High-fidelity minute-level physiologic trajectories after ROSC from linked monitor-defibrillator recordings in out-of-hospital cardiac arrest

• Registry-linked, ROSC-aligned, minute-by-minute Zoll® monitor-defibrillator data. • Enables cumulative exposure metrics for hypotension, hypoxaemia and ETCO 2. • Higher SBP/MAP and SpO 2 were associated with greater survival to hospital discharge. • Higher mean ETCO 2 was inversely associated with survival. • Neurological associations among survivors were smaller, mainly limited to SBP. Early post-ROSC physiology changes rapidly, but most studies rely on a single handover set of vital signs, which can miss trajectories and time spent hypotensive or hypoxemic. We aimed to describe minute-level early post-ROSC blood pressure and oxygenation and examine their association with outcomes. Retrospective cohort study of out-of-hospital cardiac arrest in Victoria, Australia (2019 to 2023). We linked the Victorian Ambulance Cardiac Arrest Registry to Zoll® monitor-defibrillator recordings, aligned measurements to recorded ROSC, aggregated readings into 1-minute bins, and derived per-patient mean, minimum, and minutes below thresholds for SBP, MAP and SpO 2 . Associations with outcomes were modelled using adjusted logistic regression. Primary outcome was survival to hospital discharge. Secondary outcome was good 12-month neurological outcome among survivors. Among 3,694 patients with sustained ROSC, 1,444 survived. Median ROSC-to-arrival was 58 minutes. Median per patient was 36 blood pressure and 97 SpO 2 values. Compared with SBP 100 mm Hg, survival was lower at 80 mm Hg (aOR 0.87, 95% CI 0.79 to 0.95) and higher at 140 mm Hg (aOR 1.32, 95% CI 1.11 to 1.59). SpO 2 90% versus 95% was associated with lower survival (aOR 0.70, 95% CI 0.63 to 0.79). Longer time with SBP <90 mm Hg, MAP <65 mm Hg, or SpO 2 <90% was associated with lower survival. Associations with good 12-month neurological outcome were smaller and mainly limited to blood pressure. Minute-level monitor-defibrillator data showed strong associations between early hypotension and hypoxaemia and survival after ROSC and allow cumulative exposure to be quantified.