Anesthesia and analgesia
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Anesthesia and analgesia · Mar 2000
Randomized Controlled Trial Clinical TrialSedative, amnestic, and analgesic properties of small-dose dexmedetomidine infusions.
This research determined the safety and efficacy of two small-dose infusions of dexmedetomidine by evaluating sedation, analgesia, cognition, and cardiorespiratory function. Seven healthy young volunteers provided informed consent and participated on three occasions with random assignment to drug or placebo. Heart rate, blood pressure, respiratory rate, ETCO(2), O(2) saturation, and processed electroencephalogram (bispectral analysis) were monitored. ⋯ IMPLICATIPNS: The alpha(2) agonist, dexmedetomidine, has sedation and analgesic properties. This study quantified these effects, as well as cardiorespiratory, memory and psychomotor effects, in healthy volunteers. Dexmedetomidine infusions resulted in reversible sedation, mild analgesia, and memory impairment without cardiorespiratory compromise.
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Anesthesia and analgesia · Mar 2000
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of rabeprazole, lansoprazole, and ranitidine for improving preoperative gastric fluid property in adults undergoing elective surgery.
Acid aspiration syndrome at the induction of anesthesia is still a potentially life-threatening complication. Its severity is affected by both pH and volume of the gastric juice that is aspirated. We compared the effects of rabeprazole (a new proton pump inhibitor), lansoprazole, and ranitidine on gastric fluid properties in a prospective, randomized, double-blinded fashion in 180 adult patients undergoing elective surgery. Patients were divided into six groups (n = 30 in each) according to their premedication. Patients in each group received placebo-rabeprazole (PLA-RAB), rabeprazole-placebo (RAB-PLA), rabeprazole-rabeprazole (RAB-RAB), lansoprazole-lansoprazole (LAN-LAN), placebo-ranitidine (PLA-RAN), or placebo-placebo (PLA-PLA) for the first-second medication. Each dose of the study drug was 20 mg for rabeprazole, 30 mg for lansoprazole, and 150 mg for ranitidine. The first medication was given orally at 9:00 PM on the day before surgery and the second at 5:30 AM on the day of surgery. Each patient fasted overnight and took the drug with 20 mL of water. After tracheal intubation, gastric fluid was aspirated via an orogastric tube, and the volume and pH of the aspirate was measured. Preoperative gastric fluid acidity and volume were improved by the study drugs in the following order: PLA-RAN (pH 5.3, volume 0.10 mL/kg), RAB-RAB, LAN-LAN, PLA-RAB, and RAB-PLA (pH 3.8, volume 0.22 mL/kg). The proportion of patients at risk of acid aspiration syndrome according to the traditional criteria (pH < 2.5 and volume > 0.4 mL/kg) was minimized in Groups RAB-RAB and PLA-RAN (0%). We concluded that a single morning dose of ranitidine rather than two doses (bedtime and morning) of rabeprazole was the most effective premedicant to control gastric fluid properties and to minimize the risk of aspiration pneumonitis. ⋯ Acid aspiration syndrome at the induction of anesthesia is rare but still a potentially life-threatening complication. We compared rabeprazole, lansoprazole, and ranitidine for reduction of preoperative gastric fluid acidity and volume in elective surgery and found that a combination of bedtime and morning doses of rabeprazole, or a morning dose of ranitidine, similarly minimized the variables. In adult patients who are at risk of aspirating gastric contents, improvement of gastric fluid environment by rabeprazole can reasonably be anticipated to provide protection against pneumonitis should regurgitation and aspiration of gastric contents occur.
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Anesthesia and analgesia · Mar 2000
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of epidural levobupivacaine 0.75% with racemic bupivacaine for lower abdominal surgery.
Levobupivacaine, the S(-) isomer of bupivacaine, is less cardiotoxic than racemic bupivacaine. In this prospective, randomized, double-blinded study of epidural anesthesia, the onset, extent, and duration of sensory and motor block produced by 0.75% levobupivacaine (20 mL, 150 mg) was compared with that of 0.75% racemic bupivacaine in 56 patients undergoing elective lower abdominal surgery. The time to onset of adequate sensory block (T10 dermatome) was similar in both treatment groups (13.6 +/- 5.6 min for levobupivacaine and 14.0 +/- 9.9 min for bupivacaine), with an average peak block height of T5 reached at 24.3 +/- 9.4 and 26.5 +/- 13.2 min, respectively. Time to complete regression of sensory block was significantly longer with levobupivacaine (550.6 +/- 87.6 min) than bupivacaine (505.9 +/- 71.1 min) (P = 0.016). Abdominal muscle relaxation was adequate for the scheduled procedure in all patients, and there were no significant differences between the groups in rectus abdominis muscle scores (P = 0.386) and quality of muscle relaxation as determined by the surgeon and anesthesiologist (P = 0. 505 and 0.074, respectively). In conclusion, both 0.75% levobupivacaine and 0.75% bupivacaine produced effective epidural anesthesia and their effects were clinically indistinguishable. ⋯ The results of this study indicate that the sensory and motor block produced by 0.75% levobupivacaine is equivalent to that of 0.75% racemic bupivacaine. Both local anesthetics are well tolerated and effective in producing epidural anesthesia for patients undergoing lower abdominal surgery.
