Journal of neurosurgical anesthesiology
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J Neurosurg Anesthesiol · Oct 1999
Monitoring brain PO2, PCO2, and pH during graded levels of hypoxemia in rabbits.
Brain ischemia and hypoxia are of concern when they occur following traumatic brain injury because they frequently result in potentially preventable secondary brain damage. In this study, we examined the ability of an implantable catheter (Paratrend 7; Diametrics Medical, St. Paul, MN) to continuously measure brain tissue pH, PCO2, and PO2 during graded levels of hypoxia. ⋯ As expected, there was a good correlation between the changes in pH, PCO2, and PO2 in brain tissue and sagittal sinus blood. Brain tissue PO2 was numerically lower than sagittal sinus blood at all inspired levels of oxygen. These data suggest that the Paratrend 7 may be useful in monitoring brain tissue oxygen tension in patients at risk for regional cerebral ischemia and hypoxia.
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J Neurosurg Anesthesiol · Jul 1999
Administration of hypertonic (3%) sodium chloride/acetate in hyponatremic patients with symptomatic vasospasm following subarachnoid hemorrhage.
A retrospective study was carried out to evaluate the effect of hypertonic (3%) saline chloride/acetate on various hemodynamic parameters in mildly hyponatremic patients with symptomatic vasospasm following aneurysmal subarachnoid hemorrhage (SAH). We identified 29 hyponatremic (serum sodium < 135 mEq/L) patients who received hypertonic (3%) sodium chloride/acetate as a continuous infusion. Administration of hypertonic (3%) sodium chloride/acetate resulted in higher central venous pressures and positive fluid balance, with a concomitant increase in serum sodium and chloride concentrations without metabolic acidosis. ⋯ We conclude that hypertonic (3%) sodium chloride/acetate can be administered to patients with mild hyponatremia in the setting of symptomatic vasospasm following SAH without untoward effects. Sample size and limitations of a retrospective analysis preclude conclusions about safety and efficacy of hypertonic (3%) sodium chloride/acetate administration in this patient population. However, our results support justification for a prospective, randomized, double-blind trial of hypertonic (3%) sodium chloride/acetate versus normal saline in patients with symptomatic vasospasm following SAH.
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J Neurosurg Anesthesiol · Jul 1999
Comparative StudyHeart rate variability and plasma catecholamines in patients during opioid detoxification.
It has been shown that rapid opioid detoxification is associated with increased sympathetic activity (SYMP) and plasma catecholamines. Heart rate (HR) variability may provide a noninvasive method of evaluating withdrawal and sympathetic activation caused by the reversal of opioid binding in patients who are opioid dependent. The purpose of this study was to evaluate the relationship between HR variability and plasma catecholamines during opioid detoxification. ⋯ Plasma norepinephrine and epinephrine as well as SYMP increased 300 to 400% (P < .05) during naltrexone treatment in opioid-dependent patients, and the time to peak increase in plasma norepinephrine correlated with the increase in SYMP (r = 0.89, P < .01). These results confirm that opioid detoxification increases plasma catecholamines and SYMP in a similar manner. HR rate variability may provide a low-cost real-time noninvasive method of evaluating the reversal of opioid binding in opioid-dependent patients.
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J Neurosurg Anesthesiol · Jul 1999
Randomized Controlled Trial Comparative Study Clinical TrialEffects of nonsteroidal anti-inflammatory drugs on hemostasis in patients with aneurysmal subarachnoid hemorrhage.
Platelet function is impaired by nonsteroidal anti-inflammatory drugs (NSAIDs) with prominent anti-inflammatory properties. Their safety in patients undergoing intracranial surgery is under debate. Patients with aneurysmal subarachnoid hemorrhage (SAH) were randomized to receive either ketoprofen, 100 mg, three times a day (ketoprofen group, n = 9) or a weak NSAID, acetaminophen, 1 g, three times a day (acetaminophen group, n = 9) starting immediately after the diagnosis of aneurysmal SAH. ⋯ Coagulation (prothrombin time [PT], activated partial thromboplastin time [APPT], fibrinogen concentration, and antithrombin III [AT III]) was comparable between the two groups. Ketoprofen but not acetaminophen impaired platelet function in patients with SAH. If ketoprofen is used before surgery on cerebral artery aneurysms, it may pose an additional risk factor for hemorrhage.
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J Neurosurg Anesthesiol · Jul 1999
Randomized Controlled Trial Clinical TrialEffects of clonidine on human middle cerebral artery flow velocity and cerebrovascular CO2 response during sevoflurane anesthesia.
The present study was designed to evaluate the effects of clonidine on human middle cerebral artery flow velocity and the cerebrovascular CO2 response during sevoflurane anesthesia using transcranial Doppler ultrasonography. The subjects were nine awake volunteers (group A) and 18 patients receiving oral preanesthetic medication of clonidine, 3-4 mcg/kg, (group C), or placebo (group S). In groups C and S, anesthesia was induced with inhalation of sevoflurane-nitrous oxide. ⋯ The Vmca value of group C was significantly lower than that of group S in hypercapnia, but not in hypocapnia or normocapnia. The CO2 response slope of group C was significantly lower than those of groups A and S. The results indicate that clonidine, administered as an oral preanesthetic medication, reduces Vmca in hypercapnia but not in hypocapnia or normocapnia, and reduces the cerebrovascular CO2 response during sevoflurane anesthesia.