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Association between major surgical admissions and the cognitive trajectory: 19 year follow-up of Whitehall II cohort study

BMJ 2019; 366 doi: https://doi.org/10.1136/bmj.l4466 (Published 07 August 2019) Cite this as: BMJ 2019;366:l4466

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The determinants of cognitive decline and dementia

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Re: Association between major surgical admissions and the cognitive trajectory: 19 year follow-up of Whitehall II cohort study

This study suggests that major surgery results in the equivalent of five months of cognitive ageing, but note that causality could not be established because the study was observational.

There is good evidence that surgery under general anaesthesia results in postoperative hypoxia. In one study some 20% of patients not given postoperative oxygen had measurable hypoxia (1). Furthermore, this may be persistent (2). On an observational basis I have seen significant postoperative confusion that lasts for weeks. While formal studies have failed to conclude that there are cognitive and memory problems after open-heart surgery - indeed where found, these may be pre-existing) (3) - I think it is possible that the combination of hypoxia and perioperative hypotension may contribute to any cognitive decline post-surgery, and any further prospective investigation should include short- and long-term assessments of oxygen levels. If my hypothesis is correct then more prolonged use of oxygen following surgery should become standard practice and may mitigate cognitive loss.

1. Maity A et al. Detection of hypoxia in the early postoperative period. Anesth Essays Res. 2012 Jan-Jun; 6(1): 34–37.
doi: 10.4103/0259-1162.103369

2. Sun Z et al. Postoperative Hypoxemia Is Common and Persistent: A Prospective Blinded Observational Study Analg. 2015 Sep; 121(3): 709–715. doi: 10.1213/ANE.0000000000000836

3.Is There Long-Term Brain Damage After Bypass Surgery? More Evidence Puts the Blame on Heart Disease Itself. https://www.hopkinsmedicine.org/news/media/releases/is_there_long_term_b... (accessed 10th August 2019)

Competing interests: No competing interests

10 August 2019
Andrew N Bamji
Retired consultant rheumatologist
None
Rye