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Abstract

  1. Top of page
  2. AbstractResumen
  3. Continuing Medical Education
  4. Methods
  5. Results
  6. Discussion
  7. Limitations
  8. Conclusions
  9. References

Objectives

Appropriate use of cranial computed tomography (CT) scanning in patients with mild blunt head trauma and preinjury anticoagulant or antiplatelet use is unknown. The objectives of this study were: 1) to identify risk factors for immediate traumatic intracranial hemorrhage (tICH) in patients with mild head trauma and preinjury warfarin or clopidogrel use and 2) to derive a clinical prediction rule to identify patients at low risk for immediate tICH.

Methods

This was a prospective, observational study at two trauma centers and four community hospitals that enrolled adult emergency department (ED) patients with mild blunt head trauma (initial ED Glasgow Coma Scale [GCS] score 13 to 15) and preinjury warfarin or clopidogrel use. The primary outcome measure was immediate tICH, defined as the presence of ICH or contusion on the initial cranial CT. Risk for immediate tICH was analyzed in 11 independent predictor variables. Clinical prediction rules were derived with both binary recursive partitioning and multivariable logistic regression.

Results

A total of 982 patients with a mean (± standard deviation [SD]) age of 75.4 (±12.6) years were included in the analysis. Sixty patients (6.1%; 95% confidence interval [CI] = 4.7% to 7.8%) had immediate tICH. History of vomiting (relative risk [RR] = 3.53; 95% CI = 1.80 to 6.94), abnormal mental status (RR = 2.85; 95% CI = 1.65 to 4.92), clopidogrel use (RR = 2.52; 95% CI = 1.55 to 4.10), and headache (RR = 1.81; 95% CI = 1.11 to 2.96) were associated with an increased risk for immediate tICH. Both binary recursive partitioning and multivariable logistic regression were unable to derive a clinical prediction model that identified a subset of patients at low risk for immediate tICH.

Conclusions

While several risk factors for immediate tICH were identified, the authors were unable to identify a subset of patients with mild head trauma and preinjury warfarin or clopidogrel use who are at low risk for immediate tICH. Thus, the recommendation is for urgent and liberal cranial CT imaging in this patient population, even in the absence of clinical findings.

Resumen

El Riesgo de Hemorragia Intracraneal Traumática en Pacientes con Traumatismo Craneoencefálico y Tratamiento Previo con Warfarina o Clopidogrel

Objetivos

Se desconoce la indicación adecuada de la tomografía computarizada (TC) craneal en los pacientes con traumatismo craneoencefálico leve y tratamiento previo con de anticoagulantes o antiagregantes. Los objetivos de este estudio fueron: 1) identificar los factores de riesgo para la hemorragia intracraneal traumática (HICt) inmediata en los pacientes con traumatismo craneoencefálico leve e ingesta previa de warfarina o clopidogrel, y 2) para obtener una regla de predicción clínica para identificar a los pacientes con bajo riesgo de HICt inmediata.

Metodología

Estudio observacional prospectivo de dos centros de traumatología y cuatro hospitales comunitarios que incluyeron pacientes del servicio de urgencias (SU) con traumatismo craneoencefálico contuso leve (puntuación inicial en el SU de 13 a 15 de la Escala del Coma de Glasgow) e ingesta previa de warfarina o clopidogrel. El resultado principal fue la HICt inmediata, definida como la presencia de hemorragia intracraneal o contusión en la TC craneal inicial. El riesgo para HICt inmediata se analizó en once variables predictivas independientes. Las reglas de predicción clínica se obtuvieron tanto del particionamiento recursivo binario como de la regresión logística.

Resultados

Se incluyeron en el análisis un 982 pacientes con una media de edad de 75,4 años (DE 12,6). Sesenta pacientes (6,1%; IC 95% = 4,7% a 7,8%) tuvieron una HICt inmediata. La historia de vómitos (riesgo relativo [RR] 3,53; IC 95% = 1,80 a 6,94), la alteración del nivel de conciencia (RR 2,85; IC 95% = 1,65 a 4,92), el tratamiento con clopidogrel (RR 2,52; IC 95% = 1,55 a 4,10) y el dolor de cabeza (RR 1,81; IC 95% = 1,11 a 2,96) se asociaron con un riesgo incrementado para HICt inmediata. Tanto el particionamiento recursivo binario como la regresión logística fueron incapaces de obtener un modelo de predicción clínica que identificara a un subgrupo de pacientes con bajo riesgo para una HICt inmediata.

