Oxygen delivery during cardiopulmonary bypass and acute kidney injury: Preliminary Study

Objective: to assess the relationship between oxygen delivery during cardiopulmonary bypass and the incidende of acute kidney injury in the immediate postoperative period of patients undergoing cardiac surgery, as well as to identify possible risk factors. Methods: A retrospective observational study of patients undergoing cardiac surgery scheduled between May 2016 and February 2018 was carried out in which the M-M4 System was used for online blood gases. Patients with preoperative diagnosis of chronic renal failure were excluded. For the oxigen delivery, the average of all M4 records was made. Results: 133 patients (35.3% women) with a mean age of 64.9 ± 10.9 years were studied. The incidence of acute kidney injury was 18.8% (AKI I: 12%; AKI II: 3%; AKI III: 3.8%). There was no correlation between acute kidney injury and O2 delivery (251 ± 43 vs 247 ± 52, ns), if there was a difference when patients needed renal replacement therapy (251 ± 43 vs 198 ± 18, p = 0.04). There was a significant increase risk in diabetes; HTA; pulmonary arterial hypertension; chronic atrial fibrilation; red blood cell concentrate and blood products administration in the operating room; redo for bleeding; high lactic acid and glycemia post cardiopulmonary bypass; prolonged pump and ischemia times; and combined surgery. Conclusions: There was no direct relationship between O2 delivery and acute kidney injury, although there was a significantly lower O2 delivery in patients who needed postoperative renal replacement therapy.