Anesthesia and analgesia
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Anesthesia and analgesia · Mar 1993
Effect of phenylephrine bolus administration on left ventricular function during high thoracic and lumbar epidural anesthesia combined with general anesthesia.
The effect of phenylephrine (PHE) boluses on left ventricular (LV) function was examined in patients without cardiovascular disease who developed arterial hypotension during high thoracic epidural anesthesia (TEA) combined with general anesthesia (GA) (group 1) or lumbar epidural anesthesia (LEA) combined with GA (group 2). LV function was assessed by transesophageal echocardiography (TEE) before and after central venous injection of 1 microgram/kg PHE. Fractional diameter shortening (FDS), end-systolic wall stress (ESWS), and rate-corrected velocity of circumferential fiber shortening (mVcfc) were determined. ⋯ FDS was reduced from 38% to 25% (mean, P < 0.01) in group 1 and remained unchanged in group 2. ESWS increased from 70 to 143 x 10(3) dyne.cm-2 (P < 0.01) and from 57 to 86 x 10(3) dyne.cm-2 (P < 0.05), in groups 1 and 2, respectively. mVcfc was significantly reduced from 1.11 to 0.80 circ/s (P < 0.05) in group 1 and was not altered in group 2. The authors conclude that PHE given as an intravenous bolus to patients under high TEA plus general anesthesia causes a transient impairment of LV function.
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Anesthesia and analgesia · Mar 1993
Preprogrammed infusion of alfentanil to constant arterial plasma concentration.
A variable rate infusion regimen, designed to rapidly achieve and maintain a target arterial concentration (CT) of 100 micrograms. L-1 of alfentanil, was developed using the method of Plasma Drug Efflux. This method uses a series of clearance values (Ep), calculated as the ratio of instantaneous infusion rate/arterial plasma drug concentration normalized to lean body mass (LBM), at various sampling times during a suboptimal infusion regimen. ⋯ The calculated infusion-rate-versus-time profile to produce CT was obtained from the product Ep x CT for each time point and was transferred to the read-only memory of a computerized infusion pump. This new variable infusion profile was used in four patients, and the process was repeated in three further groups of 5, 8, and 12 patients using infusion profiles calculated from the previous group. Each set of concentration data was assessed by calculating the performance error (PE), the median performance error (MDPE), i.e., bias, and the median absolute value of PE (MDAPE), i.e., inaccuracy.(ABSTRACT TRUNCATED AT 250 WORDS)
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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.