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

Traditionally, thoracic aortic rupture, suspected after blunt thoracic trauma, is characterized by a chest radiograph showing a widened mediastinum. The diagnostic machinery consecutively activated still depends heavily on the pressure as additional traumatic lesions. A patient with additional cranio-cerebral trauma would typically undergo contrast-enhanced computed tomography or magnetic resonance imaging of head, chest, and other regions. In a number of patients these analyses would confirm the presence of blood in the mediastinum without formal proof of an aortic disruption. This is because mediastinal hematomas may be caused not only by an aortic rupture, but also by numerous other blood sources including fractures of the spine and other macro- and microvascular lesions providing similar images. Therefore, aortic angiography became our preferred diagnostic tool to identify or rule out acute traumatic lesions of not only the aorta but with great vessels. However recently, a number of traumatic aortic transsections have been identified by transoesophageal echocardiography (TEE). TEE has the additional advantage of being a bed-side procedure providing additional information about cardiac function. The latter analysis allows for identification and quantification of cardiac contusions, post-traumatic myocardial infarctions, and valvar lesions which are of prime importance to develop an adequate surgical strategy and to assess the risk of the numerous emergency procedures required in patients with polytrauma. The standard approach for repair of isthmic aortic rupture is through a lateral thoracotomy. Distal and proximal control of the aorta can be achieved in a substantial number of cases before complete aortic rupture occurs and a higher proportion of direct suture repair can be achieved under such circumstances. Most proximal descending aortic procedures are performed without cardiopulmonary bypass (clamp and go) but paraplegia may occur before, during, or after the procedure. Ascending aortic lesions and disruption of the aortic arch, the supra-aortic vessels, the main pulmonary arteries, the great veins as well as cardiac lesions are best approached through a sternotomy, which may have to be extended. Cardiopulmonary bypass allowing for deep hypothermia and circulatory arrest is often required and carries its own complications. It is not clear whether the increasing proportion of ascending aortic and cardiac lesions which are observed nowadays are due to a change in trauma mechanics (i.e., speed limits, seat belts, air-bags), an improvement of the diagnostic tools or both.
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PMID:Diagnosis and management of blunt great vessel trauma. 927 44

Elective hypothermic cardiopulmonary bypass with or without circulatory arrest has been used successfully for the treatment of complex aneurysms of the descending thoracic and thoracoabdominal aorta. Hypothermia has a protective effect on spinal cord function, and its use has been associated with a low incidence of paraplegia in traditionally high-risk patients. In our series, 96 consecutive patients underwent resection and graft replacement of diseased aortic segments of the distal aortic arch, the descending thoracic aorta, or the thoracoabdominal aorta. Thirty-day mortality was 7.3%, and the incidence of spinal cord ischemic injury was 3.4%. Our experience with hypothermic cardiopulmonary bypass and circulatory arrest confirms the safety and efficacy of the technique for operations on the descending thoracic and thoracoabdominal aorta.
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PMID:Profound hypothermia for spinal cord protection in operations on the descending thoracic and thoracoabdominal aorta. 946 80

Since the publication of prior reviews on this topic, substantial clinical experience with a variety of operative strategies to prevent ischaemic cord complications has been reported. The available data on angiographic localisation of critical intercostal vessels, and, in particular, the evoked potential response to cross-clamping in patients indicates that risk of paraplegia varies considerably even among patients with equivalent TAA extent. Factors such as individual development of the ASA, patent critical intercostals, and the particulars of collateral circulation when intercostal aortic ostia are already occluded likely account for this variability. Information available from SSEP monitoring relative to the dynamic course of cord ischaemia with cross-clamping, and the parallel, if not, frustrating experience with angiographic localisation and intercostal vessel reconstruction indicates that a narrow temporal threshold of cord ischaemia with clamping is present in many patients. This reinforces the importance of both expeditious clamp intervals, critical intercostal re-anastomoses, and the desirability of neuroprotective manoeuvres during cross-clamp induced cord ischemia. As suggested in compelling experimental work our contemporary clinical experience, and predicted by prior reviewers, regional cord hypothermia provides significant promise for limiting or eliminating, in particular, immediate perioperative deficits. Avoidance of postoperative hypotension, spinal cord oedema, and preservation of critical intercostal vessels are additional strategies necessary to impact the development of delayed deficits favourably.
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PMID:Prevention of spinal cord ischaemic complications after thoracoabdominal aortic surgery. 955 Oct 47

