Anesthesia and analgesia
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Anesthesia and analgesia · Nov 1996
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of isoflurane versus fentanyl as primary anesthetics for mitral valve surgery.
We conducted a randomize study of fentanyl compared to isoflurane anesthesia in patients with pulmonary hypertension undergoing mitral valve surgery. Patients were premedicated and randomly assigned to one of two groups: 21 patients had anesthesia induced with thiopental and maintained with isoflurane; 23 patients had anesthesia induced with a fentanyl bolus and maintained with a fentanyl infusion. Adjustments of fentanyl infusion and isoflurane concentration, as well as fentanyl boluses and vasoactive/positive inotropic medication, were administered to maintain preoperative arterial blood pressure. ⋯ Adequate hemodynamic profiles were achieved in both groups with comparable use of inotropic and vasoactive medication, with the exception of norepinephrine that was administered intraoperatively to significantly (P < 0.05) more patients in the isoflurane-based anesthesia group. Neither technique was associated with acute improvement of right heart performance or pulmonary hypertension, in large part because of morphologic changes of the pulmonary arterial bed, occurring with long-standing mitral valve disease. We conclude that isoflurane-based anesthesia is adequate for this type of surgery, although there is a higher anesthetic algorithm failure rate than with fentanyl-based anesthetic technique.
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Anesthesia and analgesia · Nov 1996
Randomized Controlled Trial Clinical TrialIntraoperative antiemetic efficacy of prophylactic ondansetron versus droperidol for cesarean section patients under epidural anesthesia.
The efficacy of ondansetron and droperidol were evaluated for prophylactic treatment of nausea and vomiting in cesarean section patients under epidural anesthesia. Forty-eight ASA physical status I-II parturients requiring nonemergent cesarean section gave their consent and were randomly assigned into one of three treatment groups (n = 16 each) according to a double-blind, placebo-controlled protocol. When the fetal umbilical cord was clamped, patients received intravenously 8 mg of ondansetron or 0.625 mg of droperidol or saline depending on their treatment group. ⋯ This study showed a significantly lower incidence of nausea and vomiting and a tendency toward less severe emetic symptoms in the ondansetron and the droperidol groups than in the placebo group, but the ondansetron group was not statistically different from the droperidol group. This study is the first to report the antiemetic efficacy of prophylactic ondansetron in cesarean section patients or in patients under epidural anesthesia for abdominal surgery. Both prophylactic ondansetron and droperidol were similarly effective, and significantly better than placebo, in reducing the incidence and severity of intraoperative emetic symptoms in cesarean section patients under epidural anesthesia.
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Anesthesia and analgesia · Nov 1996
Randomized Controlled Trial Clinical TrialDexamethasone decreases vomiting by children after tonsillectomy.
We evaluated the effect of dexamethasone on vomiting after elective tonsillectomy in 133 healthy children aged 2-12 yr in a randomized, stratified, blocked, double-blind, placebo-controlled study. General anesthesia was induced by inhalation of N2O and halothane or intravenously (IV) with propofol. Anesthesia was maintained with N2O and halothane. ⋯ Vomiting, both in-hospital and postdischarge, was decreased by the prophylactic administration of dexamethasone. Each episode of in-hospital vomiting prolonged discharge by 13 +/- 2 min, mean +/- SD (P < 0.001). In conclusion, dexamethasone markedly decreased vomiting by healthy children after elective tonsillectomy in an ambulatory hospital setting.
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Anesthesia and analgesia · Nov 1996
Randomized Controlled Trial Clinical TrialEffects of a hemoglobin-based oxygen carrier (HBOC-201) on hemodynamics and oxygen transport in patients undergoing preoperative hemodilution for elective abdominal aortic surgery.
We conducted a pilot study to evaluate the effects of HBOC-201, a bovine hemoglobin-based oxygen carrier, on hemodynamics and oxygen transport in patients undergoing preoperative hemodilution for elective abdominal aortic surgery. After induction of anesthesia and isovolemic hemodilution with 1 L of lactated Ringer's solution, 13 patients were randomly assigned to receive, within 30 min, 3 mL/kg of either HBOC-201 or 6% hydroxyethyl starch (HES). Monitored variables included invasive arterial and pulmonary artery pressures, arterial and mixed venous blood gases, and calculations of cardiac index (CI), systemic and pulmonary vascular resistance indices, oxygen delivery index (DO2I), oxygen consumption index (VO2I), and oxygen extraction ratio (O2ER). ⋯ No significant changes were noticed in heart rate and pulmonary vascular resistance index. DO2I and VO2I, 30 min after the infusion of HBOC-201, were 79% (P = 0.046) and 76% (P = 0.028) of the preinfusion values, respectively, whereas CaO2 and O2ER remained unaffected. We conclude that HBOC-201, at a dose of 3 mL/kg, impairs oxygen delivery because of adverse effects on cardiac output.
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Anesthesia and analgesia · Nov 1996
Comparative StudyA comparison of the sensitivity of epidural and myogenic transcranial motor-evoked responses in the detection of acute spinal cord ischemia in the rabbit.
Monitoring motor-evoked responses to transcranial stimulation (tc-MERs) provides information about the functional status of the spinal cord during operations that pose the risk of spinal cord ischemia. Responses can be recorded from the epidural space (epidural tc-MERs) or from muscle (myogenic tc-MERs). In this study the relative sensitivity of epidural and myogenic tc-MERs to acute spinal cord ischemia was compared. ⋯ Lower extremity ischemia as a cause of changes in myogenic tc-MER amplitude was excluded by ligating the right femoral artery and demonstrating that myogenic responses were preserved for 30 min, before occluding the aorta. We conclude that myogenic responses are more sensitive to acute spinal cord ischemia than epidural responses. The rapid detection of spinal cord ischemia with transcranial myogenic motor-evoked responses could be of clinical use in assessing the adequacy of spinal cord blood flow during operations where the spinal cord is at risk.