Conclusiones

A pesar de identificar varios factores de riesgo graves, los autores fueron incapaces de identificar un subgrupo de pacientes con traumatismo craneal leve y tratamiento previo con warfarina o clopidogrel que tengan un bajo riesgo de HICt inmediata. Así, la recomendación para la TC craneal en esta población es su realización urgente y generosa, incluso en ausencia de hallazgos clínicos.


Continuing Medical Education

  1. Top of page
  2. AbstractResumen
  3. Continuing Medical Education
  4. Methods
  5. Results
  6. Discussion
  7. Limitations
  8. Conclusions
  9. References

Continuing Medical Education Activity in Academic Emergency Medicine

CME Editor: Hal Thomas, MD

Authors: Daniel K. Nishijima, MD, MAS, Steven R. Offerman, MD, Dustin W. Ballard, MD, David R. Vinson, MD, Uli K. Chettipally, MD, MPH, Adina S. Rauchwerger, MPH, Mary E. Reed, DrPH, James F. Holmes, MD, MPH,

Article Title: Risk of Traumatic Intracranial Hemorrhage In Patients With Head Injury and Preinjury Warfarin or Clopidogrel Use

If you wish to receive free CME credit for this activity, please refer to the website: http://www.wileyblackwellcme.com.

Accreditation and Designation Statement:

Blackwell Futura Media Services designates this journal-based CME activity for a maximum of 1 AMA PRA Category 1 CreditTM. Physicians should only claim credit commensurate with the extent of their participation in the activity.

Blackwell Futura Media Services is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

Educational Objectives

After completing this exercise, the participant will be able to better manage patients with minor head injuries who are on warfarin or clopidogrel.

Activity Disclosures

No commercial support has been accepted related to the development or publication of this activity.

Faculty Disclosures:

CME editor – Hal Thomas, MD: No relevant financial relationships to disclose.

Authors – Daniel K. Nishijima, MD, MAS, Steven R. Offerman, MD, Dustin W. Ballard, MD, David R. Vinson, MD, Uli K. Chettipally, MD, MPH, Adina S. Rauchwerger, MPH, Mary E. Reed, DrPH, James F. Holmes, MD,MPH,

This manuscript underwent peer review in line with the standards of editorial integrity and publication ethics maintained by Academic Emergency Medicine. The peer reviewers have no relevant financial relationships. The peer review process for Academic Emergency Medicine is double-blinded. As such, the identities of the reviewers are not disclosed in line with the standard accepted practices of medical journal peer review.

Conflicts of interest have been identified and resolved in accordance with Blackwell Futura Media Services's Policy on Activity Disclosure and Conflict of Interest. No relevant financial relationships exist for any individual in control of the content and therefore there were no conflicts to resolve.

Instructions on Receiving Free CME Credit

For information on applicability and acceptance of CME credit for this activity, please consult your professional licensing board.

This activity is designed to be completed within an hour; physicians should claim only those credits that reflect the time actually spent in the activity. To successfully earn credit, participants must complete the activity during the valid credit period, which is up to two years from initial publication.

Follow these steps to earn credit:

  • Log on to http://www.wileyblackwellcme.com
  • Read the target audience, educational objectives, and activity disclosures.
  • Read the article in print or online format.
  • Reflect on the article.
  • Access the CME Exam, and choose the best answer to each question.
  • Complete the required evaluation component of the activity.

This activity will be available for CME credit for twelve months following its publication date. At that time, it will be reviewed and potentially updated and extended for an additional twelve months.

