Objective To enhance the triage efficiency of patients with acute heart failure(AHF)by improving emergency severity index(ESI)score,and to achieve stratified care for patients with AHF.Additionally,the aim is to improve the combination of stratified scores and nursing care in emergency departments to address the limitations of current studies.Methods A retrospective nested cohort study was conducted on 120 patients with AHF admitted to the Affiliated Hospital of Guizhou Medical University from January 1,2019 to December 30,2021.According to the clinical outcomes of the patients,the patients were divided into subgroup A(71 cases,recovered after treatment,no serious complications during treatment),subgroup B[35 cases,discharged after treatment,multiple organ dysfunction syndrome(MODS),acute respiratory distress syndrome(ARDS),shock and other serious complications occurred during treatment],and subgroup C(14 cases,cardiac death during treatment).A prospective randomized controlled study involving 106 patients with AHF admitted to our hospital from January 1 to December 30,2022,was conducted,and the patients were divided into control group(53 cases)and stratified care group(53 cases)according to the random number table method.The control group received routine nursing care,while patients in the stratified care group received stratified care based on the ESI scoring clinical care pathway.The early warning score model of elderly patients with AHF was constructed with risk threshold as warning signal.The improved ESI scoring criteria were used to score AHF patients,with a total score of 25 points.The higher the score,the higher the risk.0-10 is divided into Ⅰ level risk,>10-20 is divided into Ⅱ level risk,>20 is divided into Ⅲ level risk.Implement nuring at grades Ⅲ,Ⅱ,and Ⅰ,respectively.The changes of modified ESI scores in subgroup A,subgroup B and subgroup C were observed,and Spearman correlation coefficient was used to evaluate the correlation between modified ESI scores and clinical outcomes of different severity of disease.Receiver operator characteristic curve(ROC curve)was drawn to evaluate the effectiveness of the risk threshold classification method of different nursing plan designs in the stratified nursing group and the control group,and to compare the efficiency differences of emergency nursing rescue time,rescue success rate,and stay time in the emergency department,and the incidence of complications such as MODS,ARDS,shock and nursing satisfaction during treatment between the stratified nursing group and the control group.Results The modified ESI score in subgroup C was the highest,significantly higher than that in subgroup B and A(19.6±1.7 vs.17.8±1.5,15.3±1.3,all P<0.05).Spearman correlation analysis showed that the modified ESI score was significantly positively correlated with the occurrence of complications,the occurrence of cardiac death,and the recovery after treatment(r values were 0.623,0.635,0.322,P values were 0.004,0.003,0.012,respectively).Therefore,an improved ESI score has a certain early warning effect on complications and cardiac death of patients.ROC curve analysis showed that the area under the ROC curve(AUC)of routine care for stratified care was 0.710 and 0.620,and the 95％ confidence interval(95％ CI)was 0.620-0.750 and 0.580-0.690,respectively,with Pvalues of 0.023 and 0.034.It shows that the difference between the two nursing methods is significant,and further indicates that the risk threshold classification method designed in this study is effective.With the increase of risk,the rescue time and emergency stay time of the two groups were gradually extended,and the success rate of rescue was gradually decreased,the rescue time and emergency stay time of grade Ⅲ risk were the longest and the success rate of rescue was the lowest,and the rescue time and emergency stay time of the stratified nursing group were significantly shorter than those of the control group(minutes:59.6±6.3 vs.76.5±7.2 and 57.6±5.4 vs.68.2±7.1,both P<0.05),the success rate of rescue was significantly increased[(68.7±6.1)％ vs.(54.6±5.2)％,P<0.05],and the difference of rescue time between grade Ⅰ risk and grade Ⅲ risk was the largest.There were significant differences in the success rate of rescue and the duration of emergency stay in grade Ⅲ risk.The incidence of complications such as MODS,ARDS and shock in stratified care group was significantly lower than that in control group[incidence of MODS:13.2％(7/53)vs.18.9％(10/53),incidence of ARDS:15.1％(8/53)vs.22.6％(12/53),incidence of shock:13.2％(7/53)vs.20.8％(11/53),all P<0.05],satisfaction of patients with service attitude,operation technique,comfort and timeliness were significantly improved compared with the control group[service attitude:28.3％(15/53)vs.18.9％(10/53),operation technology:30.2％(16/53)vs.20.8％(11/53),comfort:32.1％(17/53)vs.24.5％(13/53),timeliness:32.1％(17/53)vs.24.5％(13/53),all P<0.05].Conclusion Based on the modified ESI score,early risk warning thresholds are divided and stratified nursing is conducted,which is beneficial for timely intervention in AHF,effectively ensuring the clinical nursing value of patients during the implementation of medical measures,and has broad application prospects.