Early predictors of massive transfusion in combat casualties
ABSTRACT An early predictive model for massive transfusion (MT) is critical for management of combat casualties because of limited blood product availability, component preparation, and the time necessary to mobilize fresh whole blood donors. The purpose of this study was to determine which variables, available early after injury, are associated with MT. We hypothesized that International Normalized Ratio and penetrating mechanism would be predictive.
We performed a retrospective cohort analysis in two combat support hospitals in Iraq. Patients who required MT were compared with patients who did not. Eight potentially predictive variables were subjected to univariate analysis. Variables associated with need for MT were then subjected to stepwise logistic regression.
Two hundred forty-seven patients required MT and 311 did not. Mean Injury Severity Score was 22 in the MT group and 5 in the non-MT group (p < 0.001). Patients in the MT group received 17.9 U stored RBCs and 2.0 U fresh whole blood, versus 1.1 U RBCs and 0.2 U whole blood in the non-MT group (p < 0.001). Mortality was 39% in the MT group and 1% in the non-MT group (p < 0.001). Variables that independently predicted the need for MT were: hemoglobin <or= 11 g/dL, International Normalized Ratio > 1.5, and a penetrating mechanism. The area under the receiver operator characteristic curve was 0.804 and Hosmer-Lemeshow goodness-of-fit test was 0.98.
MT after combat injury is associated with high mortality. Simple variables available early after admission allow accurate prediction of MT.
Revista espanola de anestesiologia y reanimacion 06/2013; 60:73-85. DOI:10.1016/S0034-9356(13)70012-4
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ABSTRACT: BACKGROUND: Several predictive models have been developed to identify trauma patients who have had severe hemorrhage (SH) and may need a massive transfusion (MT) protocol. However, almost all these models define SH as the transfusion of 10 or more units of red blood cells (RBCs) within 24 hours of emergency department admission (also known as MT). This definition excludes some patients with SH, especially those who die before a 10th unit of RBCs could be transfused, which calls the validity of these prediction models into question. We show how a latent class model could improve the accuracy of identifying the SH patients. METHODS: Modeling SH classification as a latent variable, we estimate the posterior probability of a patient in SH based on emergency department admission variables (systolic blood pressure, heart rate, pH, hemoglobin), the 24-hour blood product use (plasma/RBC and platelet/RBC ratios), and 24-hour survival status. We define the SH subgroup as those having a posterior probability of 0.5 or greater. We compare our new classification of SH with that of the traditional MT using data from PROMMTT study. RESULTS: Of the 1,245 patients, 913 had complete data, which were used in the latent class model. About 25.3% of patients were classified as SH. The overall agreement between the MT and SH classifications was 83.8%. However, among 49 patients who died before receiving the 10th unit of RBCs, 41 (84%) were classified as SH. Seven (87.5%) of the remaining eight patients who were not classified as SH had head injury. CONCLUSION: Our definition of SH based on the aforementioned latent class model has an advantage of improving on the traditional MT definition by identifying SH patients who die before receiving the 10th unit of RBCs. We recommend further improvements to more accurately classify SH patients, which could replace the traditional definition of MT for use in developing prediction algorithms.Journal of Trauma and Acute Care Surgery 01/2013; 75:S82-S88. DOI:10.1097/TA.0b013e31828fa3d3 · 2.50 Impact Factor
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ABSTRACT: Hemostatic resuscitation might improve the survival of severely injured trauma patients. Our objective was to establish a simplified screening system for determining the necessity of massive transfusions (MT) at an early stage in trauma cases. We retrospectively analyzed the cases of trauma patients who had been transported to our institution between November 2011 and October 2013. Patients who were younger than 18 years of age or who were confirmed to have suffered a cardiac arrest at the scene or on arrival were excluded. MT were defined as transfusions involving the delivery of ≥10 units of red blood cell concentrate within the first 24 h after arrival. A total of 259 trauma patients were included in this study (males: 178, 69%). Their mean age was 49 ± 20, and their median injury severity score was 14.4. Thirty-three (13%) of the patients required MT. The presence of a shock index of ≥1, a base excess of ≤ -3 mmol/L, or a positive focused assessment of sonography for trauma (FAST) result was found to exhibit sensitivity and specificity values of 0.97 and 0.81, respectively, for predicting the necessity of MT. Furthermore, this method displayed an area under the receiver operating characteristic curve of 0.934 (95% confidence interval, 0.891-0.978), which indicated that it was highly accurate. Our screening method based on the shock index, base excess, and FAST result is a simple and useful way of predicting the necessity of MT early after trauma.01/2014; 2(1):54. DOI:10.1186/s40560-014-0054-3