Anesthesia and analgesia
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Anesthesia and analgesia · Jul 1998
Randomized Controlled Trial Clinical TrialPeripheral nerve blocks improve analgesia after total knee replacement surgery.
Total knee replacement (TKR) produces severe postoperative pain. Peripheral nerve blocks can be used as analgesic adjuncts for TKR, but the efficacy of femoral nerve blocks alone is controversial. The sciatic nerve innervates posterior regions of the knee; thus, performance of both sciatic and femoral nerve blocks may be necessary to improve analgesia after TKR. We performed this study to determine whether peripheral nerve blocks improve analgesia after TKR. In a randomized, double-blind fashion, 36 patients undergoing TKR received either femoral, sciatic-femoral, or sham nerve blocks after a standardized spinal anesthetic. Further postoperative analgesia was provided by patient-controlled i.v. morphine and ketorolac. Pain at rest and with physical therapy, morphine use, nausea, pruritus, sedation, and patient satisfaction were assessed. Patients receiving peripheral nerve blocks reported better analgesia at rest for at least 8 h after transfer to the hospital ward (P < 0.05). Morphine use was decreased by approximately 50% in the peripheral nerve block groups until the second postoperative day (P < 0.02). Side effect profiles and patient satisfaction were similar between groups. We conclude that femoral nerve blocks improve analgesia and decrease morphine use after TKR. The addition of a sciatic nerve block to the femoral nerve block did not further improve analgesic efficacy. ⋯ Performance of femoral nerve blocks improves analgesia and decreases the need for morphine after total knee replacement surgery. The addition of a sciatic nerve block to the femoral nerve block does not provide additional benefits.
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Anesthesia and analgesia · Jul 1998
Randomized Controlled Trial Clinical TrialClonidine added to the anesthetic solution enhances analgesia and improves oxygenation after intercostal nerve block for thoracotomy.
We evaluated the effect of adding clonidine to bupivacaine on postoperative pain control and oxygenation after intercostal nerve blockade (ICB) for thoracotomy, and attempted to distinguish a systemic from a local effect of clonidine. ICB with 2 mg/kg 0.5% bupivacaine was performed in 36 patients undergoing thoracotomy. Patients were randomized to one of three groups: 1) a control group that received bupivacaine with saline for ICB and an IM injection of saline, 2) an IM group that received bupivacaine with saline for ICB and an IM injection of 2 micrograms/kg clonidine, and 3) a block group that received bupivacaine with 2 micrograms/kg clonidine for ICB and an IM injection of saline. Blood gases, visual analog scale (VAS) scores, and analgesic demand were determined hourly for 8 h after arrival in the postoperative care unit (PCU). Patients in the block group had significantly lower VAS scores, higher arterial oxygen tension, and lower analgesic demand for the first 4 h in the PCU, compared with the two other groups. No difference was noted thereafter. We conclude that the addition of clonidine to bupivacaine for ICB leads to a short-term effect enhancing postoperative pain control and improving arterial oxygenation, probably mediated by a direct effect on the nerves. ⋯ Severe pain after thoracotomy can lead to impaired ventilation. We studied the effect of adding clonidine to bupivacaine for intercostal nerve blockade after thoracotomy. Clonidine administered directly on the nerves enhanced analgesia and improved oxygenation for a short time compared with systemic administration or control.
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Anesthesia and analgesia · Jul 1998
Randomized Controlled Trial Comparative Study Clinical TrialPreemptive caudal bupivacaine and morphine for postoperative analgesia in children.
We designed this double-blind study to evaluate the efficacy of preemptive epidural bupivacaine and small-dose morphine for postoperative analgesia in children after herniorraphy. Sixty children, ASA physical status I or II, who were undergoing elective hernia repair under general anesthesia were randomly allocated into two groups. Group I (preemptive group) received 0.66 mL/kg 0.25% bupivacaine with morphine 0.02 mg/kg caudally after the induction of anesthesia but 15 min before surgery. Group II (postincisional group) received the same drug mixture after surgery. Pain was assessed using an objective pain scale (OPS). Time to first postoperative analgesics (TFA), the number of supplementary analgesic used, and the amount of morphine consumed over the ensuing 24-h period were noted. The OPS score was significantly less in Group I at 0.5, 4, and 8 h (P < 0.05) than in Group II after surgery. The median OPS score recorded over 24 h was 0 for Group I and 2 for Group II, which was significantly different (P < 0.05). The TFA in Group I (12.55 +/- 3.06 h) was significantly (P < 0.05) prolonged compared with Group II (10.62 +/- 3.18 h). The total postoperative morphine consumption in Group I (2.24 +/- 1.4 mg) was significantly (P < 0.05) less than that in Group II (3.34 +/- 2.29 mg). Nevertheless, the incidence of nausea and vomiting was not significantly different between the groups. In this study, we demonstrated that preemptive epidural bupivacaine and small-dose morphine administration is superior to the same mixture given at the conclusion of surgery for pain relief. ⋯ This study was performed on two groups of 30 children undergoing hernia repair. Group I received a bupivacaine-morphine mixture caudally before surgery, and Group II received the same drugs caudally at the completion of surgery. Postoperative assessment demonstrated longer and better pain relief in Group I.
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Anesthesia and analgesia · Jul 1998
Randomized Controlled Trial Clinical TrialVisual evaluation of residual curarization in anesthetized patients using one hundred-hertz, five-second tetanic stimulation at the adductor pollicis muscle.
We were looking for a clinical test to indicate a train-of-four (TOF) ratio of approximately 0.9. We compared the adductor pollicis muscle (AP) visually evaluated response to ulnar nerve 100-Hz, 5-s tetanus (RF100 Hz) with the measured AP TOF ratio in 30 ASA physical status I or II adult anesthetized (propofol, sufentanil, N2O/O2) patients. After the induction of anesthesia, the left ulnar nerve was stimulated at the wrist (single twitch and TOF) and the resultant isometric force was measured. When TOF was assessed, the independent investigators, unaware of the left AP-measured TOF ratios, visually evaluated the presence or absence of AP fading elicited by right ulnar nerve 100-Hz, 5-s tetanus. The 30 patients were randomly allocated to receive either 0.5 mg/kg atracurium (n = 15) or 0.1 mg/kg vecuronium (n = 15). The neuromuscular blockade was allowed to resolve spontaneously. A multiple logistic regression analysis was performed by computing the 771 visual observations. The probabilities of success of 100-Hz, 5-s tetanus to detect TOF ratios of 0.8, 0.85, and 0.9 were 99%, 96%, and 67%, respectively. The sensitivity and specificity of 100-Hz, 5-s tetanus as an indicator of TOF ratios of 0.85 and 0.9 are 100% and 75%, 54% and 67%, respectively. We conclude that RF100 Hz visual assessment seems to be highly sensitive in evaluating residual paralysis, as the absence of RF100 Hz visual fading at the AP is compatible with a TOF ratio > 0.85. ⋯ After the administration of muscle relaxants, the absence of visual fading at the adductor pollicis, elicited in anesthetized patients by 100-Hz, 5-s tetanus, is compatible with a train-of four ratio > 0.85. Therefore, clinical observation of fading after 100-Hz, 5-s tetanus seems to be a highly sensitive test in evaluating residual paralysis.