thiopental and Reperfusion-Injury

The aim of this study was to determine the relationship between the antioxidant profile of anesthetics and its relation to total antioxidant capacity (TAC) of plasma in children who underwent tourniquet-induced ischemia-reperfusion (IR) injury during extremity operations.. Children were randomized into three groups: general inhalational anesthesia with sevoflurane (group S), total intravenous anesthesia (TIVA) with propofol (group T), and regional anesthesia (group R). Venous blood samples were obtained before peripheral nerve block and induction of general anesthesia (baseline), 1 minute before tourniquet release (BTR), and 5 and 20 minutes after tourniquet release (ATR). Plasma TAC as well as antioxidant potential of propofol, thiopental, and bupivacaine were measured using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay.. Plasma TAC in group T was increased significantly at 20 minutes ATR in comparison with basal and BTR values, and also was significantly higher in comparison with plasma TAC in groups S and R measured at the same time point. The radical scavenging activity of anesthetics in vitro indicated that only propofol possessed a significant antioxidative activity in the reaction with DPPH radical in comparison with thiopental and bupivacaine.. These data confirm that TIVA with propofol attenuates oxidative stress related to tourniquet-induced ischaemia-reperfusion injury in children.

Topics: Adolescent; Anesthesia, Conduction; Anesthesia, Intravenous; Anesthetics, Inhalation; Antioxidants; Biphenyl Compounds; Bupivacaine; Child; Extremities; Female; Free Radical Scavengers; Humans; Male; Methyl Ethers; Oxidative Stress; Picrates; Propofol; Reperfusion Injury; Sevoflurane; Thiopental; Tourniquets

Ischaemia-reperfusion injury resulting from interruption and restoration of blood flow might be related to free radical mediated oxidative stress and inflammation, and subsequently to post-surgery related complications. We studied the impact of renal transplantation on oxidative stress and inflammation by measuring F(2)-isoprostanes and prostaglandin F(2alpha), respectively, during transplantation and post-surgery. Additionally, due to earlier observations, two dissimilar anaesthetic agents (thiopentone and propofol) were compared to determine their antioxidative capacity rather than their anaesthetic properties. Blood samples were collected before, post-intubation, immediately, 30, 60,120, 240 min, and 12 and 24 h after reperfusion. Oxidative stress and inflammatory response were detected by measuring 8-iso-PGF(2alpha) (a major F(2)-isoprostane and a biomarker of oxidative stress) and 15-keto-dihydro-PGF(2alpha) (a major metabolite of PGF(2alpha) and a biomarker of COX-mediated inflammatory response), respectively. Reperfusion of the transplanted graft significantly increased plasma levels of 8-iso-PGF(2alpha). PGF(2alpha) metabolite levels, although elevated, did not reach statistical significance. In addition, significantly lower levels of 8-iso-PGF(2a) were observed in the propofol group compared to the thiopentone group. Together, these findings underline an augmented oxidative stress activity following an inflammatory response after human renal transplantation. Furthermore, propofol a well-known anaesthetic, counteracted oxidative stress by lowering the formation of a major F(2)-isoprostane.

Topics: Aged; Anesthetics, Intravenous; Antioxidants; F2-Isoprostanes; Female; Humans; Inflammation; Kidney Transplantation; Male; Middle Aged; Models, Biological; Molecular Structure; Oxidation-Reduction; Oxidative Stress; Postoperative Complications; Propofol; Prostaglandins F; Reperfusion Injury; Thiopental; Time Factors; Treatment Outcome

