Anaesthesia
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Randomized Controlled Trial Clinical Trial Controlled Clinical Trial
Evaluation of the influence of movement on saturation readings from pulse oximeters.
This study aimed to develop a protocol for assessing the influence of movement on oxyhaemoglobin saturation readings from pulse oximeters. Thirty-six volunteers took part in the study. In each volunteer, each hand was monitored by both a Nellcor N200 oximeter using a disposable probe and by a Datex Satlite DS103 oximeter using a clip-on finger probe. ⋯ All movements were associated with apparent decreases in oxyhaemoglobin saturation which were statistically significant for two movements with the Nellcor equipment and for four movements with the Datex equipment. Movement was associated with increases in the magnitude of pulse amplitude, but this was not quantitatively associated with magnitude of artefactual changes in saturation. Use of this standardised movement protocol allows quantification of movement artefact from pulse oximeters and should facilitate the development of equipment less affected by movement.
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Randomized Controlled Trial Comparative Study Clinical Trial
Epidural infusions of bupivacaine and diamorphine in labour.
Three different concentrations of bupivacaine, 0.125%, 0.062% and 0.031%, all with diamorphine 0.0025%, were given as an epidural infusion at 10 ml.h-1 to 63 mothers in labour. When the three infusions were compared, significant differences were found in maternal requirements for top-ups and the degree of motor block, but there were no differences in the pain scores. The reduced motor block was not associated with a reduction in the instrumental delivery rate.
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A questionnaire study was undertaken to assess the influence of recently published, simple and conclusive research on the practice of anaesthetists in four centres. The research had clearly demonstrated the benefit of subcutaneous infiltration of local anaesthetic in reducing the pain of intravenous cannulation. Of the 81% who responded, 71% were aware of the research; 43% of these anaesthetists had altered their clinical practice as a result of the research and 73% used local anaesthesia for cannulae of 18 gauge or less, compared with only 46% of those who were unaware of the research. ⋯ Senior house officers were significantly less likely to be aware of the research than other grades. Anomalies were identified between the apparent awareness of the research and routine practice agreeing with the study findings. The value of research and the incorporation of clinical findings into everyday practice is discussed.
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The output of 30 Tec 3 vaporizers (halothane, enflurane and isoflurane) was studied, starting at the point where no liquid was visible in the content window. At 6 l.min-1 and 1% v/v initial output, consistent delivery was on average maintained for in excess of 90 (range 55-120) min. Thereafter, output declined rapidly. At the flows and concentrations studied there is a significant reserve in the vaporizing chamber, but it is likely that when higher flows and concentrations are used this reserve may be substantially reduced.