Anesthesia and analgesia
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Anesthesia and analgesia · Aug 1999
Randomized Controlled Trial Clinical TrialPostoperative analgesia with no motor block by continuous epidural infusion of ropivacaine 0.1% and sufentanil after total hip replacement.
We assessed the analgesic efficacy of postoperative epidural ropivacaine 0.1% with and without sufentanil 1 microgram/mL in this prospective, randomized, single-blinded study of 30 ASA physical status I-III patients undergoing elective total hip replacement. Lumbar epidural block using 0.75% ropivacaine was combined with either propofol sedation or general anesthesia for surgery. After surgery, the epidural infusion was commenced. Fifteen patients in each group received either an epidural infusion of 0.1% ropivacaine with 1 microgram/mL sufentanil (R + S) or 0.1% ropivacaine without sufentanil (R) at a rate of 5-9 mL/h. All patients had access to i.v. piritramide via a patient-controlled analgesia device. The R + S group consumed six times less piritramide over a 48-h infusion period than the R group (median 12.7 vs 73.0 mg; P < 0.001). Motor block was negligible for the study duration in both groups. Patient satisfaction was excellent. The incidence of adverse events, such as nausea, was similar. We conclude that a continuous epidural infusion of 0.1% ropivacaine with 1 microgram/mL sufentanil is more effective than ropivacaine alone in treating pain after elective hip replacement without motor block. ⋯ This is the first randomized study comparing the efficacy of the epidural combination of ropivacaine 0.1% and sufentanil 1 microgram/mL versus plain ropivacaine 0.1% in treating pain after hip replacement. We found that ropivacaine 0.1% and sufentanil 1 microgram/mL led to a sixfold reduction in opioid requirements after total hip replacement by producing a negligible motor block.
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Anesthesia and analgesia · Aug 1999
Effects of one minimum alveolar anesthetic concentration sevoflurane on cerebral metabolism, blood flow, and CO2 reactivity in cardiac patients.
We investigated the cerebral hemodynamic effects of 1 minimum alveolar anesthetic concentration (MAC) sevoflurane anesthesia in nine male patients scheduled for elective coronary bypass grafting. For measurement of cerebral blood flow (CBF), a modified Kety-Schmidt saturation technique was used with argon as an inert tracer gas. Measurements of CBF were performed before the induction of anesthesia and 30 min after induction under normocapnic, hypocapnic, and hypercapnic conditions. Compared with the awake state under normocapnic conditions, sevoflurane reduced the mean cerebral metabolic rate of oxygen by 47% and the mean cerebral metabolic rate of glucose by 39%. Concomitantly, CBF was reduced by 38%, although mean arterial pressure was kept constant. Significant changes in jugular venous oxygen saturation were absent. Hypocapnia and hypercapnia caused a 51% decrease and a 58% increase in CBF, respectively. These changes in CBF caused by variation of Paco2 indicate that cerebrovascular CO2 reactivity persists during 1 MAC sevoflurane anesthesia. ⋯ We used a modified Kety-Schmidt saturation technique to investigate the effects of 1 minimum alveolar anesthetic concentration (MAC) sevoflurane on cerebral blood flow, metabolism, and CO2 reactivity in cardiac patients. We found that the global cerebral blood flow and global cerebral metabolic rate of oxygen remained coupled and that cerebrovascular CO2 reactivity is not impaired by the administration of 1 MAC sevoflurane.
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Anesthesia and analgesia · Aug 1999
Epidural anesthesia and analgesia are not impaired after dural puncture with or without epidural blood patch.
Previous reports have noted a decrease in the success of subsequent epidural anesthesia and analgesia in patients who have undergone prior dural puncture with or without an epidural blood patch. Our retrospective study evaluated the success of epidural anesthesia and analgesia in all patients at the Mayo Clinic who had received a prior epidural blood patch over a 12-yr period. Each epidural blood patch patient was matched to two patients undergoing epidural anesthesia after previous dural puncture (without epidural blood patch) and to two patients undergoing epidural anesthesia after previous epidural anesthetic (without dural puncture/blood patch). These patients were matched for the duration of time between the initial procedure and subsequent epidural anesthetic and the indication (surgery, labor analgesia, postoperative analgesia) for which the subsequent epidural was performed. Subsequent epidural anesthesia was successful in 28 of 29 (96.6%, exact 95% CI 82.2%-99.9%) patients who had undergone prior blood patch, 55 of 58 (94.8%, 85.6%-98.9%) patients with a history of dural puncture, and 55 of 58 (94.8%, 85.6%-98.9%) patients who had had previous epidural anesthesia. There was no significant difference in the success rate of subsequent epidural anesthesia among groups. We conclude that prior dural puncture, with or without epidural blood patch, does not affect the success rate of subsequent epidural anesthesia. ⋯ Patients with postdural puncture headache should not be denied the benefits of an epidural blood patch because of concerns about the impairment of subsequent epidural anesthetics. The success rate of subsequent epidural anesthesia and analgesia in patients who have undergone dural puncture with or without epidural blood patch is similar to that of patients who have undergone two prior epidural anesthetics.
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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 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.