Each year, traumatic brain injury (TBI) accounts for an estimated 1.4 million emergency department (ED) visits, 275,000 hospitalizations, and 52,000 deaths in the United States, at an estimated cost of 60 billion dollars.[1] With an aging population, older adults with preinjury anticoagulant or antiplatelet use represent an increasing proportion of TBI patients evaluated in the ED.[2] These patients could be well-appearing and have low-impact mechanisms of injury, such as ground level falls,[3, 4] yet frequently have life-threatening traumatic intracranial hemorrhage (tICH) requiring neurosurgical interventions and specialized critical care.[5, 6]

Thus, emergency physicians (EPs) are challenged with identifying which patients with head trauma and preinjury anticoagulant or antiplatelet use are at high risk for acute tICH and require immediate cranial computed tomography (CT) imaging. Clinical prediction rules based on large, prospective studies accurately identify patients with mild TBI who are at very low risk for tICH (sensitivity range = 83% to 100%) and neurosurgical lesions (sensitivity = 100%).[7-9] These studies, however, excluded or had very few patients with preinjury anticoagulant or antiplatelet use.

Current mild TBI guidelines for patients with preinjury anticoagulant or antiplatelet use are largely based on small, retrospective studies that suggest an increased risk for tICH following blunt head trauma.[10-12] For patients with preinjury anticoagulant use and head trauma, guidelines vary from liberal imaging (cranial CT regardless of loss of consciousness [LOC] or amnesia)[13] to more limited imaging (cranial CT provided the patient sustain LOC or amnesia).[14] For patients with preinjury antiplatelet use and head trauma, current guidelines do not list antiplatelet medications as a risk factor for tICH.[13, 15] Thus, confusion exists regarding the appropriate utilization of cranial CT in patients with blunt head trauma and anticoagulant or antiplatelet use.

The objective of this study was to prospectively derive a clinical prediction rule to identify adult patients with mild head injury and preinjury warfarin or clopidogrel use at low risk for tICH. This study represents a secondary aim of a larger prospective study evaluating the prevalence and incidence of immediate and delayed tICH in this patient population.[16]

Methods

  1. Top of page
  2. AbstractResumen
  3. Continuing Medical Education
  4. Methods
  5. Results
  6. Discussion
  7. Limitations
  8. Conclusions
  9. References

Study Design

This was a prospective, observational, multicenter study conducted at two trauma centers and four community hospitals in northern California. The study was approved by the institutional review boards at all sites with an alteration of informed consent. The sponsors of the study had no role in study design, data collection and analysis, or manuscript preparation. The corresponding author had full access to all the data and had final responsibility for the decision to submit for publication.

Study Setting and Population

Consecutive adult (≥18 years old) ED patients with preinjury warfarin or clopidogrel use (within the prior 7 days) and mild blunt head trauma (initial ED Glasgow Coma Scale [GCS] score 13 to 15) were enrolled. We defined blunt head trauma as any blunt head injury regardless of LOC or amnesia. Patients who did not receive cranial CT scans during the index ED visit were excluded from the primary analysis. We also excluded patients with known injuries transferred from outside facilities.

Study Protocol

The treating ED faculty physicians completed standardized questionnaires prior to cranial CT imaging. All physicians participating in the study received an explanation of the questionnaire with definitions of each criterion. Items in the questionnaire were based on a review of the literature on minor head trauma and included age, mechanism of injury (ground-level fall versus non–ground-level fall), warfarin use, clopidogrel use, concomitant aspirin use, headache, vomiting, LOC or amnesia, drug or alcohol intoxication, physical evidence of trauma above the clavicles, and abnormal mental status. A ground-level fall was defined as a fall from standing height or less. Headache was defined as the presence of any head pain after injury. Vomiting was defined as any postinjury emesis. LOC or amnesia was defined as witnessed LOC or failure of the patient to recall the events of the injury. Drug or alcohol intoxication was defined as clinician impression of intoxication based on history, physical examination, or laboratory testing. Physical evidence of trauma above the clavicles was defined as any external injury to the face, neck, or scalp and included abrasions, lacerations, contusions and hematomas, or fractures. An abnormal mental status was defined as an initial ED GCS score less than 15. Patients with a GCS score less than 15 but not differing from baseline (e.g., history of dementia) were not considered to have an abnormal mental status.

Cranial CT imaging and hospital admission were at the discretion of the patients' treating physicians. Electronic medical records were reviewed in a standardized fashion by research coordinators and site investigators to assess CT scan results, ED disposition, and hospital course.

At each site, approximately 10% of patients (non–randomly selected) had a separate, independent faculty physician assessment that was masked to and completed within 60 minutes of the initial assessment to evaluate the reliability of preselected clinical variables. Data on patients eligible but not enrolled during ED evaluation were abstracted from their medical records to assess for enrollment bias.