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Anesthesia and analgesia · Mar 2000
Randomized Controlled Trial Clinical TrialWhat concentration of sufentanil should be combined with ropivacaine 0.2% wt/vol for postoperative patient-controlled epidural analgesia?
In this randomized double-blinded study, we sought to determine an optimal dose-combination of sufentanil with ropivacaine 0.2% wt/vol as postoperative epidural analgesics. One hundred twenty patients undergoing major abdominal surgery under general and thoracic epidural anesthesia (T9-11) were assigned to groups receiving patient-controlled epidural analgesia with ropivacaine 0.2% wt/vol (R), ropivacaine 0.2% wt/vol + sufentanil 0.5 microg/mL (R+S0.5), 0. 75 microg/mL (R+S0.75), 1.0 microg/mL (R+S1). A visual analog score of less than 40 was considered effective, and all side effects were recorded. In randomized subgroups (10 patients per group), plasma pharmacokinetic data were obtained for both epidural drugs. Four patients in Group R and two in Group R+S0.5 were excluded because of inadequate analgesia. The drug infusion rates (range of means: 5.4-5. 9 mL/h) were similar in all patients. Analgesia was superior for sufentanil 0.75 microg/mL with no further enhancement by the larger sufentanil concentration of 1 microg/mL. Sufentanil plasma levels were within the range of the minimal effective concentrations (highest in R+S1), and there was no covariation between plasma levels and pain relief. Free ropivacaine plasma concentrations remained stable for 96 h. No severe side effects were detected, although pruritus correlated with an increasing dose of sufentanil. We conclude that the combination of ropivacaine 0.2% wt/vol and 0.75 microg/mL sufentanil provided the best analgesia with the fewest side effects of the three combinations tested. ⋯ Sufentanil is added to epidural infusions of ropivacaine 0.2% wt/vol to improve the effectiveness of postoperative pain management. Regarding the risk of side effects, however, it is still unclear what concentration of sufentanil should be added to the local anesthetic. For postoperative thoracic epidural analgesia after major abdominal surgery, the combination of ropivacaine 0.2% wt/vol and 0.75 microg/mL sufentanil resulted in an appropriate cost:benefit ratio between good analgesia and side effects.
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Anesthesia and analgesia · Mar 2000
Randomized Controlled Trial Comparative Study Clinical TrialThe efficacy of intravenous 0.15 versus 0.25 mg/kg intraoperative morphine for immediate postoperative analgesia after remifentanil-based anesthesia for major surgery.
We evaluated the effect of perioperative administration of two doses of morphine for postoperative analgesia after remifentanil-based anesthesia. The prospective, randomized study included 245 patients from 33 centers. All patients were scheduled for abdominal or urological surgery lasting more than 1 h. General anesthesia used remifentanil as the perioperative opioid (1 microg/kg as a bolus then, 0.5 microg/kg as a continuous infusion). A morphine bolus of 0. 15 mg/kg (0.15-mg group) or 0.25 mg/kg (0.25-mg group) was administered 30 min before the end of surgery. In the postanesthesia care unit, pain scores for patients were evaluated by using behavioral pain scores of 1-3, verbal pain scores of 0-3, and visual analog scale scores of 0-10). Postoperative analgesia was obtained by a morphine titration (3 mg every 5 min). Demographic and surgery characteristics were similar in both groups. The delay for first demand of morphine was similar in the 0.15-mg and the 0.25-mg groups (26 [9-60] and 30 [10-60] min, respectively). The frequency of morphine titration was similar in both groups (75% and 66%, respectively). The amount of morphine used in the postanesthesia care unit was smaller in the 0.25-mg group (0.16 [0.0-1.25] vs 0.10 [0.0-0.56] mg/kg; P = 0.008). In the 0.25-mg group, the behavioral pain score was lower at 15 min, the verbal pain score was lower at 60 min (P < 0.001), and similar at 30 min. The visual analog scale pain score at 30 min and 60 min was similar in both groups. The incidence of minor side effects was similar in both groups. However, three cases of postoperative respiratory depression occurred in the 0.25-mg group compared with no cases in the 0.15-mg group. In conclusion, perioperative administration of morphine alone does not provide entirely adequate immediate postoperative pain control after remifentanil-based anesthesia in major surgery. ⋯ The administration of 0.15 or 0.25 mg/kg perioperative morphine during remifentanil-based anesthesia for major surgery does not preclude additional morphine administration in the postanesthesia care unit. The larger dose of 0.25 mg/kg slightly improves postoperative analgesia; however, it may be responsible for postoperative respiratory depression.