Journal of neurosurgical anesthesiology
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J Neurosurg Anesthesiol · Jul 1993
Comparative StudyAirway pressure monitoring as an aid in the diagnosis of air embolism.
We designed a prospective study to compare the validity of airway pressure (AWP) monitoring with that of end-tidal CO2 (ETCO2) monitoring for early detection of air embolism. Subjects included 76 patients of both sexes who underwent neurosurgery in the sitting position. Anesthesia was maintained with O2, N2O, narcotics, pancuronium, and intermittent positive pressure ventilation (IPPV). ⋯ Murmur was noted in four patients and air aspiration in six patients. Only six patients of the 16 had an increase in AWP along with the decrease in ETCO2. We conclude that AWP monitoring is neither a sensitive nor reliable indicator of air embolism.
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J Neurosurg Anesthesiol · Jul 1993
Randomized Controlled Trial Clinical TrialClonidine premedication for craniotomy: effects on blood pressure and thiopentone dosage.
The purpose of this study was to determine whether oral clonidine premedication improves cardiovascular stability and/or reduces the requirements for drugs used to control systolic blood pressure (SBP) during elective craniotomies. We performed a double blind randomized trial involving 77 normotensive, ASA physical status I or II adults. Clonidine 4 micrograms/kg or placebo was given as oral premedication. ⋯ Two subgroups were analyzed, based on the study groups mean age and baseline SBP. Three-way analysis of variance revealed that the blood pressure effects of clonidine were almost entirely confined to patients older than 45 years. Baseline SBP had no independent effect.(ABSTRACT TRUNCATED AT 250 WORDS)
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J Neurosurg Anesthesiol · Jul 1993
Rate of cerebrospinal fluid formation, resistance to reabsorption of cerebrospinal fluid, brain tissue water content, and electroencephalogram during desflurane anesthesia in dogs.
Intracranial pressure (ICP) has been shown to increase dramatically during desflurane anesthesia, possibly as a result in part of an increase in the rate of cerebrospinal fluid (CSF) formation (Vf) or a decrease in the rate of CSF reabsorption. To examine this phenomenon, I designed a study to measure Vf, resistance to reabsorption of CSF (Ra), brain tissue water content, and the electroencephalographic activity (EEG) during desflurane anesthesia in dogs. Vf and Ra were determined using ventriculocisternal perfusion of mock CSF labeled with blue dextran. ⋯ The experimental conditions for groups 1 and 2 were (a) baseline (halothane 0.5-1.0% inspired plus thiopental 12 mg.kg-1 i.v. given over 15 min followed by i.v. infusion at 12 mg.kg-1 x h-1), (b) 0.5 MAC (3.5 +/- 0.1% expired) and (c) 1.0 MAC (7.0 +/- 0.1% expired) desflurane at normal CSF pressure, and (d) and (e) 0.5 and 1.0 MAC desflurane at increased CSF pressure (> 30 cm H2O). Group 3 (n = 6), the control group, was examined over the same time period as groups 1 and 2. In the control group, desflurane was not administered; instead, the baseline condition (i.e., halothane plus thiopental) was maintained throughout the study.(ABSTRACT TRUNCATED AT 250 WORDS)