Anesthesia and analgesia
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Anesthesia and analgesia · Jan 2003
Randomized Controlled Trial Multicenter Study Clinical TrialInterscalene brachial plexus anesthesia and analgesia for open shoulder surgery: a randomized, double-blinded comparison between levobupivacaine and ropivacaine.
We compared the onset time and quality of interscalene brachial plexus block produced with levobupivacaine and ropivacaine in 50 patients undergoing open shoulder surgery randomly allocated to receive 30 mL of 0.5% levobupivacaine (n = 25) or 0.5% ropivacaine (n = 25) injected through a 20-gauge catheter placed into the interscalene sheath using a 18-gauge insulated and stimulating Tuohy introducer. The block was also prolonged after surgery using a patient-controlled interscalene analgesia with 0.125% levobupivacaine or 0.2% ropivacaine, respectively (basal infusion rate, 6 mL/h; bolus, 2 mL; lockout period, 15 min; maximum boluses per hour, three). Three patients (two with levobupivacaine [8%] and one with ropivacaine [4%]) failed to achieve surgical block within 45 min after the injection and were excluded. The onset time of surgical block was 20 min (10-40 min) with levobupivacaine and 20 min (5-45 min) with ropivacaine (P = 0.53). Rescue intraoperative analgesia (0.1 mg of fentanyl IV) was required in eight patients in each group (34%) (P = 0.99). Forty-two patients completed the 24-h postoperative infusion (22 with levobupivacaine and 20 with ropivacaine). Postoperative analgesia was similarly effective in both groups. Total consumption of local anesthetic infused during the first 24 h was 147 mL (144-196 mL) with levobupivacaine and 162 mL (144-248 mL) with ropivacaine (P = 0.019), with a ratio between boluses received and requested of 0.8 (0.4-1.0) and 0.7 (0.4-1.0), respectively (P = 0.004). The degree of motor block of the operated limb was deeper with levobupivacaine than ropivacaine when starting postoperative analgesia; however, no further differences in degree of motor function were observed between the two groups. We conclude that 30 mL of levobupivacaine 0.5% induces an interscalene brachial plexus anesthesia of similar onset and intensity as the one produced by the same volume and concentration of ropivacaine. Postoperative interscalene analgesia with 0.125% levobupivacaine results in similar pain relief and recovery of motor function with less volume of local anesthetic than with 0.2% ropivacaine. ⋯ This prospective, randomized, double-blinded study demonstrates that 30 mL of 0.5% levobupivacaine produces an interscalene brachial plexus block of similar onset and quality as the one produced by the same volume of 0.5% ropivacaine. When prolonging the block after surgery, 0.125% levobupivacaine provides adequate pain relief and recovery of motor function after open shoulder surgery, with less volume infused during the first 24 h after surgery than 0.2% ropivacaine.
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Anesthesia and analgesia · Jan 2003
Randomized Controlled Trial Comparative Study Clinical TrialA comparative study of three warming interventions to determine the most effective in maintaining perioperative normothermia.
Perioperative hypothermia poses a challenge because of its deleterious effects on patient recovery. The current practice of applying two cotton blankets on patients during surgery is thought to be less ideal than using reflective insulation or forced-air warming. We studied 300 patients who underwent unilateral total knee replacement and were randomized equally to three groups: (a) the two-cotton-blanket group, (b) the one-reflective-blanket with one-cotton-blanket group, and (c) the forced-air-warming with one-cotton-blanket group. Tympanic temperature readings were taken before surgery in the induction room, on arrival at the recovery room, and at 10-min intervals until discharge from the recovery room. On arrival at the recovery room, the forced-air-warming group had significantly higher temperatures (adjusted for sex, age, and patient's induction room temperature) of 0.577 degrees C +/- 0.079 degrees C (95% confidence interval [CI], 0.427-0.726; P < 0.001) and 0.510 degrees C +/- 0.08 degrees C (95% CI, 0.349-0.672; P < 0.001) more than the reflective-blanket and two-cot-ton-blanket groups, respectively. The forced-air-warming group took a significantly (P < 0.001) shorter time of 18.75 min (95% CI, 13.88-23.62) to achieve a temperature of 36.5 degrees C in the recovery room as compared with 41.78 min (95% CI, 36.86-46.58) and 36.43 min (95% CI, 31.23-41.62) for the reflective-blanket and two-cotton-blanket groups, respectively. The reflective technology was less effective than using two cotton blankets, and the forced-air warming was most efficient in maintaining perioperative normothermia. ⋯ Perioperative hypothermia has deleterious effects on patient recovery. We found in patients having knee surgery that reflective technology was less effective than using two cotton blankets, whereas active surface warming with the forced-air method was most effective in maintaining normothermia.
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Anesthesia and analgesia · Jan 2003
Case ReportsAn unusual complication of total intravenous anesthesia: mutism.
