Increased diagnostic accuracy and widespread availability of computed tomography (CT) have enhanced initial trauma evaluation and facilitated nonoperative management of many types of injuries. However, concern that excessive radiation exposure could result in an increased lifetime cancer risk has prompted renewed evaluation of the potential risks and benefits of current diagnostic strategies. This supplement reviews best practices in diagnostic radiology for evaluation of the trauma patient and discusses approaches to optimize diagnostic assessment while limiting radiation exposure.
Evidence-based medicine requires a critical appraisal of the literature based upon study methodology and number of subjects. Not all references are equally robust. The findings of a large, prospective, randomized, and blinded trial should carry more weight than a case report.
To help the reader judge the strength of each reference, pertinent information about the study, such as the type of study and the number of patients in the study is included in bold type following the references, where available. In addition, the most informative references cited in this paper, as determined by the author, are highlighted.
Resuscitation involves the restoration of adequate tissue perfusion to meet the consumptive demands of the body. The ultimate goals of resuscitation are the prevention of an uncompensated anaerobic state and the reversal of metabolic hypoxia. To achieve these goals, timely intervention with an organized and targeted resuscitative strategy optimizes patient care.1-3 Achievement of these goals is dependent on a multidisciplinary approach to the management of the injured patient, and it requires careful coordination as the patient transitions from the resuscitation bay to the operating room and the intensive care unit (ICU). Strategies for the management of trauma patients during initial resuscitation are continuously evolving. This supplement reviews the current evidence in these critical and evolving areas of resuscitation to help guide the emergency clinician on current best practice.
Evidence-based medicine requires a critical appraisal of the literature based upon study methodology and number of subjects. Not all references are equally robust. The findings of a large, prospective, randomized, and blinded trial should carry more weight than a case report.
To help the reader judge the strength of each reference, pertinent information about the study, such as the type of study and the number of patients in the study is included in bold type following the references, where available. In addition, the most informative references cited in this paper, as determined by the author, are highlighted.
Points to keep in mind:
Why to Use
Annually, there are more than 1 million visits to emergency departments in the United States by blunt trauma patients who present with a concern for possible cervical spine injury. Many of these patients undergo imaging of their cervical spine, with the overwhelming majority of the studies coming back negative for a fracture (98%). This imaging is both largely unnecessary and extremely costly (> $180,000,000 annually). Application of the NEXUS criteria allows physicians to safely reduce imaging by 12% to 36% in patients presenting with concern for possible cervical spine injury, avoiding unnecessary radiographic studies and saving significant cost.
When to Use
The NEXUS criteria represent a well-validated clinical decision aid that can be used to safely rule out cervical spine injury in alert, stable trauma patients, without the need to obtain radiographic images.
Next Steps
Daniel Runde, MD
The NEXUS criteria have been prospectively validated in the largest cohort of patients ever studied for this indication. If a patient is NEXUS criteria–negative, further imaging is likely unnecessary.
Because of concerns that the NEXUS criteria do not perform as well among patients aged > 65 years, clinicians may want to consider further imaging if there is concern about the mechanism or examination in elderly patients. Although more complicated to remember, the CCR appears to perform as well or better than NEXUS in terms of sensitivity for CSI. In cases where a patient is not ruled out by the NEXUS criteria, it may be appropriate to apply the CCR. If the patient is negative for the CCR, then further imaging is probably unnecessary; for example, patients with midline cervical spine tenderness would need imaging according to the NEXUS criteria, but potentially could be cleared by the CCR if they did not have any high-risk features and could range their necks 45 degrees to the left and right.
There is also concern that the NEXUS criteria were derived and validated in an era when plain films were much more commonly ordered to assess for cervical spine injuries. CT imaging of the cervical spine is now more common, and there is some evidence that CT may identify CSIs that would be missed by NEXUS and/or the CCR.
