Viva 2

A 64-year-old previously well female had a right hemicolectomy complicated by an anastomotic breakdown with sepsis and multi-organ failure requiring a return to theatre.

After 10 days in ICU, she remains oliguric receiving intermittent renal replacement therapy but has otherwise had resolution of her organ failures.

She was extubated this morning and required re-intubation 4 hours later. 

What are the possible reasons for her failed extubation?

(This viva dealt with respiratory weaning.)

Disclaimer: the viva stem above may be an original CICM stem, acquired from their publicly available past papers. Or, perhaps it is a slightly altered version of the original CICM stem. Or, it is a completely original viva stem, concocted by the monstrously amoral author of Deranged Physiology for nothing more than his own personal amusement. In either case, because the college do not make the main viva text or marking criteria available, almost everything here has been confabulated. It might sound like a plausible viva and it could be used for the purpose of practice, but all should be aware that it does not represent the "true" canonical CICM viva station.