Expanding beyond trauma: Characterizing low titer group O whole blood (LTOWB) use in children requiring massive transfusion protocol activation.

Background: Data regarding low titer group O whole blood (LTOWB) use for hemostatic resuscitation is largely derived from trauma cohorts; studies regarding its use in uninjured pediatric patients are lacking.

Methods: The blood bank database from a single academic pediatric hospital with a massive transfusion protocol (MTP) allowing the use of LTOWB for any severe bleeding etiology was queried between 2016 and 2023. Pediatric (age <18 years) recipients of LTOWB were included; injured children were excluded. Data recorded included demographics, bleeding etiology, blood volumes, mortality (24-h and in-hospital), organ dysfunction, and, when available, posttransfusion biochemical markers of hemolysis.

Results: Of 112 recipients of LTOWB, 16 met inclusion criteria. Median (IQR) age was 13 years (8-16) and 8/16 (50%) were male. MTP was most often activated on the day of admission (median (IQR) = day 0 (0-1)), and the bleeding etiology was variable, including perioperative (8/16; 50%), gastrointestinal bleed (5/16; 31%), and extracorporeal membrane oxygenation (ECMO) cannulation (3/16; 19%). The median (IQR) weight-adjusted volume of LTOWB transfused was 19 (10-26) mL/kg, and most children (13/16; 81%) received component blood products in addition to LTOWB. The 24-h mortality rate was 25% (4/16) and in-hospital mortality was 44% (7/16). The most common complication was AKI (10/16; 63%). There were no significant differences in biochemical hemolysis markers between group O (n = 7) and non-group O (n = 9) LTOWB recipients at any time point (p = .07-.99).

Conclusions: LTOWB use was feasible in the resuscitation of children with various bleeding etiologies requiring massive transfusion. Larger prospective investigations are needed to inform guidelines for optimal use in this cohort. Methods: Retrospective Observational Study.