ISSN:0898-4921    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Insertion of cranial pins for stabilization of the head can result in a marked hypertensive response, which may adversely affect cerebral hemodynamics. The efficacy of a subanesthetic dose of intravenous ketamine (0.5 mg/kg) and/or lidocaine infiltration (1%) at pin fixation sites before pinning was studied in a prospective, double-blind, placebo-controlled, randomized trial of 40 patients. The subjects were divided into four groups of 10. Patients belonging to the placebo and lidocaine groups received intravenous normal saline (NS), followed by local infiltration with NS at pin insertion sites in the placebo group and 1% lidocaine in the lidocaine group. Patients belonging to the ketamine and ketamine-lidocaine groups received intravenous ketamine followed by local infiltration with NS in the ketamine group, and lidocaine infiltration in the ketamine-lidocaine group. Heart rate (HR) and invasive mean blood pressure (MBP) were recorded before intravenous medication and then at various time intervals until 15 minutes after pin fixation. Intergroup comparison of MBP and HR by 2-way analysis of variance revealed a significant difference between the groups and various time points (P< .05). Post hoc analysis revealed maximum increase in MBP each hour in the placebo group. Mean blood pressure response in the ketamine group was similar to the placebo group. Significant attenuation of MBP and HR was observed in the lidocaine and ketamine-lidocaine groups (P< .05). A minimal increase in HR was observed in the lidocaine-ketamine group. The current study demonstrates maximum attenuation of hemodynamic responses when a subanesthetic dose of intravenous ketamine (0.5 mg/kg) is administered with 1% lidocaine infiltration.

ISSN:0898-4921    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

In a search for a nonsurgical intervention to control intracranial hypertension during craniotomy, the authors studied the effects of dihydroergotamine on mean arterial blood pressure (MABP), intracranial pressure (ICP), cerebral perfusion pressure (CPP), cerebral blood flow (CBF), and cerebral metabolism in patients who underwent craniotomy for supratentorial brain tumors. Twenty patients were randomized to receive either dihydroergotamine 0.25 mg intravenously or placebo as a bolus dose during craniotomy. Anesthesia was induced with thiopental/fentanyl/atracurium, and maintained with isoflurane/N2O/fentanyl at normocapnia. After removal of the bone flap and exposure of intact dura, ICP was measured subdurally and dihydroergotamine/placebo was administered. Intracranial pressure and MABP were measured continuously. Cerebral blood flow (after intravenous administration of133Xe) and arteriojugular venous difference of oxygen (AVDO2) were measured before, and 30 minutes after, dihydroergotamine/placebo administration. Cerebral metabolic rate of oxygen (CMRO2) was calculated. After administration of dihydroergotamine, a significant increase in MABP from 74 to 87 mm Hg (median) and CPP from 65 to 72 mm Hg (median) were found. Simultaneously to the increase in MABP, a significant increase in ICP from 9.5 to 11.5 mm Hg (median) was disclosed, whereas no significant differences in CBF, AVDO2, or CMRO2were found. Intracranial pressure was significantly higher after dihydroergotamine than after placebo. In conclusion, no ICP decreasing effect of a bolus dose of dihydroergotamine was found when administered to patients with brain tumors during isoflurane/N2O anesthesia. Corresponding increases in MABP and ICP suggest that abolished cerebral autoregulation might explain why dihydroergotamine was associated with an ICP increase.

ISSN:0898-4921    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Magnesium sulfate therapy, standard in preventing seizures in preeclampsia, is under active investigation as a neuroprotective agent. The authors studied the effect of magnesium as a cerebral vasodilator by measuring the cerebral blood flow velocity (CBFV) response to a 5g intravenous bolus of MgSO4compared with a saline placebo after subarachnoid hemorrhage (SAH). Transcranial Doppler ultrasonography of the middle cerebral artery (MCA) was measured after each infusion. Patients were studied up to three times after SAH at prescribed time intervals. Fourteen patients (11 women, 3 men; mean age 58 years) underwent 29 studies. All patients underwent hypertensive, hypervolemic therapy. Four patients developed cerebral vasospasm. Doubling serum magnesium levels did not affect MCA CBFV but slightly lowered mean arterial blood pressure and systemic vascular resistance. Intravenous magnesium bolus did not reduce elevated CBFV in the subset of SAH patients with clinical vasospasm. The role of magnesium sulfate as a cerebral vasodilator in patients with SAH requires further study.

ISSN:0898-4921    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

This prospective, randomized, placebo-controlled, double-blind study was designed to evaluate the efficacy of ondansetron, a 5-HT3antagonist, in preventing postoperative nausea and vomiting (PONV) after elective craniotomy in adult patients. The authors also tried to discover certain predictors for postcraniotomy nausea and vomiting. We studied 170 ASA physical status I and II patients, aged 15 to 70 years, undergoing elective craniotomy for resecting various intracranial tumors and vascular lesions. A standardized anesthesia technique and postoperative analgesia were used for all patients. Patients were divided into two groups and received either saline placebo (Group 1) or ondansetron 4 mg (Group 2) intravenously at the time of dural closure. Patients were extubated at the end of surgery and episodes of nausea and vomiting were noted for 24 hours postoperatively in the neurosurgical intensive care unit. Demographic data, duration of surgery, and anesthesia and analgesic requirements were comparable in both groups. Overall, a 24-hour incidence of postoperative emesis was significantly reduced in patients who received ondansetron compared with those who received a saline placebo (39% in Group 1 and 11% in Group 2,P= .001). There was a significant reduction in the frequency of emetic episodes and rescue antiemetic requirement in patients treated with ondansetron; however, ondansetron did not significantly reduce the incidence of nausea alone (14% in Group 2 vs 5% in Group 1,P= .065). Prophylactic ondansetron had a favorable influence on PONV outcome measures such as patient satisfaction and number needed to prevent emesis (3.5). Side effects were similar in both groups. We conclude that ondansetron 4 mg given at the time of dural closure is safe and effective in preventing emetic episodes after elective craniotomy in adult patients.

