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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Spinal cord ischemia and resultant paraplegia are devastating sequelae in up to 40% of patients undergoing repair of thoracoabdominal aneurysms. We investigated the effect of intrathecal tetracaine on the neurological sequelae of spinal cord ischemia and reperfusion with aortic occlusion. Cocaine-derived anesthetics (lidocaine and its analogues) have been shown to decrease neuronal cell metabolism and also have specific neuronal membrane stabilizing effects. New Zealand white rabbits were anesthetized and spinal cord ischemia was then induced by infrarenal aortic occlusion. Animals were divided into six treatment groups. Tetracaine (groups 2 and 4) or normal saline solution (group 5) was administered intrathecally before aortic cross-clamping. Groups 1 and 3 functioned as controls. Group 6 animals received intravenous thiopental. Rabbits were classified as either neurologically normal or injured (paralyzed or paretic). Among controls, 25 minutes of aortic occlusion produced varied neurological sequelae (group 1, 3/6 injured, 50%) whereas 30 minutes resulted in more consistent injury (group 3, 5/6 injured, 83%). All rabbits that received intrathecal saline solution were paralyzed (group 5, 4/4 injured, 100%). Animals treated with intrathecal tetracaine and aortic occlusion of 30 minutes (group 4) showed significantly better preservation of neurological function (6/7 normal, 86%) than controls and saline-treated animals (groups 3 and 5). All animals treated with intrathecal tetracaine and aortic occlusion for 25 minutes (group 2) showed no signs of injury (5/5 normal, 100%), but this was not significant versus controls (group 1). Intravenous thiopental (group 6, 5/5 injured, 100%) had no beneficial effect. Intrathecal tetracaine significantly and dramatically abrogated the neurological injury secondary to spinal cord ischemia and reperfusion after aortic occlusion at 30 minutes in the rabbit model.
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PMID:Spinal cord protection during aortic occlusion: efficacy of intrathecal tetracaine. 203 27

Paraplegia is a fearful and not uncommon complication of aortic clamping in surgical procedures involving thoracic and abdominal aorta. We report a case of transient spinal cord ischemia during the early postoperative period of aortobifemoral bypass in a 69-year-old male with arteriosclerosis obliterans, hypertension, type II diabetes mellitus and COLD. The anesthetic procedure was combined (peridural + intubation and mechanical ventilation + isofluorane). Two hypotensive episodes of about 80 mmHg developed, one after induction and another in the Reanimation area. The first one had a short duration, whereas the second one required the administration of colloids, crystalloids and blood. The infrarenal aortic clamping time was 35 minutes. In the early postoperative period the patient had clinical features consistent with spinal ischemia, which progressively recovered. To prevent spinal ischemia during surgery a shorter duration than 30 minutes of aortic clamping, a higher distal perfusion pressures higher than 60 mmHg during clamping, and the attempt to exclude the least possible number of intercostal and/or lumbar vessels are recommended. Drugs (corticosteroids, naloxone) and hypothermia can be useful.
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PMID:[Spinal cord ischemia in the postoperative period of aortic surgery]. 207 98

Therapeutic efficacy of calcium channel blockers in stroke remains controversial, but previously used agents bind almost exclusively to L-type calcium channels. The newly-discovered N-type calcium channel is specific to neurons, and therapy involving blockade of this site has not been previously attempted. We assessed the neuroprotective effect of omega-conotoxin GVIA (CgTx), a blocker of N-type calcium channels, using both in vitro hypoxic injury to rat cortical neurons and an in vivo model of reversible spinal cord ischemia in the rabbit. In cell cultures, CgTx inhibited hypoxia-induced 45Ca accumulation and neuronal injury minimally, compared to the NMDA antagonist ketamine. In vivo, the duration of spinal cord ischemia which produced permanent paraplegia in 50% of control animals (ET50) was 24.0 +/- 2.6 min. Animals treated 2 h prior to ischemia with 0.5 nmol CgTx in the subarachnoid space had an ET50 of 26.9 +/- 1.8 min (P = 0.36). Animals treated 24 h prior to ischemia (all had persistent systemic tremor) had a ET50 of 28.9 +/- 1.8 min (P = 0.13). We conclude that pharmacologic modulation of the N-type calcium channel does not provide a significant protective effect against neuronal hypoxic-ischemic injury.
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PMID:Treatment with conotoxin, an 'N-type' calcium channel blocker, in neuronal hypoxic-ischemic injury. 208 77

