British journal of anaesthesia
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Fascial layers of the neurovascular sheath containing the brachial plexus influence distribution of local anaesthetic, hence increasing the risk of block failure when performing infraclavicular brachial plexus block (ICB). ⋯ When fascial layers are present in the neurovascular sheath, they impede the spread of injectate during infraclavicular brachial plexus block. Ultrasound detection of these fascial layers is unreliable in cadavers. These findings support the use of greater volumes of injectate or a multiple injection technique when performing this block.
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The posterolateral and medial aspect of the arm is supplied by the axillary (AXN) and intercostobrachial nerves (ICBN), which are not anaesthetised by an axillary brachial plexus block (ABPB). Blockade of the AXN and the ICBN has been reported in the quadrangular space (QS) posteriorly or by serratus plane block, respectively. An anterior ultrasound-guided approach to block the AXN and ICBN would be desirable to complete an ABPB at a single insertion site. ⋯ We describe a reliable ultrasonographic approach to visualise the AXN and ICBN anteriorly from the conventional ABPB approach as confirmed in this cadaver study.
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Comparative Study
Comparison between neurally-assisted, controlled, and physiologically variable ventilation in healthy rabbits.
Various ventilation strategies have been proposed to reduce ventilation-induced lung injury that occurs even in individuals with healthy lungs. We compared new modalities based on an individualised physiological variable ventilation model to a conventional pressure-controlled mode. ⋯ Individualised PVV based on a pre-recorded spontaneous breathing pattern provides adequate gas exchange and promotes a level of lung protection. This ventilation modality could be of benefit during prolonged anaesthesia, in which assisted ventilation is not possible because of the absence of a respiratory drive.
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The human p.G2434R variant of the RYR1 gene is most frequently associated with malignant hyperthermia (MH) in the UK. We report the phenotype of a knock-in mouse that expresses the RYR1 variant p.G2435R, which is isogenetic with the human variant. ⋯ RYR1 pG2435R mice demonstrated gene dose-dependent in vitro and in vivo responses to pharmacological and environmental stressors that parallel those seen in patients with the human RYR1 variant p.G2434R.
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Low positive end-expiratory pressure (PEEP) can result in alveolar derecruitment, and high PEEP or high tidal volume (VT) in lung overdistension. We investigated cardiogenic oscillations (COS) in the airway pressure signal to investigate whether these oscillations can assess unfavourable intratidal events. COS induce short instantaneous compliance increases within the pressure-volume curve, and consequently in the compliance-volume curve. We hypothesised that increases in COS-induced compliance reflect non-linear intratidal respiratory system mechanics. ⋯ Heartbeat-induced oscillations within the course of the inspiratory pressure-volume curve reflect non-linear intratidal respiratory system mechanics. The analysis of these cardiogenic oscillations can be used to detect intratidal derecruitment and overdistension and, hence, to guide PEEP and VT settings that are optimal for respiratory system mechanics.