Background
Trauma activation level is determined by prehospital criteria. The American College of Surgeons (ACS) recommends trauma activation criteria; however, their accuracy may be limited. Prehospital lactate has shown promise in predicting trauma center resource requirements. Our objective was to investigate the added value of incorporating prehospital lactate in an algorithm to designate trauma activation level.
Methods
Air medical trauma patients undergoing prehospital lactate measurement were included. Algorithms using ACS activation criteria (ACS) and ACS activation criteria plus prehospital lactate (ACS+LAC) to designate trauma activation level were compared. Test characteristics and net reclassification improvement (NRI), which evaluates reclassification of patients among risk categories with additional predictive variables, were calculated. Algorithms were compared to predict trauma center need (TCN) defined as >1unit of blood in the ED; spinal cord injury; advanced airway; thoracotomy or pericardiocentesis; ICP monitoring; emergent operative or interventional radiology procedure; or death.
Results
There were 6,347 patients included. Twenty-eight percent had TCN. The ACS+LAC algorithm upgraded 256 patients and downgraded 548 patients compared to the ACS algorithm. The ACS+LAC algorithm versus ACS algorithm had a NRI of 0.058 (95%CI 0.044, 0.071; p<0.01), with an event NRI of −0.5% and non-event NRI of 6.2%. When weighted to favor changes in under-triage, the ACS+LAC still had a favorable overall reclassification (wNRI 0.041; 95%CI 0.028, 0.054; p=0.01). The ACS+LAC algorithm increased PPV, NPV, and accuracy. Over-triage was reduced 7.2%, while under-triage only increased 0.7%. The area under the curve (AUC) was significantly higher for the ACS+LAC algorithm (0.79 vs. 0.76, p<0.01).
Conclusions
The ACS+LAC algorithm reclassified patients to more appropriate levels of trauma activation when compared to the ACS algorithm. This overall benefit is achieved by significant reduction in over-triage relative to very small increase in under-triage. In the context of trauma team activation, this trade-off may be acceptable, especially in the current healthcare environment.
Level of Evidence
Diagnostic study, Level IV