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

Thoracoabdominal aortic aneurysm repairs present many challenges, and the complication of paraplegia remains a concern for both the surgeon and the nurse caring for the patient in the postoperative period. Paraplegia can occur secondary to spinal cord ischemia from prolonged aortic clamping during the repair of the descending thoracic aorta. Paraplegia is a devastating complication for the patient and family. Multiple adjunct techniques have been instituted to prevent reduced spinal cord perfusion during and after the operation, including the use of shunts and cardiopulmonary bypass, femoral artery-femoral vein bypass, left atrial-femoral artery bypass, and selective revascularization of the dominant intercostal artery. Other methods, such as somatosensory evoked potential monitoring during the operation and regional spinal hypothermia techniques, have not reduced the incidence of paraplegia. Improved outcomes have been seen with the use of methods to reduce cerebrospinal fluid (CSF) pressure. One such method is the use of external CSF drainage during the operation, followed by use of a lumbar drain system for as long as 72 hours after the operation. This system setup uses a transducer to monitor CSF pressure and a drip chamber to drain CSF to maintain a normal pressure. This article describes thoracoabdominal aneurysms, surgical techniques to repair the aneurysm, and the use of external CSF drainage and related nursing care measures.
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PMID:Use of lumbar cerebrospinal fluid drainage in thoracoabdominal aortic aneurysm repairs. 1081 81

Systemic hypothermia exerts neuroprotective effects following trauma and ischemia caused by vascular occlusion in the brain. In the spinal cord similar effects have been demonstrated following ischemia after aortic occlusion. We have previously presented protective effects on several morphological parameters in the early period after the injury, using an established spinal cord compression injury model and systemic hypothermia. In the present study we have evaluated the effects on motor function following severe spinal cord compression trauma and treatment with moderate systemic hypothermia. Thirty Sprague Dawley rats were randomized into three groups: In group 1 (n = 4), the animals underwent a hypothermic procedure, including a 2 h hypothermic period with a body temperature of 30 degrees C, following the initial laminectomy. In group 2 (n = 12) a 50 g compression was applied to the spinal cords for 5 min, after which the animals were kept under normothermic anesthesia for 3 h. In group 3 (n = 14), the animals underwent the same trauma procedure as in group 2 and the same hypothermic procedure as in group 1. The animals were allowed to survive for 14 days, during which the motor function was recorded. This degree of trauma results in a non-reversible paraplegia, and the addition of systemic hypothermia as described above did not alter the neurological recovery as measured by two different methods of recording the motor function up to two weeks after injury. All animals survived in group 1. However, the mortality rates in group 2 were 25% and in group 3, 50%, respectively, which mirrors the severity of the trauma. The application of systemic hypothermia and the lack of experimental therapeutic success highlight the difficulties of transferring experimental beneficial neuroprotective effects to a clinically useful treatment method. In this experimental set-up the effects of the severe primary injury may overshadow the effects of the secondary injury mechanisms, which limits the therapeutic possibilities of systemic hypothermic treatment.
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PMID:Motor function changes in the rat following severe spinal cord injury. Does treatment with moderate systemic hypothermia improve functional outcome? 1089 65

Surgical repair of thoracoabdominal (TAA) and thoracic aneurysm is challenging, with the potentials for high morbidity and mortality. There is no standardized operative approach. Operative management of TAA consists of simple clamp-and-sew techniques with adjuncts, cerebrospinal fluid (CSF) drainage, naloxone administration, and intraoperative hypothermia, to protect the spinal cord. The use of CSF drainage and naloxone administration has reduced paraplegia to 3.4%, compared with 21% when none of these adjunctive spinal cord measures were used. The authors discuss their operative strategy, surgical technique, and results at the University of Wisconsin Hospital and Clinics.
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PMID:Clamp and sew techniques in thoracoabdominal aortic surgery using naloxone and CSF drainage. 1115 61

Surgery of the descending and thoracoabdominal aorta has been associated with post-operative paraparesis or paraplegia. Different strategies, which can be operative or non-operative, have been developed to minimise the incidence of neurological complications after aortic surgery. This review serves to summarise the current practice of spinal cord protection during surgery of the descending thoracoabdominal aortic surgery. The pathophysiology of spinal cord ischaemia will also be explained. The incidence of spinal cord ischaemia and subsequent neurological complications was associated with (1) the duration and severity of ischaemia, (2) failure to establish spinal cord supply and (3) reperfusion injury. The blood supply of the spinal cord has been extensively studied and the significance of the artery of Adamkiewicz (ASA) being recognised. This helps us to understand the pathophysiology of spinal cord ischaemia during descending and thoracoabdominal aortic operation. Techniques of monitoring of spinal cord function using evoked potential have been developed. Preoperative identification of ASA facilitates the identification of critical intercostal vessels for reimplantation, resulting in re-establishment of spinal cord blood flow. Different surgical techniques have been developed to reduce the duration of ischaemia and this includes the latest transluminal techniques. Severity of ischaemia can be minimised by the use of CSF drainage, hypothermia, partial bypass and the use of adjunctive pharmacological therapy. Reperfusion injury can be reduced with the use of anti-oxidant therapy. The aetiology of neurological complications after descending and thoracoabdominal aortic surgery has been well described and attempts have been made to minimise this incidence based on our knowledge of the pathophysiology of spinal cord ischaemia. However, our understanding of the development and prevention of these complications require further investigation in the clinical setting before surgery on descending and thoracoabdominal aorta to be performed with negligible occurrence of these disabling neurological problems.
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PMID:Prevention of spinal cord ischaemia during descending thoracic and thoracoabdominal aortic surgery. 1116 13

