than 50% of the sequential arteries was present in all patients. Five patients had complete obstruction of a pulmonary artery. All patients had obstructive disease in both lungs. Pulmonary thromboendarterectomy was performed through central pulmonary arteriotomies and by use of deep hypothermia and circulatory arrest. Circulatory arrest was employed in one to four periods totaling up to 60 minutes. No neurologic deficit was observed. All patients developed reperfusion edema in the lungs. All patients had improvement in pulmonary hypertension and pulmonary vascular resistance. One patient died of lung failure in the late postoperative period. All survivors had improved lung function, with two functional classes in seven patients. Improvement in one equaled three functional classes and in one, by one functional class.
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PMID:Pulmonary endarterectomy for chronic thromboembolic obstruction: recent surgical experience. 714 87

It has been suggested that the increased incidence of ventricular arrhythmias recognized below 30 degrees C might be catecholamine mediated. Elevate catecholamine concentrations have been reported in experimentally induced hypothermia in animals. Plasma concentrations of epinephrine and norepinephrine were measured during profound hypothermia and total circulatory arrest in infants under one year of age undergoing surgical correction of congenital cardiac defects. There was no significant change in either epinephrine or norepinephrine levels during surface cooling to 28 degrees C. Circulatory arrest and exsanguination at 18 degrees C were not associated with a rise in catecholamine levels. However, there was a striking rise in the levels of both epinephrine and norepinephrine with the recommencement of bypass and rewarming. The mean plasma norepinephrine concentration rose from 466 pg/ml (SE +/- 81) at circulatory arrest to 4543 pg/ml (SE +/- 2058) on rewarming bypass (p less than 0.02), while the mean plasma epinephrine concentration rose from 218 pg/ml (SE +/- 54) at circulatory arrest to 3724 pg/ml (SE +/- 1064) on rewarming bypass (p less than 0.02). The plasma catecholamine concentrations fell once cardiopulmonary bypass was discontinued, when the infant's temperature was 37 degrees C. It would, therefore, appear unlikely that the ventricular irritability recognized below 30 degrees C is due to catecholamine excess. The accumulation of catecholamines and/or metabolic products in the infants during circulatory arrest with their subsequent release into the circulation during rewarming may account for the elevation of catecholamine levels during rewarming bypass.
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PMID:The sympathetic response to profound hypothermia and circulatory arrest in infants. 736 40

Profound hypothermia with circulatory arrest is an important surgical adjuvant that allows protected cessation of cerebral blood flow for a brief period. In seven patients undergoing this procedure, continuous spectroscopic measurement of cerebral hemoglobin oxygen saturation was performed. Circulatory arrest at 18 degrees C was associated with a significant progressive desaturation (p < 0.01) of residual cerebral hemoglobin. Arrest time varied based on operative complexity (range 10 to 65 minutes), and a negative linear correlation between arrest time (y) and oxygen saturation (x) was noted (y = -0.87 x + 64). Five patients whose saturation remained above 35% had no neurological injury attributable to hypoxia. One patient (Hunt and Hess Grade 0) whose saturation fell below 35% had evidence of a global hypoxic injury at postmortem examination. Spectroscopically measured cerebral hemoglobin saturation (cerebral oximetry) may be used to monitor metabolic activity during circulatory arrest. Although the clinical utility of such monitoring cannot be established at this time, the potential may exist to prolong the safe duration of induced circulatory arrest for cerebral protection.
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PMID:Cerebral oxygen metabolism during hypothermic circulatory arrest in humans. 802 24

Both clinical and laboratory studies are being undertaken to investigate the deleterious neurologic and developmental effects associated with cardiopulmonary bypass, hypothermia, and circulatory arrest in the neonate and infant. A prospective, randomized clinical study of 171 neonates and young infants compared circulatory arrest with low-flow bypass (50 mL.kg-1.min-1). Circulatory arrest was associated with a higher incidence of early postoperative seizures as well as greater release of creatine kinase-BB. There was a strong correlation between duration of circulatory arrest and seizures (p = 0.004). The late consequences of these findings will be known at the completion of developmental assessment of all patients at 1 and 4 years of age. Laboratory studies have used a miniature piglet model that closely replicates clinical circulatory arrest. High-energy phosphate stores determined by magnetic resonance spectroscopy were maintained in animals undergoing 1 hour of low-flow bypass but became undetectable after 32 minutes of a 1-hour period of circulatory arrest. However, they returned to baseline within 3 hours of reperfusion as did cerebral blood flow and metabolism determined by microsphere studies. Piglets undergoing 1 hour of circulatory arrest showed more rapid recovery of cerebral adenosine triphosphate content and intracellular pH when managed with the pH-stat strategy during hypothermic bypass than with the more alkaline alpha-stat strategy. Other laboratory studies have examined pharmacologic methods of reducing cerebral injury associated with circulatory arrest including aprotinin, anti-CD18, neuronal receptor antagonists (MK801, NBQX), and blockade of glutamate release with adenosine in a cerebroplegia solution. These studies have suggested a number of promising approaches to improving the technique of circulatory arrest.
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PMID:Review of current research at Boston Children's Hospital. 826 70

