Blood pressure and blood pressure deficits as predictors of acute kidney injury in vasopressor dependent patients post cardiovascular surgery

BACKGROUND: Acute kidney injury (AKI) is a common and serious post-operative complication following cardiovascular surgery. AIM: The aim of the study was to evaluate the value of blood pressure and blood pressure deficits as predictors of AKI in post cardiovascular surgery vasopressors’ dependent patients. METHODS: A prospective observational, single center study, conducted on 100 patients requiring vasopressor support for more than 4 h after cardiovascular surgery. All included patients were subjected to the measurements of three or more systolic arterial pressure (SAP), diastolic arterial pressure (DAP), and mean arterial pressure (MAP) readings from the ward charts before surgery and the mean of these measures was calculated, was recorded and pre-operative systolic perfusion pressure (SPP), diastolic perfusion pressure (DPP), and mean perfusion pressure (MPP) were calculated. A vasopressor-associated average values for hemodynamic pressure-related parameters (SAP, DAP, MAP, CVP, SPP, DPP, and MPP) were calculated on the 1st 24 h after admission. The percent deficit in post-operative average parameters in relation to pre-operative parameters was determined as % parameter deficit. RESULTS: The pre-operative SAP, DAP, MAP, SPP, DPP, and MPP were significantly higher in the non-AKI compared to AKI patients while pre-operative central venous pressure (CVP) was significantly higher in AKI patients. The post-operative DAP, MAP, DPP, and MPP were also higher in non-AKI and the post-operative CVP was lower in non-AKI compared to AKI patients. CONCLUSIONS: This study concluded that the relative decrease in the perfusion pressures could be significant predictors of AKI after cardiovascular surgery in vasopressor dependent patients. The higher pre-or post-operative CVP or its relative decrease after cardiac surgery was seen also to be associated with higher incidence of AKI.