Anesthesia and analgesia
-
Anesthesia and analgesia · Feb 2004
Randomized Controlled Trial Comparative Study Clinical TrialEpidural levobupivacaine 0.1% or ropivacaine 0.1% combined with morphine provides comparable analgesia after abdominal surgery.
Ropivacaine appears attractive for epidural analgesia because it produces less motor block than racemic bupivacaine. The potential benefits of levobupivacaine with regard to motor blockade require further investigations. In this study, we compared the efficacy, dose requirements, side effects, and motor block observed with epidural levobupivacaine and ropivacaine when given in combination with small-dose morphine for 60 h after major abdominal surgery. Postoperatively, 50 patients were randomly allocated, in a double-blinded manner, to patient-controlled epidural analgesia with the same settings and without basal infusion, using 0.1% levobupivacaine or 0.1% ropivacaine. Both were combined with an epidural infusion of 0.1 mg/h morphine. Pain scores, side effects, motor block, and local anesthetic consumption were measured for 60 h. Pain scores measured on a 100-mm visual analog scale were approximately 20 mm at rest and 40 mm during mobilization in both groups. Bromage scores were 1 for all patients after the fourth postoperative hour. Consumption of levobupivacaine and ropivacaine were similar: 344 +/- 178 mg levobupivacaine versus 347 +/- 199 mg ropivacaine 48 h postoperatively. On postoperative day 2, 19 patients in the ropivacaine group versus 12 in the levobupivacaine group were able to ambulate (P < 0.05). No difference was noted concerning incidence of side effects. We conclude that when used as patient-controlled epidural analgesia and combined with small-dose epidural morphine, 0.1% levobupivacaine and 0.1% ropivacaine produce comparable postoperative analgesia with a similar incidence of side effects. ⋯ Small concentrations (0.1%) of epidural levobupivacaine and ropivacaine combined with morphine (0.1 mg/h) produce comparable analgesia and have similar side effects for similar dose requirements.
-
Anesthesia and analgesia · Feb 2004
Randomized Controlled Trial Clinical TrialThe median effective dose of nefopam and morphine administered intravenously for postoperative pain after minor surgery: a prospective randomized double-blinded isobolographic study of their analgesic action.
The aim of this study was to characterize the nature of analgesic interaction between nefopam and morphine administered i.v. for postoperative pain after minor surgery. To do so, we defined the median effective analgesic dose (ED(50)) for each drug and also the median ED(50) of their combination and compared them using the isobolographic method. Determination of median effective doses was performed by the up-and-down sequential drug administration in a two-stage study. First, in a prospective, randomized, double-blinded study, we enrolled 60 patients with mild to moderate pain after minor surgery; this was followed by an open study enrolling 30 patients. The end-point was a pain score less than 3 on a Numerical Pain Scale (0-10). Initial doses were 16 mg in group N, 5 mg in group M, and 7.5 mg of N combined with 2.5 mg of M in group N+M. The testing interval was 2 mg in group N, 1 mg in group M, and 1.5 mg of N combined with 0.5 mg of M in group N+M. ED(50) (95% confidence interval) was 5 mg (4-6 mg) for morphine, 18 mg (16-18 mg) for nefopam, and 4 mg (3.5-4.5 mg) with 12 mg (10.5-13.5 mg) for the combination of morphine and nefopam administered at a 3:1 dose ratio. Isobolographic analysis demonstrated a significant infra-additive interaction. The incidence of side effects did not differ significantly among morphine, nefopam, and their combination. These findings suggest that the combination of nefopam and morphine does not offer any advantage compared to each drug administered i.v. or alone after minor surgery. This study is the first to define the ED(50) of nefopam and morphine in postoperative patients. In conclusion, the addition of nefopam has a morphine-sparing effect, but the combination is infra-additive. ⋯ Pharmacologic interaction between nefopam and morphine shows infra-additivity but their combination may be clinically useful as morphine consumption is decreased in postoperative patients.
