Anaesthesia
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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 Comparative Study Clinical Trial
Intravenous regional anaesthesia with 0.5% prilocaine or 0.5% chloroprocaine. A double-blind comparison in volunteers.
Ten healthy male volunteers received intravenous regional anaesthesia of the upper limb on two separate occasions using 40 ml of 0.5% prilocaine or 40 ml plain 0.5% chloroprocaine by random allocation. Using a double-blind method, the onset and recovery of sensory block was tested (pinprick) in the four main nerve areas. The onset and recovery of motor block was measured by squeezing a rubber balloon connected to a manometer. ⋯ Six volunteers in the chloroprocaine group showed signs of venous irritation and/or antecubital urticaria in the test arm for 30-45 min after the deflation. Four volunteers in the chloroprocaine group had increased in heart rate (greater than 20%) and one of them short periods of junctional rhythm during the first 2 min after tourniquet deflation. Mild, short-lived CNS side effects occurred in both groups.
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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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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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The relationships between patients' height, weight, age, body mass index, gender and presence of maxillary incisors and a series of laryngoscopic factors have been studied. These included the duration of laryngoscopy, maximally applied force, mean applied force and the integral of force over time. ⋯ This latter factor was the dominant patient characteristic influencing the measured laryngoscopic factors. Use of these laryngoscopic factors as a measure of difficulty of laryngoscopy is discussed.