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

Infrarenal circumaortic occlusion devices were operatively placed in 74 New Zealand white rabbits. Two days after operation the animals were randomly assigned to one of seven treatment groups: I, control, n = 23; II, halothane, n = 8; III, thiopental, n = 12; IV, ketamine (30 mg/kg intravenously), n = 6; V, halothane+hypothermia, n = 8; VI, thiopental+hypothermia, n = 12; VII, ketamine+hypothermia, n = 5. In each group, the infrarenal aorta was occluded for 21 minutes. Final neurologic recovery after restitution of blood flow was graded as acute paraplegia, delayed paraplegia (neurologic deficit developing after initial recovery), or normal. Halothane alone was of no benefit. Hypothermia with any anesthetic was completely protective and reduced neurologic deficits to 0% compared with 91% in controls (p less than 0.05). Thiopental and ketamine treatment each reduced acute paraplegia to 17% (as compared with 61% in controls) and increased delayed paraplegia from 30% in controls to 75% and 50%, respectively (p less than 0.05 for thiopental, p = 0.10 for ketamine). The authors interpret the increase in delayed deficits and decrease in acute deficits as being the result of partial spinal cord protection. These findings document that this model of spinal cord ischemia is sufficiently sensitive to identify interventional treatments that protect the ischemic spinal cord.
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PMID:Protecting the ischemic spinal cord during aortic clamping. The influence of anesthetics and hypothermia. 161 78

Experimental studies on spinal cord (SC) injuries published from 1975 to 1989 in some of the most widely circulating neurosurgical journals were reviewed. The relatively large number of animal species utilized as well as the intensely variable dynamic or static methods employed to induce SC injury represent elements of confusion more than objective necessities in this field of research. In fact, the objective of SC injury research should be to solve the problem of severe SC injuries by either preventing and/or repairing SC damage, rather than looking for modalities to provoke a large spectrum of SC injuries with the result of establishing a correlation between for example, the clinical picture and trauma magnitude. It should be time to study all variables and treatments mainly in only one experimental model. The rat with a permanent paraplegia should represent such a model; the abdominal aorta occlusion for 45 minutes, distal to the renal arteries in rabbits should be the experimental model of choice for ischaemia. If a significant result, such as reversing permanent paraplegia, were obtained in rats, it would be logical to repeat the study in higher mammals and if successful, in humans. For the last decade of this century it is necessary to further study all the mechanisms implied in secondary SC damage as well as to attempt to repair definitive SC damage by using grafts and enhancing the potential regenerative ability of the SC with known and new growth factors. Presently, methylprednisolone, dexametasone, thiopental, naloxone, and hypothermia seem to have some clinical potentials that require studies in humans.
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PMID:Experimental studies on spinal cord injuries in the last fifteen years. 168 22

We tested, in the dog, the hypothesis that selective deep hypothermia (19 degrees to 12 degrees C) of the spinal cord protects it from the ischemia that follows double aortic cross-clamping. The extracorporal perfusion system consisted of heat exchanger and a pump, infusing saline solution at 5 degrees C into the subarachnoid space (L-6) and draining it through the cisterna magna. After 30 minutes this system cools a normally perfused spinal cord to a stable temperature gradient of 13 degrees C (inflow) to 18 degrees C (outflow). Proximal and distal intrathecal, proximal and distal aortic, and central venous pressures were continuously recorded. Rectal temperature was maintained between 36.5 degrees C and 38.5 degrees C. Eight control dogs had cross-clamping of the aorta below the left subclavian artery and above the diaphragm without cord hypothermia. Nine experimental dogs had cord hypothermia initiated 50 minutes before systemic heparinization (100 U/kg) and double cross-clamping of the aorta. Cross-clamping was maintained for 45 minutes. The aorta was then unclamped, heparin was reversed, cord cooling was discontinued, and the dura was closed. Hindlimb function of animals was graded by use of Tarlov's scale at recovery and 24 hours later. The dogs were then killed, and the cords were removed and fixed for microscopy. All control animals were paraplegic and had histologic confirmation of spinal cord infarction. All experimental animals had intact hindlimb function and normal appearing cords on histologic examination. A two-tailed Fisher's exact test (chi square) shows this difference to be significant to p = 0.00004. In the dog selective deep hypothermia of the cord avoids the ischemic injury induced by aortic cross-clamping that results in paraplegia. The implications of these findings in thoracoabdominal aortic clamping in humans is discussed.
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PMID:Selective deep hypothermia of the spinal cord prevents paraplegia after aortic cross-clamping in the dog model. 172 92

