Anaesthesia
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Randomized Controlled Trial Comparative Study
Emergency capnography monitoring: comparing ergonomic design of intensive care unit ventilator interfaces and specific training of staff in reducing time to activation.
Modern ventilators provide capnography monitoring in patients with tracheal tubes, in compliance with national and international recommendations. This technology is often not used when patients' lungs are non-invasively ventilated; however, it should be accessed immediately following tracheal intubation to confirm tube placement. This study assessed the effect of ventilation interface design on the speed with which capnography can be activated by comparing the Dräger Evita 4 and Dräger V500 before and after a specific training episode. ⋯ We used a randomised crossover design, measuring time to monitoring activation, and repeated the study after 3 months. Survival analysis showed significantly quicker activation associated with ventilator choice (V500, p < 0.0001) and training (p = 0.0058). The training improved activation speed with both machines, though this was only significant for the Evita 4 (p = 0.0097).
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Systemic toxicity through overdose of local anaesthetic agents is a real concern. By encapsulating local anaesthetics in biodegradable carriers to produce a system for prolonged release, their duration of action can be extended. This encapsulation should also improve the safety profile of the local anaesthetic as it is released at a slower rate. ⋯ Extended duration local anaesthetic formulations in current development or clinical use include liposomes, hydrophobic based polymer particles such as Poly(lactic-co-glycolic acid) microspheres, pasty injectable and solid polymers like Poly(sebacic-co-ricinoleic acid) P(SA:RA) and their combination with synthetic and natural local anaesthetic. Their duration of action, rationale and limitations are reviewed. Direct comparison of the different agents is limited by their chemical properties, the drug doses encapsulated and the details of in vivo models described.
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Randomized Controlled Trial
Effect of positioning from supine and left lateral positions to left lateral tilt on maternal blood flow velocities and waveforms in full-term parturients.
Positioning the parturient from supine to the left lateral tilt position (supine-to-tilt) may not effectively displace the gravid uterus, but turning from the left lateral position to the left lateral tilt position (left lateral-to-tilt) may keep the gravid uterus displaced and prevent aortocaval compression. Fifty-one full-term parturients were randomly placed in the left lateral position, supine-to-tilt and left lateral-to-tilt positions using a Crawford wedge. ⋯ Our results showed a lower mean (SD) femoral vein area (82.2 (14.9) vs 96.2 (16.4) mm(2)), a lower pulsatility index (3.83 (1.3) vs 5.8 (2.2)), a lower resistance index (0.93 (0.06) vs 0.98 (0.57)), a higher femoral artery area (33.3 (3.8) vs 30.9 (4.4) mm(2)) and a higher femoral vein velocity (7.9 (1.2) vs 6.1 (1.6) cm.s(-1)) with left lateral-to-tilt when compared with supine-to-tilt (all p < 0.001). Our results suggest that moving a full-term parturient from the full left lateral to the lateral tilt position may prevent aortocaval compression in full-term parturients more efficiently than when positioning the parturient from a supine to left lateral tilt position.
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Clinical Trial
Novice performance of ultrasound-guided needle advancement: standard 38-mm transducer vs 25-mm hockey stick transducer.
The optimal method to develop expertise in ultrasound-guided regional anaesthesia is unknown. Studies of laryngoscopic expertise in novices demonstrate that the choice of laryngoscope affects performance. In this study, we aimed to compare the effect of two different linear array transducers (38-mm standard vs 25-mm hockey stick) on novice performance of ultrasound-guided needle advancement. ⋯ Recruits performed the modelled task on a turkey breast model. The median (IQR [range]) composite error score was statistically significantly larger for participants in the hockey stick transducer group compared with the standard transducer group; 10.0 (7.3-14.3 [2.5-29.0]) vs 7.5 (4.5-10.0 [2.0-28.0]) respectively, (p = 0.01). This study has demonstrated that performance of ultrasound-guided needle advancement by novice operators after simple video instruction is better (as assessed using a composite error score) with a standard 38-mm transducer than with a 25-mm hockey stick transducer.
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We compared the Pentax Airway Scope(TM) with the Airtraq(TM) optical laryngoscope in an infant manikin. Twenty-three anaesthetists randomly performed tracheal intubation: at rest, (a) with the Airway Scope and (b) with the Airtraq; and during chest compressions, (c) with the Airway Scope and (d) with the Airtraq. The success rate, modified Cormack and Lehane classification for glottic view, time taken to view the glottis, and time to place the tracheal tube were recorded. ⋯ During chest compressions, the median (IQR [range]) time taken to view the glottis was 5.1 (4.0-7.2 [2.0-12.4]) s using the Airway Scope compared with 7.5 (5.0-13.2 [4.2-26.4]) s using the Airtraq (p = 0.006), and to successful placement of the tracheal tube was 9.5 (6.6-13.7 [4.5-16.2]) s using the Airway Scope compared with 11.7 (9.1-18.1 [6.2-37.4]) s using the Airtraq (p = 0.022). We conclude that both devices provided good quality views of the glottis and successful tracheal intubation in an infant manikin both at rest and during external chest compressions. Use of the Airway Scope resulted in a shorter time to view the glottis and perform successful tracheal intubation compared with the Airtraq.