Acta anaesthesiologica Scandinavica
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Acta Anaesthesiol Scand · Jan 1977
Peripheral nerve injury due to injection needles used for regional anesthesia. An experimental study of the acute effects of needle point trauma.
Nerve injury can arise as a complication peripheral nerve block anesthesia. Of the various factors involved, the trauma caused by the injection needle may be of significance. ⋯ Fascicular injury was indicated by a fluorescence microscopy technique, tracing locally applied Evans Blue Albumin, The results show that a 45 degrees-beveled needle less frequently produces fascicular damage and should therefore be recommended for use in clinical anesthesia. It is also concluded that paresthesiae, when necessary, should be elicited gently, and that intraneural injections should be avoided.
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Acta Anaesthesiol Scand · Jan 1977
Catheter technique in axillary plexus block. Presentation of a new method.
A flexible, disposable intravenous catheter can be introduced into the neuro-vascular sheath in the axilla and used for injection of local anesthetic solution to block the axillary brachial plexus. The technique is described and the results of the first 137 consecutive catheter blocks are reported and compared to a similarly evaluated series of conventional axillary blocks. The catheter method constitutes an interesting alternative to needle techniques and offers the possibility of a continuous axillary block.
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Acta Anaesthesiol Scand · Jan 1977
Comparative StudyThe cerebrovascular CO2 reactivity during the acute phase of brain injury.
Using the intra-arterial 133xenon (133Xe) method, the cerebrovascular response to acute Paco2 reduction was studied in 26 unconscious, brain-injured patients subjected to controlled ventilation. The CO2 reactivity was calculated as delta in CBF/delta Paco2. The perfusion pressure was defined as the difference between mean arterial pressure and mean intraventricular pressure. ⋯ An increase of the CO2 reactivity with time was observed, indicating normal response after 1-2 weeks. Chronic hypocapnia in six unconscious patients resulted in sustained CSF pH adaptation. The question whether a delay in CSF pH adapation exerts an influence on the CO2 reactivity, and the influence of cerebral lactacidosis on the CO2 response are discussed.
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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.
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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.