At 34,069, the number of patients enrolled in the original validation study for the NEXUS criteria was over 3.5 times greater than in the original CCR study. As applied, the rule missed 2 of the 578 patients with a clinically significant CSI, yielding a sensitivity of 99.6% (Hoffman 1998). Subsequent evaluations of the NEXUS criteria have found the sensitivity for CSI to be more variable (83%-100%), but there have been some concerns about the methodology (retrospective review) and the way the criteria were applied in several of these analyses. One trial evaluating the NEXUS criteria, in which all patients underwent CT imaging of their cervical spine, found a sensitivity of 83%, with the rule missing 2.5% (26 of 1057) of patients with fractures. Sixteen (1.5%) of these patients required prolonged time in a cervical collar, 2 (0.2%) underwent operative repair, and 1 (0.1%) had a halo placed. A retrospective analysis attempting to apply the NEXUS criteria to the validation cohort for the CCR found a sensitivity of 92.7%.
Jerome Hoffman, MD
Original/Primary Reference
Validation References
Additional References
Points to keep in mind:
Exclusion criteria:
Why to Use
Annually, there are more than 1 million visits to emergency departments in the United States by blunt trauma patients who present with a concern for possible cervical spine injury. Many of these patients undergo imaging of their cervical spine, with the overwhelming majority of the studies coming back negative for a fracture (98%). Applying the CCR allows clinicians to safely decrease the need for imaging among this patient population by over 40%. While the CCR is more complex than other cervical spine clinical decision rules, it is a more sensitive rule and potentially can be used on patients who cannot be cleared using other rules.
When to Use
The CCR is a well-validated decision rule that can be used to safely rule out cervical spine injury in alert, stable trauma patients without the need to obtain radiographic images.
Next Steps
Daniel Runde, MD
If a patient has any high-risk factors (eg, aged > 65 years, a defined dangerous mechanism, or paresthesias in the arms or legs) then cervical spine imaging is required. Cervical spine imaging is required if a patient has no high-risk factors but meets none of the defined low-risk criteria (eg, sitting position in the emergency department, ambulatory at any time, delayed [not immediate onset] neck pain, no midline tenderness, simple rear-end motor vehicle collision [excludes pushed into traffic, hit by bus/ large truck, rollover, or hit by high-speed vehicle]). If a patient has no high-risk factors and has neck pain, but meets even 1 low-risk factor, then it is safe to assess the patient's ability to rotate the neck 45 degrees to the left and right. If the patient can do this (even with some pain or discomfort), then no further imaging is required; if not, then cervical spine imaging is indicated.
In the derivation study, the authors looked at the primary endpoint of clinically significant cervical spine injury. The validation study included a convenience sample of 8924 patients, aged 16 to 64 years, who presented to 10 Canadian trauma centers with stable vital signs and a Glasgow coma scale score of 15. Among the study population, 1.7% of patients had clinically significant cervical spine injury. The CCR was found to be 100% sensitive for ruling out cervical spine injury (defined as any fracture, dislocation, or ligamentous injury). Researchers also detected 96.4% (27 of 28) cervical spine injuries that were clinically insignificant (defined as injuries that do not require stabilization or specialized treatment and are unlikely to cause any long-term problems).
Ian Stiell, MD, MSc, FRCPC
Original/Primary Reference
Validation Reference
Additional References
Why to Use
There are more than 8 million patients who present annually to emergency departments in the United States for evaluation of head trauma. The vast majority of these patients have minor head trauma that will not require specialized or neurosurgical treatment, but rates of CT imaging of the head more than doubled from 1995 to 2007. The CCHR is a well-validated clinical decision aid that allows clinicians to safely rule out the presence of intracranial injuries that would require neurosurgical intervention, without the need for CT imaging.
When to Use
Next Steps
Daniel Runde, MD
The CCHR has been validated in multiple settings and has been consistently demonstrated to be 100% sensitive for detecting injuries that will require neurosurgery. Depending on practice environment, it may not be considered acceptable to miss any intracranial injuries, regardless of whether they would have required intervention.
Clinicians may want to consider applying the New Orleans criteria for head trauma, as at least 1 trial has found them to be more sensitive than the CCHR for detecting clinically significant intracranial injuries (99.4% vs 87.3%), although with markedly decreased specificity (5.6% vs 39.7%). There are other trials in which the CCHR was found to be more sensitive than the New Orleans criteria for detecting clinically important brain injuries.
