The Use of the Revised Trauma Score as an Entry Criterion in Traumatic Hemorrhagic Shock Studies: Data from the DCLHb Clinical Trials

Abstract

The Revised Trauma Score (RTS) has been proposed as an entry criterion to identify patients with mid-range survival probability for traumatic hemorrhagic shock studies. Determination of which of four RTS strata (1-3.99, 2-4.99, 1-4.99, and 2-5.99) identifies patients with predicted and actual mortality rates near 50% for use as an entry criterion in traumatic hemorrhagic shock clinical trials. Existing database analysis in which demographic and injury severity data from two prior international Diaspirin Cross-Linked Hemoglobin (DCLHb) clinical trials were used to identify an RTS range that could be an optimal entry criterion in order to find the population of trauma patients with mid-range predicted and actual mortality rates. Of 208 study patients, the mean age was 37 years, 65% sustained blunt trauma, 49% received DCLHb, and 57% came from the European Union study arm. The mean values were: ISS, 31 (SD = 18); RTS, 5.6 (SD = 1.8); and Glasgow Coma Scale (GCS), 10.4 (SD = 4.8). The mean TRISS-predicted mortality was 34% and the actual 28-day mortality was 35%. The initially proposed 1-3.99 RTS range (n = 41) had the highest predicted (79%) and actual (71%) mortality rates. The 2-5.99 RTS range (n = 79) had a 62% predicted and 53% actual mortality, and included 76% blunt trauma patients. Removal of GCS <5 patients from this RTS 2-5.99 subgroup caused a 48% further reduction in eligible patients, leaving 41 patients (20% of 208 total patients), 66% of whom sustained a blunt trauma injury. This subgroup had 54% predicted and 49% actual mortality rates. Receiver operator curve (ROC) analysis found the GCS to be as predictive of mortality as the RTS, both in the total patient population and in the RTS 2-5.99 subgroup. The use of an RTS 2-5.99 inclusion criterion range identifies a traumatic hemorrhagic shock patient subgroup with predicted and actual mortality that approach the desired 50% rate. The exclusion of GCS <5 from this RTS 2-5.99 subgroup patients yields a smaller, more uniform patient subgroup whose mortality is more likely related to hemorrhagic shock than traumatic brain injury. Future studies should examine whether the RTS or other physiologic criteria such as the GCS score are most useful as traumatic hemorrhagic shock study entry criteria.