Anesthesia and analgesia
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Anesthesia and analgesia · Nov 2000
Randomized Controlled Trial Multicenter Study Comparative Study Clinical TrialPostoperative nausea and vomiting after sevoflurane with or without ondansetron compared with propofol in female patients undergoing breast surgery.
We studied 180 female patients undergoing breast surgery. The patients were randomly allocated to receive one of three anesthetic techniques. Compared with either propofol or sevoflurane alone, sevoflurane with ondansetron resulted in a decreased incidence of postoperative nausea and vomiting. Sevoflurane with ondansetron prophylaxis is a good alternative to propofol with respect to avoiding postoperative nausea and vomiting.
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Anesthesia and analgesia · Nov 2000
Randomized Controlled Trial Comparative Study Clinical TrialSmall-dose droperidol effectively reduces nausea in a general surgical adult patient population.
In this prospective, randomized, placebo-controlled study, we (1) determined whether 0.625 mg of IV droperidol given 30 min before emergence from general anesthesia reduces the incidence of immediate and delayed postoperative nausea and vomiting (PONV) in a general surgical adult patient population, and (2) compared the efficacy of droperidol, ondansetron, and promethazine for the rescue treatment of PONV. One hundred fifty adult patients receiving general anesthesia for >2 h received either droperidol (0.625 mg IV) or a placebo before emergence. Patients requiring treatment for PONV in the postanesthesia care unit were randomized to receive either droperidol (0.625 mg IV), ondansetron (4 mg IV), or promethazine (12. 5 mg IV). Droperidol effectively prevented PONV (6.8% in droperidol-treated patients versus 40.8% in placebo-treated patients, P: < 0.001). Droperidol, ondansetron, and promethazine were equally effective in treating established PONV, without significant differences in side effects or time to postanesthesia care unit discharge. ⋯ Droperidol 0.625 mg IV before emergence from general anesthesia effectively reduces postoperative nausea and vomiting (PONV) in the general surgical population. Our randomized, double-blinded, placebo-controlled study demonstrated a reduction in PONV from 41% to 7%. Droperidol is a safe and inexpensive alternative to ondansetron. Droperidol, ondansetron, and promethazine are also equally effective in treating PONV in the postanesthesia care unit.
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Anesthesia and analgesia · Nov 2000
Randomized Controlled Trial Clinical TrialNitrous oxide-induced increased homocysteine concentrations are associated with increased postoperative myocardial ischemia in patients undergoing carotid endarterectomy.
Nitrous oxide anesthesia causes increased postoperative plasma homocysteine levels. Acute increases in plasma homocysteine are associated with impaired endothelial function and procoagulant effects. This nitrous oxide-induced plasma homocysteine increase may therefore affect the risk of perioperative cardiovascular events. This prospective, randomized study was therefore designed to evaluate the effect of nitrous oxide anesthesia and postoperative plasma homocysteine levels on myocardial ischemia in patients undergoing carotid endarterectomy. After institutional review board approval and written informed consent, 90 ASA Class I-III patients presenting for elective carotid endarterectomy were randomized to receive general anesthesia with or without nitrous oxide. Prior to induction, on arrival in the postanesthesia care unit, and after 48 h, blood samples were obtained for homocysteine analysis. Three hours prior to induction and for 48 h postoperatively patients were monitored by a three-channel, seven-lead Holter monitor. Postoperatively in the postanesthesia care unit and at 48 h the nitrous oxide group had increased mean plasma homocysteine concentrations of 15.5 +/- 5.9 and 18.8 +/- 14.7 when compared with the nonnitrous group of 11.4 +/- 5.2 and 11.3 +/- 4.0 micromol/L, P: < 0.001. The nitrous oxide group had an increased incidence of ischemia (46% vs. 25%, P: < 0.05), significantly more ischemia (63 +/- 71 vs. 40 +/- 68 min, P: < 0.05), had more ischemic events (82 vs. 53, P: < 0.02), and had more ischemic events lasting 30 min (23 vs. 14, P: < 0.05) than the nonnitrous group. This study reconfirmed that intraoperative nitrous oxide is associated with postoperative increases in plasma homocysteine concentration. This was associated with an increase in postoperative myocardial ischemia. ⋯ Use of nitrous oxide during carotid artery surgery induces increases in postoperative plasma homocysteine concentration and is associated with increases in postoperative myocardial ischemia.
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Anesthesia and analgesia · Nov 2000
Randomized Controlled Trial Clinical TrialThe efficacy of hemodynamic and T wave criteria for detecting intravascular injection of epinephrine test doses in anesthetized adults: a dose-response study.
Recent studies have shown that an epidural test dose containing 15 microg of epinephrine has a sensitivity and specificity of 100% for detecting intravascular injection based on the systolic blood pressure (SBP) (positive if > or =15-mm Hg increase) and the T wave criteria (positive if > or =0.1 mV and 25% decrease in amplitude), whereas the modified heart rate (HR) criterion (positive if > or =10-bpm increase) produced uncertain results in sevoflurane-anesthetized adults. Because a fractional dose of the test dose may be injected intravascularly in actual clinical situations, we designed this study to determine, in a dose-related manner, the efficacy and minimum effective dose of epinephrine based on those hemodynamic and the T wave criteria. Eighty healthy adult patients were randomly assigned to one of four groups according to a simulated IV test dose under 2% end-tidal sevoflurane and nitrous oxide anesthesia after endotracheal intubation (n = 20 each). The saline group received 3 mL of normal saline IV; the epinephrine-15 group received 3 mL of 1.5% lidocaine containing 15 microg of epinephrine (1); and the epinephrine-10 and -5 groups received 2 and 1 mL of the test dose of the identical components, respectively. HR, SBP, and lead II of the electrocardiograph were recorded continuously for 5 min after the IV injection of the study drug. Sensitivities and specificities of 100% were obtained based on the HR and the SBP criteria only if 15 microg of epinephrine was injected IV, whereas sensitivities and specificities of 100% were obtained based on both T wave criteria after 15 and 10 microg of epinephrine was injected IV. Two blinded observers were able to detect all T wave changes in patients who received 15, 10, and 5 microg of epinephrine IV, resulting in 100% efficacy (P: < 0.05 versus HR and SBP criteria). We conclude that minimum effective epinephrine doses for detecting accidental intravascular injection are 15 microg on the HR and the SBP criteria, and 10 microg on both T wave criteria, and that observing T wave changes may detect even smaller (5 microg) doses of epinephrine injected IV in adult patients anesthetized with sevoflurane and nitrous oxide. ⋯ To determine whether an epidural catheter is in a blood vessel, an epidural test dose containing 15 microg of epinephrine is used. We found that a decrease in T wave amplitude appears to be more sensitive than heart rate and systolic blood pressure change for detecting accidental intravascular injection of a small dose of epinephrine-containing test dose in sevoflurane-anesthetized patients.