Anesthesia and analgesia
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Anesthesia and analgesia · Jan 1997
Randomized Controlled Trial Comparative Study Clinical TrialPrevention of hypotension during spinal anesthesia: a comparison of intravascular administration of hetastarch versus lactated Ringer's solution.
This study was designed to compare the efficacy of 6% hetastarch to that of crystalloid administration in reducing the incidence and severity of hypotension during spinal anesthesia. Forty ASA grade I patients scheduled for postpartum tubal ligations under spinal anesthesia were randomly allocated to receive either 500 mL of hetastarch solution or 1000 mL of lactated Ringer's solution prior to spinal anesthesia. Spinal anesthesia was managed identically in both groups by anesthesiologists who were unaware of the type of fluid administered. ⋯ The difference in the incidence of hypotension was significant (P < 0.05). The requirement of 5-mg bolus doses of ephedrine to maintain systolic arterial blood pressure > 75% of baseline was significantly greater in the lactated Ringer's group than in the hetastarch group (15 vs 4, P < 0.05). We conclude that an intravenous infusion of 500 mL of 6% hetastarch solution is more effective than 1000 mL lactated Ringer's solution in attenuating spinal anesthesia induced hypotension in women undergoing postpartum tubal ligation.
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Anesthesia and analgesia · Jan 1997
Randomized Controlled Trial Clinical TrialHemodynamic effects, myocardial ischemia, and timing of tracheal extubation with propofol-based anesthesia for cardiac surgery.
Recent interest in earlier tracheal extubation after coronary artery bypass graft (CABG) surgery has focused attention on the potential benefits of a propofol-based technique. We randomized 124 patients (34 with poor ventricular function) undergoing CABG surgery to receive either a propofol-based (5 mg.kg-1.h-1 prior to sternotomy, 3 mg.kg-1. h-1 thereafter; n = 58) or enflurane-based (0.2%-1.0%, n = 66) anesthetic. Induction of anesthesia consisted of fentanyl 15 micrograms/kg and midazolam 0.05 mg/kg intravenously in both groups. ⋯ Patients receiving propofol were extubated earlier (median 9.1 h versus 12.3 h, P = 0.006), although there was no difference in time to intensive care unit (ICU) discharge (both 22 h, P = 0.54). Both groups had similar hemodynamic changes throughout (all P > 0.10), as well as metaraminol (P = 0.49) and inotrope requirements (P > 0.10), intraoperative myocardial ischemia (P = 0.12) and perioperative myocardial infarction (P = 0.50). The results of this trial suggest that a propofol-based anesthetic, when compared to an enflurane-based anesthetic requiring additional dosing of fentanyl and midazolam for CPB, can lead to a significant reduction in time to extubation after CABG surgery, without adverse hemodynamic effects, increased risk of myocardial ischemia or infarction.
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Anesthesia and analgesia · Jan 1997
Randomized Controlled Trial Clinical TrialThe duration of impairment of autonomic control after anticholinergic drug administration in humans.
Impaired parasympathetic control of heart rate is associated with increased incidence of cardiac dysrhythmias and ischemia. Anticholinergic drugs, commonly administered during reversal of neuromuscular blockade, suppress parasympathetic control in the early postoperative period. This could potentially be detrimental in patients at risk of cardiovascular complications. ⋯ Both drugs resulted in a marked decrease in baroreflex sensitivity and high-frequency heart rate variability. The times to return to baseline values were approximately doubled after atropine compared to glycopyrrolate (177 +/- 22 vs 82 +/- 8 min for baroreflex sensitivity, 212 +/- 16 vs 111 +/- 14 min for high-frequency power, and 171 +/- 18 vs 95 +/- 18 min for high-frequency power normalized to total power; P < 0.01 for all variables). Atropine leads to more prolonged impairment of parasympathetic control than equipotent doses of glycopyrrolate, and its use may thus be less desirable in high-risk patients in the early postoperative period.
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Anesthesia and analgesia · Jan 1997
Randomized Controlled Trial Clinical TrialSmall-dose propofol by continuous infusion does not prevent postoperative vomiting in females undergoing outpatient laparoscopy.
This study was designed to test the hypothesis that there is a direct prophylactic antiemetic effect of small-dose propofol given by continuous infusion. Sixty female patients undergoing outpatient laparoscopy under general anesthesia were randomized to receive, in a double-blind fashion, either a bolus of 0.1 mg/kg followed by a constant infusion of 1 mg.kg-1.h-1 of propofol or an equivalent volume of 10% Intralipid (placebo) beginning 30 min before induction of anesthesia and continuing until discharge from Stage I postanesthesia care unit (PACU). Anesthesia was induced and maintained in a standard fashion in all patients. ⋯ No significant differences between Intralipid and propofol were found for any of the outcome variables tested. While small-dose propofol is an effective adjuvant in reducing chemotherapy-induced emesis, we were unable to demonstrate any beneficial effect of propofol in reducing postoperative nausea and vomiting when used as the sole prophylactic medication in this patient population. Propofol may have a synergistic effect when administered with other antiemetics, or the specific antiemetic effect of propofol, if it exists, may be dose-dependent and the dose used in this study was below the efficacy threshold.
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Anesthesia and analgesia · Jan 1997
Randomized Controlled Trial Clinical TrialSmall-dose hypobaric lidocaine-fentanyl spinal anesthesia for short duration outpatient laparoscopy. II. Optimal fentanyl dose.
We performed a double-blind, controlled trial to determine the optimal dose of intrathecal fentanyl in small-dose hypobaric lidocaine spinal anesthesia for outpatient laparoscopy. Sixty-four gynecological patients were randomized into three groups, receiving 0, 10, or 25 micrograms fentanyl added to 20 mg lidocaine and sterile water (total 3 mL). Administration was with 27-gauge Whitacre needles and patients sat upright until the block was > T-8. ⋯ Based on these results, we concluded that 25 micrograms intrathecal fentanyl is required when 20 mg lidocaine is used for hypobaric spinal anesthesia (SA) to ensure reliable, durable anesthesia, reduce shoulder-tip pain, and minimize the need for intraoperative supplementation. This dose provides longer postoperative analgesia and does not increase side effects apart from pruritus. SA with small-dose hypobaric lidocaine-fentanyl was found to be a satisfactory technique for outpatient laparoscopy, although postdural puncture headache can occur in some patients.