The Massive Transfusion Score as a decision aid for resuscitation: Learning when to turn the massive transfusion protocol on and off.

BACKGROUND

Previous work proposed a Massive Transfusion Score (MTS) calculated from values obtained in the emergency department to predict likelihood of massive transfusion (MT). We hypothesized the MTS could be used at Hour 6 to differentiate who continues to require balanced resuscitation in Hours 7 to 24 and to predict death at 28 days.

METHODS

We prospectively enrolled patients in whom the MT protocol was initiated from 2005 to 2011. Data including timing of blood products were determined at Hours 0, 6, 12, and 24. For each patient, transfusion needs were defined based on either an inappropriately low hemoglobin response to transfusion or a hemoglobin decrease of greater than 1 g/dL if no transfusion. Timing and cause of death were used to account for survivor bias. Multivariate logistic regression was used to determine independent predictors of outcome.

RESULTS

A total of 190 MT protocol activations were included, and by Hour 6, 61% required 10 U or greater packed red blood cells. Calculated at initial presentation, a revised MTS (systolic blood pressure < 90 mm Hg, base deficit ≥ 6, temperature < 35.5°C, international normalized ratio > 1.5, hemoglobin < 11 g/dL) was superior to the original MTS (including heart rate ≥ 120 beats per minute, Focused Assessment With Sonography in Trauma [FAST] status, mechanism) or the Assessment of Blood Consumption (ABC) score for predicting MT (area under the curve [AUC] MT at 6 hours, 0.68; 95% confidence interval [CI], 0.57-0.79; at 24 hours, 0.72; 0.61-0.83; p < 0.05). For those alive at Hour 6, the revised MTS was predictive of future packed red blood cell need (AUC, 0.87) in Hours 7 to 12, 24-hour mortality (AUC, 0.95), and 28-day mortality (AUC, 0.77). For each additional positive trigger of the MTS at Hour 6, the odds of death at 24 hours and 28 days were substantially increased (24-hour odds ratio, 4.6; 95% CI, 2.3-9.3; 28-day odds ratio, 2.2; 95% CI, 1.5-3.2; p < 0.0001).

CONCLUSION

Early end points of resuscitation adopted from the components of the revised MTS are predictive of ongoing transfusion. Failure to normalize these components by Hour 6 portends a particularly poor prognosis.

LEVEL OF EVIDENCE

Prognostic study, level 3.