Outcomes

The primary outcome measure was the presence of immediate tICH (defined as any ICH or contusion) as interpreted by the staff neuroradiologist on initial ED cranial CT. The patient was considered to have tICH if the radiology report was consistent with tICH. Patients with delayed tICH (initial normal CT but with a repeat CT consistent with tICH) were not considered to meet the primary outcome measure. The secondary outcome measure was the presence of neurosurgical intervention, which was defined as the use of intracranial pressure monitor or brain tissue oxygen probe, placement of burr hole, craniotomy/craniectomy, intraventricular catheter, subdural drain, or the use of mannitol or hypertonic saline.

Data Analysis

Data were compared using STATA for Windows, Rel. 11.0 (StataCorp, College Station, TX). Normally distributed continuous data were reported as the mean with standard deviations (±SDs) and ordinal or nonnormally distributed continuous data described as the median with interquartile (25% to 75%) ranges (IQR). Proportions and relative risks (RRs) are presented with 95% confidence intervals (CIs).

Eleven independent predictor variables (age 65 years or older, warfarin use, clopidogrel use, concomitant aspirin use, non–ground-level fall mechanism of injury, headache, vomiting, LOC or amnesia, drug or alcohol intoxication, evidence of trauma above the clavicles, abnormal mental status), defined a priori, underwent bivariate testing with chi-square or Fisher's exact test (in instances of small cell size). We used a standard model building approach as candidate variables predicting immediate tICH (threshold p < 0.20) were entered into a multivariable analysis using both binary recursive partitioning and logistic regression. Binary recursive partitioning was conducted with Classification and Regression Trees (CART) software (Salford Systems, San Diego, CA). We used the Gini splitting function in CART and set the misclassification costs for missing a tICH at 100:1 (relative cost of 100 for misclassifying one patient with immediate tICH to that of misclassifying one patient without tICH). Logistic regression was conducted with a random-effects model to account for random variation. Model fit was tested using the Hosmer-Lemeshow goodness-of-fit test.[17] Adjusted variables that were significant in the regression model (p < 0.05) were included in the clinical prediction rule. Derived prediction rules were validated using internal cross-validation for the recursive partitioning model and bootstrap validation for the logistic regression model. We calculated the sensitivity, specificity, and positive and negative predictive values (PPV and NPV) with 95% CIs for both derived models. Inter-rater reliability of independent variables recorded by initial and second physicians are reported as the kappa coefficient and percent agreement.

Results

  1. Top of page
  2. AbstractResumen
  3. Continuing Medical Education
  4. Methods
  5. Results
  6. Discussion
  7. Limitations
  8. Conclusions
  9. References

Between April 2009 and January 2011, a total of 1101 patients were enrolled (83.3% of all eligible patients; Figure 1). Comparison of patients enrolled and those eligible but not enrolled demonstrated similar characteristics (age, sex, medication use, ED cranial CT, and hospital admission) and outcomes (immediate tICH, neurosurgical intervention, and in-hospital mortality). Overall, 119 patients were excluded from analysis (25 transferred patients, 29 patients with nonmild head trauma, and 65 patients without cranial CT imaging at index ED visit), leaving 982 patients for data analysis.

image

Figure 1. Flow of patients in the study. CT = computed tomography; tICH = traumatic intracranial hemorrhage.

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The mean (±SD) age in the included cohort was 75.4 (±12.6) years and 464 patients (47.3%) were male. The majority of patients sustained ground-level falls (83.6%) were taking warfarin (72.7%), did not sustain LOC or amnesia (81.0%), had evidence of trauma above the clavicles (70.9%), and had normal mental status (89.5%; see Table 1 for additional characteristics of the study population).

Table 1. Patient Characteristics
Characteristicn (%) (N = 982)
  1. GCS = Glasgow Coma Scale; LOC = loss of consciousness; MVC = motor vehicle collision.

  2. a

    11 patients with concomitant warfarin and clopidogrel use.