It is controversial whether profound hypothermia (15 degrees C) provides adequate cerebral protection during a limited period of total circulatory arrest during pediatric cardiac surgery. In the present study, transcranial Doppler echography was used to monitor the blood flow velocity (BFV) pattern in the middle cerebral artery (MCA). The purpose of the study was to investigate the influence of a period of circulatory arrest on MCA BFV, as judged from the reperfusion flow velocity pattern. The MCA BFV was studied in 22 small children undergoing profound hypothermic cardiac operations after induction of anesthesia. Twelve of the children had a period of profound hypothermic circulatory arrest (15 to 74 minutes; arrest group). Circulation was maintained in the remaining 10 children (nonarrest group). Time-averaged MCA BFV was decreased and diastolic BFV was absent immediately after cardiopulmonary bypass in 10 of 12 children in the arrest group. In contrast, only 1 of 10 patients in the nonarrest group (p < 0.05) showed this pattern. Diastolic BFV normalized 54 to 328 minutes after the arrest in the arrest group. Circulatory arrest during profound hypothermia is followed by a period of low cerebral perfusion, whereby time-averaged MCA BFV is decreased and MCA BFV is absent during diastole. We speculate that this can be explained by an increase in intracranial pressure after brain edema.
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PMID:Absent diastolic cerebral blood flow velocity after circulatory arrest but not after low flow in infants. 837 25

Seven patients with complex thoracic aortic aneurysms were operated on using profound hypothermia and circulatory arrest through a left thoracotomy. Three patients had false aneurysms, 2 had large aneurysms precluding access for proximal control, 1 patient had had previous hemiarch replacement, and 1 patient had a thoracoabdominal aneurysm. All patients were cooled on partial cardiopulmonary bypass until the electroencephalogram was isoelectric (approximately 15 degrees C rectal temperature). Circulatory arrest times ranged from 7 to 56 minutes (median, 34 minutes). There was one death due to cardiac failure, and paraplegia developed in 1 patient. The 6 survivors are otherwise well at a median of 12 months postoperatively. Hypothermia and circulatory arrest is an invaluable technique for the treatment of complex aortic aneurysms requiring left thoracotomy for resection. The techniques employed are described and the indications for their use are discussed.
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PMID:Deep hypothermic arrest and left thoracotomy for repair of difficult thoracic aneurysms. 846 33

We report a case of a 48-year-old man in whom type B aortic dissection in the right aortic arch and right descending aorta was diagnosed by transesophageal echocardiography and computed tomographic scan. Angiography was necessary to define the anatomy of the branching vessels. The patient was successfully treated by interposition of a Vascutek 24-mm Dacron woven tube with a right posterolateral thoracotomy approach. Circulatory arrest in profound hypothermia and cerebral retroperfusion were used.
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PMID:Type B aortic dissection involving an isolated right-sided aortic arch. 878 30

We report the case of a 28-year-old woman with type B chronic aortic dissection extending from a ductus diverticulum aneurysm. The patient was successfully treated by interposition of a Hemashield 26-mm woven Dacron graft with a left posterolateral thoracotomy approach. Circulatory arrest through profound hypothermia and short retrograde cerebral circulation were employed during proximal anastomosis of the graft.
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PMID:Aortic dissection extending from ductus diverticulum aneurysm. 975 Apr 40

A 43-year-old male presented with a cerebral aneurysm manifesting as right facial paresthesia, without neurological deficit. Angiography revealed a large aneurysm (22 mm) of the left internal carotid artery. Intravascular treatment using placement of a detachable coil was attempted, but the coil did not stay in the aneurysmal cavity and the procedure was abandoned. The patient did not tolerate the transient balloon occlusion test of the left internal carotid artery. Therefore, the aneurysm was clipped through an open craniotomy with profound hypothermia (20 degrees C) with cardiac arrest (24 minutes). The aneurysmal dome was collapsed, allowing easy dissection of the posterior communicating artery. The closed chest method was used during the extracorporeal cardiopulmonary bypass. Postoperative angiography revealed complete neck clipping with preservation of carotid blood flow. The patient recovered well and resumed his employment. Circulatory arrest with hypothermia provides several benefits for the surgical treatment of large and giant aneurysms.
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PMID:Circulatory arrest with profound hypothermia during the surgical treatment of large internal carotid artery aneurysm--case report. 991 4


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