Anesthesia and analgesia
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Anesthesia and analgesia · Aug 2000
Randomized Controlled Trial Clinical TrialIs succinylcholine after pretreatment with d-tubocurarine and lidocaine contraindicated for outpatient anesthesia?
Because succinylcholine has obvious advantages for facilitating endotracheal intubation in the ambulatory setting (e.g., low cost, fast onset, and no need for reversal of neuromuscular block), it is important to determine whether this muscle relaxant is indeed associated with an increased incidence of postoperative myalgias, compared with alternative but more expensive nondepolarizing muscle relaxants. We studied 119 outpatients undergoing endoscopic nasal sinus surgery or septoplasty. The anesthetic technique consisted of propofol/lidocaine for induction, followed by isoflurane/nitrous oxide/oxygen for maintenance. Oral tracheal intubation was performed by using a fiberscope. Patients were randomly assigned to one of two muscle relaxant groups. Group 1 patients received d-tubocurarine 3 mg followed by succinylcholine 1.5 mg/kg. Group 2 patients received mivacurium 0.2 mg/kg. After recovery from anesthesia, patients were asked whether they had any muscle pain and/or stiffness. Pain was categorized by location and quantified by using a verbal scale (from 0 to 10). Analgesic usage and myalgias limiting ambulation were recorded. After discharge from the ambulatory surgery unit, patients were contacted by telephone on Postoperative Day 1. If patients complained of myalgias, they were contacted by telephone on Days 2 and 3. Only one patient (in the mivacurium-treated group) reported myalgia as a limiting factor in ambulation or resumption of normal activity. There were no differences between groups with respect to the incidence (21% in the succinylcholine-treated group and 18% in the mivacurium-treated group), location, or severity of myalgia. In conclusion, succinylcholine (preceded by pretreatment with d-tubocurarine and lidocaine) is not associated with an increased incidence of myalgias, compared with mivacurium, when used to facilitate tracheal intubation in patients undergoing ambulatory nasal surgery. ⋯ The results of this study show that the frequency of muscle pains after surgery in outpatients is approximately 20%, regardless of whether succinylcholine (after precurarization) or mivacurium is used to assist in insertion of the breathing tube.
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Anesthesia and analgesia · Aug 2000
Case ReportsVecuronium-induced neuromuscular blockade in a patient with cerebral palsy and hemiplegia.
We evaluated vecuronium-induced neuromuscular block in both arms of a patient with cerebral palsy and hemiplegia. A remarkable resistance to vecuronium was observed in the hemiplegia side compared with cerebral palsy side. Complete recovery from neuromuscular block should be assessed in the cerebral palsy side that shows a delayed recovery.
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Anesthesia and analgesia · Aug 2000
The efficacy and safety of epidural infusions of levobupivacaine with and without clonidine for postoperative pain relief in patients undergoing total hip replacement.
We assessed the efficacy and tolerability of epidural infusions of levobupivacaine, levobupivacaine plus clonidine, and clonidine for postoperative analgesia in 86 patients undergoing total hip replacement. For each group, an epidural cannula was inserted before surgery and 15 mL of 0.75% plain levobupivacaine was administered. Three hours later, an epidural infusion (6 mL/h) of levobupivacaine 0.125% (L), levobupivacaine 0.125% plus clonidine 8.3 microg/mL (LC) or clonidine alone (8.3 microg/mL) (C) was initiated. Morphine consumption was recorded for the following 24 h as were visual analog pain scores and the degree of sensory and motor blockade. The mean (median) morphine consumption was lowest in the combination group (LC),14 (7) mg; higher in the clonidine group (C), 23 (21) mg; and highest in the levobupivacaine group (L), 37 (36) mg (P = 0.022). The median times until the first request for analgesia which were 2. 9, 5.9, and 12.5 h for Groups L, C, and LC, respectively (P < or = 0. 01). There were no statistical differences among the groups regarding the maximum degree of postoperative motor blockade. On average, the systolic blood pressure in the two clonidine groups was slightly lower than in those from the levobupivacaine group. We conclude that the epidural administration of a combination of levobupivacaine plus clonidine is well tolerated and gives better analgesia than either drug used alone. ⋯ In patients undergoing total hip replacement, the addition of the alpha(2)-adrenergic agonist clonidine to epidural infusions of levobupivacaine significantly improved postoperative analgesia.
