Relating blood-borne O₂ delivery with renal respiratory rate. (A) Strong linear relationship between arterial blood flow and arterial oxygen delivery calculated assuming perfusion-limited gas exchange. Statistical testing by the Pearson correlation coefficient. (B) Nonsignificant relationhip between arterial oxygen delivery (D_O2^PL) and renal respiratory rate (v′_R,O2), assuming perfusion-limited transport. (C) Strong, negative correlation between the RBC oxygen-unloading time constant and renal respiration (v'_RO2). Reference range (red) determined from reference blood. (D) Strong, positive correlation between arterial D_O2 scaled by RBC initial oxygen-unloading rate (κ/τ) to model a diffusion-limited process, and renal respiration.