Anesthesia and analgesia
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Anesthesia and analgesia · Aug 2000
Randomized Controlled Trial Clinical TrialSmall-dose clonidine prolongs postoperative analgesia after sciatic-femoral nerve block with 0.75% ropivacaine for foot surgery.
To evaluate the effects of adding small-dose clonidine to 0.75% ropivacaine during peripheral nerve blocks, 30 ASA physical status I and II patients undergoing hallux valgus repair under combined sciatic-femoral nerve block were randomly allocated in a double-blinded fashion to receive block placement with 30 mL of either 0.75% ropivacaine alone (group Ropivacaine, n = 15) or 0.75% ropivacaine plus 1 microg/kg clonidine (group Ropivacaine-Clonidine, n = 15). Hemodynamic variables, oxygen saturation, and levels of sedation, as well as the time required to achieve surgical block and time to first analgesic request, were recorded by a blinded observer. Time to surgical blockade required 10 min in both groups. Patients in the Ropivacaine-Clonidine group were more sedated than patients in the Ropivacaine group only 10 min after block placement. No differences in oxygen saturation and hemodynamic variables, degree of pain measured at first analgesic request, and consumption of postoperative analgesics were observed between the two groups. The mean time from block placement to first request for pain medication was shorter in group Ropivacaine (13.7 h; 25th-75th percentiles: 11. 8-14.5 h) than in group Ropivacaine-Clonidine (16.8 h; 25th-75th percentiles: 13.5-17.8 h) (P = 0.038). We conclude that adding 1 microg/kg clonidine to 0.75% ropivacaine provided a 3-h delay in first request for pain medication after hallux valgus repair, with no clinically relevant side effects. ⋯ This prospective, randomized, double-blinded study demonstrated that, when providing combined sciatic-femoral nerve block for hallux valgus repair, the addition of 1 microg/kg clonidine to 0.75% ropivacaine prolongs the duration of postoperative analgesia by 3 h, with only a slight and short-lived increase in the degree of sedation and no hemodynamic adverse effects.
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Anesthesia and analgesia · Aug 2000
Randomized Controlled Trial Clinical TrialThe awakening concentration of sevoflurane in children.
Sevoflurane is frequently used as a rapidly acting drug for the induction of anesthesia. We investigated the awakening concentration (MAC-awake) of sevoflurane in ASA physical status I children (age range 2-10 yr). We also investigated the effects of two different doses of clonidine (2 and 4 microg/kg) on the MAC-awake of sevoflurane. Subjects were randomly divided into three groups and received placebo (n = 24), clonidine 2 microg/kg (n = 17), or clonidine 4 microg/kg (n = 22) orally, 100 min before the induction of anesthesia. Sedation scores were estimated, by using a five-point scale, after entry into the operating room, and anesthesia was induced and maintained with sevoflurane in oxygen and balanced nitrogen, without an additional anesthetic. After surgery, end-tidal sevoflurane was decreased stepwise by 0.2% at 15-min intervals, a standardized verbal command was played to the patients, and the MAC-awake was determined. The MAC-awake of sevoflurane alone was 0. 78% +/- 0.24% (mean +/- SD), which decreased to 0.36% +/- 0.09% and 0.36% +/- 0.16% (both P <0.0001, compared with the control group) after premedication with the small and large doses of clonidine, respectively. The lack of any dose-response relationship might be explained by a plateau effect. ⋯ The awakening concentration of sevoflurane in unpremedicated children was 0.78%. Oral clonidine premedication at a dose of 2 microg/kg reduced the awakening concentration to 0.36%. However, an additional decrease in this value was not observed after the administration of the larger dose of clonidine premedication (4 microg/kg).
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Anesthesia and analgesia · Aug 2000
Randomized Controlled Trial Clinical TrialThe superiority of water-diluted 0.25% to neat 1% lidocaine for trigger-point injections in myofascial pain syndrome: a prospective, randomized, double-blinded trial.
Trigger-point injection with a mixture of commercially available 1% lidocaine in sterile distilled water at a ratio of 1:3 compared with 1% lidocaine alone resulted in better efficacy and less injection pain. This simple procedure may be suitable for treatments of a wide range of myofascial pain syndromes.
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Anesthesia and analgesia · Aug 2000
Randomized Controlled Trial Clinical TrialFentanyl improves analgesia but prolongs the onset of axillary brachial plexus block by peripheral mechanism.
We evaluated the effects of fentanyl added to lidocaine for axillary brachial plexus block in 66 adult patients scheduled for elective hand and forearm surgery. In this double-blinded study, all patients received 40 mL of 1.5% lidocaine with 1:200,000 epinephrine, injected into the brachial plexus sheath using the axillary perivascular technique, and they were randomized into three groups. Group 1 was given lidocaine containing 2 mL of normal saline plus 2 mL of normal saline IV. Patients in Group 2 received lidocaine containing 100 microg fentanyl plus 2 mL of normal saline IV. Group 3 patients received lidocaine containing 2 mL of normal saline plus 100 microg fentanyl IV. Sensory and motor blockade were evaluated by using a pinprick technique and by measuring the gripping force, respectively. The success rate of sensory blockade for radial and musculocutaneous nerves and the duration of the sensory blockade significantly increased in Group 2 (323 +/- 96 min) as compared with Group 1 (250 +/- 79 min). However, onset time of analgesia was prolonged in every nerve distribution by adding fentanyl to brachial plexus block. IV fentanyl had no effect on the success rate, onset, or duration of blockade. We conclude that the addition of fentanyl to lidocaine causes an improved success rate of sensory blockade but a delayed onset of analgesia, although this may be accounted for by the decreased pH caused by the fentanyl. ⋯ It is still unclear whether the addition of a peripheral opioid is useful for nerve blockade in humans. Peripheral application of fentanyl to lidocaine for axillary brachial plexus blockade in this study provided an improved success rate of sensory blockade and prolonged duration.
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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.