The validation study (Stiell 2005) included a convenience sample of 2702 patients aged ≥ 16 years, who presented to 9 Canadian emergency departments with blunt head trauma resulting in witnessed loss of consciousness, disorientation, or definite amnesia and a Glasglow coma scale score of 13 to 15. Within the sample, 8.5% (231 of 2707) of the patients had a clinically important brain injury, and 1.5% (41 of 2707) of the patients had an injury that required neurosurgical intervention. In the validation trial, the CCHR was 100% sensitive for both clinically important brain injuries and injuries that required neurosurgical intervention, and was 76.3% and 50.6% specific, respectively, for these injuries.
Subsequent studies have all found the CCHR to be 100% sensitive for identifying injuries that require neurosurgical intervention. Applying the CCHR would allow clinicians to safely reduce head CT imaging by around 30% (range of 6%-40%, with most studies showing an estimated 30% reduction). In most studies, 7% to 10% of patients had positive CT scans for brain injuries that were considered “clinically important,” but typically, < 2% of patients required neurosurgical intervention. The high-risk criteria have consistently shown 100% sensitivity for ruling out the latter group.
Ian Stiell, MD, MSc, FRCPC
Original/Primary Reference
Stiell IG, Wells GA, Vandemheen K, et al. The Canadian CT Head Rule for patients with minor head injury. Lancet. 2001;357(9266):1391-1396.
Validation Reference
Stiell IG, Clement CM, Rowe BH, et al. Comparison of the Canadian CT Head Rule and the New Orleans Criteria in patients with minor head injury. JAMA. 2005;294(12):1511-1518.
Other References
Points to keep in mind:
Why to Use
The NEXUS chest decision instrument can help reduce unnecessary imaging by identifying patients at low risk of thoracic injury. This reduces radiation exposure and provides faster evaluation for emergency clinicians and their patients. This allows emergency clinicians to focus on treatment, evaluation of other injuries or problems, or education and reassurance.
When to Use
The NEXUS chest decision instrument can be used in the following patient populations:
Next Steps
Graham Walker, MD
The NEXUS chest decision instrument was developed by the NEXUS study group, with the goal of reducing unnecessary chest imaging in blunt trauma patients.
Derivation
The researchers first developed the rule prospectively in a study of 2628 patients at 3 trauma centers, using 12 clinical criteria. They defined significant intrathoracic injury as: pneumothorax, hemothorax, aortic or other great vessel injury, 2 or more rib fractures, ruptured diaphragm, sternal fracture, and pulmonary contusion.
Validation
The original study was subsequently validated in a study of 9905 patients. Significant intrathoracic injury was reclassified more specifically, with an expert panel weighing diagnoses to group them as major clinical significance, minor clinical significance, or no clinical significance. (See the “Definitions” section.)
To address imaging bias, the researchers at-tempted to contact all patients who did not receive imaging or had negative imaging. Among the 433 patients who 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
Minor Clinical Significance
No Clinical Significance
The NEXUS chest decision instrument for blunt chest trauma applies to patients in the emergency department who are aged ≥ 15 years and have had blunt trauma within the past 24 hours. It may be used sequentially with the NEXUS chest CT decision instrument.
Robert Rodriguez, MD
Original/Primary Reference
Validation References
Why to Use
Patients who do not have criteria for imaging according to the Ottawa ankle rule are highly unlikely to have a clinically significant fracture and do not need plain radiographs. As a result, application of the Ottawa ankle rule can reduce the number of unnecessary radiographs by as much as 25% to 30%, improving patient flow in the emergency department.
When to Use
Next Steps
Management
Calvin Hwang, MD
Patients who fulfill none of the Ottawa ankle rule criteria do not need an ankle or foot x-ray. Patients who fulfill either the foot or ankle criteria need an x-ray of the respective body part. Many experts would consider this score “one directional.” Because the rule is sensitive and not specific, it provides a clear guide of which patients do not need x-ray if all criteria are met; however, if a patient fails the criteria, the need for x-ray can be left to clinical judgment.
