Effects Of Mean Perfusion Pressure On The Occurrence Of Acute Renal Injury In Patients With Septic Shock

BackgroundAround the world,the incidence of acute kidney injury(AKI)is very high,especially in critically ill patients.Once it occurs,these patients require more intervention and predict worse short-term and long-term adverse outcomes.Through early prevention and alleviation of the occurrence and development of AKI,the clinical prognosis of patients can be improved.Maintaining optimal blood pressure is an important aspect of the prevention of AKI.Although mean arterial pressure(MAP)has played an important role in the prevention of AKI in the past,there is little evidence that MAP reflects true renal perfusion.Currently,several studies have shown that mean perfusion pressure(MPP)obtained by subtraction of Central venous pressure(CVP)from MAP is associated with the occurrence and development of AKI.It is suggested that MPP may be more helpful in preventing AKI than the widely used MAP.However,MPP is rarely studied in patients with septic shock.Therefore,it is necessary to investigate the relationship between MPP and sepsis associated acute kidney injury(SA-AKI)in patients with septic shock,and to provide a theoretical basis for the use of blood pressure in the prevention and treatment of SA-AKI.ObjectiveTo investigate whether MPP is associated with the risk of SA-AKI in patients with septic shock,and to determine the MPP threshold associated with reducing the incidence of SA-AKI.Objects and MethodsThe Critical Care Medical Information Database contains hospitalization information for patients admitted to the intensive care unit at Beth Israel Deaconess Medical Center in Boston,Massachusetts,USA between 2001 and 2012.In this study,the data of adult septic shock patients with sufficient MAP and CVP data in this database were extracted for a retrospective cohort study.Patients with septic shock were identified according to the 2016 SSC guidelines and the AKI diagnosis was determined according to the 2012 KDIGO guidelines.Multiple logistic regression was used to analyze the relationship between MPP and the risk of SA-AKI.The optimal node values of MPP were determined by using restricted cube plots.ROC curve was used to compare the predictive effectiveness of MPP and MAP for SA-AKI occurrence.ResultsA total of 1739 patients with septic shock were enrolled in the study,and the incidence of acute kidney injury was 36.6%.The incidence of acute kidney injury was higher in the low MPP group(40.6% vs.29.2%,P < 0.001)than in the high MPP group(MPP >65mm Hg).Multivariate logistic review confirmed that MPP was an independent protective factor for acute kidney injury(OR=0.98,95%CI: 0.96-0.99).Further studies showed that WHEN MPP ≤ 65 mm Hg,MPP was independently associated with the occurrence of acute kidney injury(OR=0.96,95%CI: 0.94-0.98),but not when MPP > 65 mm Hg(OR=0.99,95%CI: 0.96-1.02).High MPP(> 65 mm Hg)was a protective factor for the risk of acute kidney injury(OR=0.76,95%ci: 0.60-0.95).ROC curve showed that MPP had a higher predictive power for the occurrence of acute kidney injury than MAP(0.6093 vs.0.5598,P < 0.001).ConclusionsIn our study,there was a curvilinear relationship between MPP and the risk of AKI.MPP ≤ 65 mm Hg was independently associated with the risk of AKI.Maintaining MPP >65mm Hg during resuscitation in patients with septic shock may better reduce the incidence of AKI.MPP may be a better indicator of blood pressure recovery than MAP.Improving MPP depends on maintaining adequate MAP and avoiding high CVP.It is worthwhile to further design randomized controlled trials to explore and confirm the relationship.