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 TrialChoice of electrocardiography lead does not affect the usefulness of the T-wave criterion for detecting intravascular injection of an epinephrine test dose in anesthetized children.
Accidental intravascular injection of an epinephrine-containing test dose increases T-wave amplitude of lead II electrocardiogram (EKG) in anesthetized children. We designed this study to test whether the choice of EKG lead would affect the usefulness of simulated intravascular test dose. We studied 32 ASA physical status I infants and children (aged 6-49 mo) undergoing elective surgeries during 1.0 minimum alveolar anesthetic concentration sevoflurane and 67% nitrous oxide in oxygen. When hemodynamic stability was obtained, all subjects received IV saline 0.1 mL/kg, followed 4 min later by an IV test dose (0.1 mL/kg) consisting of 1% lidocaine with 1:200,000 epinephrine (epinephrine 0.5 microg/kg) via a peripheral vein to simulate the intravascular injection of the test dose. Heart rate and systolic blood pressure were recorded every 20 and 60 s, respectively, and leads II (n = 32), V(5) (n = 32) and either lead I (n = 15) or III (n = 17), choosing the one with greater preinjection T-wave amplitude, were continuously recorded for 4 min after the saline and the test dose injections. An IV test dose produced significant increases in heart rate, systolic blood pressure, and T-wave amplitude of all EKG leads studied in all subjects, whereas IV saline elicited no changes in these variables. Maximal increases in T-wave amplitude of leads II, I, III, and V(5) were 158% +/- 69%, 175% +/- 78%, 147% +/- 89%, and 170% +/- 72%, respectively (mean +/- SD, P > 0.05). There was no significant difference in temporal changes in T-wave amplitude among the 4 leads, and sensitivity and specificity were 100% on the basis of the T-wave criterion irrespective of the lead examined. Our results indicate that leads II, I, III, and V(5) of EKG are equally effective for detecting intravascular injection of the epinephrine-containing test dose in sevoflurane-anesthetized children. ⋯ To determine whether an epidurally administered local anesthetic has been accidentally injected into a blood vessel, a small dose of epinephrine is often added to a local anesthetic. We found that increases in T-wave amplitude in leads I, II, III, and V(5) of the electrocardiogram are equally sensitive and specific for detecting intravascular injection of the epinephrine-containing test dose in sevoflurane-anesthetized infants and children.