Early peripheral perfusion index predicts 28-day outcome in patients with septic shock

BACKGROUND:To investigate the prognostic value of the peripheral perfusion index(PPI)in patients with septic shock.METHODS:This prospective cohort study,conducted at the emergency intensive care unit of Peking University People's Hospital,recruited 200 patients with septic shock between January 2023 and August 2023.These patients were divided into survival(n=84)and death(n=116)groups based on 28-day outcomes.Clinical evaluations included laboratory tests and clinical scores,with lactate and PPI values assessed upon admission to the emergency room and at 6 h and 12 h after admission.Risk factors associated with mortality were analyzed using univariate and multivariate Cox regression analyses.Receiver operator characteristic(ROC)curve was used to assess predictive performance.Mortality rates were compared,and Kaplan-Meier survival plots were created.RESULTS:Compared to the survival group,patients in the death group were older and had more severe liver damage and coagulation dysfunction,necessitating higher norepinephrine doses and increased fl uid replacement.Higher lactate levels and lower PPI levels at 0 h,6 h,and 12 h were observed in the death group.Multivariate Cox regression identifi ed prolonged prothrombin time(PT),decreased 6-h PPI and 12-h PPI as independent risk factors for death.The area under the curves for 6-h PPI and 12-h PPI were 0.802(95%CI 0.742-0.863,P<0.001)and 0.945(95%CI 0.915-0.974,P<0.001),respectively,which were superior to Glasgow Coma Scale(GCS),Sequential Organ Failure Assessment(SOFA)scores(0.864 and 0.928).Cumulative mortality in the low PPI groups at 6 h and 12 h was signifi cantly higher than in the high PPI groups(6-h PPI:77.52%vs.22.54%;12-h PPI:92.04%vs.13.79%,P<0.001).CONCLUSION:PPI may have value in predicting 28-day mortality in patients with septic shock.

Initial 24-h perfusion index of ICU admission is associated with acutekidney injury in perioperative critically ill patients: A retrospective cohortanalysis

Background:The relationship between perfusion index(PI)and organ dysfunction in patients in the intensivecare unit(ICU)is not clear.This study aimed to explore the relationship between PI and renal function in theperioperative critical care setting and evaluate the predictive efficiency of PI on patients with acute kidney injury(AKI)in the ICU.Methods:This retrospective analysis involved 12,979 patients who had undergone an operation and were admitted to the ICU in Peking Union Medical College Hospital from January 2014 to December 2019.The distributionof average PI in the first 24 h after ICU admission and its correlation with AKI was calculated by Cox regression.Receiver operating characteristic(ROC)curves were generated to compare the ability of PI,mean arterial pressure(MAP),creatinine,blood urea nitrogen(BUN),and central venous pressure(CVP)to discriminate AKI in thefirst 48 h in all perioperative critically ill patients.Results:Average PI in the first 24 h served as an independent protective factor of AKI(Odds ratio[OR]=0.786,95%confidence interval[CI]:0.704–0.873,P<0.0001).With a decrease in PI by one unit,the incidence of AKIincreased 1.74 times.Among the variables explored for the prediction of AKI(PI,MAP,creatine,BUN,and CVP),PI yielded the highest area under the ROC curve,with a sensitivity of 64.34%and specificity of 70.14%.A cut-offvalue of PI≤2.12 could be used to predict AKI according to the Youden index.Moreover,patients in the low PIgroup(PI≤2.12)exhibited a marked creatine elevation at 24–48 h with a slower decrease compared with thosein the high PI group(PI>2.12).Conclusions:As a local blood flow indicator,the initial 24-h average PI for perioperative critically ill patients canpredict AKI during their first 120 h in the ICU.

Effect of mean arterial pressure change by norepinephrine on peripheral perfusion index in septic shock patients after early resuscitation

Background:The peripheral perfusion index(PI),as a real-time bedside indicator of peripheral tissue perfusion,may be useful for determining mean arterial pressure(MAP)after early resuscitation of septic shock patients.The aim of this study was to explore the response of PI to norepinephrine(NE)-induced changes in MAP.Methods:Twenty septic shock patients with pulse-induced contour cardiac output catheter,who had usual MAP under NE infusion after early resuscitation,were enrolled in this prospective,open-label study.Three MAP levels(usual MAP-10 mmHg,usual MAP,and usual MAP+10 mmHg)were obtained by NE titration,and the corresponding global hemodynamic parameters and PI were recorded.The general linear model with repeated measures was used for analysis of variance of related parameters at three MAP levels.Results:With increasing NE infusion,significant changes were found in MAP(F=502.46,P<0.001)and central venous pressure(F=27.45,P<0.001)during NE titration.However,there was not a significant and consistent change in continuous cardiac output(CO)(F=0.41,P=0.720)and PI(F=0.73,P=0.482)at different MAP levels.Of the 20 patients enrolled,seven reached the maximum PI value at usual MAP-10 mmHg,three reached the maximum PI value at usual MAP,and ten reached the maximum PI value at usual MAP+10 mmHg.The change in PI was not significantly correlated with the change in CO(r=0.260,P=0.269)from usual MAP-10 mmHg to usual MAP.There was also no significant correlation between the change in PI and change in CO(r=0.084,P=0.726)from usual MAP to usual MAP+10 mmHg.Conclusions:Differing MAP levels by NE infusion induced diverse PI responses in septic shock patients,and these PI responses may be independent of the change in CO.PI may have potential applications for MAP optimization based on changes in peripheral tissue perfusion.

Mean airway pressure has the potential to become the core pressure indicator of mechanical ventilation: Raising to the front from behind the clinical scenes

Mean airway pressure(Pmean)is a common pressure monitoring parameter of mechanical ventilators that is closely correlated with mean alveolar pressure and represents stresses applied to the lung parenchyma during ventilation.Pmean is determined by the peak inspiratory pressure,positive end-expiratory pressure(PEEP),and inspiratory-to-expiratory time ratio with dynamic and real-time characteristics,which represents mechanical power affected by the ventilator mode.Additionally,Pmean is an important parameter that affects hemodynamics.Tidal forces and PEEP increase pulmonary vascular resistance(PVR)in direct proportion to their effects on Pmean.Therefore,Pmean is increasingly considered to be related to the prognosis of patients on mechanical ventilation.We propose a 3P strategy(Pmean,central venous pressure[CVP],and perfusion index[PI])which is indicated to achieve circulation protection mechanical ventilation with flow priority.Titrating the appropriate CVP and meeting PI to ensure tissue perfusion with a lower Pmean are the core purposes.Pmean links the circulatory and respiratory systems and is expected to become a potential parameter for intelligent ventilation.