Anesthesia and analgesia
-
Anesthesia and analgesia · Aug 1996
Randomized Controlled Trial Comparative Study Clinical TrialIntracranial pressure and hemodynamic effects of remifentanil versus alfentanil in patients undergoing supratentorial craniotomy.
Remifentanil hydrochloride is an ultra-short-acting esterase metabolized mu-opioid receptor agonist. The purpose of this study was to provide preliminary information regarding the effects of this drug on intracranial pressure (ICP) and mean arterial pressure (MAP) in patients scheduled for craniotomy. Twenty-six patients undergoing excision of supratentorial space-occupying lesions were anesthetized with 0.3-0.8 vol% isoflurane in a 2:1 mixture of nitrous oxide:oxygen. ⋯ Both drugs were associated with a dose-dependent decrease in MAP. Remifentanil was 31 times more potent than alfentanil for effects on MAP. We conclude that remifentanil produces similar cerebral perfusion pressure effects as does alfentanil.
-
Anesthesia and analgesia · Aug 1996
Randomized Controlled Trial Comparative Study Clinical TrialEffects of ondansetron on emesis in the first 24 hours after craniotomy in children.
Children undergoing neurosurgical resection are at high risk for postoperative nausea and vomiting. Ondansetron, a selective serotonergic (5-HT3) antagonist, is effective in reducing postoperative vomiting in several high-risk populations. In a prospective, randomized study, we compared the prophylactic use of intravenous ondansetron, 0.15 mg/kg, versus placebo for the prevention of emesis in 60 children, aged 2-18 yr, undergoing craniotomies for resective procedures. ⋯ For the entire 24-h interval, the incidence of emesis in children who received ondansetron (57%) was not significantly different from that in those who received placebo (66%); however, in the first 8 h, the incidence was 25% (ondansetron) vs 44% (placebo) (P = not significant). In those receiving placebo, there was no difference in emesis between patients undergoing operations above versus below the tentorium. Although our sample size was too small to completely exclude any beneficial effect, ondansetron appears ineffective in preventing postoperative emesis in this patient population.
-
Anesthesia and analgesia · Aug 1996
Randomized Controlled Trial Comparative Study Clinical TrialAn evaluation of antidepressants in rheumatic pain conditions.
In a randomized, double-blind, parallel study, fluoxetine and amitriptyline were compared with placebo in the treatment of chronic rheumatic pain. A total of 59 patients were evaluated during 4 wk of treatment and received 20 mg fluoxetine, 25 mg amitriptyline, or placebo daily. Pain intensity, pain relief, vital variables, and global evaluation were used to assess efficacy. ⋯ At the end of the fourth week, fluoxetine was superior in efficacy to amitriptyline. The incidence of adverse effects was significantly greater with amitriptyline; dryness of the mouth was the most predominant side effect. We conclude that fluoxetine is an effective analgesic with fewer side effects.
-
Anesthesia and analgesia · Aug 1996
Randomized Controlled Trial Clinical TrialThe effects of varying volumes of crystalloid administration before cesarean delivery on maternal hemodynamics and colloid osmotic pressure.
The value of intravenous crystalloid administration in preventing spinal-induced hypotension in the parturient has recently been questioned. Also, the association between increasing crystalloid volume and decreasing postpartum colloid osmotic pressure (COP) raises concern regarding the risk of maternal and fetal pulmonary edema. To study the dose-response effect of varying amounts of crystalloid volume prior to spinal anesthesia, we measured maternal hemodynamic variables and maternal and fetal COP in three groups of healthy parturients receiving spinal anesthesia for elective cesarean delivery. ⋯ Total ephedrine and additional intravenous (i.v.) fluid administered did not differ among groups. The 20- and 30- mL/kg groups showed a larger decline in maternal COP than the 10-mL/kg group; no differences in neonatal COP were seen with varying preload. We conclude that increasing the amount of i.v. crystalloid administered to 30 mL/kg in the healthy parturient does not significantly alter maternal hemodynamics or ephedrine requirements after spinal anesthesia and has no apparent benefit.
-
Anesthesia and analgesia · Aug 1996
Comparative StudyIn vivo imaging of human limbic responses to nitrous oxide inhalation.
Human behavioral studies have shown that nitrous oxide, in subanesthetic concentrations, impairs psychomotor function, cognitive performance, and learning and memory processes. However, the cerebral mechanisms of such effects remain unknown. Positron emission tomography (PET) was used to map the brain areas associated with nitrous oxide effects. ⋯ Nitrous oxide inhalation was associated with significant activation in the anterior cingulate cortex, a limbic area known to mediate psychomotor and cognitive processes. Deactivation was found in the posterior cingulate, hippocampus, parahippocampal gyrus, and visual association cortices in both hemispheres; the former two regions are known to mediate learning and memory. These areas identified by PET in vivo may provide the neuroanatomical basis for the behavioral responses associated with subanesthetic nitrous oxide inhalation.