The association of anesthesia in the sitting beach-chair position with intra-operative stroke, continues to be controversial. Although some studies have identified this as a risk, it is still a rare complication, albeit devastating.
Expert opinion suggests intra-arterial blood pressure monitoring is best practice, but most importantly with consideration for actual cerebral perfusion pressure given the sitting position.
Some research suggests regional anaesthesia, possibly combined with spontaneous ventilation GA (rather than relaxation GA with IPPV) offers unique benefits that better maintain cerebral oxygenation, although the exact difference is unclear.
Similarly, the benefit and role of non-invasive cerebral perfusion monitoring has not been conclusively shown, although it appears logical that it may offer benefit in these patients.
Case studies of patients suffering cerebral ischaemia under beach-chair, do point to combinations of poor intra-operative blood pressure management and possibly pre-existing mild cardiovascular disease (eg. hypertension) as contributing to some degree.summary
Why the excitement?
Since the landmark 2017 WOMAN trial (collected below) showed that tranexamic acid (TXA) may reduce mortality in post-partum haemorrhage, TXA has increasingly been found in close proximity to where obstetric spinal anaesthetics are commonly performed.
TXA's operating theatre ubiquity has also been enhanced by it's replacement of aprotonin in cardiac surgery (Myles 2017, Koster 2015), after the former's associated mortality bump, along with the increasingly routine use of TXA in major joint surgery to reduce bleeding and transfusion (Ho 2003, Poeran 2014).
Recent reviews have identified 21 case reports of mistaken intrathecal administration of TXA over 60 years of anaesthetic publications – although it is likely many cases have been unreported.
Seems rare - why should I be concerned?
- Intrathecal TXA has a 50% mortality, and frequently leaves survivors with permanent neurological injury.
- Once recognised, immediate, aggressive management may improve outcome (particularly, CSF lavage).
- Although rarely published, the increased use of intra-operative TXA may bring it into close proximity with common intrathecal drug ampoules, increasing the risk of this devastating error. Case report publication dates support the increasing incidence.
- Knowing the potential for this error is the first step to avoiding it both personally and systemically.
- Almost all cases involve drug swap errors with major human factor contributions.
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