Demographics
Age, mean (SD), yr75.4 (12.6)
Male sex464 (47.3)
Mechanism of injury
Ground level fall821 (83.6)
Fall from height36 (3.7)
MVC, < 35 miles per hour15 (1.5)
MVC, ≥ 35 miles per hour23 (2.3)
MVC, unknown speed8 (0.8)
Pedestrian struck by automobile4 (0.4)
Bicyclist struck by automobile4 (0.4)
Direct blow51 (5.2)
Unknown mechanism15 (1.5)
Other mechanism5 (0.5)
Medication usea
Warfarin use714 (72.7)
Clopidogrel use279 (28.4)
Concomitant aspirin use45 (4.6)
Clinical history
Vomiting41 (4.2)
Headache349 (35.5)
LOC or amnesia187 (19.0)
Physical exam
Alcohol intoxication34 (3.5)
Any evidence of trauma above the clavicles696 (70.9)
Trauma to face367 (37.4)
Trauma to neck33 (3.4)
Basilar skull fracture2 (0.2)
Scalp abrasion149 (15.2)
Scalp contusion292 (29.5)
Scalp laceration170 (17.3)
Normal mental status (GCS 15)879 (89.5)
ED course
Admitted to hospital346 (33.1)

There were 60 patients (6.1%; 95% CI = 4.7% to 7.8%) with the primary outcome of immediate tICH diagnosed on initial ED cranial CT. None of the 65 patients who did not receive initial ED cranial CT scans were later diagnosed with immediate tICH, although two patients were lost to follow-up.

Of the 60 patients diagnosed with immediate tICH, there were 12 patients (20.0%; 95% CI = 10.8% to 32.3%) who received neurosurgical interventions. These are listed in Table 2 and most frequently involved craniotomy/craniectomy (seven patients, 11.7%) and mannitol administration (five patients, 8.3%). Ten of the 60 patients (16.7%; 95% CI = 8.3% to 28.5%) with immediate tICH died during hospitalization.

Table 2. Neurosurgical Interventions
InterventionNo. (%) of patients (n = 60)
Intracranial pressure monitor or oxygen probe0
Burr hole3 (5.0)
Craniotomy/craniectomy 7 (11.7)
Intraventricular catheter placement2 (3.3)
Subdural drain2 (3.3)
Mannitol use5 (8.3)
Hypertonic saline use0
Total patients with neurosurgical interventions12 (20.0)

Clopidogrel use, headache, vomiting, drug or alcohol intoxication, and abnormal mental status were associated with an increased risk for immediate tICH on bivariate analysis (p < 0.20) (Table 3). Binary recursive partitioning was unable to derive a prediction rule that reliably identified a subset of patients at low risk for tICH.

Table 3. RR Ratios for the Clinical Variables for tICH (Bivariate Analysis)
Clinical VariabletICH Present, n/N (%)tICH Absent, n/N (%)RR (95% CI)
  1. LOC = loss of consciousness; RR = relative risk; tICH = traumatic intracranial hemorrhage.

Age 65 yr and older50/60 (83.3)750/922 (81.3)1.14 (0.59–2.20)
Warfarin use31/60 (51.7)683/922 (74.1)0.40 (0.25–0.65)
Clopidogrel use30/60 (50.0)249/922 (27.0)2.52 (1.55–4.10)
Concomitant aspirin use4/60 (6.7)41/922 (4.4)1.49 (0.56–3.92)
Non–ground-level fall mechanism10/60 (16.7)151/922 (16.4)1.02 (0.53–1.97)
Headache 30/60 (50.0)319/922 (34.6)1.81 (1.11–2.96)
Vomiting8/60 (13.3)33/922 (3.6)3.53 (1.80–6.94)
LOC or amnesia15/60 (25.0)172/922 (18.7)1.42 (0.81–2.49)
Drug or alcohol intoxication4/60 (6.7)30/922 (3.3)1.99 (0.77–5.18)
Trauma above the clavicles41/60 (68.3)655/922 (71.0)0.89 (0.52–1.50)
Abnormal mental status15/60 (25.0)88/922 (9.5)2.85 (1.65–4.92)

Multivariable logistic regression identified vomiting (adjusted odds ratio [aOR] = 3.68; 95% CI = 1.55 to 8.76) and abnormal mental status (aOR = 3.08; 95% CI = 1.60 to 5.94) as associated with immediate tICH (Table 4). The Hosmer-Lemeshow goodness-of-fit test had a p-value of 0.004, suggesting poor calibration of the model. Test characteristics of the clinical prediction rule consisting solely of these two variables were poor (sensitivity = 37%, specificity = 87%, PPV = 16%, NPV = 95%). All clinical variables measured for inter-rater reliability had substantial agreement (range = 91% to 97%; Table 5).[18]

Table 4. Adjusted Risk for Traumatic Intracranial Hemorrhage (Multivariable Analysis)
VariableaOR (95% CI)
  1. aOR = adjusted odds ratio.