A hypoperfusion-reperfusion human model is observed during and soon after laparoscopic surgery. The aim of the study was to research the preventive effects of etomidate, thiopental, and propofol in induction on hypoperfusion- reperfusion phenomenon during laparoscopic cholecystectomy.. Thirty-six consecutive ASA I-II patients were randomized into three groups of 12 patients each. Anaesthesia was induced with etomidate in group 1, thiopental in group 2, and propofol in group 3. Venous blood samples were obtained at different time points for measurement of plasma malondialdehyde (MDA) levels. Arterial blood and gastric juice samples were obtained for the calculation of gastric intramucosal pH (pHi). Also changes in aminotransferases, alkaline phosphatase and total bilirubin levels were assessed.. There was a significant decrease in pHi at 1 min before desufflation (BD) and 20 min after desufflation (AD) compared with before insufflation (BI) in all groups. Plasma level of MDA was significantly increased in group 1 at 1 min BD and 20 min AD compared with before induction of anaesthesia (baseline). Malondialdehyde levels were decreased significantly in group 3 and increased non-significantly in group 2 at the same time points. Also AST and ALT levels were significantly increased in both groups 1 and 2 at 24 h postoperatively.. Propofol with antioxidant activity may offer many advantages by scavenging reactive oxygen species and their metabolites in case of anticipated hypoperfusion-reperfusion phenomenon, such as would occur in laparoscopic surgery.

Topics: Adult; Alanine Transaminase; Alkaline Phosphatase; Analysis of Variance; Anesthetics, Intravenous; Aspartate Aminotransferases; Bilirubin; Cholecystectomy, Laparoscopic; Etomidate; Female; Gastric Mucosa; Humans; Hydrogen-Ion Concentration; Insufflation; Lipid Peroxidation; Male; Malondialdehyde; Middle Aged; Propofol; Reperfusion Injury; Thiopental; Time Factors

The aim of this study was to investigate the neuroprotective effects of propofol, thiopental, etomidate, and midazolam as anesthetic drugs in fetal rat brain in the ischemia-reperfusion (IR) model.. Pregnant rats of day 19 were randomly allocated into eight groups. Fetal brain ischemia was induced by clamping the utero-ovarian artery bilaterally for 30 min and reperfusion was achieved by removing the clamps for 60 min. In the control group, fetal rat brains were obtained immediately after laparotomy. In the sham group, fetal rat brains were obtained 90 min after laparotomy. In the IR group, IR procedure was performed. No treatment was given in the IR group. One milliliter intralipid solution, 40 mg/kg propofol, 3 mg/kg thiopental, 0.1 mg/kg etomidate, and 3 mg/kg midazolam was administered intraperitoneally in the vehicle group, propofol group, thiopental group, etomidate group, and midazolam group, respectively, 20 min before IR procedure. At the end of the reperfusion period, the whole brains of the fetal rats were removed for evaluation of thiobarbituric acid reactive substances and for examination by electron microscopy.. According to lipid peroxidation data, all the anesthetic drugs provide neuroprotection; however, ultrastructural findings and mitochondrial scoring confirms that only propofol and midazolam provides a strong neuroprotective effect.. Propofol and midazolam may be used to protect fetal brain in case of acute fetal distress and hypoxic injury as a first choice anesthetic drug in cesarean delivery.

Topics: Animals; Disease Models, Animal; Embryo, Mammalian; Etomidate; Female; Lipid Peroxidation; Male; Microscopy, Electron, Transmission; Midazolam; Neurons; Neuroprotective Agents; Pregnancy; Propofol; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Statistics, Nonparametric; Thiobarbituric Acid Reactive Substances; Thiopental; Time Factors

The fact that a considerable amount of clinical conditions suffering from ischemia-reperfusion injury (IRI) occur under general anesthesia has triggered researchers to focus on the effects of anesthetic drugs on IRI. Hence, the aim of this study was to compare the use of different anesthetic drugs in a skeletal IRI model. Tourniquet IRI method was performed and two experimental groups were established as sham-control and IRI group. Rats in each group were anesthetized either with thiopental, ketamine, propofol or etomidate. Malondialdehyde, superoxide dismutase, catalase, and glutathione peroxidase were measured in skeletal muscle via a spectrophotometer. Zinc, iron, copper, and selenium were evaluated by atomic absorption spectrophotometer. In rats anesthetized with thiopental (40 mg/kg, i.p.), malondialdehyde values in IRI group were higher and glutathion peroxidase levels were lower compared to sham-control group. However, superoxide dismutase and catalase activities were identical. On the other hand, while the level of zinc in IRI group attenuated, no differences in iron and copper values were determined. Rats anesthetized with ketamine (60 mg/kg), propofol (100 mg/kg), or etomidate (20 mg/kg) did not show increased malondialdehyde levels in comparison with control levels. While the drugs did not cause a distinction in the levels of superoxide dismutase, catalase, glutathion peroxidase, iron, and copper, zinc was in a lower level in IRI group compared to sham-control. In conclusion, ketamine, propofol, and etomidate, with anesthetic doses, denoted efficacious effects on IRI; hence the drugs might be preferred in certain operations with the risk of IRI.