The authors report 21 cases of heparin-induced thrombocytopenia with ischemic vascular complications. The clinical presentations were peripheral arterial ischemia (16 cases), hemiplegia (1 case) and deep vein thrombosis (4 cases). The vascular surgeon confronted by these complications in an emergency situation should recognise the difficulties of clinical diagnosis (atypical forms) and biological investigations (problems of tests of platelet aggregation). Arterial occlusions are usually accessible to disobliteration with a Fogarty catheter without peroperative heparinisation. Delayed diagnosis explains the seriousness of these complications; in our series of 21 patients, there were 2 deaths, 1 paraplegia, 4 amputations due to arterial problems, 4 severe post-deep vein thrombosis conditions, two of which followed trans-metatarsal amputation. The diagnosis of heparin-induced thrombocytopenia implies immediate withdrawal of heparin therapy. A relay with a low molecular weight heparin is not without risk and should only be undertaken after a negative platelet aggregation test (with the low molecular weight heparin). These tests are rarely practicable in emergency situations and a relay using oral anti-vitamin K antagonists with a rapid onset of action is probably the safest option.
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PMID:[Ischemic vascular complications following thrombopenia induced by heparin. Diagnostic and therapeutic problems]. 212 62

Paraplegia is a devastating complication of surgery on the descending thoracic aorta. During surgical repair, the aorta is cross-clamped, and nitroprusside is often used to treat arterial hypertension that can occur above the cross-clamp. Twenty-one dogs were studied to determine the effects of nitroprusside on intraspinal pressures, mean aortic pressures below the cross-clamp, and spinal cord perfusion pressure. Perfusion pressure in spinal radicular arteries originating below the aortic cross-clamp was estimated as the distal aortic pressure minus intraspinal pressure. Nitroprusside was used to return the mean arterial pressure above the cross-clamp to values similar to the pre-cross-clamp levels in 7 dogs. Fourteen animals did not receive sodium nitroprusside. Aortic cross-clamping resulted in small but significant increases in intraspinal pressure (4.3 +/- 0.8 to 7.5 +/- 0.9 mm Hg in non-nitroprusside-treated dogs, and 3.4 +/- 1.0 to 5.6 +/- 1.5 mm Hg in the nitroprusside group before nitroprusside). Nitroprusside caused a further increase in intraspinal pressure (5.6 +/- 1.5 to 8.3 +/- 2.2 mm Hg) and a decrease in aortic pressure below the cross-clamp (26 +/- 5 to 18 +/- 4 mm Hg). The increase in intraspinal pressure and the decrease in aortic pressure below the cross-clamp after nitroprusside resulted in a decrease in spinal cord perfusion pressure from 19 +/- 5 mm Hg to 11 +/- 4 mm Hg. Because nitroprusside decreases spinal cord perfusion pressure and may increase the risk of spinal cord ischemia, the avoidance of large doses of nitroprusside to arbitrarily return mean arterial pressure above the cross-clamp to pre-cross-clamp levels is recommended.
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PMID:Sodium nitroprusside decreases spinal cord perfusion pressure during descending thoracic aortic cross-clamping in the dog. 213 65

Excitotoxin-induced neural tissue damage is mediated through specific receptors. We studied the in vivo effect of two selective N-methyl-D-aspartate receptor antagonists on the compressed spinal cord segments of rats harboring a thoracolumbar epidural tumor. The effect of a single intramuscular treatment with either MK-801 (3 mg/kg) or ketamine (110 mg/kg) given at the onset of paraplegia was evaluated 30 hours later. In saline-treated control animals, significant increases in water content, prostaglandin E2, and 6-keto-prostaglandin F1 alpha were evident. Treatment with either agent resulted in a normal water content in the compressed segments but had no effect on prostaglandin synthesis. Evaluation of the effect of treatment on the course of the disease required dose reduction by 45% for ketamine and by 30% for MK-801, to avoid the excessive sedative effect. Treatment was started at the first appearance of neurological dysfunction (Grade 1) and continued to paraplegia (Grade 5). The mean time interval between Grades 1 and 5 was 2.1 +/- 0.3 days in saline-treated control animals, and it was not significantly altered by either ketamine or MK-801. Our study indicates that in the end stage of epidural compression, when ischemia is present, excitotoxins probably participate in the evolution of a cytotoxic edema. It is suggested that treatment initiated at the onset of paraplegia may still reduce the cytotoxic edema, but its potential clinical value requires further investigations.
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PMID:Experimental neoplastic spinal cord compression: effect of ketamine and MK-801 on edema and prostaglandins. 216 98

