LAUSR

Type of funding sources: Public hospital(s). Main funding source(s): Supported by a grant from the Novo Nordisk Foundation. Time to return of spontaneous circulation (ROSC) after out-of-hospital cardiac arrest (OHCA) is closely associated with the likelihood of survival but may also impact hemodynamic stability after ROSC. The aim of this study is to investigate the association between invasive hemodynamics and time to ROSC during the first 48 hours of admission. In this substudy of the BOX trial, adult comatose patients who had been resuscitated after an OHCA with a presumed cardiac cause and had a sustained ROSC were studied. Patients were divided into tertiles according to time to ROSC. Invasive hemodynamic evaluation was performed using a pulmonary artery catheter and invasively measured mean arterial pressure (MAP). Systemic vascular resistant index (SVRI) and cardiac index (CI) were adjusted for body surface area (BSA). We included 714 patients, 243 with ≤13 minutes to ROSC (tertile 1), 235 patients with 14-23 minutes to ROSC (tertile 2), and 236 patients above ≥24 minutes to ROSC (tertile 3). We found no difference in age (p=0.90) or sex (p=0.92) in the three groups. Furthermore, we found no difference in witnessed cardiac arrest (p=0.29) or bystander cardiopulmonary resuscitation (p=0.58) between the tertiles. Upon the first 48 hours of admission, systemic vascular resistant index (SVRI) (p=0.64), cardiac index (p=0.51), and mean arterial pressure (MAP) (p=0.79) were similar in the three groups, while the average heart rate and the use of noradrenaline (NA) were significantly higher (p<0.0001) in patients with prolonged time to ROSC (Figure 1). In patients resuscitated after an OHCA, similar central hemodynamics were achieved irrespective of prolonged time to ROSC but at the cost of a higher dose of noradrenaline in the first 48 hours.