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Anesthesia and analgesia · Aug 2000
Prednisolone-induced muscle dysfunction is caused more by atrophy than by altered acetylcholine receptor expression.
Large doses of glucocorticoids can alter muscle physiology and susceptibility to neuromuscular blocking drugs by mechanisms not clearly understood. We investigated the effects of moderate and large doses of prednisolone on muscle function and pharmacology, and their relationship to changes in muscle size and acetylcholine receptor (AChR) expression. With institutional approval, 35 Sprague-Dawley rats were randomly allocated to receive daily subcutaneous doses of 10 mg/kg prednisolone (P10 group), 100 mg/kg prednisolone (P100 group), or an equal volume of saline (S group) for 7 days. A fourth group of rats was pair fed (food restricted) with the P100 rats for 7 days (FR group). On Day 8, the nerve-evoked peak twitch tensions, tetanic tensions, and fatigability, and the dose-response curves of d-tubocurarine in the tibialis cranialis muscle were measured in vivo and related to muscle mass or expression of AChRs. Rate of body weight gain was depressed in the P100, FR, and P10 groups compared with the S group. Tibialis muscle mass was smaller in the P100 group than in the P10 or S groups. The evoked peak twitch and tetanic tensions were less in the P100 group than in the P10 or S groups, however, tension per milligram of muscle mass was greater in the P100 group than in the S group. The 50% effective dose of d-tubocurarine (microg/kg) in the tibialis muscle was smaller in the P10 (33.6 +/- 5.4) than in the S (61.9 +/- 5.0) or the P100 (71.3 +/- 9.6) groups. AChR expression was less in the P10 group than in the S group. The evoked tensions correlated with muscle mass (r(2) = 0.32, P < 0.001), however, not with expression of AChR. The 50% effective dose of d-tubocurarine did not correlate with muscle mass or AChR expression. Our results suggest that the neuromuscular dysfunction after prednisolone is dose-dependent, and derives primarily from muscle atrophy and derives less so from changes in AChR expression. ⋯ The mechanisms by which chronic glucocorticoid therapy alters neuromuscular physiology and pharmacology are unclear. We suggest that the observed effects are dose-dependent and derive primarily from muscle atrophy and derive less from changes in acetylcholine receptor expression.
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Anesthesia and analgesia · Aug 2000
Absorption of carbon dioxide by dry soda lime decreases carbon monoxide formation from isoflurane degradation.
This study was performed to determine whether the absorption of carbon dioxide (CO(2)) influences the formation of carbon monoxide (CO) from degradation of isoflurane in dry soda lime. Isoflurane (0. 5%), CO(2) (5%), a combination of the two in oxygen, and pure oxygen were separately passed through samples of 600 g of completely dried soda lime (duration of exposure, 60 min; flow rate, 5 L/min). Downstream of the soda lime, we measured concentrations of CO, isoflurane, and CO(2) as well as the gas temperature. CO(2) increased the peaks of CO concentration (842 +/- 81 vs 738 +/- 28 ppm) and shortened the rise time of CO to maximum values (12 +/- 2 vs 19 +/- 4 min). However, CO(2) inhibited total CO formation (99 +/- 10 vs 145 +/- 6 mL). At the same time, CO(2) absorption by the soda lime decreased in the presence of CO formation (from 21.4 +/- 0. 8 to 19.4 +/- 0.9 g). The temperature of the gases increased during the passage of both isoflurane and CO(2) (to 32.6 +/- 2.0 degrees C and 39.4 +/- 4.0 degrees C, respectively), but the largest increase (to 41.5 +/- 2.1 degrees C) was recorded when isoflurane and CO(2) simultaneously passed through the dry soda lime. We assume that the simultaneous reduction in CO formation and CO(2) absorption is caused by the competition for the alkali hydroxides present in most of soda lime brands. ⋯ We determined, in vitro, that carbon monoxide (CO) formation from isoflurane by dry soda lime is reduced by carbon dioxide (CO(2)). We believe that the potential for injury from CO is less in the clinical milieu than suggested by data from experiments without CO(2) because of an interdependence between CO formation and CO(2) absorption.