Anesthesia and analgesia
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Anesthesia and analgesia · Mar 1998
Randomized Controlled Trial Comparative Study Clinical Trial0.125% ropivacaine is similar to 0.125% bupivacaine for labor analgesia using patient-controlled epidural infusion.
We compared the effects of 0.125% ropivacaine with 0.125% bupivacaine in laboring patients using patient-controlled epidural analgesia (PCEA). Fifty-one ASA physical status I or II term parturients with functioning epidural catheters were randomized to receive ropivacaine or bupivacaine using a prospective, double-blind design. Basal infusions (6 mL/h) were supplemented with patient-controlled boluses (5 mL) every 10 min as required. For inadequate analgesia, patients were administered 10-mL boluses of study solution until comfortable. There were no differences in verbal pain scores, amount of local anesthetics used, sensory levels, motor blockade, labor duration, mode of delivery, side effects, or patient satisfaction between the two local anesthetics. We conclude that 0.125% ropivacaine and bupivacaine are clinically indistinguishable and are both highly effective for labor analgesia using PCEA. ⋯ This study compared labor analgesia from 0.125% ropivacaine and 0.125% bupivacaine using patient-controlled epidural analgesia. We found no significant differences in local anesthetic use, analgesic characteristics, or side effects between 0.125% ropivacaine and 0.125% bupivacaine. We conclude that these two drugs are clinically indistinguishable at this concentration.
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Anesthesia and analgesia · Mar 1998
Randomized Controlled Trial Clinical TrialAlfentanil as an adjuvant to epidural bupivacaine in the management of postoperative pain after laparotomies: lack of evidence of spinal action.
In this double-blind study, we compared the efficacy of epidural versus i.v. administration of alfentanil in combination with small-dose bupivacaine for postoperative pain relief. Thirty-two patients were randomly allocated to one of two study groups. Patients from both groups received an epidural loading dose of 60 mg of bupivacaine (12 mL of 0.5%). Subsequently, patients in the epidural (EPI) group received an infusion (8 mL/h) of 0.125% bupivacaine (10 mg/h) plus alfentanil (0.36 mg/h) and an i.v. infusion (8 mL/h) of NaCl 0.9%. Patients in the i.v. group received an epidural infusion (8 mL/h) of 0.125% bupivacaine (10 mg/h) and an i.v. infusion (8 mL/h) of alfentanil (0.36 mg/h). Infusions were maintained for 24 h. These dose regimens were such that equivalent subanalgesic plasma concentrations of alfentanil were obtained. Patient-controlled analgesia with morphine was available to both groups. Time to onset of postoperative pain and morphine consumption were used as variables to compare the two regimens. Measured plasma concentrations of alfentanil during the postoperative observation period were similar (< 20 ng/mL) in both groups. Median times to onset of postoperative pain (EPI 600 min, i.v. 360 min) and total morphine consumption (EPI 11 mg, i.v. 10 mg) did not differ between the groups (P > 0.2). We conclude that, in combination with epidural bupivacaine 0.125%, an i.v. infusion of alfentanil is equally effective as an epidural infusion of alfentanil if the plasma concentrations are the same. The study did not demonstrate a spinal mechanism of action for alfentanil. ⋯ This randomized, double-blind study showed that, when combined with small-dose bupivacaine (0.125%), epidurally administered alfentanil is not more effective than i.v. administered alfentanil for postoperative pain management when the regimens are such that equivalent subanalgesic plasma alfentanil concentrations are obtained. A spinal mechanism of action for alfentanil could therefore not be demonstrated.
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Anesthesia and analgesia · Mar 1998
Randomized Controlled Trial Clinical TrialProphylactic ephedrine attenuates the hemodynamic response to propofol in elderly female patients.
