Anaesthesia
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A previously fit patient underwent laparoscopic cholecystectomy. During the procedure arterial oxygen saturation fell and clinical examination revealed signs of a right pneumothorax confirmed by chest X ray. Aspiration of the pleural cavity and analysis of the gas removed showed it to be composed entirely of carbon dioxide. Possible mechanisms of entry of carbon dioxide into the pleural space are discussed.
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Randomized Controlled Trial Clinical Trial
Perineuronal morphine in intercostal block.
In a double-blind, randomised study the potential benefits of combining low-dose morphine with bupivacaine for intercostal nerve blocks for analgesia after biliary surgery were investigated. There was no significant improvement in pain scores or consumption of supplementary analgesics when morphine was added to bupivacaine. This investigation supports the findings of other workers who showed that perineural morphine was ineffective for postoperative pain relief.
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Oxygen delivery using nasal prongs was assessed using a lung model for spontaneous ventilation. The analogue lung was attached to a manikin, which provided a model of the 'face and pharynx' to which the nasal prongs were applied. ⋯ The study demonstrated enormous variability in the both the peak-inspired (26.3-90.0%) and end-expired concentrations (25.2-78.6%) of oxygen delivered to the trachea. There was a regular relationship between the ratio of peak inspiratory flows, expressed over fresh gas inflow and the end-expired oxygen concentrations which could allow estimation of inspired oxygen concentration.
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Randomized Controlled Trial Clinical Trial
Factors influencing epidural catheter migration.
The incidence and amount of migration of epidural catheters was investigated in a prospective randomised study of 153 women who required analgesia in labour. Inward or outward migration occurred in 36% of patients. Inward migration by 1-3 cm occurred in 21 (13.7%) patients and outward migration by 1 cm or more occurred in 34 (22.2%); three (2%) catheters migrated out through the skin. ⋯ However, the pattern of problems was different. All cases of failed epidural block occurred in patients whose epidural catheter migrated outward by 2.5 cm or more. Unilateral blockade was not more likely if migration of 1 cm or more occurred.
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Doxacurium was administered to 50 adult patients for determination of potency (n = 10), onset and duration of clinical relaxation (n = 40). Cumulative dose-response showed the ED95 to be 33.24 micrograms.kg-1 (95% confidence limits 27.4-39.3). Doxacurium 33 micrograms.kg-1 was then administered to four groups of 10 patients each who had anaesthesia maintained with either fentanyl-droperidol or halothane and nerve stimulation carried out with single-twitch stimulation at 0.1 Hz or train-of-four stimulation at 2 Hz every 12 s. ⋯ The mean (SD) durations of clinical relaxation (recovery of single twitch or first response in train-of-four to 25%) were 65 (22.8), 52 (21.7), 70 (33.4) and 72 (21.0) min respectively with individual values ranging from 31 to 103 min. Although halothane administration increased the duration of clinical relaxation and train-of-four stimulation accelerated the onset of effect, the changes due to these were not significant. There were no adverse effects on heart rate or indirectly measured arterial pressure.