ICU Cases · Oxygen & gas exchange
Hot case — the bedside: interpreting a hypoxaemic blood gas
A CICM hot case — a bedside encounter testing the interpretation of the hypoxaemic blood gas: the A-a gradient, the shunt vs V/Q mismatch distinction, the lung-protective strategy, and the conservative oxygen target.
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Prompt
At the bedside of a ventilated patient with a PaO2/FiO2 of 110, the nurse asks you to interpret the blood gas and adjust the ventilator.
Presentation
You are taken to the bedside of a 65-year-old ventilated patient on day 2 of a severe ARDS. She is on a FiO2 of 0.8, a PEEP of 12, a tidal volume of 6 mL/kg, and the morning blood gas shows a PaO2 of 88, a PaCO2 of 42, a pH of 7.36, and a lactate of 2.0. The saturation is 93 per cent. The nurse asks you to interpret the gas and adjust the ventilator.[1]
References3ShowHide
- [1]Bersten AD, Soni N (eds) Oh's Intensive Care Manual. 8th edition, Elsevier, 2018.
- [2]Marino PL The ICU Book. 4th edition, Lippincott Williams & Wilkins, 2014.
- [3]Chu DK, Kim LH, Young PJ, et al. Mortality and morbidity in acutely ill adults treated with liberal versus conservative oxygen therapy. Lancet, 2018.PMID 29726345