Abdominal perfusion pressure (APP) is a novel, clinically measurable parameter to explain the circulatory compromise in the abdominal cavity, defined as the difference between the mean arterial pressure (MAP) and the intrabdominal pressure (IAP).Kidneys are especially vulnerable intrabdominal organ to the circulatory compromise and the third spacing in multiorgan dysfunction syndrome (MODS) patients. And this study was to evaluate the relationship of the APP to AKI assessed by RIFLEPatients and methods: 106 MODS patients were included in the study, routine laboratory investigations and vital signs were recorded and APP and RIFLE score were assessed daily for the first three days.Results: AKI patients had lower APP (86.3 ± 9.0 vs 78.4 ± 18.5 P 0.009). Patients with APP < 60mmHg showed worse RIFLE scores (0=0/18, R=1/6, I=2/27, F=13/39 p=0.03). APP was significantly correlated with urine output and fluid gain(r=0.239 and -0.225, P 0.013 and 0.021 respectively). SOFA & Lactate were the significant predictors for APP. Low APP was associated with increased mortality (85.4±16.5 vs 77.9±17.5 p 0.06).ConclusionLow APP causes deterioration of kidney function and oliguria is the first and sensitive predictor. Low APP is also associated with increased morbidity and mortality.