Topics: Anesthetics, Dissociative; Anesthetics, Intravenous; Animals; Disease Models, Animal; Etomidate; Female; Ketamine; Muscle, Skeletal; Propofol; Rats; Rats, Wistar; Reperfusion Injury; Thiopental; Zinc

Ischemia/reperfusion (I/R) occurs in a number of pathological conditions, including myocardial infarction, stroke, aortic surgery, cardiopulmonary bypass surgery, organ transplantation, resuscitation, and critical care. Massive and abrupt release of oxygen-free radicals after reperfusion triggers oxidative damage. Before critical operations or after resuscitation, it would be wise to find a suitable prophylactic treatment to avoid I/R damage. We aimed to determine whether several commonly used intravenous anesthetics protect against renal I/R injury.. Animals were randomly divided into seven groups, each consisting of six animals: sham group, control group, thiopental group, propofol group, intralipid group, etomidate group, and ketamine group. At the end of the 60-min ischemic period, 60 min reperfusion was established and the materials administered 15 min before the reperfusion. At the end of the reperfusion period, the samples of blood and tissue were reaped for biochemical and serological evaluation.. I/R procedure significantly increased malondialdehyde (MDA) levels, decreased catalase (CAT) activities, and superoxide dismutase (SOD) levels. The lowest MDA mean level was in the thiopental group and the highest MDA mean level was in control group. The lowest CAT mean level was in the intralipid group and the highest CAT mean level was in the etomidate group. The lowest SOD mean level was in the control group and the highest SOD mean level was in the propofol group.. Thiopental and propofol, especially thiopental, are more effective to protect renal I/R injury.

Topics: Anesthetics, Dissociative; Anesthetics, Intravenous; Animals; Antioxidants; Catalase; Etomidate; Fat Emulsions, Intravenous; Ketamine; Kidney; Lipid Peroxidation; Malondialdehyde; Propofol; Rats; Rats, Wistar; Reperfusion Injury; Superoxide Dismutase; Thiopental

Testicular torsion is a urological emergency that requires immediate surgical intervention to prevent testicular damage. The aim of the study was to investigate the preventive effects of thiopental and propofol as anesthetics on testicular ischemia-reperfusion injury.. Forty male Wistar Albino rats were randomly assigned to four groups of 10 rats each. During 5 h, anesthesia was induced and maintained with thiopental in groups 1 and 2 and with propofol in groups 3 and 4. Groups 2 and 4 received left testicular ischemia (torsion) during 1 h and reperfusion (detorsion) during 4 h. Groups 1 and 3 (control groups) had no testicular torsion and detorsion. At the end of 5 h, animals were killed and both ipsilateral and contralateral testes were removed for histopathologic examination and measurement of tissue MDA (malondialdehyde) and NO (nitric oxide) levels.. In the contralateral testes of all the groups, MDA and NO measurements were not different from ipsilateral testes of the control groups. Between the groups 1 and 3, there were no differences in MDA and NO levels. Although torsion/detorsion of testes in group 4 caused significantly increased levels of tissue MDA and NO values compared with group 3, ischemia-reperfusion in group 2 caused a further increase in these levels compared with group 4. The ipsilateral testes in the control groups did not show any morphological changes. Testicular torsion/detorsion in rats with thiopental anesthesia (group 2) caused significantly greater histopathologic injury levels than rats with propofol anesthesia (group 4).. Our results suggest that propofol as an anesthetic agent may prevent testicular damage by scavenging reactive oxygen and nitrogen species and inhibiting lipid peroxidation in an animal model of testicular torsion and detorsion.