Mild hypothermia and the 21-aminosteroids have both been neuroprotective in several models of cerebral ischemia. In this study we compared the effects of mild hypothermia and the 21-aminosteroid U-74389G, alone and in combination on neurologic and histopathologic outcome after temporary spinal cord ischemia. Forty male anesthetized New Zealand white rabbits were randomized to four groups (n = 10): (a) normothermia (control); (b) U-74389G (3 mg/kg intravenously [i.v.] before aortic occlusion, 1.5 mg/kg i.v. and 10 mg/kg intraperitoneally after occlusion); (c) mild hypothermia (4 degrees C epidural temperature decrease); and (d) mild hypothermia combined with U-74389G. Spinal cord ischemia was produced by 40 min of infrarenal aortic balloon occlusion. Forty-eight hours after the procedure, the neurologic status of the animals was assessed (Tarlov score) and the animals were killed for histologic evaluation. In the normothermic control group, eight of 10 animals became paraplegic. There was a significant reduction of the incidence of paraplegia and overall neurologic deficits and a significant improved Tarlov score in the mild hypothermic group (one animal paraplegic) and in the group with both mild hypothermia and U-74389G (two animals with a mild paraparesis). The histopathologic scores showed significantly less damage in both hypothermic groups. In group 2, U-74389G administration did not improve neurologic or histopathologic outcomes. The results of the current study demonstrate that a slight decrease of intraischemic spinal cord temperature significantly improved neurologic and histopathologic outcomes after experimental spinal cord ischemia. Protection by the 21-aminosteroid at normothermic conditions, or additional protection when U-74389G was added to mild hypothermia, could not be demonstrated.
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PMID:Effect of mild hypothermia and the 21-aminosteroid U-74389G on neurologic and histopathologic outcome after transient spinal cord ischemia in the rabbit. 955 66

Deep hypothermic cardiocirculatory arrest is the commonest method of brain protection during transverse aortic arch surgery. Its principle drawbacks consist in the limited safe ischemic period and in the coagulative, renal and pulmonary complications related to low body temperatures and prolonged cardiopulmonary bypass time. Different selective cerebral perfusion techniques have recently raised the interest of some surgical teams in an effort to obviate these problems. The authors' initial experiences with 22 patients, ranging in age from 19 to 78 years (mean, 55 +/- 15 years), who underwent ascending aorta and/or aortic arch replacement using selective cerebral perfusion and moderately hypothermic cardiopulmonary bypass are reported here. Acute aortic dissection and atherosclerotic aneurysm were the commonest lesions observed: ascending aorta associated with partial or complete arch replacement was the most widely performed procedure. With regard to the perfusion technique, after regular cardiopulmonary bypass had been established through the iliac vessels, selective cerebral perfusion was started after aortic arch vessels cannulation (innominate artery, bilateral common carotid artery, innominate artery and left common carotid artery, or right common carotid artery) using a single roller pump separately from the systemic circulation, and brain perfusion was achieved by blood cooled at 30 degrees C, at a flow rate that ranged from 300 ml/min to 1500 ml/min, at a perfusion pressure of approximately 65 mmHg, with the patient maintained at moderate hypothermia (30 degrees C rectal). To perform distal aortic repair, if transverse aortic arch or proximal descending aorta cross-clamping was not feasible, cardiopulmonary bypass flow was lowered to 300-350 ml/min and an open anastomosis was performed, while independently assuring cerebral perfusion (six patients). There were three hospital deaths (mortality rate of 13.6%; s.d. 6.0-25.5%; 70% confidence limit), but none because of cerebral accident. No paraplegia occurred. One patient suffered from right hemiparesis, neither renal nor pulmonary complications were observed. Two chest reexplorations were necessary for bleeding, which were partially related to hemocoagulative disorders. In our experience, the technique of moderately hypothermic cardiopulmonary bypass and selective cerebral perfusion in aortic surgery has provided good results with regard to cerebral protection and organ function preservation. Therefore, allowing a prolonged distal aortic reconstruction period, it may be considered as a safe alternative to profound hypothermia associated with cardiocirculatory arrest in aortic arch surgery.
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PMID:Moderately hypothermic cardiopulmonary bypass and selective cerebral perfusion in ascending aorta and aortic arch surgery. Preliminary experience in twenty-two patients. 972 20

