[Rapid induction with vecuronium/fentanyl combinations for coronary artery surgery: influence on cardiovascular responses and plasma fentanyl concentrations].

Cardiovascular effects of fentanyl (60 micrograms.kg-1.min-1)/vecuronium combination for rapid induction were studied in fifty five patients for coronary artery bypass grafts. Cardiovascular and cerebral profiles of patients who had rapid fentanyl administration (39 patients) or slow fentanyl administration (15 patients) were compared with base line values and between each group. Plasma samples were assayed for epinephrine, norepinephrine, growth hormone, anti diuretic hormone and fentanyl. There were no differences in all hemodynamic parameters between each group. However, in the rapid administration group, statistically significant changes were detected in the heart rate, cardiac index, stroke volume index and left ventricular stroke work index. The changes in the heart rate were small and returned to the baseline value after sternotomy. A decrease in cardiac index after induction depends on a decrease in stroke volume index rather than in the heart rate. In rapid administration group, the EEG showed low frequency activity within a minute. The hormonal stress responses were significantly attenuated in both groups. High plasma concentrations of fentanyl could be achieved at the intubation. The data demonstrate that rapid induction by fentanyl is safe and convenient.

Release of thromboxane A2 by low-dose almitrine in the hypoxic dog.

Potentiation of hypoxic pulmonary vasoconstriction by a low dose of almitrine bismesylate (1 microgram.kg-1.min-1) was evaluated in terms of blood chemical mediator concentrations. Time course changes in the blood concentrations of adrenaline, noradrenaline, serotonin, histamine, thromboxane TXB2 and 6-keto-PGF1 alpha were monitored after administration of almitrine bismesylate for 15 min at 1 microgram.kg-1.min-1) in hypoxic and normoxic beagles. The low almitrine dose significantly increased TXB2 levels in hypoxic beagles, but the levels remained virtually unchanged in the normoxic animals with almitrine bismesylate and in the hypoxic animals with solvent. TXB2 levels did not increase when the almitrine infusion was increased to 5 micrograms.kg-1.min-1 for 15 min in hypoxic conditions. These findings suggest that almitrine is involved in arachidonic acid metabolism at a low rate of infusion and that thromboxane release from hypoxic areas of the lung may cause local vasoconstriction.

Continuous infusion of vecuronium in children.

The average dose of vecuronium required in children continuous infusion to attain a steady state block of 90% was determined. The electromyographic (EMG) response and mechanical response to supramaximal stimulation of the ulnar never recorded simultaneously, were significantly correlated in four children. The steady-state infusion rate requirement of vecuronium was 1.4 +/- 0.03 micro g/kg/min during 2% enflurane anesthesia and 3.1 +/- 0.03 micro g/kg/min during 1% halothane anesthesia. The spontaneous recovery time to 25% of the control by EMG during halothane and enflurane anesthesia was 12.6 +/- 1.1 and 10.3 +/- 1.5 min, respectively, after termination of the infusion. There was no cumulative effect after prolonged vecuronium infusion.

Plasma levels of vitamin E and lipoperoxide during paediatric anaesthesia.

We measured plasma levels of vitamin E (total tocopherol) and lipoperoxide in seventeen neonates (less than 10 days), twenty infants (1-12 months) and ten children (1-5 years) during anaesthesia. The seventeen neonates were randomly divided into two groups; seven who received 30 mg X kg-1 of alpha-tocopheryl acetate intramuscularly before anaesthesia and ten who did not. The 20 infants were divided into three groups: Group 1: eight infants who did not receive vitamin E; Group 2: six who received 30 mg X kg-1 of alpha-tocopheryl acetate orally for three days before anaesthesia; Group 3: six who received 30 mg X kg-1 of alpha-tocopheryl acetate intramuscularly three hours before anaesthesia. In the neonates who did not receive alpha-tocopheryl acetate, plasma vitamin E and lipoperoxide levels were unchanged following surgery. In Group 1 infants, plasma vitamin E levels decreased (p less than 0.05) and plasma lipoperoxide levels increased (p less than 0.05). In both neonates who received vitamin E and Group 3 infants the mean plasma vitamin E levels increased significantly (p less than 0.05) following surgery. In Group 2 infants, the levels of plasma vitamin E before surgery were high, as compared to the other groups: however, plasma vitamin E levels decreased following surgery. In the children, the plasma vitamin E levels were unchanged, while the plasma lipoperoxide levels decreased significantly (p less than 0.05) during anaesthesia. It is suggested from our studies that plasma vitamin E levels decrease and plasma lipoperoxide levels increase during anaesthesia and surgery in infants; however, those levels are unchanged in neonates.

Plasma cortisol levels in paediatric anaesthesia.

We measured plasma cortisol levels during surgery in seven neonates within ten days after birth and in 14 infants ranging in age from three months to 11 months. The 14 infants were divided into two groups; Group I included eight infants in whom general anaesthesia was maintained with oxygen, nitrous oxide and a muscle relaxant, Group II, six infants in whom general anaesthesia was maintained with oxygen, nitrous oxide, halothane and a muscle relaxant. In the neonates, the changes in mean plasma cortisol levels during anaesthesia were not statistically significant. In both Group I and Group II infants, the mean cortisol levels gradually rose during anaesthesia, but the initial rise in plasma cortisol levels was suppressed in the patients who received halothane.