Topics: Anesthetics, Intravenous; Animals; Male; Malondialdehyde; Nitric Oxide; Propofol; Rats; Rats, Wistar; Reperfusion Injury; Testis; Thiopental

Lidocaine and thiopental improve recovery when administrated during hypoxia and ischemia; however, the effect of pre- or postinsult treatment alone is unknown. We applied either lidocaine or thiopental to hippocampal slice cultures from 20-day-old rats either before or after 10 min of oxygen-glucose deprivation (OGD). Propidium iodide (PI) fluorescence was used as an indicator of neuronal death for 7 days after OGD. OGD-induced neuronal death, in both the Cornus Ammonis 1 (CA1) and the dentate gyrus regions, peaked the first day after ischemia. Preinsult administration of either lidocaine (10, 100 microM) or thiopental (250, 600 microM) significantly reduced the damage measured on the first and second days after OGD; these drugs also significantly decreased the summed daily post-OGD PI fluorescence in both regions. Postinsult administration of lidocaine (10, 100 microM) or thiopental (250, 600 microM) significantly decreased the PI fluorescence on the first day after OGD; postinsult administration of these drugs also attenuated the summed daily post-OGD PI. These data indicate that the administration of lidocaine or thiopental either before or directly after OGD reduced neuronal damage in this in vitro model of cerebral ischemia. Postischemic administration is frequently the first opportunity for treatment.. Lidocaine or thiopental applied either 10 min before or 10 min directly after oxygen-glucose deprivation reduced neuronal cell death in rat hippocampal slice cultures. Postinsult administration is often the first opportunity for treatment after stroke; lidocaine and thiopental reduced damage caused by oxygen-glucose deprivation, an in vitro model of stroke.

Topics: Animals; Cell Death; Cell Hypoxia; Glucose; Hippocampus; Ischemia; Lidocaine; Neuroprotective Agents; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Thiopental

Evidence suggests that early postischemic hyperemia is mediated by both neurological and vascular mechanisms. We hypothesized that if neuronal activity were primarily responsible for reperfusion hyperemia, then electrocerebral silence induced by intracarotid anesthetics (propofol and pentothal) would attenuate the hyperemic response. New Zealand white rabbits were subjected to 10 min of cerebral ischemia using bilateral carotid occlusion and systemic hypotension. Subsequently, carotid occlusion was released, and the mean arterial blood pressure was increased to baseline values. In the control group, intracarotid saline was periodically injected during reperfusion. In the treatment groups, intracarotid propofol or thiopental was administered to maintain electrocerebral silence for 10 min. Physiological data were measured at baseline, during ischemia, and at reperfusion. Satisfactory data were available for 16 of 19 rabbits. Mean arterial blood pressure, end-tidal CO(2), and cerebral blood flows decreased significantly in both groups during carotid occlusion. During early reperfusion, a similar percent increase in cerebral blood flow from baseline values was observed in all 3 groups (192% +/- 76%, 218% +/- 84%, and 185% +/- 101% for saline, propofol, and pentothal, respectively). These results suggest that suppression of neuronal activity during reperfusion does not affect early hyperemia after transient cerebral ischemia.. Intracarotid injection of anesthetic drugs in doses that are sufficient to produce electrocerebral silence do not obtund early cerebral hyperemia after transient cerebral ischemia. This suggests that vascular, not neuronal mechanisms, are primarily responsible for early postischemic cerebral hyperperfusion.

