摘要:

Craniotomy for resection of cerebral arterial venous malformation has been associated with postoperative hypertension, which necessitates administration of large doses of antihypertensive medications to control blood pressure. Controlling blood pressure is essential because hypertensive episodes can lead to postoperative cerebral hemorrhage with increases in morbidity and mortality. We measured vasoactive peptide and catecholamine release in 13 patients who underwent resection of an arterial venous malformation and in a control group of 6 patients who presented for clipping of unruptured cerebral aneurysms. Plasma renin activity, angiotensin I and II, vasopressin, aldosterone, epinephrine, and norepinephrine levels were measured intraoperatively and for 36 h postoperatively. Analysis of variance was used to assess sample and group effects. A significant interaction between sample and groups was found for norepinephrine (p < 0.001) and renin (p = 0.002). Our data suggest that elevated plasma renin and norepinephrine levels are in part responsible for postoperative hypertension in patients undergoing resection of arterial venous malformations. Blocking the release of these hormones may help control blood pressure after surgery for removal of arterial venous malformations.

ISSN:0898-4921    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Administration of indomethacin may aid treatment of intracranial hypertension, and the present study was conducted to determine the optimal dose. In healthy volunteers, cerebral blood flow (CBF) has been shown to decrease considerably after a bolus dose of indomethacin, 0.4 mg/kg, followed by continuous infusion, 0.4 mg/kg/h. This decrease was sustained for 6 h without any evidence of adaptation. In a randomized study in healthy volunteers, indomethacin, 0.1, 0.2, and 0.3 mg/kg, was given as bolus, followed by continuous infusion of 0.1, 0.2, and 0.3 mg/kg/h. CBF decreased from normal levels (52–74 ml/100 mg/min) to 38–51 ml/100 g/min. There were no differences among the three groups in CBF reduction, and the reduction was sustained during the 6-h infusion period. Rectal application of 100 mg indomethacin was found to reduce CBF from normal levels (54–74 ml/100 mg/min) to 33–18 ml/100 mg/min. These low levels were only sustained for2h, and values returned to normal over the next 6 h. We observed no rebound phenomenon 2 h after stopping the infusion and no rebound after 100 mg of rectally applied indomethacin. Since a dose as low as 0.1 mg/kg/h is effective, it is possible to treat most patients in a 24-h schedule without going over maximum recommended doses.

ISSN:0898-4921    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

To determine preoperative predictors of blood pressure reduction following dural opening during surgical evacuation of hematoma, we retrospectively assessed preoperative variables including clinical profile, hemodynamic parameters, neurological findings, and computed tomography (CT) scan results in 56 patients with traumatic acute subdural hematoma (ASDH). Patients were divided into two groups according to the degree of changes in mean arterial pressure (MAP) in response to dural opening. Group A (n = 18) had a MAP reduction >20%, and group B (n = 38) had a MAP change within $pm;20% of baseline values (5 min before opening the dura). Significant relationships were found between MAP reductions >20% and Glasgow coma scale (GCS) scores, abnormalities of the mesencephalic cistern on CT scan, pupillary abnormalities, and degree of midline shift. Low GCS score, absence of the mesencephalic cistern on CT scan, and bilaterally dilated pupils were particularly strong predictors of this amount of blood pressure reduction. The clinical outcomes of patients with MAP reduction >20% following dural opening during surgery were significantly poorer than those of patients without this amount of blood pressure reduction. Our findings suggest that blood pressure reduction following opening of the dura in patients undergoing surgical evacuation of hematoma for traumatic ASDH may be predicted by careful preoperative assessment of neurological and CT scan findings.

ISSN:0898-4921    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

The occurrence of venous air embolism (VAE) during neurosurgery in the sitting position is well documented. The optimal position of an air aspiration catheter appears to be with the catheter tip at the junction of the right atrium and superior vena cava (SVC). A number of localization techniques have been described, with the electrocardiographic guided technique being the most commonly employed. This case report describes the use of transesophageal echocardiography (TEE) for the precise and timely placement of a right atrial-SVC air aspiration catheter.

ISSN:0898-4921    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Neurosurgery can be complicated by the clinical situation commonly referred to as “tight brain,” in which the brain presses against the inner table of the skull or protrudes through the craniotomy site. We report here a retrospective study of 32 patients who had undergone elective craniotomy for resection of supratentorial mass lesions. We determined the relationship between lumbar cerebrospinal fluid pressure (CSFP) and brain relaxation and whether brain relaxation varies with anesthetic technique. Patients had received one of four anesthetic techniques: 1 MAC isoflurane (ISO), 1 MAC desflurane (DES), 50% N2O with 0.5 MAC ISO, or 50% N2O with 0.5 MAC DES. Lumbar CSFP had been.recorded before the induction of anesthesia (baseline) and immediately prior to dural incision. Charts were retrospectively reviewed for evidence of tight brain, which was considered present if mannitol had been administered, CSF had been drained via the lumbar needle, or the surgical dictation noted the brain was tight at the time of dural incision. Tight brain occurred in 10 of 32 patients. CSFP (mean ± SD) was significantly greater in the tight than in the nontight group both at baseline (11 ± 5 vs. 8 ± 3 mm Hg, p < 0.05) and immediately prior to dural incision (13 ± 7 vs. 9 ± 4 mm Hg, p < 0.05). Tight brain did not occur in any patient with CSFP < 6 mm Hg, but it did occur in all patients with CSFP > 17 mm Hg. Within the range of 6–17 mm Hg, CSFP was not predictive of brain relaxation. Tight brain was more common in patients receiving 1 MAC ISO or DES (9 of 20 patients; 45%) than in patients receiving 0.5 MAC ISO or DES with 50% N2O (1 of 12 patients; 8%, p < 0.05). We conclude that in patients undergoing elective craniotomy for resection of a supratentorial mass lesion, brain relaxation is not predictive of CSFP. Although CSFP values at the extremes of the observed distribution (>17 mm Hg or <6 mm Hg) did correlate with brain relaxation, within the range of 6–17 mm Hg, CSFP did not predict brain relaxation. Additionally, the data from this study suggest that in patients undergoing elective craniotomy for resection of a supratentorial mass lesion, tight brain may occur with a lower frequency in patients receiving 0.5 MAC ISO or DES with 50% N2O than in patients receiving 1 MAC ISO or DES.

