Anaesthesia
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Comparative Study
Neurotoxicity of perineural vs intraneural-extrafascicular injection of liposomal bupivacaine in the porcine model of sciatic nerve block.
Liposomal bupivacaine is a prolonged-release local anaesthetic, the neurotoxicity of which has not yet been determined. We used quantitative histomorphometric and immunohistochemical analyses to evaluate the neurotoxic effect of liposomal bupivacaine after perineural and intraneural (extrafascicular) injection of the sciatic nerve in pigs. In this double-blind prospective randomised trial, 4 ml liposomal bupivacaine 1.3% was injected either perineurally (n = 5) or intraneurally extrafascicularly (n = 5). ⋯ After harvesting the sciatic nerves, no changes in nerve fibre density or myelin width indicative of nerve injury were observed in any of the groups. Intraneural injections resulted in longer sensory blockade than perineural (p < 0.003) without persistent motor or sensory deficit. Sciatic nerve block with liposomal bupivacaine in pigs did not result in histological evidence of nerve injury.
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Lung resection is associated with significant perioperative morbidity, and a proportion of patients will require intensive care following surgery. We set out to characterise this population, assess their burden of disease and investigate the influence of anaesthetic and surgical techniques on their admission rate. Over a two-year period, 1169 patients underwent surgery, with 30 patients (2.6%) requiring unplanned intensive care. ⋯ Logistic regression (following adjustment for Thoracoscore) revealed that an open surgical approach was associated with higher likelihood of admission (p = 0.025, odds ratio = 5.25). There was also a trend towards increased likelihood of admission in patients who received volatile anaesthesia (p = 0.061, odds ratio = 2.08). This topic has been selected for further investigation as part of the 2015 Association of Cardiothoracic Anaesthetists (ACTA) second national collaborative audit, with this study providing pilot data before a multi-centre study.
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Observational Study
An observational study of the 'isolated forearm technique' in unparalysed, spontaneously breathing patients.
The isolated forearm technique enables a patient, otherwise paralysed by neuromuscular blockade, to communicate by movement if wakeful during surgery. The positive response rate to verbal command is high (~32%). The 5th National Audit Project recommended that this monitoring technique should become more widely taught and considered, so this study was designed to assess its utility as a standard of care in unparalysed patients. ⋯ Even at extubation, when patients moved to expel the airway, there was no response to command until after wakening. These results suggest that in contrast to its use in paralysed patients, the isolated forearm technique does not yield useful information about the patient's state of wakefulness in the unparalysed. Another interpretation is that unparalysed patients are less prone to wakefulness than the paralysed.