Journal of neurosurgical anesthesiology
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J Neurosurg Anesthesiol · Jul 2004
Individual value of brain tissue oxygen pressure, microvascular oxygen saturation, cytochrome redox level, and energy metabolites in detecting critically reduced cerebral energy state during acute changes in global cerebral perfusion.
The authors assessed the diagnostic value of brain tissue oxygen tension (PbrO2), microvascular oxygen saturation (SmvO2), cytochrome oxidase redox level (Cyt a+a3 oxidation), and cerebral energy metabolite concentrations in detecting acute critical impairment of cerebral energy homeostasis. Each single parameter as well as derived multimodal indices (arteriovenous difference in oxygen content [AVDO2], cerebral metabolic rate for oxygen [CMRO2], fractional microvascular oxygen extraction [OEF]) were investigated during controlled variation of global cerebral perfusion using a cisternal infusion technique in 16 rabbits. ⋯ Glutamate concentrations and the lactate/pyruvate ratio varied significantly only between moderately reduced cerebral perfusion and frank ischemia (complete loss of BEA and brain stem vasomotor control). Therefore, PbrO2, SmvO2, and Cyt a+a3 oxidation, but not glutamate and the lactate/pyruvate ratio, reliably predict the transition from moderately to critically reduced cerebral perfusion with impending energy failure.
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J Neurosurg Anesthesiol · Jul 2004
Clinical TrialRectal temperature reflects tympanic temperature during mild induced hypothermia in nonintubated subjects.
Mild induced hypothermia holds promise as an effective neuroprotective strategy following acute stroke and cardiac arrest. Dependable noninvasive measurements of brain temperature are imperative for the investigation and clinical application of therapeutic hypothermia. Although the tympanic membrane temperature correlates best with brain temperature, it is a cumbersome location to record from continuously in the clinical setting. Data are lacking regarding the relationship between rectal and tympanic temperatures in nonintubated humans undergoing induced hypothermia via surface cooling. ⋯ : Our data suggest that Ttym and Trec are not related during the induction of hypothermia via surface cooling but correlate during the maintenance phase, with a -0.3 degrees C gradient. These findings support the use of rectal temperature as a measure of tympanic and, therefore, brain temperature during maintenance of induced hypothermia in nonintubated humans.
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J Neurosurg Anesthesiol · Jul 2004
Case ReportsAnesthetic considerations in a patient with mitral valve disease for posterior fossa surgery.
Mitral valve disease in patients undergoing posterior fossa surgery enhances the inherent risk of the procedure and can complicate the anesthetic management. A great challenge for the anesthesiologist is to choose the most appropriate perioperative technique that balances the specific anesthetic considerations of both the cardiac and the neurologic diseases. The authors describe the anesthetic management of a patient with a meningioma in the posterior fossa requiring craniectomy and tumor decompression. She was also diagnosed with severe mitral regurgitation and moderate mitral stenosis.
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Managing children with diabetes insipidus (DI) in the perioperative period is complicated and frequently associated with electrolyte imbalance compounded by over- or underhydration. In this study the authors developed and prospectively evaluated a multidisciplinary approach to the perioperative management of DI with a comparison to 19 historical control children. Eighteen children either with preoperative DI or undergoing neurosurgical operations associated with a high risk for developing postoperative DI were identified and managed using a standardized protocol. ⋯ In all children managed in this fashion, perioperative serum sodium concentrations were generally maintained between 130 and 150 mEq/L, and no adverse consequences of this therapy developed. In the 24-hour period evaluated, the mean change in serum sodium concentrations between the historical controls was 17.6 +/- 9.2 mEq/L versus 8.36 +/- 6.43 mEq/L in those children managed by the protocol. Hyponatremia occurred less frequently in the children managed with this protocol compared with historical controls.