Warfarin use0.62 (0.70–5.49)
Clopidogrel use1.68 (0.19–14.72)
Vomiting3.68 (1.55–8.76)
Headache1.60 (0.93–2.77)
Drug or alcohol intoxication1.61 (0.50–5.16)
Abnormal mental status3.08 (1.60–5.94)
Table 5. Interrater Reliability of Clinical Variables
VariableKappa (95% CI)% Agreement (95% CI)
  1. GCS = Glasgow Coma Scale; LOC = loss of consciousness.

GCS score0.65 (0.58–0.70)90.8 (84.9–96.2)
Evidence of trauma above clavicles0.93 (0.86–1.0)97.3 (92.2–99.4)
Vomiting0.65 (0.33–0.97)96.3 (90.9–99.0)
Headache0.80 (0.67–0.92)91.7 (84.9–96.2)
LOC or amnesia0.84 (0.71–0.97)95.4 (89.6–98.5)
Drug or alcohol intoxication0.56 (0.00–0.71)97.3 (92.2–99.4)

Discussion

  1. Top of page
  2. AbstractResumen
  3. Continuing Medical Education
  4. Methods
  5. Results
  6. Discussion
  7. Limitations
  8. Conclusions
  9. References

We were unable to derive a clinical prediction rule to accurately identify the presence of immediate tICH on cranial CT in patients with mild blunt head trauma and preinjury warfarin or clopidogrel use. Two clinical variables, vomiting and abnormal mental status, were significantly associated with increased risk for immediate tICH on multivariable logistic regression. These two variables, however, were absent in a substantial number of our cohort of patients with tICH.

To our knowledge this is the first prospective study to evaluate risk factors for immediate tICH in patients with mild head injury and preinjury anticoagulant or antiplatelet use. Prior retrospective studies were also unable to identify a number of clinical predictors for immediate tICH in this patient population. Li et al.[10] were unable to identify any clinical predictors for abnormal cranial CT scans in patients with head injury and preinjury warfarin use. Brewer et al.[3] found only LOC to be significantly associated with immediate tICH in trauma registry patients with preinjury warfarin or clopidogrel use and a GCS of 15.

The results of this study have a number of clinical implications. First, this study suggests that it is difficult to identify a low-risk group of patients with preinjury warfarin or clopidogrel use and blunt head trauma who may be safely managed without cranial CT imaging. The inability to derive a clinical prediction rule is likely the result of the relative lack of differentiating clinical characteristics between patients with immediate tICH and those without. Patients in our study were relatively well-appearing and homogenous; they were 65 years and older with ground-level falls, normal mental status, and few clinical symptoms. However, despite being well-appearing, these patients were still at risk for immediate tICH. Seven of the 60 patients (12%) with immediate tICH had low mechanisms of injury (ground-level fall), no clinical symptoms (no history of LOC or amnesia, headache, vomiting), and normal clinical examinations (no intoxication, normal mental status, and no evidence of trauma above the clavicles). Second, current National Institute for Health and Clinical Excellence head injury guidelines (updated 2007) recommend urgent (<1 hour) CT imaging in patients with head injury and preinjury warfarin use, provided that they sustain LOC or amnesia.[14] However, 45 of 60 (75%) of patients with immediate tICH in our study did not sustain LOC or amnesia. We thus recommend liberal cranial CT imaging for these patients, even those with minimal head trauma who do not sustain LOC or amnesia. Finally, patients with immediate tICH have high morbidity and mortality; 20% required neurosurgical intervention and 17% died during hospitalization. This emphasizes the importance of rapid diagnosis of tICH with cranial CT imaging to determine the need for reversal of anticoagulant or antiplatelet effects with medications and blood products. Patients with delayed reversal of anticoagulation have increased morbidity and mortality.[19] Furthermore, in patients who require immediate neurosurgical intervention, rapid and efficacious reversal to an appropriate international normalized ratio (INR) level is essential; patients with INR levels > 1.25 have increased postoperative mortality.[20-22]

