Anesthesia and analgesia
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Anesthesia and analgesia · Apr 2004
Clinical TrialThe influence of anthracycline therapy on cardiac function during anesthesia.
Cardiotoxicity is a well recognized complication of anthracycline (AC) therapy. Subtle abnormalities in myocardial function that become apparent only after exercise may exist in survivors of childhood cancer who have previously received AC, yet have normal resting cardiac function. To evaluate if anesthesia-induced changes in cardiac function differ in pediatric patients with previous AC therapy from healthy children and adolescents, we evaluated in a prospective study 43 patients, of whom 42 were analyzed. Twenty-one patients (AC-group), mean age 9.6 yr (range, 3-16 yr), who had received 193 (30-490) mg/m(2) of AC as a mean cumulative dose with normal resting cardiac function (shortening fraction [SF] 0.34, normal value > 0.30) underwent removal of a Hickman catheter under general anesthesia. Twenty-one patients, mean age 10.9 yr (range, 4-17 yr), who underwent placement of a Hickman catheter before chemotherapy served as the control. All children were premedicated with midazolam 0.5 mg/kg orally. Anesthesia was induced by sodium thiopental (5 mg/kg), fentanyl (3 micro g/kg), and rocuronium (0.6 mg/kg) and maintained with isoflurane (1 MAC) in N(2)O/O(2) (70/30). Before induction (baseline), 5 and 20 min after intubation (T1 and T2), and 20 min after extubation (control), cardiac function was assessed by transthoracic (baseline, control) and transesophageal (T1, T2) echocardiography. Compared with baseline (SF: 34.9 +/- 3.7 [AC], 34.1 +/- 3.7 [C] [not significant]; stroke volume index [SVI] 36 +/- 6 mL/m(2)[AC], 35 +/- 4 mL/m(2)[C] [not significant]; cardiac index [CI] 3.6 +/- 0.6 L/min/m(2)[AC], 3.2 +/- 0.5 L/min/m(2)[C] [not significant]), we found a significant decrease in SF and SVI in both groups at T1 (SF: 26.2 +/- 3.6 [AC] versus 28.6 +/- 3.6 [C] [P < 0.05]; SVI: 26 +/- 4 mL/m(2) [AC] versus 30 +/- 46 mL/m(2) [C] [P < 0.05]) and T2 (SF: 24.1 +/- 3.2 [AC] versus 28.2 +/- 2.5 [C] [P < 0.01], SVI: 26 +/- 6 mL/m(2) [AC] versus 31 +/- 5 mL/m(2) [C] [P < 0.01]), which was significantly greater in the AC group. There were no significant changes of variables of diastolic function (E/A ratio, isovolumetric relaxation time) between both groups. Previous treatment with AC may enhance the myocardial depressive effect of anesthetics even in patients with normal resting cardiac function. ⋯ Previous treatment with anthracylines, a group of chemotherapeutic drugs in use for childhood cancer, may enhance the myocardial depressive effect of anesthetics even in children and adolescents with normal resting cardiac function.
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Anesthesia and analgesia · Apr 2004
The variable effects of dopamine among human isolated arteries commonly used for coronary bypass grafts.
The direct actions of dopamine on human arterial coronary bypass grafts are not well known. We investigated its effects on isolated rings cut from radial arteries (RA), gastroepiploic arteries (GEA), and internal mammary arteries (IMA) harvested from patients undergoing coronary artery bypass surgery. Dopamine produced dose-dependent contractile responses in RA, an effect independent of the presence of a functional endothelium. The contractions were enhanced by the dopamine A(1) (DA(1))-receptor antagonist SCH23390, whereas they were blocked by an alpha(1)-adrenergic antagonist, prazosin. Results qualitatively similar to these were obtained in both GEA and IMA, although the contractile responses were far smaller. In RA, DA enhanced the norepinephrine (NE)-induced contraction, and this action of dopamine was enhanced by SCH23390. In GEA, small concentrations (<10(-7) mol/L) of DA attenuated the NE-induced contraction but larger concentrations did not. In IMA, DA induced a vasorelaxation on the NE-contraction only at higher concentrations (10(-6)-10(-5) mol/L). In both GEA and IMA, the dopamine-induced vasorelaxations on the NE contraction were completely inhibited by SCH23390. These results suggest that the affinities of DA for DA(1)- and alpha(1)-adrenergic receptors may explain its variable contractile and vasorelaxant effects among these arteries. ⋯ Differing affinities of dopamine for dopamine A(1)- and alpha(1)-adrenergic receptors may lead to it having variable contractile and vasorelaxant effects among the arteries supplying grafts for coronary bypass surgery.
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Anesthesia and analgesia · Apr 2004
Randomized Controlled Trial Clinical TrialPerioperative intravenous lidocaine has preventive effects on postoperative pain and morphine consumption after major abdominal surgery.
Sodium channel blockers are approved for IV administration in the treatment of neuropathic pain states. Preclinical studies have suggested antihyperalgesic effects on the peripheral and central nervous system. Our objective in this study was to determine the time course of the analgesic and antihyperalgesic mechanisms of perioperative lidocaine administration. Forty patients undergoing major abdominal surgery participated in this randomized and double-blinded study. Twenty patients received lidocaine 2% (bolus injection of 1.5 mg/kg in 10 min followed by an IV infusion of 1.5 mg. kg(-1). h(-1)), and 20 patients received saline placebo. The infusion started 30 min before skin incision and was stopped 1 h after the end of surgery. Lidocaine blood concentrations were measured. Postoperative pain ratings (numeric rating scale of 0-10) and morphine consumption (patient-controlled analgesia) were assessed up to 72 h after surgery. Mean lidocaine levels during surgery were 1.9 +/- 0.7 microg/mL. Patient-controlled analgesia with morphine produced good postoperative analgesia (numeric rating scale at rest,
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Anesthesia and analgesia · Apr 2004
Randomized Controlled Trial Comparative Study Clinical TrialThe effects of spread of block and adrenaline on cardiac output after epidural anesthesia in young children: a randomized, double-blind, prospective study.
Epidural anesthesia is considered to be without significant hemodynamic consequence in young children. However, conversely to adults, few studies have investigated cardiac output. Using transesophageal Doppler monitoring of cardiac output, we prospectively investigated hemodynamic alterations in 48 children (median age, 22.5 mo) receiving sevoflurane general anesthesia combined with caudal or thoracolumbar epidural anesthesia. They were randomly assigned to receive 0.8 mL/kg of plain local anesthetic mixture (lidocaine 1% + bupivacaine 0.25% (50/50) + 1 microg/mL of fentanyl) or 1 mL/kg of the same mixture with 5 microg/mL of adrenaline. No significant hemodynamic alteration was elicited in caudal and thoracolumbar groups receiving the plain mixture except a moderate decrease in heart rate. Conversely, a mixture with adrenaline added provoked a significant decrease in mean arterial blood pressure by 14% and 17%, in systemic vascular resistance by 24% and 40%, and an increase in cardiac output by 20% and 34% in caudal and thoracolumbar groups, respectively. The adrenaline effect was greater by the thoracolumbar than the caudal approach. In young children, epidural anesthesia induces an increase in cardiac output only when adrenaline is added to local anesthetics, probably through its systemic absorption from the epidural space. ⋯ Epidural anesthesia may induce significant hemodynamic changes, well documented in adults. Using noninvasive hemodynamic monitoring in children, we reported an increase in cardiac output and a decrease in arterial blood pressure only when epinephrine was added to epidurally-injected local anesthetics.