Background: The incidence of delayed intracranial hemorrhage (DICH) in patients on warfarin has been reported to be 0.35% - 7.2%. No previous literature has reported on the utility of internationalized normalized ratio (INR) in predicting delayed intracranial hemorrhage in the setting of head trauma patients at a trauma center. The current study seeks to investigate INR as a risk stratification variable to identify head trauma patients who may be managed without repeat head CT (HCT) scanning.
Methods: Retrospective study at an urban ED, Level II trauma center. All cases of head injuries from March 2014 to December 31, 2017 were included. DICH was defined as negative initial CT scan, but positive repeat scan performed within 24 hours of the original imaging. Demographic analysis conducted used descriptive statistics of the two groups: with or without DICH, using Wilcoxon signed-rank, Chi-square and Student's t-tests, for Glasgow Coma Scale (GCS), Injury Severity Score (ISS), heart rate (HR), initial systolic blood pressure (SBP), age, gender and platelet count.
Results: 393 patients had repeat HCT or presented >12 hours after trauma event with single HCT. Four resulted in DICH: incidence 1.02%. Among 80 patients with INR<2, no DICH was identified; Negative predictive value = 1, sensitivity = 100%. Range of INR for positive DICH was 2.6-3.0. Correlation of factors: ISS (p=.017), gender (p<0.0001); GCS (p=.56), HR (p=.909), SBP (p=.139), age (p=.05), and platelets (p=.396).
Conclusion: No patient with an INR2, the severity of injury in conjunction with shared decision making can be utilized to develop a disposition plan for warfarin users with head injury.