Anesthesiology
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Randomized Controlled Trial Clinical Trial
Chloroprocaine antagonism of epidural opioid analgesia: a receptor-specific phenomenon?
Sixty healthy patients scheduled for elective cesarean delivery under epidural anesthesia were randomized to receive either lidocaine or 2-chloroprocaine as the primary local anesthetic agent. When patients first complained of postoperative pain in the recovery room, they were given either fentanyl 50 micrograms or butorphanol 2 mg, epidurally, in a randomized, blinded fashion. Postoperative analgesia, quantitated on a visual analogue scale, as well as time elapsed until first request for supplemental opioid, did not differ for patients receiving butorphanol after either 2-chloroprocaine or lidocaine anesthesia. ⋯ We conclude that 2 mg of butorphanol epidurally provides approximately 2 to 3 h of effective analgesia after cesarean delivery with either lidocaine or 2-chloroprocaine anesthesia. Epidural fentanyl seems to be antagonized when 2-chloroprocaine, but not lidocaine, is used as the primary local anesthetic agent. We suggest a possible mu-receptor-specific etiology for this effect.
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Randomized Controlled Trial Clinical Trial
Does perioperative tactile evaluation of the train-of-four response influence the frequency of postoperative residual neuromuscular blockade?
The authors conducted a randomized controlled clinical trial to evaluate the usefulness of perioperative manual evaluation of the response to train-of-four (TOF) nerve stimulation. A total of 80 patients were divided into four groups of 20 each. For two groups (one given vecuronium and one pancuronium), the anesthetists assessed the degree of neuromuscular blockade during operation and during recovery from neuromuscular blockade by manual evaluation of the response to TOF nerve stimulation. ⋯ The median (and range of) TOF ratios recorded in the recovery room were 0.75 (0.33-0.96) and 0.79 (0.10-0.97) in the vecuronium groups monitored with and without a nerve stimulator, respectively. These ratios were significantly higher than those found in the pancuronium groups, which wre 0.66 (0.06-0.90) and 0.63 (0.29-0.95), respectively. However, no difference was found between the vecuronium and pancuronium groups in the number of patients showing clinical signs of residual neuromuscular blockade, as evaluated by the 5-s head-lift test.(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Clinical Trial
Epidural clonidine analgesia after cesarean section.
Epidurally administered clonidine has been reported to produce postoperative analgesia. To assess the efficacy, safety, and appropriate dose of epidural clonidine for post-cesarean section analgesia, we designed a double-blind, placebo-controlled study. Sixty women were randomly assigned to receive epidural administration of saline bolus followed by 24-h saline infusion, 400-micrograms clonidine bolus followed by 10 micrograms/h clonidine infusion, or 800-micrograms clonidine bolus followed by 20 micrograms/h clonidine infusion. ⋯ Clonidine decreased heart rate (one patient required atropine for asymptomatic bradycardia) and produced transient sedation. The 800-micrograms clonidine dose prolonged resolution of local anesthetic-induced motor blockade compared to saline. The results suggest that epidurally administered clonidine provides analgesia, as measured by decreased need for supplemental morphine, after cesarean section, but continuous infusion is required for analgesia of more than 6 h duration.
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Randomized Controlled Trial Clinical Trial
High thoracic segmental epidural anesthesia diminishes sympathetic outflow to the legs, despite restriction of sensory blockade to the upper thorax.
To evaluate whether, after high thoracic segmental epidural anesthesia, sympathetic blockade spreads caudally beyond sensory blockade, we assessed regional skin temperatures by infrared telethermometry in 53 nonpremedicated patients at constant ambient temperature. Either bupivacaine (4.2 ml, 0.75%, n = 10) or an equal volume of saline (placebo, n = 10) was injected at the C7-T2 epidural space in a randomized double-blinded fashion. ⋯ Midthoracic injection also increased significantly skin temperature on the foot (great toe: +4.0 degrees C +/- 4.9; little toe: +3.6 degrees C +/- 4.8) but not on the hand. In contrast, with lumbar epidural anesthesia, skin temperature increased significantly on the foot (great toe: +8.5 degrees C +/- 2.5; little toe: +8.6 degrees C +/- 2.8) but decreased significantly on the hand (thumb: -3.1 degrees C +/- 2.1; digit 5: -2.8 degrees C +/- 2.5).(ABSTRACT TRUNCATED AT 250 WORDS)
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To determine the relationship among diaphragm, orbicularis oculi, and adductor pollicis blockade, train-of-four stimulation was applied to the phrenic, facial, and ulnar nerves in 16 adult patients anesthetized with alfentanil-propofol-oxygen. Vecuronium 0.04 or 0.07 mg/kg was given. The response of the adductor pollicis was measured with a force transducer, and that of the other muscles by electromyography (EMG). ⋯ With 0.04 mg/kg, time to maximum diaphragmatic blockade was 2.9 +/- 0.3 min, compared with 3.7 +/- 0.6 min at the orbicularis oculi (no significant difference [NS]) and 6.6 +/- 0.4 min at the adductor pollicis (P less than 0.001). With vecuronium 0.07 mg/kg the values were 2.2 +/- 0.3, 3.4 +/- 0.5 (P = 0.024), and 6.3 +/- 0.6 (P less than 0.001), respectively. Time to 75% T1 recovery was similar at the diaphragm and the orbicularis oculi, but significantly longer at the adductor pollicis.(ABSTRACT TRUNCATED AT 250 WORDS)