We report a case of mutism secondary to total IV anesthesia with propofol, as an unusual complication that we have not found in the literature.
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Anesthesia and analgesia · Jan 2003
Randomized Controlled Trial Comparative Study Clinical TrialTarget-controlled infusion for remifentanil in vascular patients improves hemodynamics and decreases remifentanil requirement.
Remifentanil is a potent ultra-short-acting opioid, which permits rapid emergence. However, remifentanil is expensive and may have detrimental effects on hemodynamics in case of overdose. Target-controlled infusion (TCI) permits adapting infusion to pharmacokinetic models. In this prospective randomized study, we compared intra- and postoperative hemodynamics, remifentanil requirement during anesthesia, and postoperative morphine requirement in patients scheduled for carotid surgery, and receiving either continuous IV weight-adjusted infusion of remifentanil (RIVA) or TCI for remifentanil (TCIR). Forty-six patients were enrolled in this study: all were anesthetized by using TCI for propofol. Twenty-three received RIVA (0.5 micro g. kg(-1) x min(-1)) for the induction of anesthesia and endotracheal intubation, with the infusion rate decreased to 0.25 micro g x kg(-1) x min(-1) after intubation, then adapted by step of 0.05 micro g x kg(-1) x min(-1) according to hemodynamics. Twenty-three patients received TCIR (Minto model, Rugloop), with an effect-site concentration at 4 ng/mL during induction, then adapted by step of 1 ng/mL according to hemodynamics. All patients received atracurium and a 50% mixture of N(2)O/O(2). Hemodynamic variables were recorded each minute. The number and duration of hemodynamic events were collected, and total doses of anesthetics (remifentanil and propofol) and vasoactive drugs were noted in both groups of patients. Data were analyzed by using unpaired t-tests. RIVA was significantly associated with more frequent episodes of intraoperative hypotension (16 versus 6, P < 0.001) and more frequent episodes of postoperative hypertension and/or tachycardia requiring more frequent administration of beta-adrenergic blockers (16 vs 10, P < 0.04) in comparison with TCIR. The need for morphine titration was not significantly different between groups. TCIR led to a significantly smaller requirement of remifentanil (700 +/- 290 versus 1390 +/- 555 micro g, P < 0.001) without difference in propofol requirement. This prospective randomized study demonstrated that, during carotid endarterectomy, in comparison with patients receiving remifentanil using continuous RIVA, TCI results in less hypotensive episodes during the induction of anesthesia, in fewer episodes of tachycardia and/or hypertension and a smaller beta-adrenergic blocker requirement during recovery, and a decrease in remifentanil requirement. Recommendations to prefer TCI for remifentanil administration during carotid endarterectomy may be justified. ⋯ Remifentanil for intraoperative analgesia in carotid artery surgery is associated with a better stability in perioperative hemodynamics when administered in target-controlled infusion compared with continuous weight-adjusted infusion. This may be related to a smaller requirement of this drug when using target-controlled infusion, as well as a smooth mode of administration.
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Anesthesia and analgesia · Jan 2003
Randomized Controlled Trial Clinical TrialThe analgesic effect of interscalene block using clonidine as an analgesic for shoulder arthroscopy.
Used as the sole analgesic, clonidine produces analgesia after central neural blockade and intraarticular injection but not after axillary block. In this study, we sought to determine whether interscalene clonidine induces analgesia for shoulder arthroscopy. Forty patients scheduled for shoulder arthroscopy were prospectively included in this double-blinded study. Using a nerve stimulator technique, an interscalene catheter was inserted. The patients were randomly divided into two groups. The interscalene group (n = 20) received clonidine 150 micro g in 15 mL of saline through the catheter and 1 mL of subcutaneous saline, and the systemic group (n = 20) received 15 mL of saline through the catheter and clonidine 150 micro g (1 mL) subcutaneously. All patients underwent general anesthesia for surgery. On completion of arthroscopy, all patients received, via a patient-controlled analgesia, on demand a bolus of 8 mL of ropivacaine 0.2% through the catheter with a 1-h lockout period. Postoperative pain was measured every 4 h using the visual analog scale (VAS) for 24 h. Additional postoperative analgesia was available with parenteral nalbuphine if required until VAS < 3. VAS scores in the recovery room were significantly higher in the systemic group compared with the interscalene group (P < 0.0001). Analgesic duration was significantly longer in the interscalene group (P < 0.00001), and ropivacaine consumption was significantly less than in the systemic group (P < 0.0001). No significant difference was observed between groups for nalbuphine consumption. Side effects were comparable in the two groups. ⋯ Clonidine administered via an interscalene catheter enhanced analgesia compared with systemic administration. Nevertheless, the adverse effect of clonidine at this dose limits its use for routine management for postoperative analgesia.