Anesthesia and analgesia
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Anesthesia and analgesia · Nov 1995
Randomized Controlled Trial Clinical TrialEpidural ropivacaine infusion for postoperative analgesia after major lower abdominal surgery--a dose finding study.
Ropivacaine exhibits less cardiotoxicity and causes less motor block than bupivacaine when used in equianalgesic doses. This makes ropivacaine potentially well suited for epidural infusion for postoperative analgesia. The aim of this study was to determine which of three concentrations of epidurally administered ropivacaine infused for postoperative analgesia would attenuate intravenous opioid analgesia requirements while also minimizing motor block. ⋯ Total PCA morphine use was more over the 21-h period in Group S than all the ropivacaine groups, being significantly so for Group 2 (median values: Group S, 43.3 mg; Group 1, 18.7 mg; Group 2, 7.5 mg; Group 3, 19 mg; for Group 2, P = 0.03). Visual analog scale (VAS) scores on coughing were significantly lower (i.e., less pain) than control for all ropivacaine groups after 4 h of infusion and also for Groups 2 and 3 after 8 h of infusion. (Median VAS (mm) on coughing at 8 h: Group S = 70, Group 1 = 56, Group 2 = 32, Group 3 = 0; for Groups 2 and 3, P < 0.05 compared to Group S). There was a dose-related increase in the amount of motor block, with Group 3 having significantly more motor block than all other groups at 4 and 8 h.(ABSTRACT TRUNCATED AT 250 WORDS)
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Anesthesia and analgesia · Nov 1995
Randomized Controlled Trial Clinical TrialThe effects of anesthetic technique on the hemodynamic response and recovery profile in coronary revascularization patients.
This study was undertaken to assess the effects of propofol (versus enflurane, fentanyl, and thiopental) on hemodynamic stability and recovery characteristics when used for maintenance of anesthesia during elective coronary artery bypass grafting (CABG) procedures. Ninety premedicated patients scheduled for elective coronary revascularization had anesthesia induced with fentanyl 25 micrograms/kg intravenously (i.v.). When the mean arterial blood pressure (MAP) increased 10% above preoperative baseline values, patients were randomized to receive one of four anesthetic treatments: enflurane, 0.25-2.0%; fentanyl, 10-20 micrograms/kg i.v. bolus doses; propofol, 50-250 micrograms.kg-1.min-1 i.v.; or thiopental, 100-750 micrograms.kg-1.min-1 i.v.. ⋯ During CPB, fentanyl-treated patients required vasoconstrictors more often than patients in the other three treatment groups (14/22 vs 6/24, 4/23, and 5/21 in the enflurane, propofol, and thiopental groups, respectively) (P < 0.01). Although fentanyl-treated patients had significantly greater requirements for inotropic support during weaning from CPB than propofol-treated patients (14/22 vs 7/23) (P < 0.038), there were no significant differences among the groups in the postbypass or ICU periods. Propofol-treated patients responded to verbal stimuli (2.1 +/- 1.3h vs 4.0 +/- 3.5h, 4.7 +/- 2.7h, and 5.6 +/- 3.6h in the enflurane, fentanyl, and thiopental groups, respectively) (P = 0.01) and followed commands earlier (propofol 7.3 +/- 5.2h vs enflurane 12.5 +/- 5.7h, fentanyl 13.1 +/- 6.6h, and thiopental 12.8 +/- 6.7 h) (P = 0.01).(ABSTRACT TRUNCATED AT 400 WORDS)
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Anesthesia and analgesia · Nov 1995
Cerebral metabolic consequences of hypotensive challenges in hemodiluted pigs with and without cardiopulmonary bypass.
We tested the hypothesis that progressive aortic hypotension with bicarotid occlusion produces greater reductions in cerebral blood flow (CBF) and more flow-metabolism mismatching with hemodilution during cardiopulmonary bypass (CPB) than with hemodilution alone. In Yorkshire pigs randomized to hemodilution with CPB (n = 10) or hemodilution without CPB (control; n = 9), the effects of bicarotid ligation and graded hypotension on CBF (microspheres), the electroencephalogram (EEG), and cortical energy metabolites were examined. After bicarotid ligation, systemic flow was reduced for 15-min intervals of 80, 60, and 40 mm Hg aortic pressure, followed by a cortical brain biopsy. ⋯ Although CBF remained 40% lower at each level of hypotension in CPB than control animals (P < 0.05), EEG scores showed no intergroup differences, indicating similar flow-metabolism matching. Brain metabolites were similar between CPB and control groups (adenosine triphosphate, 9.6 +/- 2.4 vs 12.4 +/- 1.9 mumol/g; adenosine diphosphate, 6.0 +/- 0.7 vs 6.3 +/- 0.4 mumol/g; adenosine monophosphate, 4.8 +/- 0.9 vs 3.8 +/- 0.8 mumol/g; creatine phosphate, 8.3 +/- 1.8 vs 7.9 +/- 1.0 mumol/g; and lactate, 178.4 +/- 20.2 vs 150.8 +/- 13.9 mumol/g). Thus, despite significantly lower CBF during hypotension with bicarotid occlusion in hemodiluted animals during normothermic CPB, cortical electrical activity and the balance between flow and metabolism did not differ from those in control animals without CPB.
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Anesthesia and analgesia · Nov 1995
Aprotinin prolongs whole blood activated partial thromboplastin time but not whole blood prothrombin time in patients undergoing cardiac surgery.
Aprotinin is being used increasingly to limit cardiopulmonary bypass (CPB)-induced coagulation derangements. Since whole blood prothrombin time (PT) and activated partial thromboplastin time (APTT) assays are beneficial in the treatment of bleeding after CPB, we studied the potential effect of aprotinin on these whole blood assays. Blood specimens from 151 cardiac surgical patients were obtained in two phases: prior to heparin administration, before CPB, and subsequent to heparin neutralization after CPB. ⋯ Whole blood PT results were similar between normal saline. (NS)- and aprotinin-spiked specimens before CPB (A, 12.9 +/- 1.5s; NS, 12.8 +/- 1.5s; P = 0.76) and after CPB (A, 17.5 +/- 2.4s; NS, 17.7 +/- 2.4s; P = 0.58). In contrast, whole blood APTT results were prolonged in aprotinin-spiked specimens prior to CPB (A, 63.3 +/- 32.2s; NS, 38.6 +/- 16.3s; P < 0.0001) and after CPB (A, 65.9 +/- 23.7s; NS, 45.7 +/- 14.4s; P < 0.0001). A dose-dependent prolongation of whole blood APTT by aprotinin was demonstrated by a greater mean difference in APTT (P = 0.0001) between specimens spiked with NS or 200 KIU (17.5 +/- 12.2s) vs 400 KIU (27.8 +/- 21.5s) of aprotinin.(ABSTRACT TRUNCATED AT 250 WORDS)