Limitations

  1. Top of page
  2. AbstractResumen
  3. Continuing Medical Education
  4. Methods
  5. Results
  6. Discussion
  7. Limitations
  8. Conclusions
  9. References

Our results should be interpreted in the context of several limitations. There were relatively few patients who met the primary outcome of immediate tICH (60 patients). However, there were enough outcomes for the accepted ratio of 10 outcomes of interest for every variable entered into the regression model.[23] Furthermore, including more patients with tICH would not resolve the fact that many patients with immediate tICH appeared to have no risk factors for tICH beyond age and anticoagulant use. The relatively few outcomes also limited our ability to conduct subgroup analyses by type of medication use (warfarin or clopidogrel) or by INR level.

As this was an observational study, CT scans were not obtained on all patients, and ethical considerations prevented CT scanning solely for study purposes. Some patients not undergoing CT scans during their initial ED visits potentially had undiagnosed tICH. However, none were identified in clinical follow-up, which is a reasonable method to evaluate for clinically important outcomes when the definitive test is not ethical or feasible.[24]

Conclusions

  1. Top of page
  2. AbstractResumen
  3. Continuing Medical Education
  4. Methods
  5. Results
  6. Discussion
  7. Limitations
  8. Conclusions
  9. References

While we identified several risk factors for immediate traumatic intracranial hemorrhage, we were unable to identify a subset of patients with mild head trauma and preinjury warfarin or clopidogrel use who are at low risk for immediate traumatic intracranial hemorrhage. We thus recommend urgent and liberal cranial computed tomography imaging in this patient population, even in the absence of clinical findings.

References

  1. Top of page
  2. AbstractResumen
  3. Continuing Medical Education
  4. Methods
  5. Results
  6. Discussion
  7. Limitations
  8. Conclusions
  9. References
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    Faul M, Xu L, Wald MM, Coronado VG. Traumatic Brain Injury in the United States: Emergency Department Visits, Hospitalizations, and Deaths 2002–2006. Atlanta, GA: US Department of Health and Human Services, CDC, 2010.
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    McMillian WD, Rogers FB. Management of prehospital antiplatelet and anticoagulant therapy in traumatic head injury: a review. J Trauma. 2009;66:94250.
  • 3
    Brewer ES, Reznikov B, Liberman RF, et al. Incidence and predictors of intracranial hemorrhage after minor head trauma in patients taking anticoagulant and antiplatelet medication. J Trauma. 2011;70:E15.
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    Sasser SM, Hunt RC, Faul M, et al. Guidelines for field triage of injured patients: recommendations of the National Expert Panel on Field Triage, 2011. MMWR Recomm Rep. 2012;61:120.
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    Reynolds FD, Dietz PA, Higgins D, Whitaker TS. Time to deterioration of the elderly, anticoagulated, minor head injury patient who presents without evidence of neurologic abnormality. J Trauma. 2003;54:4926.
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    Rockswold GL, Leonard PR, Nagib MG. Analysis of management in thirty-three closed head injury patients who “talked and deteriorated.” Neurosurgery. 1987;21:515.
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    Stiell IG, Wells GA, Vandemheen K, et al. The Canadian CT Head Rule for patients with minor head injury. Lancet. 2001;357:13916.
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    Haydel MJ, Preston CA, Mills TJ, Luber S, Blaudeau E, DeBlieux PM. Indications for computed tomography in patients with minor head injury. N Engl J Med. 2000; 343:1005.
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    Smits M, Dippel DW, de Haan GG, et al. External validation of the Canadian CT Head Rule and the New Orleans Criteria for CT scanning in patients with minor head injury. JAMA. 2005; 294:151925.
  • 10
    Li J, Brown J, Levine M. Mild head injury, anticoagulants, and risk of intracranial injury. Lancet. 2001; 357:7712.
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    Mina AA, Knipfer JF, Park DY, Bair HA, Howells GA, Bendick PJ. Intracranial complications of preinjury anticoagulation in trauma patients with head injury. J Trauma. 2002; 53:66872.
  • 12
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