High-fidelity minute-level physiologic trajectories after ROSC from linked monitor-defibrillator recordings in...

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 (2019-2023). We linked the Victorian Ambulance Cardiac Arrest Registry to Zoll® monitor-defibrillator recordings, aligned measurements to recorded ROSC, aggregated readings into 1-min bins, and derived per-patient mean, minimum, and minutes below thresholds for SBP, MAP and SpO₂. 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 3694 patients with sustained ROSC, 1444 survived. Median ROSC-to-arrival was 58 min. Median per patient was 36 blood pressure and 97 SpO₂ values. Compared with SBP 100 mm Hg, survival was lower at 80 mm Hg (aOR 0.87, 95% CI 0.79-0.95) and higher at 140 mm Hg (aOR 1.32, 95% CI 1.11-1.59). SpO₂ 90% versus 95% was associated with lower survival (aOR 0.70, 95% CI 0.63-0.79). Longer time with SBP <90 mm Hg, MAP <65 mm Hg, or SpO₂ <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.