Anesthesia and analgesia
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Anesthesia and analgesia · Aug 2003
Randomized Controlled Trial Clinical TrialThe central nervous system and cardiovascular effects of levobupivacaine and ropivacaine in healthy volunteers.
We compared the central nervous system (CNS) and cardiovascular effects of levobupivacaine and ropivacaine when given IV to healthy male volunteers (n = 14) in a double-blinded, randomized, crossover trial. Subjects received levobupivacaine 0.5% or ropivacaine 0.5% after a test infusion with lidocaine to become familiar with the early signs of CNS effects (e.g., tinnitus, circumoral paresthesia, hypesthesia). The development of CNS symptoms was assessed at 1-min intervals and study drug administration was terminated when the first CNS symptoms were recognized. Thereafter, symptoms were recorded at 1-min intervals until symptom resolution. Hemodynamic variables were assessed by transthoracic electrical bioimpedance. Continuous 12-lead electrocardiogram monitoring was also performed. There was no significant difference between levobupivacaine and ropivacaine for: the mean time to the first onset of CNS symptoms (P = 0.870), mean total volume of study drug administered at the onset of the first CNS symptom (P = 0.595), stroke index (P = 0.678), cardiac index (P = 0.488), acceleration index (P = 0.697), PR interval (P = 0.213), QRS duration (P = 0.637), QT interval (P = 0.724), QTc interval (P = 0.737), and heart rate (P = 0.267). Overall, fewer CNS symptoms were reported for levobupivacaine than ropivacaine (218 versus 277). This study found that levobupivacaine and ropivacaine produce similar CNS and cardiovascular effects when infused IV at equal concentrations, milligram doses, and infusion rates. ⋯ This study compared directly, for the first time, the toxicity of levobupivacaine and ropivacaine in healthy volunteers. Levobupivacaine and ropivacaine produced similar central nervous system and cardiovascular effects when infused IV at equal concentrations, milligram doses, and infusion rates.
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Anesthesia and analgesia · Aug 2003
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of two regional anesthetic techniques for outpatient knee arthroscopy.
Small dose lidocaine spinal anesthesia and 3% 2-chloroprocaine epidural anesthesia provided comparable discharge times for outpatient knee arthroscopy. The incidence of transient neurologic symptoms with small-dose lidocaine spinal anesthesia was 12%.
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Anesthesia and analgesia · Aug 2003
Randomized Controlled Trial Comparative Study Clinical TrialPostoperative sensitization and pain after cesarean delivery and the effects of single im doses of tramadol and diclofenac alone and in combination.
Combining different analgesic mechanisms can reduce postoperative pain. We investigated postoperative pain and sensory sensitization in a double-blinded, placebo-controlled, randomized, single-dose comparison of the monoaminergic and micro -opioid agonist tramadol, 100 mg, and diclofenac 75 mg given IM in combination or alone in 120 patients who had elective cesarean delivery. The time to first postoperative demand for rescue analgesia, pain, tramadol pharmacokinetics, and electrical sensory thresholds at or distant from the incision were studied. The median time to first rescue (interquartile range) was 197 min (70-1000 min) with tramadol plus diclofenac, 48 min (25-90 min) with tramadol plus placebo, 113 min (35-270 min) with diclofenac plus placebo, and 55 min (30-100 min) with double placebo (tramadol plus diclofenac versus all other groups, P < 0.05). Pain intensity decreased markedly over time in all groups, and time and drug effects were significant (analysis of variance; P < 0.00001). Side effects were similarly minimal with all treatments. Pain thresholds at or distant from the incision increased significantly after surgery only with tramadol plus diclofenac. Preoperative sensory thresholds correlated with postoperative sensory changes (r > 0.53; P < 0.0001). The pharmacokinetics of tramadol and O-desmethyltramadol were unchanged by diclofenac. The combination of tramadol and diclofenac resulted in improved analgesia compared with monotherapy. Only the analgesic combination prevented both primary and secondary hyperalgesia. Preoperative sensory thresholds may allow prediction of postoperative sensitization. ⋯ The parenteral combination of tramadol and diclofenac resulted in more prolonged and pronounced postoperative analgesia and reduced sensory sensitization compared with the single drugs, with no increase in side effects.
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Anesthesia and analgesia · Aug 2003
Randomized Controlled Trial Clinical TrialThe effect of exogenous epinephrine on the incidence of hypotensive/bradycardic events during shoulder surgery in the sitting position during interscalene block.
Sudden hypotensive and/or bradycardic events (HBE) have been reported in 13%-28% of patients undergoing shoulder surgery in the sitting position during interscalene block. The Bezold-Jarisch reflex is the most likely mechanism for these events. It has been hypothesized that exogenous epinephrine might be a key component to the occurrence of HBE. We conducted this prospective, randomized study to verify this hypothesis. Patients received a local anesthetic solution with (Group E; n = 55) or without (Group P; n = 55) epinephrine for interscalene block; no further exogenous epinephrine was administered. Blood pressure control was achieved with IV urapidil, a peripheral vasodilator, as needed. The incidence of HBE was 11% in Group P versus 29% in Group E (P = 0.015). Increased intraoperative heart rate and arterial blood pressure were recorded in Group E (P = 0.000). Urapidil was administered to 13% of Group P and to 31% of Group E patients (P = 0.018). Urapidil administration induced a HBE in 4% of Group P and in 5% of Group E patients. We conclude that exogenous epinephrine is involved in the development of HBE in this setting. ⋯ Sudden hypotensive and/or bradycardic events occur during shoulder surgery in the sitting position during interscalene block. In this study, we demonstrated that the presence of epinephrine in the local anesthetic mixture significantly increases the incidence of these events.
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Anesthesia and analgesia · Aug 2003
Randomized Controlled Trial Clinical TrialThe effect of mixing lidocaine with propofol on the dose of propofol required for induction of anesthesia.
Lidocaine is used to reduce pain associated with propofol injection, either mixed with propofol or preceding it as a separate injection. The addition of lidocaine to propofol causes destabilization of the emulsion and reduces anesthetic potency in rats and humans. We conducted a randomized double-blinded study on 67 patients to assess the effect of mixing lidocaine with propofol on the dose of propofol required for the induction of anesthesia. Patients in Group S (n = 32) received IV lidocaine 0.2 mg/kg followed by an infusion of propofol whereas those in Group M (n = 35) received IV normal saline (placebo) followed by an infusion of a freshly prepared mixture of propofol 1%/lidocaine 1% in 10:1 volume ratio. The infusion was stopped when the subjects lost consciousness, as detected by the syringe-drop method. There was no statistically significant difference between the two groups in the mean (95% confidence interval) doses of propofol required for loss of consciousness: 2.0 (1.8-2.2) mg/kg for Group S versus 1.9 (1.7-2.0) mg/kg for Group M (P = 0.206). Mixing 20 mg of lidocaine with 200 mg of propofol is unlikely to affect the dose of propofol required for the induction of anesthesia. ⋯ Adding lidocaine to propofol destabilizes the propofol emulsion. A randomized double-blinded trial found no statistically significant difference in the doses of propofol required for the induction of anesthesia whether administered as a freshly prepared propofol 1%/lidocaine 1% 10:1 mixture or as a separate injection after a dose of lidocaine.