Journal of neurosurgical anesthesiology
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Core body temperature is normally rigidly regulated by effective thermoregulatory responses that are triggered by small deviations in core and skin temperature. All general anesthetics so far tested markedly impair thermoregulatory control, increasing the range of temperatures not triggering protective responses by approximately 20-fold. Inhibition of thermoregulatory control--and reemergence of protective responses--are major factors influencing intraoperative temperature. ⋯ Forced air appears to be the most effective clinically practical cooling method. Mild hypothermia is also associated with serious complications including myocardial ischemia, impaired resistance to surgical wound infections, coagulopathies, and postoperative shivering. Consequently, patients deliberately made hypothermic during neurosurgery should subsequently be actively rewarmed.
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J Neurosurg Anesthesiol · Jan 1995
Comparative StudyBrain edema and neurologic status with rapid infusion of 0.9% saline or 5% dextrose after head trauma.
We previously reported that intravenous (i.v.) administration of large volumes (0.2 ml/g) of either an isotonic dextrose-free solution or 5% dextrose solution given over 18 h after closed head trauma (CHT) in rats did not significantly affect neurological severity score or brain tissue specific gravity. However, it is possible that with more rapid administration, isotonic or 5% dextrose i.v. solutions may alter neurological outcome after CHT. Our study examined whether neurological severity score, brain tissue specific gravity and water content, and blood composition were significantly altered when 0.25 ml/g of either 0.9% saline or 5% dextrose was given i.v. over 0.5 h (rather than over 18 h) after CHT. ⋯ There were no statistically significant differences in neurologic outcome and brain edema between the untreated and the saline-treated groups. However, 5% dextrose i.v. increased mortality (group 6 and 11, 50 and 0% survivors, respectively), decreased specific gravity in the noncontused hemisphere, and worsened neurologic outcome with and without CHT. Blood osmolality remained stable in comparison to the baseline value of 291.9 +/- 7.4 mOsm/kg (mean +/- SD).(ABSTRACT TRUNCATED AT 250 WORDS)
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J Neurosurg Anesthesiol · Jan 1995
Comparative StudyEffect of intrathecal saline injection and Valsalva maneuver on cerebral perfusion pressure during transsphenoidal surgery for pituitary macroadenoma.
Cerebrospinal fluid pressure (CSFP) was monitored through a lumbar intrathecal catheter in 32 patients undergoing transsphenoidal excision of pituitary macroadenomas. In the first 20 patients, standardized intermittent Valsalva maneuvers were followed by intrathecal saline injections in 2.5-ml increments. Their effects on CSFP, mean arterial pressure (MAP), and therefore, cerebral perfusion pressure (CPP) were compared. ⋯ Peroperative data, including surgical conditions, and post-operative morbidity, with special reference to low-pressure headache and meningeal infection, were analyzed in all 32 patients. Operative conditions produced with intrathecal saline were judged excellent or good in 75% of patients. However, because this technique can decrease the CPP excessively, we recommend that it be used only with continuous CSFP monitoring.
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J Neurosurg Anesthesiol · Oct 1994
Sevoflurane versus halothane anesthesia after acute cryogenic brain injury in rabbits: relationship between arterial and intracranial pressure.
The relationship between intracranial pressure and arterial blood pressure during sevoflurane or halothane anesthesia was evaluated in New Zealand white rabbits after cryogenic brain injury. Fourteen rabbits were randomized to be anesthetized with 1.5 MAC of sevoflurane or halothane in oxygen. All animals were paralyzed with pancuronium, and mechanically ventilated. ⋯ Intracranial pressure in the halothane anesthesia group increased from 9 +/- 1 to 32 +/- 3 mm Hg during the same range of blood pressure. Linear regressions of intracranial pressure on mean arterial pressure were performed for each of the two anesthetic groups. The slope of the regression line for the sevoflurane animals (0.491) was significantly greater than that for the halothane animals (0.323, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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J Neurosurg Anesthesiol · Oct 1994
Evaluation of a 7.5 French pulmonary catheter for continuous monitoring of cerebral venous oxygen saturation.
We studied a 7.5 French Opticat fiberoptic catheter/Oximetrix computer system as a tool for continuous monitoring of oxygen saturation of jugular venous blood. Eight healthy volunteers had a catheter placed with the tip in the bulb of the right internal jugular vein. During baseline condition, hyperventilation, and rebreathing, jugular venous oxygen saturations ranging from 35 to 85% were obtained. ⋯ A difference of > 12% oxygen saturation between the paired values was obtained for all of these pairs. The regression coefficient for the remaining 135 data pairs was 0.95, the mean difference was -0.54%, and the limits of agreement were -9.5 to 8.4%. We conclude that the 7.5 French Opticat catheter is useful if values obtained during improper light intensity are excluded.