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    NEXUS Chest Decision Instrument for Blunt Chest Trauma

    Determines which patients require chest imaging after blunt trauma.
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    INSTRUCTIONS

    Applies to patients ≥15 years old with blunt trauma within the past 24 hours in the ED.

    When to Use
    Pearls/Pitfalls
    Why Use
    • Pregnant patients with minor trauma
    • Patients who are of indeterminate risk
    • Young patients, in whom radiation exposure is more risky
    • The NEXUS Chest Decision Instrument can rapidly identify “very low-risk” patients with blunt thoracic trauma who would not benefit from chest imaging.
    • It was developed due to the concern of radiation from Chest CT that is now common in the evaluation of trauma patients, and was developed at 3 Level 1 trauma centers in over 2600 patients.
    • It uses 7 criteria to identify this low-risk cohort who have a <2% chance of having any thoracic injury (and 1% chance of having clinically significant thoracic injuries).
    • It was designed to not miss any injuries, but is not very specific -- just because a patient may not meet low-risk criteria does not mean the patient must be imaged.

    Points to keep in mind:

    • 1 isolated rib fracture was not included as a “thoracic injury.”
    • Some providers may disagree with the study's definitions of “clinically significant.”
    • Clavicular tenderness is not included as “chest wall tenderness.”
    • Distracting injury is purposefully vaguely defined and is at the discretion of the provider: “any condition thought by the clinician to be producing sufficient pain to distract the patient from a second (intrathoracic) injury.” From the original paper:
      • Long bone fractures;
      • Visceral injuries requiring surgical consultation;
      • Large lacerations, degloving injuries, or crush injuries;
      • Large burns, and
      • Any other injury producing acute functional impairment.
      • Physicians may also classify any injury as distracting if it is thought to have the potential to impair the patient’s ability to appreciate other injuries.
    • Intoxication is also similarly intentionally vague:
      • A history of intoxication or recent intoxicating ingestion is provided by a patient or observer;
      • Test of bodily secretions positive for alcohol or drugs;
      • Patient has physical evidence suggesting intoxication (odor of alcohol, slurred speech, ataxia, dysmetria, or other cerebellar findings), or behavior consistent with intoxication and unexplained by medical or psychiatric illness.

    This decision instrument can help reduce unnecessary imaging by identifying patients at low risk of thoracic injury, which reduces radiation exposure and provides faster evaluation for emergency providers and their patients, allowing them to focus on treatment, evaluation of other injuries or problems, or education and reassurance.

    Result:

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    Next Steps
    Evidence
    Creator Insights

    Advice

    • Adequate pain control is always important in patients with trauma.
    • Consider initial evaluation with chest x-ray in stable patients with isolated chest trauma.
    • CT will obviously find many more injuries than x-ray, regardless of their true clinical significance.
    • CT may be more useful in patients with multiple injuries or those who are sicker.

    Formula

    Addition of the selected points, see below.

    Facts & Figures

    Criteria Point Value
    Age > 60 years +1
    Rapid deceleration mechanism (fall > 20 ft or MVC > 40 mph) +1
    Chest pain +1
    Intoxication +1
    Altered mental status +1
    Distracting painful injury +1
    Tenderness to chest wall palpation +1

    Score interpretation:

    • NEXUS Score is 99% sensitive for clinically significant thoracic injury.
    • If NEXUS ≥1:
      • In well-appearing patient with no evidence of multi-organ injury, consider CXR only without CT.
      • In ill-appearing patients and/or those who will receive workup for other serious injury, consider chest CT as well.

    Evidence Appraisal

    The NEXUS Chest Decision Instrument was developed by the National Emergency X-Radiography Utilization Study (NEXUS) study group, looking to reduce unnecessary chest imaging in blunt trauma patients.

    Derivation

    • They first developed the rule prospectively in 3 trauma centers in 2,628 patients, asking about 12 clinical criteria.
    • They defined a “significant intrathoracic injury” as: pneumothorax, hemothorax, aortic or other great vessel injury, two or more rib fractures, ruptured diaphragm, sternal fracture, and pulmonary contusion.

