PT  - JOURNAL ARTICLE
AU  - Emma M Chang
AU  - Andrew Bretherick
AU  - Gordon B Drummond
AU  - J Kenneth Baillie
TI  - Predictive validity of effective shunt fraction in critically ill patients
AID  - 10.1101/491167
DP  - 2018 Jan 01
TA  - bioRxiv
PG  - 491167
4099  - http://biorxiv.org/content/early/2018/12/10/491167.short
4100  - http://biorxiv.org/content/early/2018/12/10/491167.full
AB  - Accurate measurement of pulmonary oxygenation is important for classification of disease severity and quantification of outcomes in clinical studies. We compared predictive validity of established tension-based methods with two new measures of shunt fraction: (1) a non-invasive effective shunt (ES); and (2) inferred values from an integrated mathematical model of gas exchange (DB). Median absolute error (MAE) values for the four measures considered were: alveolar-arterial difference, 7.30kPa; PaO2/FIO2 ratio, 2.41kPa; DB, 2.13kPa; ES: 1.88kPa. ES performed significantly better than other measures (p<10−10 in all comparisons). While the simplicity of P/F is suitable for routine use, the superior predictive validity of ES should make this measure the preferred choice where physiological accuracy is important, such as for use as surrogate outcome in clinical research.