Anesthesia and analgesia
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Anesthesia and analgesia · Aug 1998
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of clonidine with conventional preanesthetic medication in patients undergoing coronary artery bypass grafting.
In this controlled study, we compared clonidine with conventional premedication in 35 patients undergoing coronary artery bypass grafting (CABG). After premedication with clonidine 5 microg/kg p.o. (Group C, n = 11), lorazepam 60 microg/kg p.o. (Group L, n = 13), or morphine 0.1 mg/kg plus scopolamine 6 microg/kg i.m. (Group M, n = 11), sedation, anxiety, and quality of premedication were graded. After the administration of sufentanil 2.0 microg/kg over 12.5 min, a computer-assisted infusion device targeted a sufentanil effect-site concentration of 0.75 ng/mL. Hemodynamic variables, end-tidal isoflurane concentration (ET-ISO), the electroencephalographic spectral edge, and the serum sufentanil concentration (SUF) were measured. There were no intergroup differences in anxiety, sedation, quality of premedication, the dose of sufentanil causing unconsciousness, or the electroencephalographic (EEG) response to induction. Intraoperative SUF was stable, with no intergroup difference. The average prebypass ET-ISO was lower in Group C than in Group M. The ET-ISO and peak ET-ISO after intense surgical stimulation were lower in Group C versus Groups L and M. Mean arterial blood pressure was lower in Group C versus Groups L and M. There were no intergroup differences in pharmacologic intervention, time to extubation, or intensive care unit stay. Clonidine produces sedation, anxiolysis, and quality of premedication comparable to conventional premedication. Compared with other drugs, clonidine does not alter the dose of sufentanil inducing unconsciousness or EEG slowing, but it uniquely reduces isoflurane requirements. ⋯ In patients undergoing coronary artery bypass grafting, clonidine produces sedation and relieves anxiety as effectively as conventional premedication. Clonidine does not uniquely alter the dose of sufentanil inducing unconsciousness or electroencephalographic slowing, but it significantly reduces isoflurane requirements.
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Anesthesia and analgesia · Aug 1998
Randomized Controlled Trial Comparative Study Clinical TrialIntrathecal hypobaric versus hyperbaric bupivacaine with morphine for cesarean section.
Both hyper- and hypobaric solutions of bupivacaine are often combined with morphine to provide subarachnoid anesthesia for cesarean section. Differences in the baricity of subarachnoid solutions influence the intrathecal distribution of anesthetic drugs and would be expected to influence measurable clinical variables. We compared the effects of hyper- and hypobaric subarachnoid bupivacaine with morphine to determine whether one has significant advantages with regard to intraoperative anesthesia and postoperative analgesia in term parturients undergoing elective cesarean section. Thirty parturients were randomized to receive either hyper- or hypobaric bupivacaine (15 mg) with morphine sulfate (0.2 mg). Intraoperative outcomes compared included extent of sensory block, quality of anesthesia, and side effects. Postoperative outcomes, including pain visual analog scale scores, systemic analgesic requirements, and side effects, were monitored for 48 h. Sedation effects were quantified and compared using Trieger and digit-symbol substitution tests. We detected no differences in sensory or motor block, quality of anesthesia, quality of postoperative analgesia, incidence of side effects, or psychometric scores. Both preparations provide highly satisfactory anesthesia for cesarean section and effective postoperative analgesia. ⋯ Dextrose alters the density of intrathecal bupivacaine solutions and is thought to influence subarachnoid distribution of the drug. We randomized parturients undergoing cesarean section to one of two often used spinal bupivacaine preparations, hypobaric and hyperbaric. We detected no differences in clinical outcomes between groups.
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Anesthesia and analgesia · Aug 1998
Randomized Controlled Trial Comparative Study Clinical TrialTopical lidocaine-prilocaine cream (EMLA) versus local infiltration anesthesia for radial artery cannulation.
