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    NEXUS Chest CT Decision Instrument for CT Imaging

    Identifies blunt trauma patients with clinically significant thoracic injuries.
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    INSTRUCTIONS

    Use in awake, non-intubated, hemodynamically stable blunt trauma patients ≥15 years old in whom a CT chest is considered as part of the normal diagnostic evaluation.

    When to Use
    Pearls/Pitfalls
    Why Use

    Blunt trauma patients in whom CT chest is considered as part of the diagnostic evaluation.

    • The NEXUS CT Chest Decision Instrument is comprised of two parts, one that maximizes sensitivity for major injury and the other for major or minor injury.
    • Uses findings from routine trauma exam.
    • 100% sensitive for aortic and great vessel injury (a key component of the rule, as these are devastating injuries that must not be missed).
    • Can be used sequentially with NEXUS Chest Decision Instrument for Blunt Chest Trauma.

    Identifies patients that can safely be ruled out for clinically significant thoracic and intra-thoracic injuries, potentially safely reducing CT scanning by 25-37% in blunt trauma patients.

    Clinically Major Thoracic Injuries
    All Thoracic Injuries
    About the Creator
    Dr. Robert Rodriguez
    Content Contributors
    • Michael Jones, MD

    Result:

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    Next Steps
    Evidence
    Creator Insights

    Advice

    If any criteria are positive, major or minor thoracic injury can NOT be excluded, and further workup, including but not limited to CT chest, is warranted.

    Management

    Should be used in conjunction with standard trauma evaluation and resuscitation.

    Critical Actions

    Clinical decision tools are meant to assist practitioners with making appropriate and evidence based decisions in the management of patients. The NEXUS CT Chest Decision Instrument suggests that a CT chest can be safely avoided in situations where the provider suspects thoracic injury, is considering CT imaging and answers negatively to the NEXUS CT Chest Decision Instrument. In these situations, the provider can feel confident that significant thoracic and intra-thoracic injuries are not missed.

    Formula

    Series of Yes/No questions as listed.

    Facts & Figures

    If any criteria are positive, major or minor thoracic injury can NOT be excluded.

    Evidence Appraisal

    The NEXUS CT Chest Decision Instrument was prospectively derived and validated by Rodriguez et al in a cohort of 11,477 blunt trauma patients (6,002 patients for derivation phase and 5,475 for validation). Seven parameters from a list of 14 were selected by recursive partitioning.

    For major injury only, the tool was 99.2% sensitive (95% CI 95.4%–100%), and 31.7% specific (95% CI 29.9%–33.5%). Negative predictive value (NPV) was 99.9% (95% CI 99.3%–100%).  The tool was 100% sensitive for aortic and great vessel injuries.

    For either major or minor injury, sensitivity was 90.7% (95% CI 88.3%–92.8%), specificity 37.9% (95% CI 35.8%–40.1%), and NPV 91.8% (95% CI 89.7%–93.6%).

    Literature

    Dr. Robert Rodriguez

    From the Creator

    Why did you develop the NEXUS Chest CT Decision Instruments (DI)? Was there a clinical experience that inspired you to create this tool for clinicians?
    Our development of the NEXUS Chest CT DIs arose during our original NEXUS CXR study work. At this time (around 2005-2008), we noted that chest CT was becoming increasingly common -- both independently and as part of head-to-pelvis CT (pan-scan). Compared to CXR, chest CT is much more expensive and is associated with radiation to radiosensitive anatomical regions, which may induce cancer in the disproportionately young trauma population. We performed a study that demonstrated low yield of trauma chest CT for clinically significant injury in certain scenarios that further pushed us to perform our chest CT DI development work.

    What pearls, pitfalls and/or tips do you have for users of the NEXUS Chest CT DI? Are there cases when they have been applied, interpreted, or used inappropriately?
    Two pitfalls: First, these DIs are intended to be used in awake, non-intubated, hemodynamically stable, adult (15 years or older) trauma patients—NOT critically ill, severely injured, poly-trauma patients or for intubated patients. To apply these DIs, clinicians have to be able to assess whether patients have criteria, such as chest wall or sternal tenderness.

    Second, these are one-way rules that only tell you whether CT may be safely omitted, and you should only apply NEXUS Chest CT in patients that you initially believe to need chest CT. The presence of 1 or more DI criteria does not dictate the need for chest CT in patients who would not otherwise be imaged. Misapplication of these DIs to other patients who were not being considered for CT may paradoxically lead to unnecessary increases in imaging.

    In terms of pearls we have 3:

    1. In developing these DIs, we were very cognizant of time pressures and mental work-load associated with implementation of complicated decision rules. All of our criteria are very simple elements of the standard trauma history and physical exam that should not take extra time. For ease of use the 4 physical exam criteria (chest wall, sternum, thoracic spine and scapula tenderness) may be simply lumped together as any bony tenderness of the thorax or upper back.
    2. We also recognized inherent differences in opinion regarding the need to diagnose minor thoracic injuries. We therefore developed 2 DIs: For clinicians who believe that nearly all injuries should be detected, we recommend the “All” DI, which detects both clinically major and minor injuries with high sensitivity. For those who believe that only management-changing injuries are important, we recommend “Major”, which retains very high sensitivity for clinically major injuries (with slightly lower sensitivity for minor injuries). Major has higher specificity, thereby sparing a larger number of patients from CT.
    3. We recommend the incorporation of the NEXUS Chest DIs and algorithm as checklists into chart templates and electronic medical records to further streamline and simplify clinicians' decision-making.

    What recommendations do you have for healthcare providers once they have applied the NEXUS Chest CT DI? What are the next steps?
    In terms of charting or documenting their decision-making, clinicians may state that a “patient meets NEXUS Chest CT low risk criteria for injury” or “patient ruled out for significant thoracic injury by NEXUS Chest CT” in a manner similar to that used with the NEXUS Cervical Spine or other decision rules.

    How does the NEXUS Chest CT DI compare with your NEXUS chest DI for blunt trauma?
    Our NEXUS Chest DIs (NEXUS CXR and NEXUS Chest CT) are meant to be used sequentially. For most patients we recommend first applying NEXUS CXR. If a patient is deemed low risk by this NEXUS CXR, then no imaging (neither CXR nor chest CT) is recommended. If chest CT is being considered after CXR, then apply NEXUS Chest CT to determine whether CT may be safely omitted.

    Any other comments on the NEXUS Chest CT DI?
    Overall, our NEXUS Chest DIs provide clinicians with evidence-based mechanisms to use basic physical exam and history findings for selective imaging, instead of reflexive imaging, to safely and efficiently rule out injury in appropriate patients. By safely eliminating the need for imaging upfront, our DIs and algorithm will decrease costs, save provider and patient time, and decrease unnecessary radiation exposure.

    About the Creator

    Robert Rodriguez, MD, is a professor of clinical emergency medicine and the residency research director at UCSF School of Medicine. He is also an attending emergency room physician. Dr. Rodriguez's research interests include deriving decision instruments for imaging in blunt trauma, critical care in the ED, infectious disease presentations to the ED, homeless and immigrant population access and care in the ED, and defensive medicine.

    To view Dr. Robert Rodriguez's publications, visit PubMed

    Content Contributors
    • Michael Jones, MD