Anesthesia and analgesia
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Anesthesia and analgesia · Jun 2000
Randomized Controlled Trial Clinical TrialLumbar sympathetic block for sympathetically maintained pain: changes in cutaneous temperatures and pain perception.
Lumbar sympathetic block (LSB) is used in the management of sympathetically maintained pain states. We characterized cutaneous temperature changes over the lower extremities after LSB. Additionally, we examined the effects of iohexol, a radio-opaque contrast medium, on temperature changes and pain relief. After institutional review board approval and written, informed consent, 28 LSBs were studied in 17 patients. Iohexol or normal saline was injected in a randomized, double-blinded fashion before bupivacaine. Lower extremity cutaneous temperatures were measured. Pain, allodynia, interference with daily function, and perceived pain relief were reported in a subset of 15 LSBs for 1 wk after the block. The distal lower extremity ipsilateral to the LSB had the greatest magnitude (8.7 degrees +/- 0.8 degrees C) and rate (1.1 degrees +/- 0.2 degrees C/min) of temperature change. The great toe temperature was within 3 degrees C of core temperature within 35 min after LSB. There were no differences in temperature change between the groups. The iohexol group had greater relief of pain until the morning of the first postblock day (P = 0.002) and longer perceived relief of pain (P = 0.01). The maximum temperature of the great toe correlated with allodynia relief (P = 0.0007). Thus clinicians should expect ipsilateral toe temperatures to increase to within approximately 3 degrees C of core temperature. Iohexol does not alter the efficacy of LSB and may improve relief of symptoms. The magnitude of temperature change may predict relief of allodynia. ⋯ Cutaneous toe temperatures approaching core temperature provide a useful monitor of lumbar sympathetic block and may predict relief of sympathetically maintained pain. Iohexol will not compromise temperature changes or pain relief.
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Anesthesia and analgesia · Jun 2000
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of remifentanil and alfentanil for use with propofol in patients undergoing minimally invasive coronary artery bypass surgery.
Most patients undergoing minimally invasive direct coronary artery bypass surgery can be awakened and tracheally extubated in the operating room. We have compared two techniques of total IV anesthesia in this patient population: 30 patients (aged 44 to 74 yr; 24 male) premedicated with temazepam were randomly assigned to receive either remifentanil-propofol or alfentanil-propofol. Anesthesia was induced with remifentanil 2 microg/kg or with alfentanil 40 microg/kg, with propofol, and maintained with remifentanil at 0.25 or 0.5 microg x kg(-1) x min(-1) or alfentanil at 0.5 or 1 microg x kg(-1) x min(-1). The stable maintenance infusion rate of propofol was adjusted for age. Times to awakening and tracheal extubation were recorded. Postoperatively, IV morphine provided by patient-controlled analgesia was used for 48 h. Times to awakening and tracheal extubation (mean +/- SD) were shorter (P < 0. 01) in patients receiving remifentanil, and interpatient variations in times to awakening and tracheal extubation smaller (awakening 25 +/- 7 vs 74 +/- 32 min, and extubation 27 +/- 7 vs 77 +/- 32 min). Analysis of variance revealed that postoperative consumption of morphine was dependent on both the intraoperative opioid and the time elapsed after surgery (P < 0.05): patient-controlled analgesia morphine use during the first 3 h after awakening was more in patients receiving remifentanil (P < 0.01). ⋯ Recovery of patients undergoing Minimally Invasive Direct Coronary Artery Bypass Surgery is significantly shorter and more predictable after total IV anesthesia with remifentanil-propofol than with alfentanil-propofol, which may be important if the goal is that patients will be awakened and tracheally extubated in the operating room.
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Anesthesia and analgesia · Jun 2000
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of the costs and efficacy of ondansetron versus dolasetron for antiemetic prophylaxis.
The optimal dose and timing of 5-HT(3) antagonist administration for prophylaxis against postoperative nausea and vomiting (PONV) remains controversial. Although 5-HT(3) antagonists seem to be most effective when administered near the end of surgery, there are no data on the comparative efficacy or costs associated with the 5-HT(3) antagonists dolasetron and ondansetron when administered at the end of the operation. In this double-blinded study, 200 outpatients undergoing otolaryngologic procedures with a standardized general anesthetic received 4 (O4) or 8 mg (O8) of ondansetron or 12.5 (D12.5) or 25 mg (D25) of dolasetron IV within 30 min before the end of surgery. A blinded observer recorded the emetic episodes, maximum nausea score, recovery room resource and drug use, nursing time spent managing PONV, times to achieve discharge criteria from the Phase 1 and 2 recovery units, postdischarge emesis, and patient satisfaction. Total costs were calculated by using the perspective of a free-standing surgicenter. There were no differences in patient demographics, incidence of PONV, need for rescue medications, time spent in the recovery areas, unanticipated hospital admissions, or patient satisfaction among the four treatment groups. The mean total costs (95% confidence intervals) to prevent PONV in one patient were lowest in the D12.5 group: $23.89 (17.18-28.79) vs $37.81 (30.29-45.32), $33.91 (28.92-39.35), and $75.18 (61.13-89.24) for D25, O4, and O8, respectively. Excluding nursing labor costs did not alter this finding: $18.51 (14.18-22.85), $34.77 (28.03-41.49), $31.77 (28. 92-39.35), and $71.76 (58.17-85.35) for D12.5, D25, O4, and O8, respectively. We conclude that 12.5 mg of dolasetron IV is more cost effective than 4 mg of ondansetron IV for preventing PONV after otolaryngologic surgery and is associated with similar patient satisfaction. ⋯ When administered at the end of surgery, 12.5 mg of dolasetron IV is as effective as 25 mg of dolasetron IV, 4 mg of ondansetron IV, and 8 mg of ondansetron IV in preventing emetic symptoms after otolaryngologic surgery and was associated with similar patient satisfaction at a reduced cost. There were no differences in the antiemetic efficacy of the 4 and 8 mg doses of ondansetron.