In a randomized trial, we compared topical anesthesia by a lidocaine-prilocaine cream (EMLA; Laboratorie ASTRA, Manterre, France) with subcutaneous local lidocaine infiltration for radial artery cannulation. Patients included 538 adults scheduled for coronary angiography using a radial approach. EMLA was applied 2 h before radial cannulation, and lidocaine infiltration was performed 5 min before cannulation. The primary end point was pain as assessed by a verbal numerical scale (0 = no pain, 10 = extreme pain). Pain was less severe in the EMLA group than in the lidocaine infiltration group (Score of 2 vs 7; P = 0.0001). Additional lidocaine infiltration was required significantly less frequently in the EMLA group (relative risk 0.19). The failure rate of cannulation was significantly lower in the EMLA group (relative risk 0.38), and insertion time was shorter (4 versus 6 min). We conclude that EMLA, compared with lidocaine infiltration, reduces pain associated with radial artery cannulation and improves the success rate of the procedure. Routine application of EMLA should be performed in awake patients 2 h before radial artery cannulation. ⋯ In a randomized trial, we compared topical anesthesia by a lidocaine-prilocaine cream (EMLA) with subcutaneous local lidocaine infiltration for radial artery cannulation in 538 adults patients. EMLA reduced pain associated with radial artery cannulation and improved the success rate of the procedure.
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Anesthesia and analgesia · Aug 1998
Modifications of the inotropic responses to alpha- and beta-adrenoceptor stimulation by propofol in rat myocardium.
Propofol induces cardiovascular depression but without significant effect on intrinsic myocardial contractility in many species. However, its interactions with adrenoceptor stimulation are unknown. We studied the effects of propofol (1 and 10 microg/mL) and its solvent on the inotropic response induced by phenylephrine (10(-8)-10(-4) M) or isoproterenol (10(-8)-10(-4) M) in rat left ventricular papillary muscles in vitro (Krebs-Henseleit solution, 29 degrees C, pH 7.40, calcium 0.5 mM, stimulation frequency 12 pulses/min). We also studied the lusitropic effects in isotonic and isometric conditions. In control groups, phenylephrine (127% +/- 3% of baseline; P < 0.05) and isoproterenol (169% +/- 11% of baseline; P < 0.05) induced a positive inotropic effect. Propofol (10 microg/mL) completely abolished the positive inotropic effect of phenylephrine (100% +/- 3% of baseline; P = not significant). In contrast, at the lowest concentration (1 microg/mL), propofol did not modify the positive inotropic effect of phenylephrine. Propofol did not modify the inotropic effect of isoproterenol. Propofol (10 microg/mL) enhanced the positive lusitropic effect of isoproterenol under low-load (P < 0.05) but not under high-load conditions. ⋯ A high concentration of propofol abolished the positive inotropic effect of alpha- but not beta-adrenoceptor stimulation and enhanced the positive lusitropic effect of beta-adrenoceptor stimulation.
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Anesthesia and analgesia · Aug 1998
Randomized Controlled Trial Comparative Study Clinical TrialEffects of spinal needle type on lateral distribution of 0.5% hyperbaric bupivacaine.
To evaluate the influence of needle type on the lateral distribution of 0.5% hyperbaric bupivacaine, 30 patients undergoing lower limb surgery were placed in the lateral position with the side to be operated on dependent and underwent dural puncture by either a 25-gauge Whitacre (n = 15) or a 25-gauge Quincke (n = 15) spinal needle. The needle hole was turned toward the dependent side and 8 mg of 0.5% hyperbaric bupivacaine was injected over 30 s. The lateral position was maintained for 15 min while a blind observer recorded loss of pinprick sensation and degree of motor block on both the dependent and nondependent sides every 5 min until regression of motor block by 1 degree on the dependent side. Thirty minutes after the patients were placed in the supine position, unilateral sensory block was observed in 10 patients in the Whitacre group (66%) and in 2 patients in the Quincke group (13%) (P < 0.05). No differences in the rate of unilateral motor block were observed (73% and 40% in Whitacre and Quincke groups, respectively). We conclude that when a small dose of 0.5% hyperbaric bupivacaine is injected slowly into patients in the lateral position for 15 min, the Whitacre spinal needle provides a more marked differential block of sensory nerve roots between dependent and nondependent sides compared with the Quincke needle. ⋯ Because unilateral spinal anesthesia can be advantageous for lower limb surgery, we evaluated the influence of the Whitacre and Quincke spinal needle types on the lateral distribution of small-dose 0.5% hyperbaric bupivacaine injected slowly into adult patients.