ISSN:0898-4921    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Cerebrovascular reactivity to CO2in clinical and experimental studies has been found to be impaired during increased intracranial pressure (ICP). However, from previous study results it has not been possible to estimate whether the impairment was caused by elevated ICP, or caused by decreased cerebral perfusion pressure (CPP). The current study was carried out in a group of unmanipulated control rats and in six investigation groups of six rats each: two groups with elevated ICP (30 and 50 mm Hg) and spontaneous arterial blood pressure (MABP), two groups with spontaneous ICP and arterial hypotension (77 and 64 mm Hg), and two groups with elevated ICP (30 and 50 mm Hg) and arterial hypertension (124 mm Hg). Intracranial hypertension was induced by continuous infusion of lactated Ringer's solution into the cisterna magna, arterial hypotension by controlled bleeding, and arterial hypertension by continuous administration of norepinephrine intravenously. Cerebral blood flow (CBF) was measured repetitively by the intraarterial133Xe method at different levels of arterial PCO2. In each individual animal, CO2reactivity was calculated from an exponential regression line obtained from the corresponding CBF/PaCO2values. By plotting each individual value of CO2reactivity against the corresponding CPP value from the seven investigation groups, CPP was significantly and directly related to CO2reactivity of CBF (P< .001). No correlation was found by plotting CO2reactivity values against the corresponding MABP values or the corresponding ICP values. Thus, the results show that CO2reactivity is at least partially determined by CPP and that the impaired CO2reactivity observed at intracranial hypertension and arterial hypotension may be caused by reduced CPP.

ISSN:0898-4921    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Previous studies have shown that laparoscopic interventions are associated with increases in intracranial pressure. However, the consequences on cerebral blood flow (CBF) are unknown. This study investigates the effects of carbon dioxide (CO2) pneumoperitoneum on CBF in pigs. Ten pigs (weight, 20–26 kg) were anesthetized with 1.4% isoflurane and fentanyl (1 &mgr;g/kg per minute). Mechanical ventilation (fraction of inspired oxygen = 0.4) was set to maintain normocapnia (end-tidal CO2tension = 35 mm Hg). Arterial and central venous catheters were placed for measurement of mean arterial blood pressure and central venous pressure. Bilateral internal carotid artery blood flow was measured using two transient time flow probes placed around both carotid arteries (with ligated external carotid arteries). Cortical and subcortical cerebral blood flow was measured using laser Doppler flowmetry. Sagittal sinus pressure was measured via a superior sagittal sinus catheter. After baseline measurements, the peritoneal cavity of the animals was insufflated with CO2to achieve an intraabdominal pressure of 12-mm Hg. After 10 minutes of stable CO2, pneumoperitoneum measurements were repeated. Increases in central venous pressure (6.3 ± 2.1 to 11.1 ± 3.0 mm Hg) and sagittal sinus pressure (8.0 ± 2.8 to 11.9 ± 3.0 mm Hg) were noted during CO2pneumoperitoneum (P< .05). Bilateral internal carotid artery blood flow (46.0 ± 7.4 vs 47.7 ± 7.1 mL/100g per minute), cortical CBF (263 ± 115 vs 259 ± 158 tissue perfusion units), and subcortical CBF (131 ± 145 vs 133 ± 149 tissue perfusion units) did not change during CO2pneumoperitoneum. The current data show that CO2pneumoperitoneum increases sagittal sinus pressure without changing CBF. Increases in sagittal sinus pressure are likely related to decreases in cerebral venous drainage caused by increases in intraabdominal pressure.

ISSN:0898-4921    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

To examine the effects of calcium antagonists nimodipine and magnesium sulfate (MgSO4) on tissue endogenous antioxidant levels, the authors studied superoxide dismutase (SOD) and glutathione peroxidase (GPx) levels in rabbit brain 1 hour after experimental head trauma. Forty New Zealand rabbits were anesthetized and randomly divided into four groups. Group 1 (n = 10) was the sham operated group. Group 2 (n = 10), the control group, received head trauma and no treatment. Group 3 (n = 10) received head trauma and intravenous (IV) 2 &mgr;gr/kg nimodipine. Group 4 (n = 10) received head trauma and IV 100 mg/kg MgSO4. Head trauma was delivered by performing a craniectomy over the right hemisphere and dropping a weight of 20 g from a height of 40 cm. In the right (traumatized) hemisphere, SOD and GPx decreased by 57.60% ± 9.60% and 72.93% ± 5.51% respectively from sham values. Magnesium sulfate, but not nimodipine, reduced the magnitude of decrease of SOD and GPx to 19.43% ± 7.15% and 39.01% ± 7.92% respectively from sham values. In the left (nontraumatized) hemisphere, MgSO4increased SOD to 42.43% ± 24.76% above sham values. The authors conclude that MgSO4treatment inhibited the decrease in SOD and GPx levels in experimental brain injury.

ISSN:0898-4921    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

The authors present the case of an anemic 22-month-old child undergoing lower extremity surgery in whom the lower limit of cerebral autoregulation was shifted to the right.

ISSN:0898-4921    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

An unusual case of massive oropharyngeal swelling and macroglossia occurring after cervical spine surgery performed on a patient in the prone position is described. Possible etiological factors are reviewed, and measures to prevent these complications are suggested.

ISSN:0898-4921    

出版商:OVID    

年代:2001

数据来源: OVID