The diagnosis and surgical treatment of aneurysms of the descending thoracic aorta is difficult and some aspects of management remain controversial. We report 53 patients treated in the period 1983-1988; 25.9% of them had previously been erroneously diagnosed as having mediastinal cysts or tumours. Duplex scanning and computerised tomography were valuable adjuncts in establishing the correct diagnosis, which was confirmed by aortography in 52 patients. Of 49 patients operated upon electively three died with a mortality rate of 6.1%; of the 4 patients operated upon as emergencies 2 died. Fifty patients survived the operative procedure and of the 3 operated upon under normothermia 1 developed paraplegia, whereas of the 47 patients operated upon under moderate hypothermia (30 degrees-31 degrees C) only 1 developed paraplegia.
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PMID:General moderate hypothermia in the surgical treatment of descending thoracic aortic aneurysms. 186 69

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

The combination of deep hypothermia and circulatory arrest has been used in a variety of cardiovascular surgical techniques and is presented in this article as an elective method in the treatment of type B dissecting aneurysms that may or may not involve the distal aortic arch. Out of 190 patients operated on with acute aortic dissection, 10 patients with type B underwent surgical procedures, between January 1985 and December 1987, four with acute dissection (less than 14 days evolution), and six with chronic dissection (more than 14 days evolution). The approach was by left posterolateral thoracotomy with cardiopulmonary bypass using femoro-femoral cannulation, deep hypothermia, and circulatory arrest. The duration of circulatory arrest was between 27 and 58 minutes, mean 37 minutes. Extracorporeal circulation (ECC) lasted between 68 and 142 minutes, with a mean perfusion time of 83.7 minutes, and temperature fell to 14 degrees C and 16 degrees C. Intrahospital mortality was 20% (two patients). No long-term mortality has been recorded. Eighty percent of the patients (eight patients) are alive and showed good evolution between 10 and 44 months following surgery, with a long-term mean survival of 24 months and 23 days. The only neurological complication was a single case of right unilateral blindness followed by complete visual recuperation. Myocardial and spinal cord protection are excellent, without any incidence of postoperative infarct or paraplegia. Postsurgical blood loss ranged from 200 to 650 mL with a mean of 385 mL. Acute renal insufficiency was not detected. We believe that the combined techniques of deep hypothermia and circulatory arrest used electively, and not just out of occasional necessity, is a viable choice that allows easier surgical manipulation of type B dissection aneurysms and complete resolution of those involving retrograde dissection to the aortic arch. In addition. this combined technique does not increase postoperative mortality in this critically dangerous disease.
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PMID:Deep hypothermia and circulatory arrest as an elective technique in the treatment of type B dissecting aneurysm of the aorta. 253 79

The authors report two cases of hypothermia due to a treatment associating Bethanechol and Adreno-Blockers. They emphasize the mechanisms of thermoregulation and discuss the pathophysiology of such hypothermia incidents. The most evident explanation is heat loss, principally mediated through Bethanechol, whereas mechanisms of heat preservation are prevented by Adreno-Blockers. Patients susceptible to this risk must be carefully monitored.
Paraplegia 1989 Feb
PMID:Effects of bethanechol and adreno-blockers on thermoregulation in spinal cord injury. 256 76