This study was undertaken to evaluate the role of cerebrospinal fluid (CSF) drainage and left atrial to femoral artery (LAFA) bypass in preventing postoperative neurologic complications for patients who had undergone descending and thoracoabdominal aortic aneurysm (TAAA) repair. LAFA bypass and CSF drainage were used as adjuncts in the treatment of 8 patients with descending and 13 patients with TAAAs (December 1999 to March 2000). LAFA bypass was established with the use of a centrifugal Biomedicus pump. Distal flows were maintained between 1.5 and 2.5 L/min during the procedures. Mean LAFA bypass time was 40 (range, 21 to 60 min). The CSF pressure was kept below 10-12 mmHg during the operations and for the first 72 hr postoperatively. All patients received heparin (1 mg/kg), which was reversed at the completion of the procedure. Passive hypothermia (rectal temperature: 32 degrees-34 degrees C) was used in all cases. All patent T8-L1 intercostal arteries were reattached to the graft. There were 13 men and 8 women. The median age was 56 years (range, 49 to 78). Chronic aortic dissection was the cause of the aneurysm in 9 patients (43%), trauma in 1 patient (5%), and medial degeneration in 11 patients (52%). There were four type I (19%), four type II (19%), and five type III (24%) TAAA. In eight patients (38%) the entire descending thoracic aorta was aneurysmal. Our results showed that the use of CSF drainage and LAFA bypass prevents paraplegia/paraparesis after repair of thoracoabdominal and descending thoracic aneurysms.
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PMID:Left atrial femoral bypass and cerebrospinal fluid drainage decreases neurologic complications in repair of descending and thoracoabdominal aortic aneurysms. 1122 44

The most feared complication of thoracoabdominal clamping is the paraplegia or paraparesis following ischemic injury of the spinal cord. Early intraoperative recognition of this complication has not been solved yet. In our earlier experiment we found significant alterations of CSF glucose, lactate, pCO2 and Neuron Specific Enolase (NSE) levels during 60 minutes thoracoabdominal aortic clamping in dogs. The analysis of these parameters proved to be proper to follow metabolism of the spinal cord during this type of surgery. In our present paper we studied protective effect of regional hypothermia using peridural cooling by registration of above parameters. Statistical analysis of our data showed prevention of production of anaerobe metabolites in animals with icy peridural irrigation. The biochemical approach is appropriate for monitoring effectiveness of regional hypothermia of the spinal cord during aortic surgery.
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PMID:[Effect of regional hypothermia on cerebrospinal fluid parameters during thoracoabdominal aorta clamping in dogs]. 1129 26

Selective cerebral perfusion (SCP) and open distal anastomosis (OD) with hypothermia has been used as a popular means for circulatory assistance in aortic arch surgery. Although SCP has become accepted for brain protection, the influence of OD accompanying circulatory arrest on lower body ischemia is not known. We studied gastric tonometry (gastric intramucosal pH [pHi]) to estimate splanchnic ischemia during OD, and its relationship to postoperative organ function. In five patients (pts) (range, 65-78 years; mean, 71 years; group OD) who underwent arch replacement using SCP and OD with moderate hypothermia (25 degrees C) during the period from March to August of 1999, pHi was measured precardiopulmonary bypass (pre-CPB), 30 min of CPB (CPB30), 10 min after OD (OD10), at end of CPB, and post-CPB. Eight pts (range, 52-78 years; mean; 66 years) who underwent standard CPB (33 degrees C) during the same period (coronary artery bypass surgery in six and valve surgery in two) served as controls (group C). In group OD, pHi was significantly decreased at OD10 (7.35 +/- 0.03 at CPB30 vs. 7.23 +/- 0.07 at OD10, p < 0.05) but recovered by the end of CPB (7.32 +/- 0.02). Creatinine clearance on the first postoperative day (1POD) was significantly (p < 0.05) lower in group OD (82 +/- 40 ml/min) than in group C (126 +/- 25 ml/min), although there was no significant difference in preoperative values between the two groups. The pHi at OD10 did not correlate with the duration of OD (range, 30-47 min; mean, 38 min), whereas pHi at OD10 significantly correlated with BUN (r = -0.973, p = 0.0054), Cr(r = -0.977, p = 0.0043), and CCr (r = 0.908, p = 0.0328) on 1POD. One patient in group OD developed paraplegia and renal failure postoperatively. His pHi at OD10 was severely decreased to 7.11. These results suggest that intraoperative monitoring of pHi may be useful for the evaluation of visceral organ ischemia during OD in arch replacement and may contribute to improved technique for circulatory assistance in aortic surgery.
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PMID:Gastric intramucosal pH during lower body circulatory arrest under open distal anastomosis with selective cerebral perfusion in aortic arch repair. 1157 35

