Anesthesia and analgesia
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Anesthesia and analgesia · Jun 1999
Randomized Controlled Trial Clinical TrialAdding clonidine to lidocaine for intravenous regional anesthesia prevents tourniquet pain.
Tourniquet pain often complicates the use of the pneumatic tourniquet during surgical procedures performed under IV regional anesthesia. Clonidine-containing local anesthetic solutions have better analgesic properties than plain solutions when used for spinal, epidural, or peripheral blocks. We tested the hypothesis that the addition of clonidine may improve the quality of IV regional anesthesia, especially tourniquet tolerance. Forty patients were allocated randomly in a double-blinded, randomized study to receive 40 mL of 0.5% lidocaine and either 1 mL of isotonic saline or clonidine (150 microg). A double-cuffed tourniquet was kept inflated until patients complained of pain, leading to release of the distal cuff. Pain at the tourniquet site, at the surgical site, and in the distal part of the arm was rated on a visual analog scale (VAS) and a verbal rating scale (VRS) every 15 min during tourniquet placement and every 15 min for 1 h after tourniquet deflation. Motor blockade, sedation, arterial pressure, and heart rate were also recorded. VAS and VRS scores were significantly lower in the clonidine group 30 and 45 min after tourniquet inflation. The tolerance for the distal tourniquet was also significantly longer in the clonidine group (median [range]: 22 [10-40] vs 10 [5-20] min; P < 0.05); motor blockade was comparable between the two groups. Pain was not different in the two groups after tourniquet release. The clonidine group experienced a higher degree of sedation. We conclude that clonidine improves tourniquet tolerance when added to a local anesthetic solution. ⋯ A 150-microg dose of clonidine added to lidocaine improved tourniquet tolerance during IV regional anesthesia.
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Anesthesia and analgesia · Jun 1999
Randomized Controlled Trial Clinical TrialEpidural ropivacaine for the initiation of labor epidural analgesia: a dose finding study.
The purpose of our study was to determine the lowest concentration of ropivacaine that offers pain relief for the initiation of labor epidural analgesia. Women in active labor were enrolled in this prospective, randomized, double-blinded study to receive either ropivacaine 0.20% (Group I), ropivacaine 0.15% (Group II), or ropivacaine 0.10% (Group III). After placement of the epidural catheter, 13 mL of the study medication was administered. Fifteen minutes later, the adequacy of analgesia was assessed. If the woman reported that her degree of analgesia was not adequate, an additional 5 mL of the study medication was given, the degree of pain relief was reassessed 15 min later, and the study was concluded. A sequential study design was used to assess the success rates. We found that 26 of 28 (93%) women in Group I had adequate analgesia, compared with only 18 of 28 (64%) in Group II (P = 0.014) and 4 of 12 (33%) in Group III (P = 0.003). We conclude that ropivacaine 0.20% offers adequate analgesia significantly more often than either ropivacaine 0.15% or ropivacaine 0.10%. If one selects ropivacaine as the sole local anesthetic for the initiation of labor epidural analgesia, the minimal concentration should be 0.20%. ⋯ The lowest effective concentration of ropivacaine for the initiation of labor epidural analgesia has not been determined. We found that ropivacaine 0.20% offers adequate analgesia significantly more often than either ropivacaine 0.15% or ropivacaine 0.10%. If one selects ropivacaine as the sole local anesthetic for the initiation of labor epidural analgesia, the minimal concentration should be 0.20%.