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 TrialInfusion of propofol, sufentanil, or midazolam for sedation after aortic surgery: comparison of oxygen consumption and hemodynamic stability.
We conducted a prospective, randomized study to compare quality of sedation, hemodynamic stability, and oxygen consumption of three different drugs for continuous i.v. sedation in the immediate postoperative period in patients scheduled for aortic surgery (propofol [n = 12], sufentanil [n = 12], or midazolam [n = 12]). After arrival in the recovery room, patients were randomized into one of the following groups: Group P (continuous infusion of propofol 2 mg x kg(-1) x h(-1)), Group S (continuous infusion of sufentanil 0.25 microg x kg(-1) x h(-1), with bolus doses of midazolam 2 mg to maintain sedation at 3-4 on the Ramsay scale), and Group M (continuous infusion of midazolam 0.07-0.15 microg x kg(-1) x h(-1) to maintain sedation at 3-4 on the Ramsay scale). The three drugs were associated with similar hemodynamic stability, incidence of myocardial ischemia, and comparable kinetics and mean values for VO2, but a significant higher number of peaks for VO2 in Group S during the period of rewarming. To obtain an appropriate Ramsay score, we needed to increase the rate of administration of the drug in Group P, and to decrease this rate in Group M. After the drugs were discontinued, Group P required mechanical ventilation for less time. In conclusion, propofol is as effective as sufentanil or midazolam in controlling increased VO2 postoperatively. The initial dose of 2 mg x kg(-1) x h(-1) had to be increased for most patients. In addition, propofol sedation is associated with a quicker recovery compared with midazolam and sufentanil. ⋯ A prospective, randomized comparison of propofol, sufentanil and midazolam infusions revealed similar effects on hemodynamics, oxygen consumption, and rate of myocardial ischemia after aortic surgery, although propofol was associated with a quicker recovery compared with midazolam and sufentanil.
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Anesthesia and analgesia · Aug 1998
Randomized Controlled Trial Clinical TrialKetamine attenuates the interleukin-6 response after cardiopulmonary bypass.
Cardiopulmonary bypass (CPB) has been proposed as a model for studying the inflammatory cascade associated with the systemic inflammatory response syndrome. Serum interleukin-6 (IL-6) concentration seems to be a good indicator of activation of the inflammatory cascade and predictor of subsequent organ dysfunction and death. Prolonged increases of circulating IL-6 are associated with morbidity and mortality after cardiac operations. In the present study, we compared the effects of adding ketamine 0.25 mg/kg to general anesthesia on serum IL-6 levels during and after elective coronary artery bypass grafting (CABG). Thirty-one patients undergoing elective CABG were randomized to one of two groups and prospectively studied in a double-blind manner. The patients received either ketamine 0.25 mg/kg or a similar volume of isotonic sodium chloride solution in addition to large-dose fentanyl anesthesia. Blood samples for analysis of serum IL-6 levels were drawn before the operation; after CPB; 4, 24, and 48 h after surgery; and daily for 6 days beginning the third day postoperatively. Ketamine suppressed the serum IL-6 response immediately after CPB and 4, 24, and 48 h postoperatively (P < 0.05). During the first 7 days after surgery, the serum IL-6 levels in the ketamine group were significantly lower than those in the control group (P < 0.05). On Day 8 after surgery, IL-6 levels were no different from baseline values in both groups. A single dose of ketamine 0.25 mg/kg administered before CPB suppresses the increase of serum IL-6 during and after CABG. ⋯ In this randomized, double-blind, prospective study of patients during and after coronary artery bypass surgery, we examined whether small-dose ketamine added to general anesthesia before cardiopulmonary bypass suppresses the increase of the serum interleukin-6 (IL-6) concentration. Serum IL-6 levels correlate with the patient's clinical course during and after coronary artery bypass. Ketamine suppresses the increase of serum IL-6 during and after coronary artery bypass surgery.
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Anesthesia and analgesia · Aug 1998
Randomized Controlled Trial Clinical TrialThe influence of epidural needle bevel orientation on spread of sensory blockade in the laboring parturient.
Both asymmetrical sensory blockade and dural puncture are undesirable outcomes of epidural analgesia. Identifying the epidural space with the needle bevel oriented parallel to the longitudinal axis of the patient's back limits the risk of headache in the event of dural puncture. However, rotating the bevel to direct a catheter cephalad may risk dural puncture. We prospectively studied the effects of needle rotation on the success of labor epidural analgesia and on the incidence of dural puncture. One hundred sixty ASA physical status I or II laboring parturients were randomly assigned to one of four groups. The epidural space was identified with the bevel of an 18-gauge Hustead needle directed to the patient's left. It was then rotated as follows: Group 0 = no rotation, final bevel orientation left (n = 39); Group 90 = rotation 90 degrees clockwise, bevel cephalad (n = 43); Group 180 = rotation 180 degrees clockwise, bevel right (n = 36); Group 270 = rotation 270 degrees clockwise, bevel caudad (n = 42). A single-orifice catheter was inserted 3 cm, and analgesia was induced in a standardized fashion. Dural puncture was evenly distributed among the groups (4.4%). There were more dermatomal segments blocked, fewer one-sided blocks, and more patients comfortable at 30 min with the needle bevel directed cephalad. Using a catheter inserted through a needle oriented in the cephalad direction increases the success of epidural analgesia. ⋯ This prospective study shows that an epidural catheter inserted through a needle oriented in the cephalad direction increases the success of labor analgesia in the parturient. Carefully rotating the needle cephalad does not increase the risk of dural puncture, intravascular catheters, or failed blocks.