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Anesthesia and analgesia · Jun 2000
Randomized Controlled Trial Clinical TrialThe effects of plasma fentanyl concentrations on propofol requirement, emergence from anesthesia, and postoperative analgesia in propofol-nitrous oxide anesthesia.
To determine the effects of plasma fentanyl concentrations on intraoperative propofol requirements, emergence from anesthesia, and relief of postoperative pain, we studied 60 ASA physical status I and II patients undergoing spine fusion. The patients were randomly assigned to four study groups according to the expected intraoperative plasma fentanyl concentrations. Group I received an infusion of saline, and Groups II, III, and IV received fentanyl infusions to maintain the blood levels at 1.5, 3.0, and 4.5 ng/mL, respectively. An infusion rate of propofol was adjusted to keep the mean arterial pressure within 15% of the control value. Inspired nitrous oxide concentrations were maintained at 67%. The following were investigated in each group: 1) an average propofol infusion rate, 2) time to spontaneous eye opening and recovery of orientation (name, date, and place), and 3) total dose of fentanyl used for 24 h after admission to the postanesthetic care unit. Average propofol infusion rates were 10.1 +/- 2.5 (mean +/- SD), 7.5 +/- 1.2, 5.7 +/- 1.1, and 4.9 +/- 1.2 mg. kg(-1). h(-1), in Groups I, II, III, and IV, respectively. Groups receiving fentanyl infusion had significantly smaller infusion rates of propofol (P < 0.01) than the group receiving saline. Among the three fentanyl infusion groups, Group II (P < 0.01) had more than Groups III and IV. The time to spontaneous eye opening and the recovery of orientation were directly related to plasma fentanyl concentrations. The plasma fentanyl levels between Groups III and IV were the same. The total amount of IV patient-controlled analgesia fentanyl during postoperative 24 h increased significantly when the order of plasma fentanyl concentrations was reversed, 913.1 +/- 58.4, 553.4 +/- 129, 222.7 +/- 73.4, and 135.1 +/- 69.5 microg in Groups I, II, III, and IV, respectively. These results suggest that the addition of fentanyl infusions had ceiling effects that reduce the intraoperative propofol requirements according to the plasma fentanyl concentrations. The ceiling effect was demonstrated in the recovery of consciousness but not in the fentanyl requirements for postoperative analgesia. ⋯ The addition of fentanyl, a potent opioid, reduced the intraoperative requirement of propofol, an IV anesthetic, in the order of the plasma fentanyl concentrations. The ceiling effects of fentanyl were demonstrated in the reduction of propofol requirements and recovery of consciousness but not in the fentanyl requirements for postoperative analgesia.
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Anesthesia and analgesia · Jun 2000
Randomized Controlled Trial Clinical TrialOrnipressin (Por 8): An efficient alternative to counteract hypotension during combined general/epidural anesthesia.
We sought to evaluate the efficacy and side effect profile of a small dose of ornipressin, a vasopressin agonist specific for the V1 receptor, administered to reverse the hypotension associated with combined general/epidural anesthesia. A total of 60 patients undergoing intestinal surgery were studied. After the induction of anesthesia, 7-8 mL of bupivacaine 0.5% with 2 microg/kg clonidine and 0.05 microg/kg sufentanil after an infusion of 5 mL of bupivacaine 0.06% with 0.5 microg x kg(-1) x h(-1) clonidine and 0.1 microg/h of sufentanil were administered by an epidural catheter placed at T7-8 vertebral interspace. When 20% reduction of baseline arterial blood pressure developed, patients were randomly assigned to receive, in a double-blinded design, dopamine started at 2 microg x kg(-1) x min(-1), norepinephrine started at 0.04 microg x kg(-1) x min(-1), or ornipressin started at 1 IU/h. Fifteen patients presenting without hypotension were used as control subjects. Beside routine monitoring, S-T segment analysis, arterial lactacidemia, and gastric tonometry were performed. Ornipressin restored arterial blood pressure after 8 +/- 2 vs 7 +/- 3 min in the norepinephrine group and 11 +/- 3 min in the dopamine group (P < 0.05). This effect was achieved with 2 IU/h of ornipressin in most of the patients (11 of 15). Ornipressin did not induce any modification of the S-T segment; however, it significantly increased intracellular gastric PCO(2) (P < 0.05), indicating splanchnic vasoconstriction. ⋯ In the population studied, small-dose ornipressin was effective to restore arterial blood pressure without causing major ischemic side effects.