Viva 3

A 72 year old female is admitted following a laparotomy for a perforated gastric ulcer. She was  thought   to  have  aspirated at  the  induction   of anaesthesia, but  was  otherwise  stable throughout the case. On arrival in the ICU she is haemodynamically stable, is ventilated  on an SIMV mode,

°     10 breaths per minute,

°     Tidal volume = 700ml,

°     PEEP = 5cm H2O,

°     Inspiratory time 25%

°     Inspiratory Pause 10%,

°     FiO2  = 0.4.

The junior registrar working with you is unsure what this mode of ventilation  is, and asks you to explain how this mode of ventilation  works.

1.  Can you draw a flow vs time, a pressure vs time and a volume vs time curve to explain this mode of ventilation  to the junior registrar?

The rest of the viva focussed on pressure control and pressure support ventilation

Areaof weakness identified by examiners:

°    Candidates struggled to draw basic ventilatory graphics, frequently confused volume with flow.
°    In PCV mode, did not realise that PIP =plateau pressure
°    When given a printed graphics of PSV, they were not able to state the settings from the graphics.
°     This aspect of intensive care is fundamental to what we do on a daily basis and most modern ventilators have graphics on their screen and it was disappointing that a large number of candidates did not perform well in this section.

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.