Fig. 2
From: Acute kidney injury following cardiac surgery: current understanding and future directions
Perioperative concentrations of plasma-free hemoglobin (Hb) in acute kidney injury (AKI) and risk-matched control patients. Hb concentrations at baseline, 30 minutes into cardiopulmonary bypass (CPB), immediately following CPB, at ICU admission, 6 hours after ICU admission, and on the mornings of postoperative days (POD) 1, 2, and 3 in patients who developed AKI and in risk-matched (including identical CPB times) control patients who did not develop AKI. Postoperative AKI was associated with higher circulating concentration of free Hb during and immediately following CPB (P < 0.01) and throughout the study period (P = 0.006)