Discussion
Pediatric trauma patients encompass a population particularly prone to radiation exposure, given their increased susceptibility to ionizing radiation, and often receive care at non-pediatric hospitals which may not have attention to pediatric protocol dosing. Given the broad acceptance of non-operative management in trauma, there is a reasonable concern whether such widespread use of advanced imaging is warranted in all pediatric patients, particularly since surgical decision-making and interventions are now primarily driven by the physiologic status of the patients. Specifically, studies have shown that CT scans rarely influence the decision for operative intervention in trauma patients such as those who have sustained blunt abdominal trauma [
20]. In patients who have been managed non-operatively, CT scans have shown limited value in directing further management and follow-up [
21].
While an increase in imaging with a higher activation status appears intuitive, the CT dose factor reflecting the 10-fold CT dose increase between general trauma consults and general stats and a similar near 12-fold increase between general consults and NAT stats are both completely unexpected and grossly exceeded our expectations. A National Academy of Science report has estimated that children aged 15 and below have a 40% increase in cancer rate with exposures in the range of 10 to 20 mSv [
22]. Twenty-one percent of our trauma alerts and stats received doses within this range for a
single trauma evaluation which is a very important baseline determination for future epidemiologic analysis. Furthermore, children with multiple trauma evaluations would be at even higher risk over time. The sharp increase in radiation exposure with activation status may be a result of (i) a higher index of suspicion in higher activation statuses, (ii) imaging decisions based on the presumption of injuries by mechanisms, and (iii) the pressure to identify all injuries expeditiously in the initial trauma evaluation.
Identifying the actual radiation doses are important to determine the actual exposures our population of children is receiving. Prior trauma studies have analyzed average radiation exposure
based on estimations averaged across all levels of traumas extrapolated from the literature. The largest study queried the NTDB in 2010 included 84,863 patients and showed the mean effective CT radiation dose to be 12.0 mSv
15; however, the radiation doses were not based on actual radiologic records and were actually extrapolated from the literature. Also with such huge numbers of traumas that are not differentiated out by level of severity, it is easy to recognize that the simple trauma consults or low grade traumas would outnumber the more severe ones and thus power this finding to underestimate the amount of imaging a moderate or severe trauma work-up needs. Clearly with one trauma being 12 mSV, then, a child with just one trauma evaluation would potentially be in the concerning zone of cumulative radiation exposure. Our study shows that the real exposure is much higher for a stat activation so averaging all trauma activations may not give a clear accounting of which traumas actually receive a concerning amount of radiation. The National Survey of Children’s Health (NSCH) has reported that 22.6% of children have over two serious trauma evaluations so the impact of higher radiation dosing on top of multiple trauma evaluations has serious epidemiologic consequences [
23]. Additionally, the study [
15] excluded patients who were not imaged within the first 24 h of admission and did not account for (i) those who were imaged subsequently and (ii) the less worrisome traumas who were not imaged at all, as opposed to our study which included the entirety of imaging for all patients during the full encounter including OSH imaging.
The subset analysis of NAT patients in our study provided a focus on a less studied patient group. A recent study has shown that 6.2 out of 100,000 children under the age of 18 have endured severe physical abuse [
24]. Furthermore, this rate is nine times higher in patients under the age of one [
24]. Since these patients suffer polytrauma, they are particularly prone to more frequent trauma evaluations and more extensive imaging compared to the corresponding cohort in the same activation status. The reason for extensive imaging appears bipartite. First, given the higher likelihood of multiple injuries, the pre-existing high level of suspicion in trauma patients is further justified. Second, positive imaging findings serve as evidentiary proof in investigations once legal action is pursued. While a recent study has stressed the importance of surgical evaluations in non-accidental traumas [
25], a detailed analysis of radiation exposure in this subset has yet to be conducted.
