Tissue Oxygen Saturation Combined With Serum Lactic Acid Can Predict Cardiac Surgery-Associated Acute Kidney Injury.

OBJECTIVES

To investigate the potential contribution of tissue oxygenation prediction in cardiac surgery-associated acute kidney injury (CSA-AKI) using near-infrared spectroscopy (NIRS) and serum lactate level measurements.

DESIGN

A retrospective study analyzing tissue oxygenation parameters and serum lactate levels during the perioperative period in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB).

SETTING

A single-center cardiac surgery unit in which patients underwent procedures requiring CPB.

PARTICIPANTS

A cohort of 391 patients who underwent cardiac surgery with CPB.

INTERVENTIONS: Measurement of brain tissue oxygen saturation (SctO2) and skeletal muscle tissue oxygen saturation (StO2) using NIRS. Perioperative serum lactate levels were collected through blood gas analysis via radial artery catheterization.

MEASUREMENTS AND MAIN

RESULTS

Tissue oxygen saturation measured by NIRS: During CPB, the SctO2 cutoff was 56.75% and the StO2 cutoff was 65.85%; after CPB, the SctO2 cutoff was 60.15% and the StO2 cutoff was 67.20%. These values demonstrate high predictive accuracy for CSA-AKI. Serum lactate levels: Postoperative levels ≥2.65 mg/L were independent predictors of CSA-AKI. Predictive model: The 5 independent significant variables combined had an area under the receiver operating characteristic curve of 91.8% (95% confidence interval, 0.762-0.887).

CONCLUSIONS

Tissue oxygen saturation measured during CPB and elevated postoperative serum lactate levels are valuable early parameters for predicting CSA-AKI risk in patients undergoing cardiac surgery with CPB. These findings highlight the clinical utility of these parameters in guiding early intervention strategies.