A transformation of oxygen saturation (the saturation virtual shunt) to improve clinical prediction model calibration and interpretation

Pediatric Research
Guohai ZhouJ Mark Ansermino

Abstract

The relationship between peripheral oxygen saturation (SpO2) and the inspired oxygen concentration is non-linear. SpO2 is frequently used as a dichotomized predictor, to manage this non-linearity. We propose the saturation virtual shunt (VS) as a transformation of SpO2 to a continuous linear variable to improve interpretation of disease severity within clinical prediction models. We calculate the saturation VS based on an empirically derived approximation formula between physiological VS and SpO2. We evaluated the utility of the saturation VS in a clinical study predicting the need for facility admission in children in a low resource health-care setting. The transformation was saturation VS = 68.864 × log10(103.711 - SpO2) - 52.110. The ability to predict hospital admission based on a dichotomized SpO2 produced an area under the receiver operating characteristic curve of 0.57, compared to 0.71 based on the untransformed SpO2 and saturation VS. However, the untransformed SpO2 demonstrated a lack of fit compared to the saturation VS (goodness-of-fit test p value < 0.0001 vs 0.098). The observed admission rates varied non-linearly with the untransformed SpO2 but varied linearly with the saturation VS. The saturation VS estimates a...Continue Reading

References

Mar 1, 1979·Journal of Applied Physiology: Respiratory, Environmental and Exercise Physiology·J W Severinghaus
Aug 1, 1989·Journal of Applied Physiology·R K Ellis
Oct 5, 1988·Journal of the National Cancer Institute·F E HarrellB G Pollock
Jul 1, 1973·British Journal of Anaesthesia·S R BenatarJ F Nunn
Jan 12, 2013·Journal of Clinical Epidemiology·Bart SpruijtRianne Oostenbrink
Apr 10, 2015·Physiological Measurement·Walter KarlenJ Mark Ansermino

❮ Previous
Next ❯

Related Concepts

Related Feeds

Basal Ganglia

Basal Ganglia are a group of subcortical nuclei in the brain associated with control of voluntary motor movements, procedural and habit learning, emotion, and cognition. Here is the latest research.