Acta anaesthesiologica Scandinavica
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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
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
Comparative Study Clinical Trial Controlled Clinical TrialKetamine and diazepam as anaesthesia for forceps delivery. A comparative study.
In a clinically controlled trial in forceps delivery, a comparison was made between the general anaesthesia induced by ketamine and that by a combination of diazepam and N2O. Local anaesthesia was added in the diazepam group for episiotomy and suturation. The indication for operative delivery was in all cases a prolonged second stage of labour. ⋯ One mother in each group required ventilation with oxygen due to respiratory depression of short duration. Three of the children in the ketamine group and two in the diazepam group had subnormal Apgar score with slight acidosis. This was probably not attributable to the anaesthesia.
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Acta Anaesthesiol Scand · Jan 1977
General anaesthesia or lumbar epidural block for caesarean section? Effects on the foetal heart rate.
Caesarean section was performed in 10 patients under general anaesthesia and in 10 other patients under epidural block. The foetal heart rate was monitored continuously during anaesthesia and operation with a scalp electrode and a cardiotocograph. There was no major difference between the two anaesthetic techniques in their effect on the foetal heart rate. ⋯ The operative time was longer in the epidural group than in the general anaesthesia group, due to a higher frequency of Pfannenstiel incisions and repeat caesarean sections in the epidural group. Clinically, all newborns seemed to be unaffected, with normal Apgar scores. Epidural block seems to be a good alternative to general anaesthesia for caesarean section, particularly when a long operative time is expected.