Photo by Nina Matthews
Pregnant woman
PHILADELPHIA—Results of a single-center study suggest that, when it comes to massive transfusion in pregnancy, a 1:1 ratio of red blood cells (RBCs) to plasma is not needed to maintain adequate hemostasis.
A 2:1 ratio produces prothrombin times (PTs), activated partial thromboplastin times (PTTs), and fibrinogen levels within references ranges.
Vanessa Plasencia, MLS (ASCP)CM, of Texas Children’s Hospital in Houston, presented these findings at the AABB Annual Meeting 2014 (abstract S43-030G).
She noted that hospital staff perform approximately 4500 to 5000 deliveries per year, and they define massive transfusion as 4 or more RBC units in 1 hour or 10 or more RBC units in 24 hours.
The hospital’s initial obstetric massive transfusion protocol was 4 units of RBCs and 4 units of plasma to be issued in a cooler. Four units of group AB thawed plasma or liquid plasma were always available.
To determine if this protocol is optimal, Plasencia and her colleagues conducted a retrospective review of patient records from April 2012 to June 2014. During this time, there were 28 cases of massive transfusion.
Two of these patients died and were excluded from the study. One, who had placental abruption, received 131 RBC units and 48 plasma units (ratio=2.7:1). The other, who had placenta percreta, received 90 RBC units and 52 plasma units (ratio=1.7:1).
The median age of the remaining 26 patients was 34 years (range, 24-44). Four of these patients had placenta accreta, 2 had placenta increta, 14 had placenta percreta, and 6 had other complications (such as placental abruption, diabetes, and risks due to advanced-age pregnancy).
A median of 12 RBC units (range, 9-20) and 9 plasma units (range, 5-19) were issued. And a median of 8 RBC units (range, 6-12) and 5 plasma units (range, 4-8) were actually transfused. That translates to RBC-to-plasma ratios of 1.4:1 (range, 1.0-2.0) and 1.7:1 (1.3-2.5), respectively.
So despite the hospital’s protocol of a 1:1 RBC-to-plasma ratio, the actual ratio of transfusion in practice was approximately 2:1, Plasencia noted. And the patients had PT, PTT, and fibrinogen values within reference ranges.
Coagulation data were collected after transfusions took place, once patients were stable. The median PT was 14.8 seconds (range, 14.1-15.2), the median PTT was 29.9 seconds (range, 27.6-33.3), and the median fibrinogen was 283 mg/dL (range, 225-325).
Because of these results, Texas Children’s Hospital decided to change its massive transfusion protocol for obstetrics to a 2:1 RBC-to-plasma ratio. Now, the hospital issues 4 units of RBCs and 2 units of plasma in its initial blood package.