Topics: Anesthetics, Intravenous; Animals; Brain; Carotid Artery, Internal; Cerebrovascular Circulation; Electroencephalography; Hemodynamics; Hyperemia; Ischemic Attack, Transient; Propofol; Rabbits; Reperfusion Injury; Thiopental

To investigate the effects of propofol, midazolam and thiopental sodium on outcomes and amino acid accumulation in focal cerebral ischemia-reperfusion in rats.. Male Sprague Dawley (SD) rats were scheduled to undergo 3-hour middle cerebral artery occlusion by intraluminal suture and 24-hour reperfusion. Neurologic outcomes were scored on a 0-5 grading scale. Infarct volume was shown with triphenyltetrazolium chloride staining and measured by an image analysis system. Concentrations of various amino acids (aspartate, glutamate, glycine, taurine, and gama-aminobutyric acid) were measured after 3 hours of reperfusion using high performance liquid chromatography. Propofol, midazolam and thiopental sodium were given intraperitoneally at the beginning of reperfusion.. Both propofol and midazolam attenuated neurological deficits and reduced infarct and edema volumes. Propofol showed better neurological protection than midazolam while thiopental sodium did not exhibit any protective effect. Both propofol and midazolam decreased excitatory amino acids accumulation, while propofol increased gama-aminobutyric acid accumulation in ischemic areas in reperfusion.. Propofol and midazolam, but not thiopental sodium, may provide protective effects against reperfusion induced injury in rats subjected to focal cerebral ischemia. This neurological protection may be due to the acceleration of excitatory amino acids elimination in reperfusion.

Topics: Adenosine Triphosphate; Animals; Brain; Brain Edema; Brain Ischemia; Excitatory Amino Acids; Male; Midazolam; Myocardial Infarction; Neuroprotective Agents; Propofol; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Thiopental

We are systematically exploring in our exsanguination cardiac arrest (CA) outcome model in dogs suspended animation (SA), i.e. immediate preservation of brain and heart for resuscitative surgery during CA, with delayed resuscitation. We have shown in dogs that inducing moderate cerebral hypothermia with an aortic arch flush of 500 ml normal saline solution of 4 degrees C, at start of CA 20 min no-flow, leads to normal functional outcome. We hypothesized that, using the same model, adding thiopental (or even better thiopental plus phenytoin) to the flush at ambient temperature (24 degrees C), which would be more readily available in the field, will also achieve normal functional outcome. Thirty dogs (20-28 kg) were exsanguinated over 5 min to CA of 20 min no-flow, and resuscitated by closed-chest cardiopulmonary bypass. They received assisted circulation to 2 h, 34 degrees C post-CA to 12 h, controlled ventilation to 20 h, and intensive care to 72 h. At CA 2 min, the dogs received an aortic arch flush of 500 ml saline at 24 degrees C by a balloon-tipped catheter, inserted through the femoral artery (control group 1, n=14). In group 2 (n=9), thiopental (variable total doses of 15-120 mg/kg) was added to the flush and given with reperfusion. In group 3 (n=7), thiopental (15 or 45 mg/kg) plus phenytoin (10, 20, or 30 mg/kg) was given by flush and with reperfusion. Outcome was assessed in terms of overall performance categories (OPC 1, normal; 2, moderate disability; 3, severe disability; 4, coma; 5, brain death), neurologic deficit scores (NDS 0-10%, normal; 100%, brain death), and histologic deficit scores (HDS, total and regional). The flush reduced tympanic temperature to about 36 degrees C in all groups. In control group 1, one dog achieved OPC 1, three OPC 2, six OPC 3, and four OPC 4. In thiopental group 2, two dogs achieved OPC 1, two OPC 3, and five OPC 4. In thiopental/phenytoin group 3, one dog achieved OPC 1, two OPC 3, and four OPC 4 (p=0.5). Median NDS were 36% (IQR 22-62%) in group 1; 51% (IQR 22-56%) in group 2; and 55% (IQR 38-59%) in group 3 (p=0.7). Median total HDS were 67 (IQR 56-127) in group 1; 60 (IQR 52-138) in group 2; and 76 (IQR 48-132) in group 3 (p=1.0). Thiopental and thiopental/phenytoin dogs achieved significantly lower HDS only in the putamen. Thiopental in large doses caused side effects. We conclude that neither thiopental alone nor thiopental plus phenytoin by flush, with or without additional intravenous infusion, can cons