Thoracoabdominal aneurysm surgery is associated with a high incidence of morbidity and mortality. Spinal cord ischemia and the risks of paraparesis or paraplegia remain devastating complications. The mechanisms of spinal cord injury involve both acute ischemic injury and delayed reperfusion injury. Blood flow to the spinal cord frequently arises in the segment of the aorta requiring aortic cross clamping. As such, there is an obligate period of blood flow disruption. Multiple strategies have evolved to reduce the ischemic interval and to provide adjunct interventions to reduce the impact of the ischemia. Despite a multidisciplinary approach, a spinal cord ischemia is present in approximately 4 to 16% of patients, depending on the type of aneurysm and other comorbid diseases. Cerebral spinal fluid drainage, distal perfusion techniques, intercostal artery anastomosis, hypothermia techniques, and mechanisms of ischemic preconditioning are interventions employed to reduce the risk of paraplegia after thoracal-abdominal aortic surgery. Surgeons, anesthesiologists, and perfusionist are intimately involved in the decision making as to which interventions will be employed in a given case. Although these adjuncts have been evaluated in multiple animal and human protocols, the efficacy of each intervention when looked at in isolation remains difficult to determine fully. This is attributable, in part, to the complex mechanisms of the patient injury, the inherint risks of the surgical procedure, and the confounding effects of comorbid disease states. Nonetheless, clinicians must have comprehensive understanding of these various interventions and their application. This review serves as an overview of these various interventions with special emphasis on outcome data.
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PMID:Thoracoabdominal aneurysm surgery and the risk of paraplegia: contemporary practice and future directions. 1191 23

Paraplegia is a devastating complication of operations requiring transient occlusion of the descending thoracic aorta. Many animal models of spinal cord ischemia have been utilized to examine the efficacy of various neuroprotective methods. In this study, we establish a rabbit model of spinal cord ischemia by selective temporary occlusion of lumbar arteries and examine the protective effects of systemic mild hypothermia in this model. Animals were divided into the following four groups: sham group (group A, n = 6); 10 min ischemia, normothermia (39 degrees C) (group B, n = 6); 20 min ischemia, normothermia (group C, n = 6); and 30 min ischemia, mild hypothermia (35 degrees C) (group D, n = 6). After 7 d of reperfusion, three rabbits in group B and five rabbits in group C developed paraplegia (Tarlov's score = 0). In contrast, all rabbits preserved hindlimb motor function (Tarlov's score = 4) in groups A and D. Histological findings indicated that the number of motor neurons in the anterior horns in group C were significantly fewer than in group A. A large number of motor neurons were preserved in group D. Hypothermia is known to be an effective and reliable method of neuroprotection, but the risk of complications rises at deep hypothermia. Our current results confirm that systemic, mild hypothermia is a safe and effective neuroprotective method during ischemia-reperfusion injury of the spinal cord.
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PMID:Selective occlusion of lumbar arteries as a spinal cord ischemia model in rabbits. 1268 53

Recent experiences from several centers indicate that the overall risk of spinal cord ischemia during thoracoabdominal aortic aneurysm repair has decreased to 5-8%. The results from these centers are rather consistent, despite the use of a variety of spinal protection strategies. An alternative to the various distal aortic perfusion techniques is selective spinal cooling by cold saline lavage. The principle advantage of selective hypothermia is the avoidance systemic heparinization and extracorporeal by-passes, while affording comparable spinal protection. The primary method of spinal cooling was pioneered by Cambria et al. at Massachusetts General Hospital. In their experience, paraplegia or paresis occurred in 6.9% of patients (5-year period, 170 cases). An alternative to the Cambria method utilizes readily available perfusion supplies and offers the potential advantages of lower cerebral spinal fluid-systemic blood pressure differences, more expedient cooling, and deeper spinal hypothermia. This report describes this method and the clinical course of a patient treated with it.
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PMID:Selective deep spinal hypothermia with vacuum-assisted cerebral spinal fluid drainage for thoracoabdominal aortic surgery. 1293 25


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