The original derivation study in 1992 included nonpregnant patients aged > 18 years who presented to Ottawa civic and general hospitals with a new injury < 10 days old. The initial pilot study included 155 patients, while the full-scale study included 750 patients. Any fracture that was not an avulsion of ≤ 3 mm was considered a clinically significant fracture. This resulted in the initial criteria: aged ≥ 55 years, inability to bear weight immediately after the injury and for 4 steps in the emergency department, or bone tenderness at the posterior edge or tip of either malleolus for the ankle. For the foot, criteria included pain in the midfoot and bone tenderness at the navicular bone, cuboid, or the base of the fifth metatarsal (Stiell 1992).
Further validation and refinement was completed in 1993, through a prospective study of 1032 patients in the validation and refinement phase of the study with 121 clinically significant fractures. The rules were further refined by removing the age cutoff from the ankle rule and cuboid tenderness from the foot rule, but the weight-bearing criterion was added to the foot rule. Sensitivity of the refined rules for both foot and ankle fractures was 100%, and ankle specificity increased to 41% and foot specificity to 79% (Stiell 1993).
An additional 453 patients were prospectively enrolled in the second phase of the study, where the refined rules were validated, yielding a sensitivity of 100% for both ankle and midfoot fractures.
A study of 670 children aged 2 to 16 years at 2 separate sites found that the Ottawa ankle rule again had a sensitivity of 100% for both clinically significant ankle and midfoot fractures. This study also found that ankle x-rays could have been reduced by 16% and foot x-rays by 29% if the rules were in use at the time of the study. Subsequent meta-analysis of the Ottawa ankle rule in children found 12 studies with 3130 patients and 671 fractures, with a pooled sensitivity of 98.5% and an overall reduction in x-ray utilization by 24.8%.
Ian Stiell, MD, MSc, FRCPC
Original/Primary Reference
Validation Reference
Other References
Why to Use
Patients with knee trauma who do not meet the criteria for imaging according to the Ottawa knee rule are highly unlikely to have a clinically significant fracture and do not need plain radiographs. As a result, application of the Ottawa knee rule can cut down on the number of unnecessary radiographs by 20% to 30%. This has proven to be cost-effective for patients without reducing quality of care (Nichol 1999).
When to Use
Next Steps
Calvin Hwang, MD
Tips and precautions from the creators at the University of Ottawa:
Patients who do not have any of the Ottawa knee rule criteria present do not need an x-ray. If 1 or more of the conditions are met, then an x-ray is recommended.
Many experts would consider this score “one directional.” Because the rule is sensitive and not specific, it provides a clear guide to which patients do not need x-ray if all criteria are met; however, if a patient fails the criteria, the need for x-ray can be left to clinical judgment.
The original derivation study by Stiell et al was done in 1995 and included nonpregnant patients aged > 18 years who presented to Ottawa civic and general hospitals with a new injury that is < 7 days old and resulted from acute blunt trauma to the knee. The study enrolled 1054 subjects, of whom 68 had fractures, with 66 of the fractures deemed to be clinically significant (ie, not a simple avulsion fragment of < 5 mm in breadth without associated complete tendon or ligament disruption). Using recursive-partitioning techniques, the authors derived the 5 variables of the decision rule. When applied to the study population, their decision rule had sensitivity of 100% and specificity of 54% for identifying fractures and would have led to a 28% relative reduction in x-ray utilization.
Stiell et al prospectively validated their decision rule in the same patient population. They performed telephone follow-up 14 days after the patient's emergency department visit to determine the possibility of a missed fracture. Sensitivity of the decision rule was again 100%, identifying 63 clinically important fractures out of 1096 patients. Specificity was similar to the derivation study at 49%, and there was a 28% relative reduction in x-ray utilization.
Stiell et al also prospectively implemented the decision rule in different teaching and community emergency departments. They found a relative reduction in x-ray usage of 26.4%, while maintaining a sensitivity of 100% for detecting 58 knee fractures out of 3907 patients, and a specificity of 48%. Moreover, there was a significant reduction in time to discharge and total medical charges in patients who did not get an x-ray.
