Early post-resuscitation profiles after out-of-hospital cardiac arrest: A latent class analysis

Background Early cardiopulmonary heterogeneity after out-of-hospital cardiac arrest (OHCA) may be associated with prognosis and treatment response. Objectives To identify early post-resuscitation profiles and explore their associations with outcomes and randomized treatment effects. Methods In this post hoc analysis of the BOX pulmonary artery catheter substudy, latent class analysis (LCA) was applied to early clinical, echocardiographic, and invasive hemodynamic variables. The primary outcome was 365-day all-cause mortality. Exploratory cross-cohort replication used a separately fitted LCA in the Targeted Temperature Management (TTM) cohort, with 180-day mortality. Results Among 700 BOX patients, a two-class model was selected. Class 2 (n = 352) showed longer time to return of spontaneous circulation (ROSC), higher lactate, greater cardiopulmonary dysfunction, higher filling pressures, and greater noradrenaline requirements. Mortality was 48% in Class 2 versus 21% in Class 1. No treatment interaction was detected for mean arterial pressure (MAP; P = 0.606), oxygenation (P = 0.483), or fever-control duration (P = 0.946). Mortality discrimination was not superior to time to ROSC alone. In 152 TTM patients, mortality was 38% versus 24% (P = 0.057), with less pronounced hemodynamic separation. Conclusion Two early post-resuscitation profiles were identified after OHCA, with more pronounced separation in filling pressures than cardiac output in BOX. The profiles were associated with prognosis but did not identify differential responses to the randomized interventions. Trial registration BOX trial, ClinicalTrials.gov identifier NCT03141099; TTM trial, ClinicalTrials.gov identifier NCT01020916.