NPPB and acute kidney injury: BNP and NT-proBNP are well-known predictive factors for major cardiac events, however, recent researches have demonstrated the clinical and prognostic implications of BNP and NT-proBNP in predicting AKI in several medical settings, such as critical illness (18), severe burn (16), coronary heart disease (14) and cardiac surgery (19, 20), but, its relationship with AKI after noncardiac surgery had rarely been investigated.