Value Of Plasma Osmolality In Assessing Prognosis In Patients With Severe Acute Pancreatitis

Background:Acute pancreatitis(AP)is a pancreatic inflammatory disease of pancreatic tissue self-digestion,edema,bleeding and even necrosis after pancreatic enzyme activation,most AP patients are mildly self-limited,but about 20%of patients can develop severe acute pancreatitis(SAP)with persistent organ failure,and the mortality rate is as high as 36%-50%.Although there have been a large number of studies on the early assessment of AP severity,the current scoring system has its limitations and the accuracy of clinical prediction is unstable,and the exploration of simple,non-invasive,high-sensitivity and specificity clinical scoring system remains a major challenge for the diagnosis and treatment of AP.Plasma osmolality refers to the concentration of solute particles in blood vessels,which are essential for maintaining cell morphological function and blood volume.Studies have shown that plasma osmolality can be used as a prognostic indicator for stroke,heart failure,coronary heart disease,acute kidney injury and other diseases,and is obviously related to the prognosis of patients in intensive care units and emergency admissions.In the early stage of SAP,the body was in a state of systemic inflammatory response syndrome,blood volume depletion,vascular endothelial dysfunction,reninangiotensin system activation,clinical fasting,fluid replacement and continuous renal replacement therapy and other therapeutic measures,abnormal distribution of body fluids,water and electrolyte disorders,and eventually led to changes in plasma osmolality.This study aimed to investigate the value of plasma osmolality in the prognosis of patients with severe acute pancreatitis.Methods:1.Extract the clinical data of patients with severe acute pancreatitis in the 20082019 Medical Information Mart for Intensive Care Ⅳ(MIMIC-Ⅳ).According to the 90-day clinical outcome,patients were divided into survival group and death group,and the group differences were compared,and the risk factors for death of SAP patients were analyzed by logistic.According to the results of the initial biochemical examination at the time of admission,the plasma osmolality was calculated,and the patients were divided into low plasma osmolality group(<280mmol/L),normal plasma osmolality group(280～310mmol/L)and high plasma osmolality group(>310mmol/L),compared the in-hospital mortality,30-day mortality,90-day mortality,and ICU residence time of the three groups,and analyzed the correlation between plasma osmolality and clinical outcomes and existing scoring systems.Locally weighted regression was used as Lowess smoothing curve to further explore the relationship between plasma osmolality and clinical outcomes.Finally,the subject working curve(ROC)was used to evaluate the prognostic value of plasma osmolality in patients with SAP.2.Retrospective analysis of clinical data of 65 patients diagnosed with severe acute pancreatitis from January 1,2018 to September 2022 from the Department of Critical Care Medicine,Affiliated Hospital of Yangzhou University.According to the plasma osmolality group,the general data,clinical data and clinical outcome differences between the groups were analyzed,and the ROC curve was used to verify the prognostic value of plasma osmolality on the prognosis of SAP patients.Results:1.A total of 1598 patients were included in the MIMIC-Ⅳ.database,including 1375 in the survival group and 223 in the death group.The analysis of differences between groups showed that the mean plasma osmolality level in the death group was significantly higher than that in the survival group(301.5± 13.3 VS 307.9±19.2,P<0.001).Binary logistic multivariate regression analysis showed that elevated plasma osmolality was an independent risk factor for death within 90 days in patients with SAP(OR=1.628,P=0.004).According to plasma osmolality stratification,the analysis of differences between groups showed that the in-hospital mortality,30-day mortality,90day mortality and length of stay in the intensive care unit were significantly higher in the high plasma osmolality group and the low plasma osmolality group than those in the normal plasma osmolality group(P<0.001).The locally weighted LOWESS smoothing curve also showed that high or low osmolality led to adverse outcomes in patients with severe pancreatitis,with an overall "U" correlation,but plasma osmolality was not significantly correlated with ICU residence time in patients with severe acute pancreatitis.ROC analysis showed that the areas under the ROC curve for plasma osmolality to predict in-hospital mortality,30-day mortality and 90-day mortality in SAP patients were 0.667,0.646 and 0.620,respectively,and the prediction accuracy of plasma osmolality and SOFA score was higher than that of plasma osmolality or SOFA score alone.2.A total of 65 SAP patients from the Department of Critical Care Medicine,Affiliated Hospital of Yangzhou University were included in the study.The analysis of differences between groups showed that compared with the normal plasma osmolality group,the plasma osmolality group was more likely to have circulatory failure,and the incidence of multi-organ failure was higher(P<0.05).The proportion of in-hospital allcause mortality(P=0.012)and adverse clinical outcomes(P=0.001)was significantly increased in the high plasma osmolality group,while the increase in plasma osmolality was not significantly different from respiratory failure,renal failure,renal replacement therapy time,vasoactive drug use,total length of hospital stay,ICU length of stay and hospital cost in patients with SAP.The optimal cut-off value for plasma osmolality predicting the development of SAP to MODS was 296.94 mmol/L(AUC=0.713),the optimal cut-off value for predicting in-hospital death in SAP patients was 307.96 mmol/L(AUC=0.786),and the optimal cut-off value for predicting adverse clinical outcomes in SAP patients was 301.54mmol/L(AUC=0.84).Conclusion:1.Abnormal plasma osmolality at the initial admission is associated with poor prognosis in patients with severe acute pancreatitis,and elevated plasma osmolality is an independent risk factor for death within 90 days in patients with severe acute pancreatitis。2.Plasma osmolality has limited value as a single indicator for predicting clinical outcomes,and the combination with SOFA score can improve the accuracy of early assessment of the severity of patients with SAP,and it can be considered as a supplementary indicator of the SAP prognostic evaluation system.