A 67-year-old man underwent graft replacement for the descending thoracic aortic aneurysm with the aid of temporary external bypass. Intraoperative evoked spinal potentials (ESPs) were monitored to detect the spinal cord ischemia. Incomplete paraplegia with sensory dissociation was developed in this patient after surgery, despite well maintained ESPs throughout the aortic cross-clamping. ESPs have been widely used as a mean of detecting early impairment of spinal neural conduction during aortic surgery. However, ESPs are principally mediated through posterior and lateral column pathways and they are not always a reliable monitor to predict paraplegia in aortic surgery.
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PMID:[A case report of descending thoracic aortic aneurysm associated with anterior spinal artery syndrome despite no marked ESP changes]. 221 47

Of 27 patients admitted to our level I trauma center with acute disruption of the thoracic aorta, two patients died of exsanguination before aortic repair. One patient had massive leakage from the aneurysm after aortography and died during surgery. All patients suffered from multiple injuries. Eighty-three percent of the patients had major operations in addition to the aortic repair. "Clamp and sew" technique was used in 18 patients (75%), two of whom had multiple tears of the aortic arch. Heparin-coated shunts were used in five patients (20.8%), and a cardiopulmonary bypass was performed in one patient who had multiple tears. Three postoperative deaths were related to polytrauma, cardiogenic shock, and sepsis. Paraplegia developed in three patients, two of whom had multiple aortic lesions necessitating longer ischemia time during the repair. Only one patient had complete neurologic deficit at the 1-year follow-up. In our series, neither surgical procedure proved superior. We conclude that the "clamp and sew" technique for repair of the disrupted thoracic aorta may allow for a more favorable outcome.
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PMID:Traumatic disruptions of the thoracic aorta: treatment and outcome. 223 67

Three unusual cases are reported in which communicating syringomyelia presented acutely. The first patient presented with paraplegia, the second with acute respiratory distress secondary to bilateral vocal cord paralysis, and the third with symptoms of acute brain-stem ischemia. Each patient had a communicating spinal cord syrinx associated with a posterior fossa and foramen magnum region anomaly (a huge posterior fossa arachnoid cyst in one and Chiari malformations in two). The mechanisms of craniospinal pressure dissociation and hindbrain herniation are discussed, along with other reported emergency presentations of syringomyelia.
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PMID:Acute presentations of syringomyelia. Report of three cases. 229 73

The effectiveness of Fluosol-DA (Green Cross Corporation, Osaka, Japan) on circulatory dynamics and neurologic outcome in dogs with ischemic spinal cord injury produced by aortic crossclamping was tested. The control group (receiving saline solution) had an elevated mean aortic proximal pressure (112.9 +/- 30.2 mm Hg versus 175.3 +/- 20.5 mm Hg, p greater than 0.05) and a drastic drop in mean distal aortic pressure (112.9 +/- 30.2 mm Hg versus 29.8 +/- 11.2 mm Hg, p less than 0.05). Although the same trend occurred in dogs treated prophylactically with Fluosol-DA, these changes were not statistically significant. However, there was a significant difference in mean distal aortic pressure during the ischemic phase between the two groups (58.9 +/- 16.0 mm Hg versus 29.8 +/- 11.2 mm Hg, p less than 0.05). Postoperatively all animals had mean arterial pressures within the normal range. All dogs in the control group were paraplegic (partial or complete); the treatment group had one dog with partial paraplegia. The difference between the mean neurologic scores of the two groups was of high statistical significance (3.7 +/- 0.5 versus 1.6 +/- 1.0, p less than 0.05). Our preliminary results show that prophylactic use of Fluosol-DA has favorable effects on hemodynamics and neurologic outcome in dogs with spinal cord ischemia produced by aortic crossclamping. The high propensity of the drug to carry oxygen and carbon dioxide and to provide nutritional support to the ischemic area with resultant improvement in local microcirculation and blood rheology are some speculative mechanisms advocated for these changes.
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PMID:Preventive effect of Fluosol-DA for paraplegia encountered after surgical treatment of the thoracic aorta. Preliminary results in a dog model. 231 88


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