SpO2arvona

SpO2arvona is a coined term used in theoretical physiology to denote a proposed index that links arterial oxygen saturation (SpO2) with tissue-level oxygen utilization. It is not an established clinical metric and has no standardized definition or measurement protocol.

In speculative models, SpO2arvona is defined in several ways. One common formulation imagines it as a product of SpO2 and the estimated tissue oxygen extraction fraction (OEF) derived from near-infrared spectroscopy or other surrogate signals. A variant expresses SpO2arvona as the ratio of SpO2 to venous oxygen saturation (SvO2) or to regional oxygen saturation. These formulations are hypothetical and are used mainly to illustrate supply–demand mismatches in teaching and fictional scenarios.

Context and use: In medical education and theoretical simulations, SpO2arvona can help discuss scenarios where SpO2 is normal but tissue oxygen use is impaired, or conversely. It is sometimes invoked in discussions of shock, sepsis, or high-altitude physiology as a conceptual bridge between arterial oxygenation and tissue metabolism.

Limitations and status: Since there is no validated method or reference range, SpO2arvona cannot inform clinical decisions. Measurement would require multi-modal monitoring and assumptions about tissue metabolism, making it prone to error. Further research would be needed to standardize definitions, validate correlations with outcomes, and determine clinical utility.