The Ottawa knee rule has also been prospectively validated in populations outside of Canada. Two studies, 1 in Spain and another in the United States, found that the Ottawa knee rule had a sensitivity of 100% and 98%, specificity of 52% and 19%, and a reduction in x-ray usage by 49% and 17%.
The rule was applied to children aged 2 to 16 years in a prospective, multicenter validation study in 2003. That study found the decision rule to be 100% sensitive in finding 70 fractures out of 750 children, with a specificity of 42.8% and a potential reduction in x-ray usage by 31.2%.
The Ottawa knee rule has been compared to the Pittsburgh decision rule, another well-validated clinical decision rule. A cross-sectional comparison of the 2 rules showed that both had sensitivities of 86%, although the Pittsburgh decision rule was significantly more specific. However, this study only included patients aged 18 to 79 years and excluded pediatric patients.
Ian Stiell, MD, MSc, FRCPC
Original/Primary Reference
Validation References
Other References
Why to Use
Early initiation of massive transfusion has been shown to improve survival in critical trauma patients. The ABC score reduces delay in determining need for massive transfusion in a trauma patient, while also providing consistency in appropriateness of transfusion by minimizing practice variations among clinicians.
When to Use
The ABC score should be used in trauma patients for whom massive transfusion is being considered.
Next Steps
Cullen Clark, MD
Activation of a massive transfusion protocol (MTP) triggers the release of packed red blood cells, platelets, and fresh frozen plasma at frequent intervals until the MTP is called off.
The original study (Nunez 2009) was a retrospective review performed at Vanderbilt University Medical Center using the institution’s trauma registry. The study population was derived from all trauma patients (n = 596) admitted to the hospital over the course of a year. Patients included were Level I trauma activations transported directly from the scene who received any blood transfusion while admitted. The ABC score was created by the trauma faculty based on clinical experience, and logistic regression modeling was used to determine the odds ratio of requiring MTP for each parameter of the score.
Of the total cohort, 76 patients (12%) required massive transfusion in the first 24 hours. Based on the number of patients who received massive transfusion and were identified using the ABC score, researchers found the best cutoff to be a score ≥ 2, giving a sensitivity of 75% and specificity of 86%. Compared with the Trauma Associated Severe Hemorrhage scoring system and the McLaughlin score using the same dataset, the ABC score was shown to be the most accurate in predicting need for MTP.
The validation study (Cotton 2010) was a retrospective review using trauma databases from 3 institutions: Vanderbilt University Medical Center, Johns Hopkins Hospital, and Parkland Memorial Hospital. The inclusion and exclusion criteria were the same as the original study. The study population was again derived from trauma patients admitted to 1 of the 3 hospitals over the course of a year. The sample size of the study was 1604, including 586 patients from the original study. There was signifi-cant variation in demographics between the centers involved, but the massive transfusion rate in the first 24 hours of admission was similar (approximately 15%) for each hospital. There was little variability between each institution’s cohort in the percentage of patients correctly classified as meeting the ABC score cutoff for MTP, among those who received massive transfusions. For each institution, sensitivity ranged from 76% to 90% and specificity ranged from 67% to 87%. Negative predictive value was 97% and positive predictive value was 55%.
The validation study also measured the accuracy of the ABC score at predicting need for massive transfusion in the first 6 hours of admission. Sensitivity was 87% and specificity was 82% with slightly higher negative predictive value (98%) and lower positive predictive value (55%) compared to prediction of massive transfusion need in the first 24 hours.
The major limitation to both studies was their retrospective nature. A prospective trial is ongoing. The study shows a novel means of quickly predicting the need for massive transfusion based on objective measures. While there is good data showing that early activation of MTP improves survival rates in severely injured trauma patients, a prospective study will be necessary to determine if utilization of the ABC score improves patient outcomes.
Bryan Cotton, MD
Original/Primary Reference
Validation References
Additional References
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