Anesthesia and analgesia
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Anesthesia and analgesia · Aug 1999
Randomized Controlled Trial Multicenter Study Comparative Study Clinical TrialThe effects of rapacuronium on histamine release and hemodynamics in adult patients undergoing general anesthesia.
Neuromuscular blocking drugs may have variable effects on heart rate (HR) and blood pressure. Rapacuronium is a rapid-acting, steroidal-derived neuromuscular blocking drug whose hemodynamic effects have not been characterized. We studied the effects of 1, 2, and 3 mg/kg rapacuronium on histamine release, HR, and blood pressure in 47 ASA physical status II or III adult patients after the induction of anesthesia with etomidate/fentanyl/N2O. Plasma histamine concentrations were measured before induction and immediately before and 1, 3, and 5 min after the rapid administration of rapacuronium. Mean arterial pressure (MAP) decreased after rapacuronium administration, but there were no significant differences among the groups for changes in HR or MAP, and there was no correlation between changes in MAP or HR and increases in histamine levels. There were no changes in HR or MAP among five patients who had significant (> or = 1 ng/mL) increases in histamine from baselin. Seven patients had bronchospasm without increases in plasma histamine levels. Rapacuronium 2-3 mg/kg increased plasma histamine levels. However, clinically significant histamine-related sequelae did not occur in this population with 1- to 3-mg/kg doses of rapacuronium, and cardiovascular changes were not directly correlated with histamine release. Rapacuronium administration can produce hypotension via mechanisms that do not seem to be related to histamine release. ⋯ Rapacuronium, a new steroidal-derived muscle relaxant, may release histamine and produce slight changes in blood pressure and heart rate after administration.
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Anesthesia and analgesia · Aug 1999
Randomized Controlled Trial Clinical TrialAnalgesia, pruritus, and ventilation exhibit a dose-response relationship in parturients receiving intrathecal fentanyl during labor.
Several studies have characterized the 50% and 95% effective doses (ED50 and ED95, respectively) of intrathecal sufentanil for labor analgesia. Few have investigated these same criteria for the less expensive alternative, fentanyl. In addition, the ventilatory effects of intrathecal fentanyl at clinically relevant doses are unclear. We performed this study to establish the dose-response relationship of intrathecal fentanyl for both analgesia and ventilatory depression. Ninety parturients in active early labor (< or = 5 cm dilation) received intrathecal fentanyl 5, 7.5, 10, 15, 20, or 25 micrograms in a double-blinded, randomized fashion (n = 15 patients in each group). Parturients were monitored for degree of pain (measured using a 100-mm visual analog pain scale), blood pressure, arterial oxygen saturation (SaO2), respiratory rate, ETCO2, and fetal heart rate 0, 1, 5, 10, 15, 20, 25, and 30 min after the administration of intrathecal fentanyl. An absolute visual analog pain scale score < or = 25 mm was defined a priori as analgesic success. The percentage of parturients who achieved analgesic success was used to construct quantal dose-response curves, from which the ED50 and ED95 values were derived for the total population (mixed parity) and the nulliparous and multiparous subpopulations separately. Overall ED50 and ED95 values (95% CI) were 5.5 (3.4-7.2) and 17.4 (13.8-27.1) micrograms, respectively. Nulliparous values were lower (5.3 and 15.9 micrograms, respectively) than multiparous values (6.9 and 26.0 micrograms, respectively) but were within the 95% CIs of the total population. Pruritus incidence in parturients with analgesic success displayed a dose-response relationship identical to that seen for analgesia. ETCO2 displayed a dose-related increase, particularly at doses > or = 15 micrograms, without concomitant changes in respiratory rate or SaO2, which suggests a decrease in tidal volume. Even in the absence of overt signs or symptoms of somnolence, intrathecal fentanyl at doses within the effective analgesic range induced a change in ventilation that may last longer than the 30-min period we studied. ⋯ Intrathecal fentanyl induces rapid and satisfying dose-dependent analgesia in early labor; however, it also produces dose-related decreases in ventilation in the absence of overt somnolence.
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Anesthesia and analgesia · Aug 1999
Randomized Controlled Trial Comparative Study Clinical TrialA cost comparison of methohexital and propofol for ambulatory anesthesia.
Methohexital is eliminated more rapidly than thiopental, and early recovery compares favorably with propofol. We designed this study to evaluate the recovery profile when methohexital was used as an alternative to propofol for the induction of anesthesia before either sevoflurane or desflurane in combination with nitrous oxide. One hundred twenty patients were assigned randomly to one of four anesthetic groups: (I) methohexital-desflurane, (II) methohexital-sevoflurane, (III) propofol-desflurane, or (IV) propofol-sevoflurane. Recovery times after the anesthetic drugs, as well as the perioperative side effect profiles, were similar in all four groups. A cost-minimization analysis revealed that methohexital was less costly for the induction of anesthesia. At the fresh gas flow rates used during this study, the costs of the volatile anesthetics for maintenance of anesthesia did not differ among the four groups. However, at low flow rates (< or = 1 L/min), the methohexital-desflurane group would have been the least expensive anesthetic technique. In conclusion, methohexital is a cost-effective alternative to propofol for the induction of anesthesia in the ambulatory setting. At low fresh gas flow rates, the methohexital-desflurane combination was the most cost-effective for the induction and maintenance of general anesthesia. ⋯ Using methohexital as an alternative to propofol for the induction of anesthesia for ambulatory surgery seems to reduce drug costs. When fresh gas flow rates < or = 1 L/min are used, the combination of methohexital for the induction and desflurane for maintenance may be the most cost-effective general anesthetic technique for ambulatory surgery.
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Anesthesia and analgesia · Aug 1999
Randomized Controlled Trial Clinical TrialPerioperative dextromethorphan reduces postoperative pain after hysterectomy.
We studied the effect of dextromethorphan, an N-methyl-D-aspartate antagonist, on analgesic consumption and pain scoring after abdominal hysterectomy. In this double-blinded study, 50 patients were randomized into two groups. Group DM was given oral dextromethorphan 40 mg with their premedication, then 40 mg three times per day for the next 2 days. Group P received placebo at identical times. Postoperative analgesic requirements were assessed using a patient-controlled analgesia system and subsequent oral analgesic intake using a set protocol. Pain was assessed at rest and on movement using a visual analog scale 4, 24, 48, and 72 h after the operation. Median pain scores at rest were significantly lower at 48 and 72 h and also for the sum of all resting pain scores. Mean morphine consumption was less in Group DM (1.1 vs 1.5 mg/h; P = 0.054). Usage of oral diclofenac, given every 8 h as needed, did not differ between groups, but consumption of codydramol (paracetamol 500 mg and dihydrocodeine 10 mg) was significantly less in Group DM. We conclude that the use of oral dextromethorphan has an analgesia-sparing effect and some beneficial effects on pain scoring at rest after abdominal hysterectomy. ⋯ Patients given dextromethorphan before and after surgery had a significant reduction in some pain scores at rest, but not on movement. There was a trend to lower morphine requirements in the first 24 h. Over the next 48 h, oral analgesic usage was significantly reduced.