Additionally, it is important to understand the significance of the skeletal surveys performed in NAT patients which utilizes 23–24 plain films. The amount of exposure is diminishingly small since each plain film of the abdomen/pelvis accounts for a mean effective dose of only 0.015 mSv in a newborn to 0.05 mSv in a 15-year-old [
26]. While X-ray scans impart significantly less radiation than CT scans, their high utilization demonstrates the comprehensive nature of imaging to prove a NAT case for legal intervention.
An advantage of our study was the inclusion of outside hospital (OSH) imaging which was uploaded to our imaging database. As a result, we were able to note the incidence of repeated imaging upon transfer and compare actual outside hospital radiation dosing with pediatric dosing at our pediatric center. Although overall and children’s hospital CT doses correlated with activation status, we found that OSH CT doses did not have a similar correlation. Instead, trauma alerts received the most radiation followed by consults and then trauma stats. Alerts may have received the most radiation as OSH physicians may have viewed them as a group of patients just stable enough to be managed without specialist consultation at a children’s hospital. As a result, they likely performed a complete work-up and later realized they needed to transfer the patients to a children’s hospital. Presumably, the lowest CT dose in the trauma stats group is likely related to the realization that the patient should not be managed at the OSH and required transfer soon after the initial images were obtained.
The redundancy in imaging upon transfer was also shown in a prior study in which a high incidence of repeated CT scans in transferred trauma patients along with higher hospitalization costs were reported [
27]. This is particularly concerning since the reason for re-imaging in these patients reflects the lack of coordination between hospitals and timely access to transferred imaging studies. ED/trauma staff must advocate for the establishment of timely communication between major trauma centers and outside hospitals to reduce the delivery of excess radiation.
Our study had the additional advantage of evaluating the full hospital stay as opposed to initial evaluations limited to the first 24 h. There is currently no data in the literature explicitly reflecting the propensity of repeated imaging of admitted trauma patients over the entire hospital stay. Our study showed that patients who received multiple CT scans as well as repeat full body plain film scans were often those who were hospitalized.
A prior study by Groner et al., [
28] has suggested that traumas worked up by an emergency medicine attending physician are less likely to receive excessive radiation compared to an on-call trauma surgery resident who has less experience and is not constantly present with the patient. While this study highlighted only moderate level traumas at the authors’ institution, such a model may benefit lower and higher activation statuses as well. As such, we advocate further education of surgical trainees and the new trauma model [
28] that proposes that trauma surgeons should play the role of consultants rather than primary responders. Our study highlights the importance of adherence to the principle of maintaining radiation exposure “as low as reasonably achievable” (ALARA) [
29]. The ALARA principles involve four cornerstones to decrease radiation dosimetry: (1) use weight-based protocols, (2) consider alternative non-radiating modalities, (3) use focused or limited-view studies when clinically appropriate, and (4) dissuade repeat CT studies.
These strategies advocate low-dose pediatric-specific protocols and other techniques such as flash CT, minimizing thin-cut CT imaging, utilizing “justification and optimization” determinations in granting CT requests (to avoid additional or unnecessary radiation exposure), and dedicated pediatric CT imaging services with pediatric-specific CT technologists to improve compliance with adjusted lower CT exposure parameters and lower estimated effective doses of radiation delivered to pediatric patients. These ALARA strategies have resulted in much greater compliance with pediatric dose-adjusted CT protocols and well-recognized reduced radiation exposure to patients.
The majority of pediatric trauma patients are managed at non-pediatric (adult) trauma hospitals, since children are quickly transported to the nearest hospital initially for evaluation and thus are exposed to twice the radiation dose that they would have been exposed to in a pediatric hospital with a pediatric CT imaging dose reduction protocol in effect [
30]. Moreover, in an age during which the paradigm of “pan-scanning” is common practice, we must enforce protocols to minimize radiation exposure in our patients. For this to occur, the entire multidisciplinary team including ED staff, pediatric/trauma surgeons, and radiologists must be on board.