ISSN:0898-4921    

出版商:OVID    

年代:1996

数据来源: OVID

ISSN:0898-4921    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Long-term chronic anticonvulsant therapy produces a resistance to the effects of all nondepolarizing neuromuscular blocking agents studied to date. Since the metabolism of mivacurium is unique among the nondepolarizing neuromuscular blocking agents, the effect of anticonvulsants on its recovery parameters was examined. Forty-five patients were separated into three groups based on the number of chronic anticonvulsant medications the subjects were taking: subjects in group 1, the control group, took no anticonvulsant medication; group 2 subjects took one medication; and group 3 subjects took two medications. Mivacurium, 0.15 mg/kg i.v., was administered after induction of general anesthesia with thiopental sodium, 4–6 mg/kg, and fentanyl 2–4 μg/kg i.v. Maintenance anesthesia consisted of N2O in O2, 0.2–0.3% end-tidal isoflurane, and a fentanyl infusion. The evoked compound electro-myograph (ECEMG) of the adductor pollicis-brevis muscle was measured for time of onset, T-1 (time at which ECEMG signal reaches 5, 25, 50, and 75% of baseline), TR (TOF ratio), and recovery index. T-l at 25% was 18.2 ± 1.8, 20.7 ± 1.9, and 21.5 ± 1.4 min for groups 1, 2, and 3, respectively, with TR at 25% being 23.7 ± 2.3, 26.9 ± 2.4, and 27.3 ± 2.3 min. No significant differences were noted in neuromuscular recovery between groups at any time point. These results fail to demonstrate the resistance to the nondepolarizing neuromuscular blockade of mivacurium that has been observed with other nondepolarizing agents.

ISSN:0898-4921    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

This study investigates the effects of surgical stimulation on cerebral blood flow velocity using transcranial Doppler sonography (TCD) in 1 and 2 maximum alveolar concentration (MAC) isoflurane anesthetized patients. Sixty ASA I and II patients undergoing breast surgery were studied. Anesthesia was maintained with 0.6% isoflurane (groups 1 and 2) or 1.2% isoflurane (groups 3 and 4) and nitrous oxide in oxygen (Fio2, 0.33). TCD recordings of middle cerebral artery mean blood flow velocity (Vmean, cm/s) were taken before each respective treatment and for the 15-min investigation period. In groups 1 and 3 (eachn= 20), the patients were exposed to surgical stimulation (skin incision). In groups 2 and 4 (eachn= 10), norepinephrine infusion (0.1 μg · kg−1· min−1) was used to increase mean arterial blood pressure (MAP) to levels similar to those seen with surgical stimulation (groups 1 or 3). Body temperature and PETCO2remained constant over time and did not vary between treatment groups. In groups 1 and 3, MAP increased 22 and 16% after surgical stimulation. In groups 2 and 4, MAP increased 28 and 36% after norepinephrine infusion. Vmeanwas increased 23 and 17% after surgical stimulation during 1 and 2 MAC isoflurane but did not change with norepinephrine infusion. These data show that cerebral blood flow velocity increases with surgical stimulation in 1 and 2 MAC isoflurane-anesthetized patients. This is not a function of changes in MAP. These data suggest that surgical stimulation increases cerebral blood flow, possibly because of arousal.

ISSN:0898-4921    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

This study evaluated the bispectral index as an indicator of anesthetic depth in relation to the cardiovascular response to intubation. Two treatments were compared: group 1 (n= 8) received propofol for induction of anesthesia (2 mg/kg bolus followed by an infusion of 0.20 mg/kg−1/min−1), group 2 (n= 8) was given 90 μg/kg midazolam 2 min before, followed by anesthesia with half-strength propofol (1 mg/kg bolus with infusion of 0.10 mg/kg−1/min−1). The bispectral index of the electroencephalogram, blood pressure, and heart rate were measured under unanesthetized conditions, during anesthetic induction, intubation, and a 15-min period after intubation. The duration of anesthesia and the total propofol requirement were recorded. Midazolam pretreatment produced transient decreases in blood pressure and the bispectral index. During anesthetic induction with propofol, blood pressure decreased 20% in both groups, and the bispectral index decreased to lower levels in group 1 (29 ± 9) than in group 2 (47 ± 22). Intubation increased blood pressure more in group 2 (50 ± 10 mm Hg) than in group 1 (30 ± 12 mm Hg). Throughout the rest of the surgery, more propofol was used in group 1 (77 ± 14 μg/kg−1/min−1) than in group 2 (42 ± 14 μg/kg−1/min−1). These results show that the decrease in bispectral index provides an indication of the blood pressure increase to intubation during propofol anesthesia. Midazolam pretreatment did not attenuate the cardiovascular response to intubation but did decrease propofol use during surgery.

