Field triage guidelines recommend transport of head-injured patients on anticoagulants or antiplatelets to a higher-level trauma center based on studies suggesting a high incidence of traumatic intracranial hemorrhage (tICH). We compared the incidence of tICH in older adults transported by emergency medical services (EMS) with and without anticoagulation or antiplatelet use and evaluated the accuracies of different sets of field triage criteria to identify tICH. This was a prospective, observational study at five EMS agencies and 11 hospitals. Older adults (≥55 years) with head trauma and transported by EMS from August 2015 to September 2016 were eligible. EMS providers completed standardized data forms and patients were followed through emergency department (ED) or hospital discharge. We enrolled 1304 patients; 1147 (88%) received a cranial computed tomography (CT) scan and were eligible for analysis. Four hundred thirty-four (33%) patients had anticoagulant or antiplatelet use and 112 (10%) had tICH. The incidence of tICH in patients with (11%, 95% confidence interval [CI] 8%-14%) and without (9%, 95% CI 7%-11%) anticoagulant or antiplatelet use was similar. Anticoagulant or antiplatelet use was not predictive of tICH on adjusted analysis. Steps 1-3 criteria alone were not sensitive in identifying tICH (27%), whereas the addition of anticoagulant or antiplatelet criterion improved sensitivity (63%). Other derived sets of triage criteria were highly sensitive (>98%) but poorly specific (<11%). The incidence of tICH was similar between patients with and without anticoagulant or antiplatelet use. Use of anticoagulant or antiplatelet medications was not a risk factor for tICH. We were unable to identify a set of triage criteria that was accurate for trauma center need.

Objective

Prehospital provider assessment of the use of anticoagulant or antiplatelet medications in older adults with head trauma is important. These patients are at increased risk for traumatic intracranial hemorrhage and therefore field triage guidelines recommend transporting these patients to centers capable of rapid evaluation and treatment. Our objective was to evaluate EMS ascertainment of anticoagulant and antiplatelet medication use in older adults with head trauma.

Methods

A retrospective study of older adults with head trauma was conducted throughout Sacramento County. All 5 transporting EMS agencies and all 11 hospitals in the county were included in the study, which ran from January 2012 to December 2012. Patients ≥55 years who were transported to a hospital by EMS after head trauma were included. We excluded patients transferred between two facilities, patients with penetrating head trauma, prisoners, and patients with unmatched hospital data. Anticoagulant and antiplatelet use were categorized as: warfarin, direct oral anticoagulants (DOAC; dabigatran, rivaroxaban, and apixaban), aspirin, and other antiplatelet agents (e.g., clopidogrel and ticagrelor). We calculated the percent agreement and kappa statistic for binary variables between EMS and emergency department (ED)/hospital providers. A kappa statistic ≥0.60 was considered acceptable agreement.

Results

After excluding 174 (7.6%) patients, 2,110 patients were included for analysis; median age was 73 years (interquartile range 62-85 years) and 1,259 (60%) were male. Per ED/hospital providers, the use of any anticoagulant or antiplatelet agent was identified in 595 (28.2%) patients. Kappa statistics between EMS and ED/hospital providers for the specific agents were: 0.76 (95% CI 0.71-0.82) for warfarin, 0.45 (95% CI 0.19-0.71) for DOAC agents, 0.33 (95% CI 0.28-0.39) for aspirin, and 0.51 (95% CI 0.42-0.60) for other antiplatelet agents.

Conclusions

The use of antiplatelet or anticoagulant medications in older adults who are transported by EMS for head trauma is common. EMS and ED/hospital providers have acceptable agreement with preinjury warfarin use but not with DOAC, aspirin, and other antiplatelet use.

Study objective

Field triage guidelines recommend that emergency medical services (EMS) providers consider transport of head-injured older adults with anticoagulation use to trauma centers. However, the triage patterns and the incidence of intracranial hemorrhage or neurosurgery in these patients are unknown. Our objective is to describe the characteristics and outcomes of older adults with head trauma who are transported by EMS, particularly for patients who do not meet physiologic, anatomic, or mechanism-of-injury (steps 1 to 3) field triage criteria but are receiving anticoagulant or antiplatelet medications.

Methods

This was a retrospective study at 5 EMS agencies and 11 hospitals (4 trauma centers, 7 nontrauma centers). Patients aged 55 years or older with head trauma who were transported by EMS were included. The primary outcome was the presence of intracranial hemorrhage. The secondary outcome was a composite measure of inhospital death or neurosurgery.

Results

Of the 2,110 patients included, 131 (6%) had intracranial hemorrhage and 41 (2%) had inhospital death or neurosurgery. There were 162 patients (8%) with steps 1 to 3 criteria. Of the remaining 1,948 patients without steps 1 to 3 criteria, 566 (29%) had anticoagulant or antiplatelet use. Of these patients, 52 (9%) had traumatic intracranial hemorrhage and 15 (3%) died or had neurosurgery. The sensitivity (adjusted for clustering by EMS agency) of steps 1 to 3 criteria was 19.8% (26/131; 95% confidence interval [CI] 5.5% to 51.2%) for identifying traumatic intracranial hemorrhage and 34.1% (14/41; 95% CI 9.9% to 70.1%) for death or neurosurgery. The additional criterion of anticoagulant or antiplatelet use improved the sensitivity for intracranial hemorrhage (78/131; 59.5%; 95% CI 42.9% to 74.2%) and death or neurosurgery (29/41; 70.7%; 95% CI 61.0% to 78.9%).

Conclusion

Relatively few patients met steps 1 to 3 triage criteria. For individuals who did not have steps 1 to 3 criteria, nearly 30% had anticoagulant or antiplatelet use. A relatively high proportion of these patients had intracranial hemorrhage, but a much smaller proportion died or had neurosurgery during hospitalization. Use of steps 1 to 3 triage criteria alone is not sufficient in identifying intracranial hemorrhage and death or neurosurgery in this patient population. The additional criterion of anticoagulant or antiplatelet use improves the sensitivity of the instrument, with only a modest decrease in specificity.