Low-Cost Blood Test May Enable Screening for Increased Bleeding Risk After Injury

From their retrospective review of approximately 1,340 trauma patients, ages 0 to 17 years, researchers from the Trauma Program at Children's Hospital Los Angeles (CHLA; Los Angeles, CA, USA) have suggested that an AH could be widely implemented to identify patients who may need intervention and thus improve the course and outcome of their trauma resuscitation.

Adult trauma studies have shown that a drop in hematocrit (test for percentage of the volume of whole blood that is made up of red blood cells) can occur immediately after injury – predicting ongoing occult blood loss. To date, the use of hematocrit in triaging bleeding pediatric trauma patients had not been investigated. In examining medical records of all patients who presented to CHLA’s level-1 pediatric trauma center between 2005 and 2013, the researchers found that an AH of 35-or-less was able to identify children requiring intervention (blood transfusion, angioembolization, or operation) for bleeding, up to 67 hours after arrival.

The results showed a significant difference in AH between patients who subsequently required a transfusion and those who did not. The cutoff figure of 35-or-less had a 94% sensitivity, 77% specificity, and 99.9% negative predictive value, indicating that use of this cutoff provides a reliable screening tool.

Unintentional injury from trauma is the leading cause of death in children over one year of age. Clinical assessment of young children can be far more challenging than adults, identifying their injuries (especially intra-abdominal) and assessing blood loss in children often requires additional resources and expense. "A quick and cost-effective measure, such as AH, to identify pediatric patients who are at a high risk for bleeding could provide a critical improvement in optimizing care for children, while reducing costs," said principal investigator Christopher P. Gayer, MD, PhD, FAAP, FACS, of Trauma Attending, Division of Pediatric Surgery, CHLA.

"AH can be done rapidly in the trauma bay, is relatively inexpensive, causes minimal harm, and can aid in critical decision-making and rapid identification of occult bleeding. Our results show that a hematocrit level of less than 35% on admission predicts a greater likelihood for the need of transfusion in pediatric blunt trauma patients," said first author Jamie Golden, MD, research fellow, CHLA.

The physicians noted that while a doctor's concern in the face of clinical signs of hemorrhagic shock should always take priority over lab data, a repeat hematocrit can be quickly performed if clinically indicated. They added that their study results, conducted retrospectively at a single site, require validation in a prospective, multicenter study.

The study, by Golden J et al, was published in the October, 2015, issue of the Journal of Trauma and Acute Care Surgery.

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