Acta anaesthesiologica Scandinavica
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Acta Anaesthesiol Scand · Jan 1977
The relationship between disposition and duration of action of congeneric series of steroidal neuromuscular blocking agents.
The renal and hepatic elimination and biotransformation, as well as the relation between disposition and duration of action of pancuronium and two of its analogues, dacuronium and ORG.6368, have been investigated in the cat. In pharmacokinetic studies, appreciable amounts of the latter two compounds were found in the urine, bile and liver 8 h after their intravenous administration. Various proportions of the injected dose of the respective drugs were metabolized. ⋯ The intensity and duration of action of the neuromuscular blocking effect of the three compounds were studied after intravenous and "close" intraarterial injection. On the basis of these pharmacokinetic and neuromuscular studies, it was concluded that the short duration of action of ORG.6368 is due primarily to its early hepatic uptake. The possibility cannot be excluded, however, that differences in the kinetics of the drug action of ORG.6368 and the other two compounds also contributed significantly to the differences seen in the duration of action of these compounds.
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Acta Anaesthesiol Scand · Jan 1977
Comparative StudyHypoxia-induced vasoconstriction in isolated perfused lungs exposed to injectable or inhalation anesthetics.
Investigations during the last two decades have revealed a tendency to inpaired pulmonary gas exchange in patients during general anesthesia. In the awake state, arterial hypoxemia is counteracted by a mechanism which tends to normalize the ventilation/perfusion ratio of the lungs by way of a hypoxia-induced vasoconstriction in poorly ventilated areas. This results in a redistribution of perfusion to more adequately ventilated lung regions. ⋯ The experiments showed that the response was unaffected by N2O and injectable anesthetics, while a reversible, dose-dependent damping effect was demonstrated for the volatile inhalation anesthetics, ether, halothane and methoxyflurance. The effect could be demonstrated at blood concentrations comparable to those used in clinical anesthesia, and it was not due to a general paralysis of the vascular smooth muscle. The findings might, at least in part, explain the occurrence of arterial hypoxemia during general inhalation anesthesia.
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Acta Anaesthesiol Scand · Jan 1977
Intubation of newborns and infants: a solution to the problem of water condensation.
Treatment with humidified air in intubated newborns and infants its often complicated by the embarrassing problem of water condensation. This problem is solved by the humidification system described below, in which the tube delivering humidified air is surrounded by an Armaflex-insulated spiral-wire tube. Through the space between the two tubes, an adjustable air warmer delivers dry air at a temperature and flow rate such that the temperature of the humidified air in the delivery tube is maintained above its dew-point temperature.
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Acta Anaesthesiol Scand · Jan 1977
Systemic and regional blood flow during epidural anesthesia with epinephrine in the Rhesus monkey.
Hemodynamic and regional blood flow measurements were made in five rhesus monkeys before and 10, 20, 40 and 80 min after induction of high epidural anesthesia (T1) with lidocaine (1%) containing 1:200,000 epinephrine. Following induction of epidural anesthesia with epinephrine, there were significant decreases in heart rate, mean arterial pressure, cardiac output and myocardial and renal blood flow. ⋯ Vascular resistance in the lower extremity was significantly decreased during anesthesia, indicating arteriolar dilatation. Also, during anesthesia, the lungs received a significantly increased proportion of the microspheres, suggesting an increased peripheral arteriovenous shunting of microspheres due to the arteriolar dilatation.
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Acta Anaesthesiol Scand · Jan 1977
Arrhythmias during halothane anaesthesia II: the influence of atropine.
The effect of i.v. atropine premedication on cardiac rhythm was studied in healthy adult patients during thiopental-N2O/O2-halothane anesthesia without intubation. A higher incidnece of arrhythmias was seen in younger patients in close relation to administration of atropine, but the overall incidence during anesthesia was identical in atropine groups and the control groups. ⋯ No consistent changes in blood pressure were observed as the result of arrhythmias or changes in heart rate. It is concluded that atropine should be reserved for situations where severe bradycardia and hypotension occur, or can be expected to occur, and not given automatically, since cardioacceleration which is inherent in its action may be injurious to patients with limited cardiac reserve.