Acta anaesthesiologica Scandinavica
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Acta Anaesthesiol Scand · Jan 1977
Comparative StudyHuman hepatic blood flow and its relation to systemic circulation during intravenous infusion of bupivacaine or etidocaine.
Fifteen healthy young volunteers were studied before and during an intravenous infusion of a local anaesthetic agent. Seven received bupivacaine and eight etidocaine in a dose rate of 2 mg/min over a period of 150 min. Variables of the central systemic circulation and also the hepatic blood flow were measured repeatedly. ⋯ In contrast, these three drugs had the same decreasing effect upon the splanchnic vascular resistance, which caused an almost identical increase in the estimated hepatic blood flow. The calculated vascular resistance in the systemic circulation, excluding the splanchnic, was unchanged during the infusion of etidocaine, while it decreased during the infusion of bupivacaine. Most of this discrepancy was due to the different plasma concentrations of the drugs.
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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
Glomerular filtration rate during halothane anaesthesia and epidural analgesia in combination with halothane anaesthesia.
Pre- and peroperative determination of glomerular filtration rate (GFR) was performed in nine patients operated during light halothane anaesthesia (group A) and in nine patients operated during epidural analgesia in combination with light halothane anaesthesia (group B). In group A, the mean GFR decreased insignificantly by 7% and the mean arterial blood pressure increased significantly by 10%. In group B, the mean GFR decreased significantly by 19% and the mean arterial blood pressure decreased significantly by 15%. It is suggested that the difference in change in GFR between the two groups was caused by differences in mean arterial blood pressure.
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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
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.