British journal of anaesthesia
-
We have compared three treatment strategies, that aim to prevent repetitive alveolar collapse, for their effect on gas exchange, lung mechanics, lung injury, protein transfer into the alveoli and surfactant system, in a model of acute lung injury. In adult rats, the lungs were ventilated mechanically with 100% oxygen and a PEEP of 6 cm H2O, and acute lung injury was induced by repeated lung lavage to obtain a PaO2 value < 13 kPa. Animals were then allocated randomly (n = 12 in each group) to receive exogenous surfactant therapy, ventilation with high PEEP (18 cm H2O), partial liquid ventilation or ventilation with low PEEP (8 cm H2O) (ventilated controls). ⋯ Conversion of active to non-active surfactant components increased significantly in the partial liquid ventilation group and in the group ventilated with high PEEP. In the surfactant group and partial liquid ventilation groups, less lung injury was found compared with the ventilated control group and the group ventilated with high PEEP. We conclude that although all three strategies improved PaO2 to > 50 kPa, the impact on protein transfer into the alveoli, surfactant system and lung injury differed markedly.
-
Randomized Controlled Trial Clinical Trial
Influence of bolus size on efficacy of postoperative patient-controlled analgesia with piritramide.
We have examined the influence of bolus size on efficacy, opioid consumption, side effects and patient satisfaction during i.v. patient-controlled analgesia (PCA) in 60 patients (ASA I-II, aged 32-82 yr) after abdominal surgery. Patients were allocated randomly, in a double-blind manner, to receive PCA with a bolus dose of either piritramide 0.75 mg or 1.5 mg (lockout 5 min) for postoperative pain control. ⋯ There were no significant differences in the number of applied bolus doses, pain scores, pain relief (VAS), sedation, nausea, pruritus and patient satisfaction. We conclude that a PCA regimen with a bolus dose of piritramide 0.75 mg and a lockout time of 5 min was effective in the treatment of postoperative pain, but did not reduce the occurrence of side effects.
-
Randomized Controlled Trial Clinical Trial
Effect of sevoflurane concentration on inhalation induction of anaesthesia in the elderly.
We have conducted a randomized, double-blind comparison of 4% and 8% sevoflurane for induction of anaesthesia in unpremedicated patients aged more than 60 yr. Sevoflurane was inhaled in 50% nitrous oxide using a vital capacity breath technique, and mean, systolic and diastolic arterial pressures and heart rate were monitored continuously using a Finapres cuff. In the 8% sevoflurane group, time to successful laryngeal mask insertion was significantly shorter (mean 168 (SD 34) s vs 226 (62) s; P < 0.01) and achieved more often at the first attempt than in the 4% sevoflurane group. ⋯ No patient had apnoea lasting longer than 1 min. A total of 69% of patients described induction as pleasant and 85% would choose to have it again. We conclude that compared with 8% sevoflurane, the use of 4% sevoflurane in the elderly resulted in greater cardiovascular stability but at the cost of prolonged and occasionally unsuccessful induction.
-
Randomized Controlled Trial Clinical Trial
A low concentration of nitrous oxide reduces dyspnoea produced by a combination of hypercapnia and severe elastic load.
We have measured how a low concentration of nitrous oxide affected respiratory sensation and ventilation. Severe dyspnoea was induced in nine normal subjects by a combination of hypercapnia and inspiratory elastic load (50 cm H2O litre-1). Subjects were asked to rate their sensation of respiratory discomfort using a visual analogue scale (VAS) while breathing either 20% nitrous oxide or 20% nitrogen gas mixture. ⋯ Inhalation of 20% nitrous oxide reduced the sensation of respiratory discomfort from a median VAS score of 6.5 (range 5.0-8.1) before inhalation to 3.6 (2.4-5.9) during inhalation (P < 0.05). There was no significant change in minute ventilation but tidal volume increased during inhalation of 20% nitrogen did not alter VAS scores or ventilatory variables. We found that a low concentration of nitrous oxide greatly alleviated the intensity of dyspnoea without changing respiratory load compensation.