Decreased mean perfusion pressure as an independent predictor of acute kidney injury after cardiac surgery

Abstract

Acute kidney injury after cardiac surgery (AKICS) is common. Previous studies examining the role that mean arterial pressure (MAP) during cardiopulmonary bypass (CPB) may have on AKICS have not taken into account how baseline central venous pressure (CVP) and mean perfusion pressure (MPP) (i.e. MAP − CVP) can influence its evolution. To assess whether the change in MPP to the kidneys (i.e. delta MPP or DMPP) during CPB compared to baseline is an independent predictor of AKICS. After ethical approval, a retrospective observational study was performed on all patients undergoing CPB between October 2013 and June 2015 at a university-affiliated hospital. Known risk factors for the development of AKICS were recorded, as were the MPP values at baseline and during CPB. From this, statistical modelling was performed to identify predictors of postoperative AKICS. 664 patients were identified. Analysis was performed on 513 patients after exclusion. On logistic regression, significant and independent predictors of AKICS included: d20DMPP (cumulative duration of MPP values during CPB that were 20% below baseline and exceeded three consecutive minutes) (P = 0.010); baseline CVP; age; pre-operative creatinine level; and left ventricular (LV) dysfunction (ejection fraction (EF) < 45%). On alternative modelling, the cumulative number of MPP values during CPB that were 10% below baseline was also independently associated with AKICS (P = 0.003). Modelling without taking into account CVP also supported this association. The duration of differences in perfusion pressure to the kidneys during CPB compared to baseline is an independent predictor of AKICS.

Provisional Decision-Making for Perioperative Blood Pressure Management: A Narrative Review

“…Consequently, they concluded that the BP before anesthesia induction could not be used as the baseline BP, while the BP measured in the preoperative holding area could be used as the baseline BP. Hu et al had consistent findings with theirs [33]: the BP measured at the holding area before surgery was considered the baseline BP, and there was an association between baseline MAP and acute kidney injury (AKI) in patients after cardiac surgery, implying that this baseline BP could be used as an important predicting factor for AKI. To ascertain whether baseline BP obtained at different time points can optimize intraoperative brain function, Drummond et al [34] defined the baseline BP as the average of three or more ambulatory clinic BP values 7 months earlier and compared them to the first BP measured in the operating cabinet in a retrospective study.…”

Intraoperative Urine Oxygen in Cardiac Surgery and 12-Month Outcomes

“…In larger prospective studies, we would encourage the analysis of other intraoperative variables such as blood pressure and perfusion pressure during cardiac surgery as these hemodynamic variables have been associated with postoperative AKI. 22,23 Intraoperative PuO 2 during the post-CPB period was associated with poor 12-month outcomes in this small observational cohort study. Larger prospective studies are warranted to validate these findings and to help determine whether real-time PuO 2 monitoring during CPB surgery can lead to improved outcomes.…”

“…Analysis was done primarily using PuO2 as the predictor variable in our univariable models. In larger prospective studies, we would encourage the analysis of other intraoperative variables such as blood pressure and perfusion pressure during cardiac surgery as these hemodynamic variables have been associated with post-operative AKI 22,23 .…”

Searching Optimal Target of Perfusion Pressure for Managing Acute Kidney Injury in Critically Ill Patients: An Analysis of Three Large Open Databases

“…Personal hemodynamic management is proposed to achieve optimal/adequate blood ow using individual targets and adaptive multiparametric approaches [16]. Previous studies mainly focused on the MPP de cit [17,18,21,22], which is de ned as the difference between the basal MPP and the present MPP, indicating that an MPP goal should be achieved to decrease the MPP de cit. We proposed the optimal target of MPP was 65 mmHg or higher, which is near lower limits of normal range (about 70-95 mmHg).…”

“…Therefore, the mean perfusion pressure (MPP), obtained by the difference between MAP and CVP, was recently proposed to be used instead of MAP to personalize the management of tissue perfusion pressure [15,16]. Earlier studies indicated that lower MPP or higher MPP de cits are correlated with the occurrence or progression of AKI [17][18][19][20][21][22]. Still, these studies were limited by the sample size, patients with a speci c disease, and composition of different outcomes of AKI, which limited the generalization to all critically ill patients.…”