    Validation

    • The study was then validated in 9,905 patients and re-classified “significant intrathoracic injury” more specifically, having an expert panel weigh diagnoses to group them as “Major Clinical Significance,” “Minor Clinical Significance,” and “No Clinical Significance” (see below).
    • To address imaging bias, they attempted to contact all patients who did not receive imaging or had negative imaging. 433 patients were contacted, none had been diagnosed with thoracic injury on follow-up.
    • The rule was 99.7% sensitive for major thoracic injury, 99% sensitive for major and minor thoracic injury, and 98.8% sensitive for any thoracic injury.

    Definitions:

    Major Clinical Significance

    • Aortic or great vessel injury (all are considered major) Ruptured diaphragm (all are considered major)
    • Pneumothorax: Received evacuation procedure (chest tube or other procedure)
    • Hemothorax: Received drainage procedure (chest tube or other procedure)
    • Sternal fracture: Received surgical intervention
    • Multiple rib fracture: Received surgical intervention or epidural nerve block
    • Pulmonary contusion: Received mechanical ventilatory assistance (including noninvasive ventilation) of any type for management

    Minor Clinical Significance

    • Pneumothorax: No evacuation procedure but observed as inpatient >24 hours
    • Hemothorax: No drainage procedure but observed as inpatient for >24 hours
    • Sternal fracture: No surgery but had in-hospital pain management or observed as inpatient >24 hours
    • Sternal fracture: No surgical intervention, no inpatient observation (pain managed on an outpatient basis)
    • Multiple rib fracture: Received in-hospital pain management or observation >24 hours
    • Multiple rib fracture: No surgical intervention, no inpatient observation (pain managed on an outpatient basis)
    • Pulmonary contusion or laceration: No mechanical ventilatory assistance but observed >24 hours

    No Clinical Significance

    • Hemothorax: No surgical intervention, no inpatient observation (managed on an outpatient basis)
    • Pneumothorax: No surgical intervention, no inpatient observation (managed on an outpatient basis)
    • Pneumomediastinum without pneumothorax: No inpatient observation (managed on an outpatient basis)
    • Pulmonary contusion or laceration: No mechanical ventilatory assistance, no surgical intervention, no inpatient observation (managed on an outpatient basis)
    Dr. Robert Rodriguez

    From the Creator

    Why did you develop the NEXUS Chest Decision Instrument for Blunt Chest Trauma? Was there a clinical experience that inspired you to create this tool for clinicians?
    I began this line of research over a decade ago, when (during a shift) I noticed that we were getting so many negative chest X-rays (CXRs) in blunt trauma patients. The CXR appeared to be a completely reflexive thing and the vast majority of our studies were non-diagnostic. With an EM resident (Anna Bjoring), I started a pilot study and recruited NEXUS colleagues from UCLA (Bill Mower) and UCSF-Fresno (Greg Hendey). We have followed the path and methods put forth by our mentor Jerry Hoffman in his landmark NEXUS C-Spine work.
    What pearls, pitfalls and/or tips do you have for users of the NEXUS Chest Decision Instrument for Blunt Chest Trauma? Are there cases in which it has been applied, interpreted, or used inappropriately?
    This is a great question. Misapplication of decision rules can paradoxically lead to greater imaging. As with essentially all imaging decision rules, NEXUS Chest was derived and validated only for the purpose of ruling out injury, not ruling it in. In other words, finding one or more NEXUS Chest criteria does not mean you must image that patient. We suggest using NEXUS Chest only in patients whom you were planning to image. Then apply NEXUS Chest to find out whether you can safely forego imaging.
    What recommendations do you have for health care providers once they have applied the NEXUS Chest Decision Instrument for Blunt Chest Trauma? Are there any adjustments or updates you would make to the instrument given recent changes in medicine?
    NEXUS Chest is easy to implement in conjunction with NEXUS C-Spine. Three criteria (altered alertness, intoxication and distracting injury) are the same and a fourth (chest wall tenderness) is analogous to the midline cervical spine tenderness criterion. We suggest that you use them in tandem for rapid evaluation of blunt trauma patients.
    Other comments? Any new research or papers on this topic in the pipeline?
    We have recently completed multicenter derivation and validation of our next rules in this line of research--the NEXUS Chest CT Decision Instruments. Using simple clinical criteria, these rules will allow trauma providers to forego chest CT in approximately 25-37% of blunt trauma patients who would otherwise get it. We hope to publish the manuscript describing this important study within the next 3 months.

    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