Anaesthesia
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Observational Study
Effect of a lateral infraclavicular brachial plexus block on the axillary and suprascapular nerves as determined by electromyography - a cohort study.
We aimed to examine to what extent a lateral infraclavicular brachial plexus block affected the axillary and the suprascapular nerve. We included patients undergoing hand surgery anaesthetised with a lateral infraclavicular brachial plexus block. Our primary outcome was the relative change in surface electromyography during maximum voluntary isometric contraction of the medial deltoid muscle (axillary nerve) and the infraspinatus muscle (suprascapular nerve) from baseline to 30 min after the block procedure. ⋯ Our results suggest that a lateral infraclavicular block provides block of the axillary nerve comparable to the block of the surgical target nerves. The suprascapular nerve is blocked to a lesser degree. Combining a lateral infraclavicular brachial plexus block with a selective suprascapular block for shoulder surgery warrants further studies.
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Intra-operative hypotension is associated with acute postoperative kidney injury. It is unclear how much hypotension occurs before skin incision compared with after, or whether hypotension in these two periods is similarly associated with postoperative kidney injury. We analysed the association of mean arterial pressure < 65 mmHg with postoperative kidney injury in 42,825 patients who were anaesthetised for elective non-cardiac surgery. ⋯ Postoperative kidney injury was associated with the product of hypotension duration and severity, that is, area under the curve, before skin incision and after, odds ratio (95%CI): 1.02 (1.01-1.04), p = 0.004; and 1.02 (1.00-1.04), p = 0.016, respectively. A substantial fraction of all hypotension happened before surgical incision and was thus completely due to anaesthetic management. We recommend that anaesthetists should avoid mean arterial pressure < 65 mmHg during surgery, especially after induction, assuming that its association with postoperative kidney injury is, at least in part, causal.