Trauma/original researchFalse-Negative FAST Examination: Associations With Injury Characteristics and Patient Outcomes
Introduction
Trauma accounts for approximately 41 million emergency department (ED) visits annually in the United States and results in significant morbidity and mortality.1, 2 Trauma also incurs substantial economic burden, with annual direct and indirect costs estimated at $80 and $406 billion, respectively.3 Trauma patients frequently require laboratory testing and imaging, including a focused assessment with sonography in trauma (FAST) examination to evaluate for intraperitoneal hemorrhage. This examination is a component of the initial evaluation of a patient who experiences blunt abdominal trauma and is also a core competency for emergency medicine and surgical residency training programs.4, 5
Results of the FAST examination are used in decision algorithms for patients with blunt abdominal trauma.6, 7, 8, 9, 10 It is also well known that the sensitivity of FAST is inadequate to rule out intra-abdominal injury.8, 9, 10, 11, 12, 13, 14, 15, 16, 17 Little is known, however, about injury patterns and physical examination findings associated with false-negative FAST examination results and the their consequences on patient outcomes.18, 19, 20, 21, 22, 23 Knowledge of which presenting patient characteristics are associated with false-negative FAST results may help clinicians identify patients at risk for pathologic intra-abdominal free fluid despite a negative FAST result. It would also be helpful to know which organ injuries predominate in those with false-negative FAST examination results. This knowledge could inform selection of patients who might benefit from further imaging or observation and which organ injuries might be missed with FAST alone.
It has been theorized that missed pathology associated with false-negative FAST results may place patients at risk for adverse outcomes.18, 19, 24 However, to our knowledge no study has been performed to assess the association of false-negative FAST results with therapeutic operative intervention, mortality, or length of hospital stay. If false-negative FAST result is highly associated with adverse events, clinicians might consider being more aggressive in the use of other imaging modalities or operative intervention. On the other hand, if there is little or no association with adverse outcomes, clinicians might opt to observe these patients.
The objectives of this study were to estimate associations between injury characteristics available during the initial ED evaluation and false-negative FAST result, specific abdominal organ injuries and false-negative FAST result, and false-negative FAST result and patient outcomes, including need for emergency operative intervention, length of hospital admission, duration of intensive care, and mortality.
Section snippets
Study Design and Setting
This was a retrospective cohort study performed at Denver Health Medical Center in Denver, CO. The center is a 477-bed urban county hospital with approximately 50,000 annual adult ED visits. It is also a Level I trauma center for the city and county of Denver and a trauma referral center for the Rocky Mountain region. Approximately 16,000 trauma patients are evaluated and treated at the center annually, and approximately 2,000 meet criteria for enrollment in the trauma registry; approximately
Results
During the study period, 6,851 patients were entered into the Trauma Registry and 1,479 (22%) had an injury to the abdomen or pelvis. Of the 1,479 patients, 354 (24%) had pathologic free fluid as a result of blunt trauma. Of the 354 patients, 332 (94%) had a FAST examination performed in the ED (Figure). Agreement on endpoint abstraction was 100% (κ=1.0) between the research assistants and principal investigator.
Of the 332 included patients, the median age was 32 years (interquartile range 23
Limitations
Inclusion criteria required patient identification through the trauma registry, which may have resulted in systematic selection of patients with higher acuity. Trauma patients without significant injuries may have been discharged from the ED and not entered into the registry. It is unlikely, however, that patients with traumatic intra-abdominal free fluid (our study population) would have been asymptomatic and thus not identified while in the ED.
FAST sensitivity in our study is estimated to be
Discussion
To our knowledge, this is the largest study to date to evaluate potential predictors of false-negative FAST result with multivariable modeling. FAST examinations are performed to facilitate disposition decisions. Positive findings can aid in the decisionmaking for emergency operative intervention or further diagnostic studies, particularly in patients with unstable vital signs. Although negative results do not eliminate the need for further testing, we have attempted to aid physicians in
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Cited by (28)
Application of Focused Assessment with Sonography for Trauma in the Intensive Care Unit
2022, Clinics in Chest MedicineeFAST exam errors at a level 1 trauma center: A retrospective cohort study
2021, American Journal of Emergency MedicineACR Appropriateness Criteria® Blunt Chest Trauma-Suspected Cardiac Injury
2020, Journal of the American College of RadiologyACR Appropriateness Criteria® Major Blunt Trauma
2020, Journal of the American College of RadiologyCitation Excerpt :The role of FAST is primarily one of triage; a positive FAST and signs of hemodynamic instability may lead to immediate surgical intervention rather than CT. Although US may be able to diagnose certain thoracic and abdominal injuries, its relatively lower sensitivity compared with CT does not make it a sufficient test to exclude injuries to these areas, particularly extraperitoneal or genitourinary injuries [5,41,42]. In a series of 128 acute trauma patients, 11 of 19 injuries that were missed by emergent US involved the genitourinary system [41].
Too fast, or not fast enough? The FAST exam in patients with non-compressible torso hemorrhage
2019, American Journal of SurgeryCitation Excerpt :This is the first study in the literature to specifically examine the performance of the FAST exam in the NCTH population. In other populations, numerous studies have highlighted the false negative rate as the key limitation of the FAST exam.7,9–32 In adults, studies have generally shown a sensitivity of 80%–88%, specificity of 98%–100%, positive predictive value of 73%–83%, negative predictive value of 84%–99%, and an accuracy of 97%–99%.12–15
Extended focused assessment with sonography in trauma
2018, BJA Education
Funding and support: By Annals policy, all authors are required to disclose any and all commercial, financial, and other relationships in any way related to the subject of this article as per ICMJE conflict of interest guidelines (see www.icmje.org). The authors have stated that no such relationships exist.
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Supervising editor: Robert D. Welch, MD, MS
Author contributions: BTL, RLB, JSH, and JLK designed the study and wrote the article. RLB and JSH performed the statistical analysis. BTL oversaw the data collection. SMK, JB, TRD, and CSG contributed to data collection. JLK takes responsibility for the paper as a whole.
The views expressed are those of the authors and do not reflect the official policy of the Department of the Army, the Department of Defense, or the US government.
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Publication date: Available online April 17, 2012.