From 1994 to 1997, 11 consecutive patients with thoracoabdominal aneurysms underwent surgery using cardiopulmonary bypass under moderate hypothermia (33 degrees C) and selective visceralartery perfusion for spinal cord and visceral organ protection. Distal perfusion pressure was maintained above 60 mmHg (mean) during cardiopulmonary bypass. In the four patients, one or two pairs of large intercostal arteries between Th10 and L2 were reimplanted. In the four patients, visceral and renal arteries were reconstructed. Surgical mortality rate within 1 month was 18.2% (2/11). One patient died of bleeding from old empyema and another of multiple organ failure. No patients had paraplegia. In conclusion, cardiopulmonary bypass with selective visceral artery perfusion under moderate hypothermia may contribute to the prevention of the occurrence of paraplegia and acute renal failure.
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PMID:Results of surgical treatment for thoracoabdominal aneurysm using cardiopulmonary bypass under moderate hypothermia and selective visceral artery perfusion. 1040 Dec 22

In experiments on dogs the authors tried to elaborate methods of protection of the spinal cord from ischaemia during surgery of an aneurysm in the thoracolumbal portion of the aorta. They used the model described in the literature with double ligature of the aorta closely below the insertion of the left-sided subclavian artery and closely above the diaphragm for a period fo 40 minutes. In the control group of 8 dogs they observed severe neurological deficiency manifested by paraplegia in 7 animals. In the second group of 8 dogs the authors used local hypothermia of the spinal cord. Hypothermia was produced by epidural administration of 5 degrees C saline which they started to administer five minutes before clamping and continued throughout the period of ischaemia. The temperature of the spinal cord dropped to 26.8 degrees C. In this group none of the dogs developed neurological damage. The results were evaluated by recording spinal somatosensory potentials, by monitoring the neurological condition according to Tarlov and by histological examination of the spinal cord. In the conclusion they emphasize that this method can protect the spinal cord from 40-minute ischaemia.
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PMID:[Epidural regional hypothermia for prevention of paraplegia in experimental aortic clamping]. 1046 85

A systematic approach to paraplegia risk in the surgical treatment of thoracoabdominal aortic aneurysms based on effective strategies identified from the experimental literature is discussed. With this approach, collateral blood flow, rather than direct intercostal reimplantation, moderate hypothermia and endorphin receptor, is emphasized blockade. The result has been a 10-fold reduction in paraplegia risk in elective patients and a 5-fold reduction in acute patients. This reduction in paralysis risk has resulted in improved short- and long-term survival.
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PMID:Thoracoabdominal aortic aneurysm. How we do it. 1051 66

There remains no consensus on the operative management of Thoracoabdominal aortic aneurysm (TAA). Our approach emphasizes operative expediency and simplicity (without circulatory assist techniques), avoiding anticoagulation and systemic hypothermia. The technique involves a fundamental clamp/sew method with specific adjuncts directed against the principle complications: epidural cooling (introduced in 1993) for spinal cord protection, regional renal hypothermia, and in-line mesenteric shunting to minimize visceral ischemia. In a cohort of over 200 TAA patients (50% Types I & II) treated during the past decade perioperative mortality has been 8% and paraparesis/paraplegia occured in 7%. These figures are halved for patients treated in elective circumstances.
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PMID:Thoracoabdominal aortic aneurysm repair: how I do it. 1051 67

The duration of spinal cord ischemia is probably the most important single factor in the pathogenesis of paraplegia after repair of descending thoracic aortic aneurysms. We describe a modification of open distal anastomosis technique originally presented by Dr. Cooley, in which we use partial cardiopulmonary bypass with femoral cannulation and mild hypothermia. Cardiopulmonary bypass is interrupted after lowering patient's temperature to 32 degrees C and the aorta is clamped using one proximal clamp. During the suturing of the distal anastomosis blood is sucked to reservoire and returned oxygenated to the patient via the venous line using a shunt which is installed between the arterial and venous lines. After completion of the distal anastomosis the graft is clamped and cardiopulmonary bypass reinstituted. Rewarming is started as bleeding intercostal arteries are sutured and proximal anastomosis performed. This modification shortens the distal ischemia time, but supports the circulation of the kidneys and splanchnic area immediately after the distal anastomosis is finished. Lowering the temperature should give additional protection for the spinal cord and the blood can be returned oxygenated to the patient. In our opinion, this combination of femoro-femoral perfusion, mild hypothermia, and open distal anastomosis offers several benefits and can be used in dissections and aneurysms, which extend up to aortic hiatus.
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PMID:Open distal anastomosis in conjunction with partial cardiopulmonary bypass and mild hypothermia for repair of descending thoracic aortic aneurysms. 1066 25


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