Anesthesia and analgesia
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Anesthesia and analgesia · Mar 1993
Comparative StudyToxicity of bupivacaine encapsulated into liposomes and injected intravenously: comparison with plain solutions.
The acute central nervous system and cardiac toxicities of 0.25% bupivacaine, without adrenalin, encapsulated in multilamellar liposomes were compared with 0.25% plain solutions with and without adrenalin after intravenous infusion at a rate of 0.15 mg.kg-1 x min-1 with an increase of 0.036 mg.kg-1 x min-1 every 10 min. Three groups of six anesthetized, unventilated rabbits were studied. The doses of bupivacaine (in mg.kg-1) which produced seizure, ventricular tachycardia, and asystole were determined. ⋯ A statistical comparison of the cumulative lethal doses of bupivacaine 0.25% with adrenalin and of liposomal bupivacaine led to a P = 0.06. Adrenalin did not modify the systemic toxicity of the local anesthetic. This study showed a reduction of nervous and cardiac toxicity of bupivacaine encapsulated in multilamellar liposomes when infused intravascularly.
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Anesthesia and analgesia · Mar 1993
Clinical TrialProlonged administration of isoflurane to pediatric patients during mechanical ventilation.
We undertook a prospective study of the effectiveness and potential toxicities of isoflurane sedation in pediatric patients undergoing mechanical ventilation who required large doses of opioids for sedation were considered eligible. Ten patients (ages 3 wk to 19 yr) received continuous isoflurane sedation for a mean duration of 131 minimum alveolar concentration (MAC)-hours (range 13-497 MAC-hours). The mean peak inorganic fluoride (F-) concentration was 11.0 microM, and the highest F- concentration was 26.1 microM after 441 MAC-hours. ⋯ Five patients demonstrated an abstinence syndrome which consisted of nonpurposeful movements and extreme agitation. All of these patients had received at least 70 MAC-hours of isoflurane. Our experience indicates that isoflurane can effectively provide sedation to pediatric patients for prolonged periods without significant adverse effects on cardiovascular, hepatic, or renal function.
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Anesthesia and analgesia · Mar 1993
Right ventricular function during orthotopic liver transplantation.
Right ventricular (RV) function was assessed in 20 patients undergoing orthotopic liver transplantation to determine its role in the hemodynamic instability frequently seen during this procedure. A modified pulmonary artery catheter equipped with a fast response thermistor was used to determine RV ejection fraction (EFrv), allowing for calculation of RV end-diastolic volume index (EDVIrv, as the ratio of stroke index [SI] to EFrv) and RV end-systolic volume index (ESVIrv, as the difference between EDVIrv and SI). The above hemodynamic measures were taken during dissection for hepatectomy (stage I), during the anhepatic stage (stage II), and after reperfusion of the grafted liver, the neohepatic stage (stage III). ⋯ RV function appeared to be well preserved throughout the procedure, as indicated by a relatively constant and supranormal EFrv, although a small and probably clinically unimportant decrease in EFrv was observed during the anhepatic stage (0.52, 0.50, and 0.55 during stages I, II, and III, respectively). There was a strong correlation between SI and EDVIrv for pooled data over a wide range of EDVIrv (60-185 mL.m-2). Although unstable central blood temperature precluded the determination of EFrv within the first 5 min after reperfusion, RV function was unaltered otherwise during uncomplicated orthotopic liver transplantation using venovenous bypass, indicating that orthotopic liver transplantation per se is not associated with significant RV dysfunction.
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Anesthesia and analgesia · Mar 1993
Effect of angiotensin II on myocardial blood flow and acid-base status in a pig model of cardiopulmonary resuscitation.
The effect of angiotensin II on myocardial blood flow and acid-base status during cardiopulmonary resuscitation (CPR) was assessed. Fourteen pigs were allocated randomly to receive either 0.9% saline (n = 7) or 0.05 mg/kg angiotensin II (n = 7) after 4 min of ventricular fibrillation and 3 min of open-chest CPR. Total myocardial blood flow (measured with radiolabeled microspheres) before, 90 s, and 5 min following drug administration was 74 +/- 18, 62 +/- 12, and 54 +/- 11 mL.min-1 x 100g-1 (mean +/- SD) in the control, and 72 +/- 17, 125 +/- 25, and 74 +/- 20 mL.min-1 x 100 g-1 in the angiotensin II group (P < 0.001 at 90 s and P < 0.05 at 5 min). ⋯ Angiotensin II was associated with an improvement of myocardial blood flow during CPR and short-term resuscitation success. The increase in myocardial perfusion is associated with a lower coronary venous PCO2 and a higher coronary venous pH. The authors conclude that angiotensin II administration facilitated cardiopulmonary resuscitation.