Initial Red Cell Infusion Rate and Escalation of Respiratory Support in Critically Ill Adults: A Target Trial Emulation

Background/Objectives: Current transfusion guidelines address when red cells should be given, not how fast. We estimated the association between the initial infusion rate of a first red cell transfusion and escalation of respiratory support in critically ill adults.

Methods

We emulated a target trial in MIMIC-IV v3.1. Of 2790 eligible adults, 1787 received a slower (50–175 mL/h) and 1003 a faster (>175–350 mL/h) initial rate; the primary outcome was escalation to advanced respiratory support or death within 12 h. Overlap weighting estimated marginal risk differences in the overlap population, with 2000 bootstrap resamples refitting the propensity-score model. Sensitivity and continuous dose–response analyses were pre-specified.