Acta anaesthesiologica Scandinavica
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Acta Anaesthesiol Scand · May 1990
Laboratory evaluation of heat and moisture exchangers. Assessment of the Draft International Standard (ISO/DIS 9360) in practice.
A lung model and test method in accordance with the ISO draft standard for evaluation of heat and moisture exchangers (HME's) was designed. The trial period was 24 h. The moisture-conserving ability of the HME was determined gravimetrically and the temperature performance was calculated from graphs obtained by temperature probes near the two ports of the HME. ⋯ The performance values obtained from all three series indicated that the reproducibility of the method was good. The difference between mean inspiration and mean expiration temperatures at the patient port (dTp) provides a useful, simple and reproducible measure of the HMEs' temperature performance. Based on these data, we suggest certain changes in the test procedures outlined in the proposed ISO draft standard.
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Acta Anaesthesiol Scand · May 1990
Randomized Controlled Trial Comparative Study Clinical TrialComparison of the effects of fentanyl on respiratory mechanics under propofol or thiopental anaesthesia.
Twenty patients were randomly anaesthetized with either thiopental 5 mg/kg followed by a 15 mg/kg/h continuous infusion, or propofol 2.5 mg/kg followed by a 9 mg/kg/h continuous infusion, paralysed with vecuronium 0.1 mg/kg, intubated and ventilated with nitrous oxide 50% in oxygen. Fifteen minutes after induction, fentanyl 5 micrograms/kg was injected. Inspiratory tracheal pressure (PT), gas flow (V) and volume (V) were continuously measured while the lungs were inflated with a constant inspiratory flow ventilator. ⋯ In both groups Crs decreased following anaesthesia. Fentanyl injection elicited an increase in Rrs (from 1.04 +/- 0.70 to 1.63 +/- 0.92 kPa x l-1 x s) and a further decrease in Crs (from 0.55 +/- 0.30 to 0.42 +/- 0.10 l x kPa-1) in the thiopental group but not in the propofol group (Rrs: 1.26 +/- 0.69 to 1.08 +/- 0.44 kPa x l-1 x s, Crs: 0.49 +/- 0.11 to 0.48 +/- 0.13 l x kPa-1). These results suggest that the dose of propofol administered in this study may prevent fentanyl-induced bronchoconstriction.
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Acta Anaesthesiol Scand · May 1990
Comparative StudyThe effect of 0.5% ropivacaine on epidural blood flow.
Twenty patients scheduled for elective abdominal surgery received epidural analgesia with 20 ml 0.5% ropivacaine or 0.5% bupivacaine. Epidural blood flow was measured by an epidural 133Xe clearance technique on the day before surgery (no local anaesthetic) and again 1 h before surgery, 30 min after injection of the local anaesthetic during continuous infusion (8 ml/h). ⋯ The median level of sensory analgesia was T3.5 and T4.5 in the ropivacaine and bupivacaine group, respectively (P greater than 0.05). The demonstrated vasoconstrictor effect of epidural ropivacaine may influence the duration of its local anaesthetic effect.
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Acta Anaesthesiol Scand · May 1990
Intra-operative epidural blockade with local anaesthetics and postoperative protein breakdown associated with hip surgery in elderly patients.
The effect of epidural anaesthesia of limited duration on postoperative protein breakdown was studied in elderly patients undergoing hip arthroplasty. Two groups of six patients each were studied. One group with halothane (C) and one with an epidural block, T8-S4, (E) as part of their general anaesthetic for surgery. ⋯ The total concentration of plasma and muscle aminoacids decreased after surgery in both groups. Muscle glutamine was decreased by 50% after surgery on the fourth postoperative day in both groups (P less than 0.05). Therefore epidural anaesthesia, limited to the period of surgery, did not attenuate the loss of body proteins which occurred during the postoperative period.
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Acta Anaesthesiol Scand · May 1990
Randomized Controlled Trial Comparative Study Clinical TrialQT interval of the ECG, heart rate and arterial pressure using propofol, methohexital or midazolam for induction of anaesthesia.
The effects of propofol 2 mg/kg, methohexital 2 mg/kg or midazolam 0.3 mg/kg were studied on the QT interval of the ECG corrected by the heart rate (QTc), heart rate and arterial pressure during induction of anaesthesia in 87 ASA class I-(II)-patients. The patients were randomly allocated to one of the three anaesthetic groups. The incidence of the patients with a prolonged QTc interval (= more than 440 ms) ranged from 29 to 41% between the groups. ⋯ After all anaesthetics, the QTc interval was significantly prolonged in the patients with a normal control QTc interval, whereas in the patients with a prolonged control QTc interval, it tended to be shortened both after propofol and methohexital and it was significantly shortened after midazolam. After injection of suxamethonium, no significant QTc interval changes occurred in the patients with a normal control QTc interval in either the propofol or the methohexital groups, whereas in the patients with a prolonged control QTc interval treated with propofol the QTc interval decreased significantly 60 s after suxamethonium when compared with the corresponding preceding values. The mean values in the propofol group in the patients with a normal control QTc interval were always below the upper limit of the normal range.(ABSTRACT TRUNCATED AT 250 WORDS)