ISSN:0898-4921    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

A case of pseudoobstruction of the colon in a patient receiving oral nimodipine therapy is presented. Early recognition of this entity, diagnostic aids, and therapy are discussed. Successful colonoscopic decompression and close observation allowed completion of nimodipine course of therapy.

ISSN:0898-4921    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Intravenous hypertonic fluid therapy has been proposed to improve secondary ischemic injury after cerebrospinal trauma. We report the case of a 14-year-old boy with vasospasm of the intracranial vertebral arteries and ischemic brain stem damage following head trauma. The patient presented with severe tetraparesis and somatosensory (SSEPs) and brain stem auditory evoked potentials (BAEPs) impairment. The patient was treated with two subsequent hypertonic saline (HS) infusions, 2.7% and 5.4%, respectively, for a period of 48 sp, followed by standard hypervolemic therapy. After the first treatment with 2.7% HS, improvement of SSEPs without neurological improvement was apparent. Relative hypervolemia was subsequently maintained by administration of crystalloids and 20% albumin for 48 h. During standard hypervolemic therapy, no clinical and/or electrophysiological change occurred. The second infusion of 5.4% HS was concomitant with further amelioration of SSEPs and improvement of motor performance. Twelve hours after the second HS infusion, the neurological status returned to preinfusion levels, while SSEPs showed no further changes. BAEPs never changed during fluid therapy. No complication occurred secondary to the infusion of HS. This case report suggests that local improvement of brain stem perfusion following hypertonic fluid therapy accounts for or relevantly contributes to the neurological and SSEPs improvement of the patient.

ISSN:0898-4921    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

We describe a case of the temporary loss of right popliteal fossa intraoperative neurogenic motor-evoked potential and the permanent loss of right median and ulnar somatosensory-evoked potentials (SSEPs) with retention of posterior tibial (SSEPs) during intramedullary spinal cord surgery in a 28-year-old man. Postoperatively, the patient had preserved motor function in all extremities and loss of proprioception, two-point discrimination, and vibration in his right upper extremity. The complementary and beneficial use of intraoperative monitoring of both motor-evoked potentials and SSEPs during spinal cord surgery is discussed.

ISSN:0898-4921    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

The effect of the volatile anesthetic desflurane on spinal and cortical somatosensory evoked potentials (SEPs) was examined in 11 Sprague-Dawley male rats. Platinum recording electrodes were placed stereotactically over the left somatosensory cortex and dorsal midline of the T11–12 spinal cord while the right posterior tibial nerve was stimulated at twice motor threshold. The effect of desflurane was examined at various concentrations ranging from 0.7 to 11.4% (2 MAC). Mean arterial blood pressure (MAP) decreased (p = 0.001) progressively with increasing end-tidal desflurane concentrations. Concentrations of 1.4% (1/4 MAC) and 2.8% (1/2 MAC) did not significantly affect the spinal SEP (SSEP) amplitude or the latency. With higher concentrations, there was a progressive decrease in amplitude of the cortical SEPs (CSEPs; p = 0.002) and SSEPs (p = 0.008). However, CSEP and SSEP latencies did not change. At 5.7% (1 MAC), three animals (33%) lost CSEPs while SSEPs remained intact. At 11.4% (2 MAC), the CSEPs were lost in all animals. Only one rat lost the SSEPs at the 2 MAC concentration of desflurane, indicating the resistance of the SSEPs to desflurane anesthesia. We conclude that desflurane anesthesia significantly alters the amplitude of SSEPs and CSEPs without a significant change in the peak latency.

ISSN:0898-4921    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Propofol has been reported to have antioxidant properties and to inhibit lipid peroxidation. In this study, we examined the ability of propofol to inhibit lipid peroxidation induced by three free radical systems (hydroxyl, ferryl, and oxo-ferryl radicals), and we compared the effect of propofol with that of vitamin E, an endogenous antioxidant. Lipid peroxidation was induced by exposing a linoleic acid emulsion to either water gamma radiation, a ferrous iron-ascorbate solution, or human hemoglobin, generating the hydroxyl, ferryl, and oxo-ferryl radicals, respectively. Each experiment was performed in triplicate with and without propofol or vitamin E at concentrations between 10--5and 10--4M. Lipid peroxidation was quantified by gas chromatography measurement of the pentane released (nmoles) from lipid decomposition. In each condition, a significant dose-response relationship was found between the release of pentane and the concentration of either propofol or vitamin E. The antioxidant activities of both agents were similar but significantly higher against the hydroxyl than the ferryl and oxo-ferryl radicals. The study suggests that propofol could be beneficial as an anesthetic or sedative drug in patients presenting pathologies associated with free radical reactions.

ISSN:0898-4921    

出版商:OVID    

年代:1996

数据来源: OVID