Acta anaesthesiologica Scandinavica
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The Venturi circuit was studied with regard to CO2 elimination in a model experiment. A mean concentration of 0.6% CO2 in the fresh gas supply to the patient was accepted. The experiments demonstrated that a soda-lime charge of 200 g will cover the elimination requirements of CO2 in a Venturi circuit for any patient below 100 kg b.w. for a period of 3 h, while a soda-lime charge of 300 g will suffice for 5 h. ⋯ In the Venturi circuit, the size of the soda-lime charge can be adjusted to suit the body weight of the patient and the expected length of the anaesthetic procedure. One soda-lime charge for each anaesthetic procedure is preferable from the point of view of hygiene. The charge should not be less than 200 g.
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Acta Anaesthesiol Scand · Apr 1985
Hypoxic pulmonary vasoconstriction in the human lung: the effect of prolonged unilateral hypoxic challenge during anaesthesia.
The influence of time on the pulmonary vasoconstrictor response to hypoxia was studied in six subjects during general anaesthesia and artificial ventilation prior to elective surgery. The lungs were intubated separately with a double-lumen bronchial catheter. After preoxygenation of both lungs for 30 min, the test lung was rendered hypoxic for 60 min by ventilation with 5% O2 in N2, with the control lung still being ventilated with 100% O2. ⋯ Prolonging the unilateral hypoxic challenge caused no further change in the redistribution of the pulmonary blood flow, but cardiac output and pulmonary artery mean pressure continued to increase to 40%-50% above control values after 1 h of hypoxia. The PVR of the test lung remained unchanged. The findings suggest that there is an immediate vasoconstrictor response to hypoxia in the human lung and that there is no further potentiation or diminution, of the response during a 60-min period of hypoxia.
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The use of regional anaesthesia in paediatric surgery remains controversial although the pharmacological and technical aspects, even in this age group, have been described. Many authors regard regional anaesthesia as contra-indicated, and consequently general anaesthesia is preferred in paediatric surgery. ⋯ Surgically excellent or satisfactory analgesia was achieved in 92-100% of the blocks. No complications were observed.
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Acta Anaesthesiol Scand · Apr 1985
Randomized Controlled Trial Comparative Study Clinical TrialIsoflurane v fentanyl for outpatient laparoscopy.
Isoflurane and fentanyl have been compared as anaesthetic agents for outpatient laparoscopy. In 50 female patients anaesthesia was induced with thiopentone and maintained with nitrous oxide 66% in oxygen combined with either isoflurane 1-2% or fentanyl 0.3 mg according to a randomized list. Suxamethonium was used to facilitate intubation and for further muscle relaxation. ⋯ Reaction times in the isoflurane patients returned to control by 3 h, whereas the fentanyl patients were 10% slower than control at 4 h (P less than 0.05 at 2 h, 3 h, 4 h). Nausea and vomiting were more frequent in the fentanyl group, and four of the fentanyl patients required naloxone. Both anaesthetic techniques provided satisfactory operating conditions, but isoflurane appeared to provide a better recovery with less side effects than fentanyl.
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Acta Anaesthesiol Scand · Apr 1985
Simulated spontaneous breathing. A new model for testing anaesthetic circuits.
A carbon-dioxide-producing lung model capable of simulating spontaneous breathing is presented. It consists of a piston in a cylinder, a mixing chamber and a dead space volume. ⋯ The model is easy to handle and accurately mimics a given breathing pattern. It seems suitable for investigations of rebreathing and carbon dioxide elimination in different anaesthetic circuits.