Objective To investigate influencing factors for failed cardiopulmonary resuscitation(CPR)in patients with respiratory and cardiac arrest.Methods A retrospective analysis was con-ducted on the clinical data of 204 patients with respiratory and cardiac arrest.All patients underwent CPR treatment and were divided into success group and failure group based on the CPR outcome.A matched case-control study based on matching design was carried out.The success and failure groups were matched at a ratio of 1 to 2 using gender,age,body mass index(BMI),and the presence or absence of hypertension,hyperlipidemia,and diabetes as covariates.Logistic regression analysis was employed to explore the influencing factors for failed CPR in patients with respiratory and cardiac ar-rest.Results Among the 204 patients,65(31.86％)had successful CPR and were included in success group,while 139(68.14％)had failed CPR and were included in failure group.After a rati-o of 1 to 2 matching design,62 patients in the success group and 124 patients in the failure group were finally included in the study.Multivariate logistic regression analysis revealed that cardiovascular disease as the cause of respiratory and cardiac arrest,CPR performed outside the hospital,a long time interval from the onset of the condition to the initiation of CPR,and a large dose of epinephrine were independent risk factors for failed CPR(P＜0.05).In contrast,the combined use of a bag-mask de-vice and endotracheal intubation during respiratory and cardiac arrest,a prolonged duration of CPR,and electrical defibrillation were independent protective factors for successful CPR(P＜0.05).Con-clusion Cardiovascular disease,out-of-hospital CPR,a long time interval from the onset of the condi-tion to the initiation of CPR,and a large dose of epinephrine are risk factors for failed CPR in patients with respiratory and cardiac arrest.The combined use of a bag-mask device and endotracheal intubation during respiratory and cardiac arrest,prolonging the duration of CPR,and electrical defibrillation are protective factors for successful CPR.The matched case-control study method based on a matc-hing design can reduce the interference of confounding factors,ensure the reliability of the results,and provide a reliable basis for the formulation of CPR intervention protocols.