-
Anesthesia and analgesia · Feb 2004
Randomized Controlled Trial Clinical TrialThe effects of remifentanil and gabapentin on hyperalgesia in a new extended inflammatory skin pain model in healthy volunteers.
We tested the responsiveness of measures of hyperalgesia in a model of UVB-induced inflammatory hyperalgesia with remifentanil, gabapentin, and the combination of both drugs in a double-blinded, active placebo-controlled, 4-way-crossover design in 16 volunteers. A circular skin area was irradiated with UVB-light 20 h before the application of gabapentin (600 mg) and 2 h later remifentanil (0.08 microg.kg(-1).min(-1), 40 min). In the sunburn spots we observed stable decreases of the heat pain perception thresholds (HPPT, mean difference, 4.45 degrees C; 95% confidence interval [CI], 3.32 degrees -5.59 degrees ) and heat pain tolerance thresholds (HPTT; mean difference, 5.43 degrees C; 95% CI, 4.50 degrees -6.35 degrees ) compared with normal skin. Further, large areas of mechanical hyperalgesia to pinprick adjacent to the erythema spots developed in all subjects. Overall remifentanil increased the HPPT (mean increase, 2.47 degrees C; 95% CI, 1.86 degrees -3.09 degrees, P < 0.001) and HPTT (mean increase, 3.18 degrees C; 95% CI, 2.65 degrees -3.71 degrees, P < 0.001) and reduced the area of secondary hyperalgesia by 59% (mean decrease, 5326 mm(2); 95% CI, 4233-6419 mm(2), P < 0.001) compared with placebo. In the sunburn remifentanil markedly increased the HPTT by 86% compared with normal skin (additional increase, 2.57 degrees C; 95% CI, 1.71 degrees -3.43 degrees). This different effect was not seen in the HPPT. With the exception of a small increase of HPTT in the sunburn (P = 0.02) gabapentin had no noticeable effect on either hyperalgesia. In conclusion, opioid analgesia was reliably demonstrated in this new extended pain model. ⋯ Opioid analgesia was reliably demonstrated in a new inflammatory model of primary and secondary hyperalgesia. Gabapentin showed no antihyperalgesic and no opioid-enhancing effect in this model.
-
Anesthesia and analgesia · Feb 2004
Meta AnalysisA dose-response meta-analysis of prophylactic intravenous ephedrine for the prevention of hypotension during spinal anesthesia for elective cesarean delivery.
We systematically reviewed available studies to determine the dose-response characteristics of prophylactic i.v. ephedrine for the prevention of hypotension during spinal anesthesia for cesarean delivery. We searched for randomized controlled trials (RCTs) or cohort studies-obtained through MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, and reference lists of published articles-in which two or more different doses of prophylactic i.v. ephedrine were used to prevent hypotension during spinal anesthesia for cesarean delivery. Four RCTs and one cohort study were found (total n = 390). There was a significant dose-response relationship in the RCTs pooled for hypotension (slope = -0.0128; 95% confidence interval [CI], -0.0213 to -0.0044), hypertension (slope = 0.0563; 95% CI, 0.0235 to 0.0892), and umbilical arterial pH (slope = -0.03; 95% CI, -0.05 to 0.00). The efficacy of ephedrine for preventing hypotension was small. At 14 mg, the number-needed-to-treat was only 7.6 (95% CI, 4.8-21.1), and this was the same as the number-needed-to-harm (7.6; 95% CI, 3.7-23.4). At larger doses, the likelihood of causing hypertension was actually more than that of preventing hypotension, and there was also a minor decrease in umbilical arterial pH. ⋯ The authors performed a systematic review of dose-response studies of i.v. bolus ephedrine for preventing hypotension during spinal anesthesia for cesarean delivery. Prophylactic ephedrine cannot be recommended. The efficacy is poor at smaller doses, whereas at larger doses, the likelihood of causing hypertension is actually more than that of preventing hypotension.