Topics: Animals; Anticonvulsants; Aorta, Thoracic; Brain Ischemia; Cardiopulmonary Resuscitation; Cerebrovascular Circulation; Dogs; Heart Arrest; Hypnotics and Sedatives; Male; Phenytoin; Reperfusion Injury; Thiopental; Time Factors

Controversy exists over the efficacy of different methods for protecting the spinal cord against experimental ischemic injury. Therefore, the authors compared the protective effects of thiopental with those of hypothermia (35 degrees C and 32 degrees C) on hindlimb motor functions and histopathology after transient spinal cord ischemia.. Twenty-seven New Zealand white rabbits were assigned to one of the four groups: a thiopental-normothermia group (burst-suppression dose of thiopental; esophageal temperature = 38 degrees C; n = 7), a halothane-mild hypothermia group (halothane, 1%; esophageal temperature = 35 degrees C; n = 7), a halothane-moderate hypothermia group (halothane, 1%; esophageal temperature = 32 degrees C; n = 6), and a halothane-normothermia group (halothane, 1%; esophageal temperature = 38 degrees C; n = 7). The animals were then subjected to 20 min of spinal cord ischemia produced by occlusion of the aorta distal to the origin of left renal artery. Hindlimb motor function was observed for 48 h after reperfusion. Histopathology of the lumbar spinal cord also was examined.. All animals in the halothane-mild hypothermia and halothane-moderate hypothermia groups were neurologically normal 48 h after ischemia. There was no statistical difference in the final neurologic status and histopathology between the thiopental-normothermia and halothane-normothermia groups. However, the final neurologic status and histopathology in both groups were worse than in the halothane-mild hypothermia or halothane-moderate hypothermia groups. There was a strong correlation between the final neurologic status and the numbers of normal neurons in the anterior spinal cord.. These results suggest that mild and moderate hypothermia protects against ischemic spinal cord injury in rabbits, and a burst-suppression dose of thiopental does not offer any advantage over halothane.

Topics: Anesthetics, Intravenous; Animals; Body Temperature; Esophagus; Evoked Potentials; Halothane; Hypothermia, Induced; Rabbits; Reperfusion Injury; Spinal Cord; Thiopental

Thiopental, a barbiturate anesthetic, which at high doses suppresses cortical electroencephalogram activity, was evaluated as a neuroprotective agent in a dog model of reversible, hindbrain ischemia. Fourteen dogs were exposed to 20 minutes of isolated brain stem ischemia after pretreatment with 35 mg per kg of thiopental or placebo. Brain stem auditory evoked potentials (BAEPs) and regional cerebral blood flow were measured before and during the ischemia and for 5 hours after reperfusion. During the ischemic period, both control and thiopental-treated animals experienced dramatic declines in the BAEPs to less than 10% of baseline. On reperfusion for 30 minutes, the BAEPs increased in both groups to near 40% of baseline. In the thiopental-treated animals, the BAEPs continued to recover variably to a mean of 70% of baseline by 5 hours of reperfusion. In contrast, untreated animals showed a decline in BAEPs after 30 minutes of reperfusion. The improved recovery of BAEPs in the thiopental-treated animals suggests that thiopental may be of some value as a cerebroprotective agent, although the mechanism remains unclear. The variability in recovery in this group implies that other factors play a significant role in mediating functional recovery from ischemic brain stem damage.

Topics: Anesthetics, Intravenous; Animals; Brain Ischemia; Brain Stem; Dogs; Evoked Potentials, Auditory, Brain Stem; Female; Male; Reaction Time; Regional Blood Flow; Reperfusion Injury; Thiopental

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.

Topics: Anesthetics; Animals; Aorta, Abdominal; Constriction; Halothane; Hypothermia, Induced; Intraoperative Care; Ischemia; Ketamine; Paraplegia; Postoperative Complications; Rabbits; Reperfusion Injury; Spinal Cord; Thiopental; Time Factors

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.

Topics: Animals; Aorta; Constriction; Injections, Intravenous; Injections, Spinal; Ischemia; Paralysis; Rabbits; Reperfusion Injury; Spinal Cord; Tetracaine; Thiopental