British journal of anaesthesia
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The neuromuscular blocking effect of repeated bolus administration of suxamethonium 1 mg/kg was observed in 10 healthy surgical patients under enflurane-nitrous oxide-oxygen anaesthesia. Tachyphylaxis and slow recovery of the thumb twitch occurred in close dose-relationships with transition of Phase I block to Phase II, using train-of-four fade as an indicator of the transition. Failure of the thumb twitch to recover to 75% of control, and subsequent step-wise depression from additional doses of suxamethonium had a sudden onset shortly after establishment of marked train-of-four fade.
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Comparative Study
A study of inflatable cuffs on endotracheal tubes. Pressures exerted on the trachea.
A simple method of measuring the pressure exerted by the cuff of an endotracheal tube on the trachea is described and has been used to measure the pressures exerted by 16 commercially available cuffs on the wall of a model trachea. The Shiley, Portex soft-seal, Kamen-Wilkinson (Bivona Fome) tubes had the lowest tracheal wall pressures. Using this method in vivo the changes in tracheal wall pressure exerted by a low-pressure cuff during percussion and vibration physiotherapy, and when the patient "fights the ventilator", were recorded.
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Comparative Study
The influence of carboxyhaemoglobin on the oxygen-binding capacity of blood. A comparison of manometric (Van Slyke) and optical (Co-Oximeter) measurements.
Oxygen content measurements determined optically by the Co-Oximeter correlated closely with those obtained using the manometric technique of Van Slyke. In those samples with a high content of carbon monoxide, the agreement between the two methods could be improved, by taking into consideration the concentration of carboxyhaemoglobin (COHb), since this plays no part in oxygen transport. ⋯ This difference was greater in those samples with a higher content of COHb. When the amount of haemoglobin combined with COHb was taken into consideration the mean corrected values approximated to the theoretical value of 1.39, thus supporting this as the mean value for the oxygen-binding capacity of haemoglobin, although the large individual variability persisted.
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Randomized Controlled Trial Comparative Study Clinical Trial
Extradural analgesia in obstetrics: a controlled trial of carbonated lignocaine and bupivacaine hydrochloride with or without adrenaline.
Four local anaesthetic solutions (2% carbonated lignocaine with or without adrenaline and 0.5% bupivacaine HCl with or without adrenaline) were used randomly for 335 continuous lumbar extradural blocks in labour. Carbonated lignocaine caused a more rapid onset of analgesia than bupivacaine HCl. The addition of adrenaline made little difference to the onset times, prolonged markedly the duration of analgesia with carbonated lignocaine and had little effect on the duration of analgesia with bupivacaine HCl. ⋯ The incidence of unblocked segments was 7-9% in the four groups. The incidence of unilateral analgesia was 6% with plain lignocaine and 13% in the other groups. Complete pain relief occurred more frequently with bupivacaine HCl than with carbonated lignocaine and the use of adrenaline had little effect on the degree of analgesia.