Association between duration of return of spontaneous circulation and outcomes after out-of-hospital cardiac arrest

Background:Return of spontaneous circulation(ROSC)is a core outcome element of cardiopulmonary resuscitation(CPR);however,the definition or criterion of ROSC is disputed and varies in resuscitation for out-of-hospital cardiac arrest(OHCA).Methods:This was a retrospective study of 126 patients with OHCA who achieved ROSC between January and December 2020.The probability of survival after OHCA related to CPR and ROSC duration was analyzed using the probability density function and empirical cumulative density functions.Results:There were no significant differences between ROSC sustained until emergency department arrival and that sustained for at least 20 minutes in terms of the 24-hour survival rate(31.3%[31/99]vs.35.7%[10/30];P=0.84),30-day survival rate(23.2%[23/99]vs.25.0%[7/30];P=0.99),or survival at 30 days with cerebral performance category(CPC)1 and 2(18.2%[18/99]vs.10.7%[3/30];P=0.44).The Kolmogorov-Smirnov test values from the empirical cumulative density functions with ROSC sustained until hospital arrival and that sustained for at least 20 minutes were 0.44,0.20,and 0.24 for CPC 1 or 2,CPC 3 or 4,and CPC 5,respectively.Conclusion:Return of spontaneous circulation is a core outcome element of CPR.It should be defined as sustained for at least 20 minutes or until arrival at the emergency department and as a basic standard for evaluating resuscitation success after OHCA.