Viva 4

A 36-year-old woman presents to the Emergency Department with a three (3) day history of dry cough and increasing shortness of breath. She is profoundly hypoxaemic and is intubated by ED staff for institution of mechanical ventilation. A chest x ray confirmed the position of the ET tube but showed bilateral diffuse opacities in the lungs.

In the ICU, the patient is placed on 100% oxygen and 10 cm H2O PEEP. She is commenced on volume control mode of ventilation and the ICU registrar has set the ventilator to deliver 500 mls tidal volume at a rate of 12 breaths per min.

A few minutes later, you are called by the bedside nurse as she is concerned by the ABG taken on 100% oxygen.

pH                 7.29 
pCO2             48 mmHg 
pO2               62 mmHg 
HCO3            20 mmol/L 
BE                 -4.3 
Sat                 88%

She weighs 60kg ideal body weight and is sedated and paralysed.

How would you approach the ventilatory support of this patient?

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.