Anaesthesia
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Bench studies have become the preferred way to evaluate the performance of airway equipment, since clinical trials are not specifically required before marketing these devices. However, it is difficult to assess the efficiency of ventilation without recording physiological data. This review analyses how efficiency of manual ventilation has been defined in recent studies, and how their results may be affected. ⋯ However, there were significant differences between the definitions of performance of ventilation, both in terms of criteria of judgement and methods of analysis. None of these approaches is able to provide a clear understanding of variability of ventilation during a given period. A new definition may increase the relevance of bench studies to clinical medicine, by more appropriately assessing the performance of ventilation.
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Randomized Controlled Trial Comparative Study
A randomised controlled comparison between stimulating and standard catheters for lumbar plexus block.
The aim of this randomised, prospective, blinded study was to evaluate if stimulating catheters can decrease the minimum effective anaesthetic volume in 50% of patients during lumbar plexus block using mepivacaine 1.5% compared with standard catheters. Fifty-eight patients of ASA physical status 1-3 were randomly allocated to receive a lumbar plexus block via a stimulating or standard catheter, with 29 in each group. ⋯ Complete lumbar plexus block was achieved with the initial dose of mepivacaine in 29 (100%) patients in the stimulating catheter group and 20 (69%) patients in the standard catheter group (p = 0.002). This study showed that use of a stimulating catheter halves the minimum effective anaesthetic volume50 of mepivacaine 1.5% while increasing the success rate in patients receiving continuous lumbar plexus block.
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Randomized Controlled Trial Comparative Study
Incidence of intravascular injection and the spread of contrast media during S1 transforaminal epidural steroid injection by two approaches: anteroposterior vs oblique.
The aim of this randomised study was to compare the incidence of intravascular injections during S1 transforaminal epidural steroid injection performed in the anteroposterior and oblique views. We also compared epidural spread patterns of contrast media, which included 201 injections at the S1 level. ⋯ There were no significant differences between the two groups for epidural spread of contrast media in cases where intravascular injections did not occur (p = 0.77). Performing S1 transforaminal epidural steroid injection in the oblique view rather than the anteroposterior view reduces the risk of intravascular injections.
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Comparative Study
Dominant hand operating probe vs needle: a comparison study of ultrasound-guided needle placement in phantom models.
We conducted a replicated crossover design study to assess if using one's dominant hand for operating a probe vs directing a needle would affect the time taken, the number of needle passes and the accuracy of an ultrasound-guided procedure in phantom models. Twenty ultrasound-novice participants completed the task 10 times for each hand arrangement (alternating between attempts). ⋯ Sixty-five per cent of participants preferred using their dominant hand to direct the needle. When learning ultrasound-guided needle procedures on phantom models, use of the dominant hand to operate the needle is associated with a shorter procedure time and fewer needle passes.
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Observational Study
Reliability of manikin-based studies: an evaluation of manikin characteristics and their impact on measurements of ventilatory variables.
Findings from manikin-based studies on ventilation are commonly directly extrapolated to clinical practice. The aim of this study was to determine how the use of manikins affects measurements of ventilatory variables. We connected a lung simulator to a manikin, which was then ventilated at different inspiratory flows. ⋯ Significant peak pressure deviations from 0.7 (0.1) cmH2 O to 10.6 (0.3) cmH2 O were also recorded during non-invasive ventilation (p < 0.001). Evaluation of manikin resistance and airway dead space may be essential to limit study bias. We suggest a recalibration of the recorded data if comparisons are made between different tests performed at different inspiratory flows.