In this study, we compared the effect of prophylactic administration of ephedrine against the hypotensive effect of propofol in elderly female patients scheduled for minor gynecological procedures. Ninety patients aged 60 yr or older were randomly allocated to one of three groups of 30 patients each to receive either normal saline, ephedrine 0.1 mg/kg, or ephedrine 0.2 mg/kg i.v. 1 min before the induction of anesthesia. Anesthesia was induced and maintained with propofol and fentanyl. Hemodynamic variables were measured before and 2, 5, 10, 15, 30, and 60 min after induction. The decrease in blood pressure and heart rate (HR) was significantly less in each of the ephedrine groups (P < 0.001). Furthermore, the decrease was less in the large-dose group compared with the small-dose group (P < 0.05). Twelve patients in the control group experienced a decrease in systolic blood pressure to < 80 mmHg, compared with only one patient in the ephedrine groups (P < 0.001). In conclusion, the prophylactic injection of ephedrine significantly attenuated, but did not completely abolish, the decrease in blood pressure associated with induction of anesthesia with fentanyl and propofol. Ephedrine 0.2 mg/kg was slightly more effective than ephedrine 0.1 mg/kg. ⋯ The prophylactic effect of ephedrine to counteract the hypotensive effect of propofol induction of anesthesia was investigated in three groups of elderly female patients given 0.1 or 0.2 mg of ephedrine or placebo before induction. Both ephedrine doses markedly attenuated, but neither of them abolished, the decrease in blood pressure.
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Anesthesia and analgesia · Mar 1998
Absence of renal and hepatic toxicity after four hours of 1.25 minimum alveolar anesthetic concentration sevoflurane anesthesia in volunteers.
Sevoflurane is degraded by CO2 absorbents to Compound A. The delivery of sevoflurane with a low fresh gas flow increases the generation of Compound A. The administration of Compound A to rats can produce injury to renal tubules that is dependent on both the dose and duration of exposure to Compound A. The present study evaluated renal and hepatic function in eight volunteers after a 1-L/min delivery of 3% (1.25 minimum alveolar anesthetic concentration) sevoflurane for 4 h. Volunteers gave their informed consent and provided 24-h urine collections before and for 3 days after sevoflurane anesthesia. Urine samples were analyzed for glucose, protein, albumin, and alpha- and pi-glutathione-S-transferase. Daily blood samples were analyzed for markers of renal and liver injury or dysfunction. Circuit Compound A and plasma fluoride concentrations were determined. During anesthesia, the average maximal inspired Compound A concentration was 39 +/- 6 (mean +/- SD). The median mean arterial pressure, esophageal temperature, and end-tidal CO2 were 62 +/- 6 mmHg, 36.5 +/- 0.3 degrees C, and 30.5 +/- 0.5 mm Hg, respectively. Two hours after anesthesia, the plasma fluoride concentration was 50 +/- 9 micromol/L. All markers of hepatic and renal function were unchanged after anesthesia (repeated-measures analysis of variance P > 0.05). Low-flow sevoflurane was not associated with renal or hepatic injury in humans based on unchanged biochemical markers of renal and liver function. ⋯ Sevoflurane delivered in a 3% concentration with a fresh gas flow of 1 L/min for 4 h generated an average maximal Compound A concentration of 39 ppm but did not result in any significant increase in sensitive markers of renal function or injury, including urinary protein, albumin, glucose, and alpha- and pi-glutathione-S-transferase.
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Anesthesia and analgesia · Mar 1998
Learning manual skills in anesthesiology: Is there a recommended number of cases for anesthetic procedures?
The learning process is a multidimensional function with a wide intra- and interindividual scattering. To determine the learning process in anesthesia, we evaluated 11 first-year residents according to their rate of success or failure when applying manual anesthesiological skills, such as performance of spinal, epidural, or brachial plexus anesthesia and tracheal intubation or insertion of an arterial line. Epidural anesthesia was the most difficult procedure (P < 0.05). Significant differences were found between epidural anesthesia and tracheal intubation (P < 0.05), insertion of an arterial line (P < 0.05), and brachial plexus block (P < 0.05), as well as between spinal anesthesia and orotracheal intubation (P < 0.05). Learning curves are a valid tool for monitoring institutional and individual success. ⋯ To investigate the learning process in anesthesia, typical anesthetic procedures were performed by inexperienced residents during their first year. Learning curves were generated for each procedure performed. Epidural anesthesia was the most difficult procedure to perform (P < 0.05).