An examination of 15 patients with postoperative aneurysms of the thoracic aorta was performed. The aneurysms were formed approximately within 15.6 years after operations on the thoracic aorta: for coarctation of the aorta--9 patients, aorta aneurysms--3 patients, open arterial ducts--1 patients, stenosing aortitis--2 patients. Operations were made on 13 patients, 2 patients were not operated upon. In 12 patients moderate hypothermia was used, one patient was operated under conditions of normothermia. The average time of the aorta compression was 42.7 min. Prostheses were used in 9 patients, lateral plasty with a synthetic flap--in 3 patients. Direct anastomosis of the aorta ends after aneurysm resection was used in 1 patient. There were no cases of paraplegia or lethal outcomes. Good results were obtained in all the patients.
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PMID:[Postoperative aneurysms of the thoracic aorta]. 272 4

Thoracoabdominal aortic aneurysms can be repaired successfully with acceptable rates of morbidity and mortality. Twenty-three men and seven women (an average age of 67 years) underwent 23 elective and seven emergency operations. Pulmonary complications were the most common, but renal insufficiency and paraplegia were the most serious postoperative problems. The average time of suprarenal aortic occlusion was 47 minutes, but neither renal insufficiency nor paraplegia was directly related to suprarenal clamp time. Four deaths occurred after elective procedures, two from postoperative bleeding (one death from a technical error) and two deaths from multisystem organ failure. Four late deaths were caused by myocardial infarction. The remaining patients are alive at two to 79 months after infarction. DeBakey's technique (multiple sidearm grafts from the main aortic graft) was used in the first three procedures, and the graft inclusion technique of Crawford, in the remainder. The graft inclusion technique reduced operating time and loss of blood by 50 per cent and intraoperative fluid requirements by 33 per cent. Hypothermia was minimized by extraperitoneal, rather than intraperitoneal, abdominal aortic exposure, heated ventilation and warmed intravenous fluids. Selective renal cooling was performed by catheter perfusion of the renal arteries. Extreme care must be taken in making openings and attaching grafts to visceral arteries to avoid troublesome hemorrhage. In contrast with patients with infrarenal aneurysms, those with thoracoabdominal aneurysms require prolonged ventilatory support and have considerably higher fluid requirements. Precise surgical technique is mandatory.
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PMID:Clinical observations and lessons learned in the treatment of patients with thoracoabdominal aortic aneurysms. 296 43

Among 70 patients operated upon for acute dissection of the ascending aorta between 1977 and 1984, 14 (age range 40-72 years) benefited from emergency aortic arch repair motivated by the presence in, or extension to, this segment of the portal of entry, or by lesions of the supra-aortic main vessels. The operation was performed under cardiopulmonary bypass in all cases. Cerebral protection was ensured in 9 patients by deep hypothermia alone or with circulatory arrest for a mean period of 5 minutes (7 cases), and in 5 patients by continuous brain perfusion (carotid blood flow 4 ml/kg/min; perfusion pressure 70 mmHg). Repair consisted of ascending aorta replacement combined with gluing of the arch whenever possible, or bevelled resection in the concavity of the arch, or complete aortic arch replacement with reimplantation of the cervico-cerebral vessels when necessary. In every case the gelatin-resorcin-formalin glue was used to reinforce the aortic wall or the areas with sutures. Operative mortality was nil. Hospital mortality was 28.5%. In patients operated upon under deep hypothermia alone or associated with circulatory arrest the main complications were neurological (4 cases) and respiratory (3 cases) disorders; these were responsible for the death of 3 patients. A fourth patient died of mediastinitis. No neurological or respiratory complication occurred in patients who had brain perfusion. The mean follow-up period was 37 months (range 7-84 months). Late mortality was nil. All but one patient (sequelae of paraplegia) are in excellent clinical condition. Post-operative angiography alone or combined with computerized tomography showed satisfactory blood distribution in all cases and no aneurysm formation on the dissected aorta despite a persistent false lumen.
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PMID:[Emergency surgical repair of acute aortic arch dissection. Apropos of 14 cases]. 310 1


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