Anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
A prospective, randomised clinical evaluation of a new safety-orientated injectable drug administration system in comparison with conventional methods.
Fifteen anaesthetists were observed while providing anaesthesia for 15 pairs of adult cardiac surgical operations, using conventional methods for one of each pair and a new drug administration system designed to reduce error for the other. Aspects of each method were rated by users on 10-cm visual analogue scales (10 being best). ⋯ The new system saved preparation time both before anaesthesia (median [range] = 180 [32-480] vs. 360 [120-600] s; p=0.013) and during anaesthesia (10 [2-38] vs. 12 [10-60] s; p=0.009). Prefilled syringes for the new system increased costs by euro 23.00 per anaesthetic (p = 0.041), but this increase is likely to be offset by the potential of the new system to decrease costly iatrogenic harm by preventing drug error.
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Randomized Controlled Trial Comparative Study Clinical Trial
A comparison of 8% and 12% sevoflurane for inhalation induction in adults.
Sevoflurane is a non-pungent volatile anaesthetic agent with a low blood-gas solubility coefficient. It has been studied in concentrations of up to 8% for induction of anaesthesia. Previous work has suggested that there may be a ceiling effect with increasing concentration of sevoflurane above 6%, but there are no published studies using 12% sevoflurane. ⋯ Sevoflurane was administered using two adapted datum vaporisers with the interlock removed. Induction with 12% sevoflurane compared to 8% sevoflurane produced a significant decrease in the time to achieve central pupils, corresponding to surgical anaesthesia and the third part of Guedel's stage 3 of anaesthesia (mean time (SD) 201 s (81) and 247 s (39), respectively, p < 0.05). Twelve-percent sevoflurane produced a similar stable cardiovascular profile to 8% sevoflurane, and there was no increase in respiratory complications.
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Cerebral injury in children undergoing cardiopulmonary bypass (CPB) remains a major source of morbidity. The effect of cardiopulmonary bypass temperature on cerebral function in terms of serum S100beta protein level and cerebral oxygenation monitored by near infrared spectroscopy (NIRO-300) in children is not known. In this study, 18 children undergoing open-heart surgery at the Hospital for Sick Children in London were equally assigned by minimisation to warm (35 +/- 1 degrees C) or cold (25 +/- 1 degrees C) CPB. ⋯ However, cerebral oxygenation in terms of tissue oxygen index (TOI) was significantly impaired during rewarming from cold CPB. Five patients were desaturated (TOI < 50%) during rewarming in the cold bypass group compared to two in the warm patients. This study supports the use of warm CPB in children undergoing open-heart surgery, although further studies recruiting more patients are warranted.
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Depth of anaesthesia has proved to be a complex process to quantify. Monitors based on bispectral analysis of the electroencephalogram and auditory evoked potential have been available, but only recently has a monitor based on entropy become available. This study determined state entropy and response entropy in nine healthy volunteers during propofol hypnosis with a brief intervening period of wakefulness. ⋯ However, an overlap was observed in real time indices between different stages of the Observer's Assessment of Alertness/Sedation Scale. Only three of the nine volunteers had explicit memories from the episode of wakefulness. Electroencephalographic entropy monitors seem to have potential for staging clinical hypnotic effects.