ISSN:0898-4921    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

We report a case of subarachnoid hemorrhage in which, even after having obtained a normal jugular bulb oxyhemoglobin saturation, cerebrovenous desaturation developed, and brain death occurred. The limitations of jugular bulb oxyhemoglobin saturation without intracranial pressure monitoring are discussed. We conclude that if increased intracranial pressure is suspected, use of jugular bulb oxyhemoglobin saturation monitoring alone would appear to be substantially limited.

ISSN:0898-4921    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

We describe the case of a 33-year-old woman who suffered a delayed-onset arterial gas embolism following a significant venous air embolism during surgery to remove an acoustic neuroma. We report the management of the problem and discuss the mechanisms by which this event might have occurred.

ISSN:0898-4921    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Cerebral air embolism occurred in a patient undergoing posterior fossa surgery performed in the sitting position for acoustic neuroma removal. The patient experienced two episodes of venous air embolism, as evidenced by precordial Doppler, end-tidal carbon dioxide reduction, and oxygen desaturation. In both cases, air was aspirated from the central venous catheter; during the second episode there was arterial hypotension and electrocardiogram changes, and air bubbles were visualized in the cerebellar arteries. The patient did not regain consciousness after surgery and developed early tonic-clonic convulsions and electroencephalogram status epilepticus, which was treated with barbiturate coma. Intracardiac septal defects were not detected by trans-esophageal echocardiography, and computerized tomography of the brain demonstrated multifocal discrete ischemic areas in the cerebral hemispheres. The patient died 6 days after surgery without having regained consciousness. This case appears to represent the occurrence of transpulmonary passage of venous air embolism.

ISSN:0898-4921    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Two cases are described of patients, undergoing surgery for intracranial pathology, who developed polyuria intraoperatively. The urine output decreased to within normal range shortly after the administration of ketorolac, a nonsteroidal antiinflammatory drug. The possible mechanisms producing the increased urinary output and the influence of prostaglandins on renal function are discussed.

ISSN:0898-4921    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Electroencephalogram (EEG) burst-suppression can be produced with several anesthetic agents. Discussions of burst-suppression suggest that it has been viewed by many as a relatively uniform physiologic state independent of the agent used to produce it. This view may be an oversimplification. In this study, relatively deep EEG burst-suppression (suppression to burst time ratio, 4:1) was induced in rats with isoflurane (I), thiopental (T), etomidate (E), and propofol (P). Burst duration, maximum peak-to-peak voltage, area under the curve, and the ratio of power in high versus low frequencies of EEG recorded in both cortex and subcortex (thalamus) were determined. Analysis of the bursts revealed significant differences in duration [I, 1.4 ± 0.4 (SD); T, 0.8 ± 0.5; E, 0.3 ± 0.1; P, 0.4 ± 0.1 seconds], peak-to-peak voltage (I, 488 ± 146; T, 285 ± 106; E, 310 ± 87; P, 249 ± 50 μ V), and area under the curve (I, 111 ± 24; T, 35 ± 31; E, 17 ± 7; P, 21 ± 4 μ V-s) for all agent pairs except etomidate and propofol. Suppression phase analysis revealed considerable residual activity with all four agents, although peak-to-peak voltage (I, 129 ± 29; T, 64 ± 20; E, 62 ± 11; P, 40 ± 15 μ V) and area under the curve (I, 73 ± 17; T, 37 ± 14; E, 30 ± 5; P, 22 ± 10 μ V-s) were greatest with isoflurane. The cortical versus subcortical comparison revealed, for all agents, greater peak-to-peak voltage and area under the curve in the subcortex. The data indicate that the electrophysiologic characteristics of burst-suppression vary among the four agents, with the possible exception of etomidate and propofol. The data suggest that the neurophysiologic states associated with burst-suppression produced by various anesthetics should not be assumed to be uniform.

ISSN:0898-4921    

出版商:OVID    

年代:1996

数据来源: OVID