Acta anaesthesiologica Scandinavica
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Acta Anaesthesiol Scand · Apr 1981
Interscalene brachial plexus block: area of analgesia, complications and blood concentrations of local anesthetics.
In a prospective clinical study including 100 patients, the consequences of using the interscalene approach to block the brachial plexus were investigated according to the area of analgesia, complications, and blood concentrations of local anesthetics. Sufficient analgesia of the shoulder and the upper part of the arm was obtained in 98-99% of the cases, whilst the area of analgesia in the forearm and the hand was more variable. ⋯ No toxic reactions were seen. The complications were in accordance with those reported in other publications.
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Acta Anaesthesiol Scand · Apr 1981
Central haemodynamics and oxygen transport with and without continuous positive pressure ventilation after open-heart surgery.
Twelve patients, subjected 20 h earlier to coronary artery bypass surgery, were studied on discontinuation of the postoperative mechanical ventilation employing PEEP+5 cmH2O (CMV+PEEP). Compared to the values obtained during CMV+PEEP, cardiac index and mixed venous blood oxygen tension increased with change to spontaneous ventilation at ambient pressure, employing a 28% O2 Ventimask for the intubated patient. ⋯ The observations suggest that after open-heart surgery, CMV using a PEEP as low as +5 cmH2O may exert, in comparison to controlled oxygen therapy ;during spontaneous breathing, a significant lowering effect on the already compromised cardiac performance. This necessitates continuous weighing of the beneficial effects obtained by employing postoperative CMV+PEEP, against the adverse haemodynamic effects, although the alterations in cardiac output may partly ensue from the changes in metabolism, muscular effort and oxygen consumption during the two modes of ventilation, although there was no significant increase in oxygen consumption.
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Acta Anaesthesiol Scand · Apr 1981
Influence on cerebral blood flow of infusion of sodium bicarbonate during respiratory acidosis and alkalosis in the dog.
In anaesthetized dogs, a mixed acid-base disturbance was induced by adding a pronounced metabolic alkaline to an established respiratory acidosis or alkalosis. Cerebral blood flow (CBF) was measured by the radioisotope washout method. ⋯ Acid-base analysis of cerebrospinal fluid (CSF) indicated an increased bicarbonate concentration. Hypercapnia is suggested to facilitate the passage of bicarbonate over the blood-brain barrier, leading to cerebral vasoconstriction by means of increased extravascular pH.
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The value of transcutaneous oxygen tension (tcPO2) as an oxygen parameter during uncomplicated thoracic anaesthesia was examined in ten patients anaesthetized with oxygen-nitrous oxide and enflurane or flunitrazepam/fentanyl. tcPO2 was measured with the Radiometer TCM-I monitor at 45 degrees C. Measuring interference due to the anaesthetic agents was not observed. tcPO2 was found to be lower than the arterial tension (PaO2) at any inspiratory oxygen fraction (FIO2). When the peroperative readings were related to the preoperative values, no statistically significant difference was found between PaO2 and tcPO2 at FIO2 - 0.5, 0.4 and 0.3 (P greater than 0.3). ⋯ This disparity indicates a decrease in the tcPO2/PaO2 ratio with increasing PaO2. It is concluded that tcPO2 cannot substitute for PaO2, but tcPO2 and PaO2 proved to be equally useful as oxygen parameters in the examined patients. Interpretation of tcPO2 during anaesthesia, however, necessitates a preoperative measurement as reference.