Frequently Asked Questions
- What is our overall research aim?
We are working to develop an effective screening tool for pediatric abusive head trauma (AHT).
- What makes a screening tool effective?
An effective screening tool is simple, safe, inexpensive, reliable, readily accessible, evidence-based, and highly sensitive—to minimize missed cases.
- What steps have been taken to achieve this overall research aim? PediBIRN investigators have conducted sequential, prospective, multicenter studies to derive and to validate an AHT screening tool that demonstrates all of these qualities. This new AHT screening tool comes in the form of a clinical prediction or decision tool.
- What is a clinical prediction or decision rule? A clinical prediction rule is an evidence-based tool that measures and then combines the predictive contributions of multiple clinical variables, test results or findings to estimate the probability of a diagnosis, prognosis, or therapeutic response in an individual patient. A clinical prediction rule rises to the level of a clinical decision rule (CDR) if and when physicians use the rule to guide a specific clinical decision.
- How are CDRs used in clinical practice? Clinical decision rules are most likely to be useful in situations in which clinical decision making is complex, when clinical stakes are high, or when there are opportunities to achieve cost-savings without compromising patient care.
- Do we need a CDR for pediatric AHT? Yes. Physicians have demonstrated bias and disparities in their decisions to launch or forgo child abuse evaluations in their young patients hospitalized with acute head trauma. More importantly, doctors have “missed” or “misdiagnosed” cases of AHT masquerading as accidental trauma. Patients whose AHT is missed or misdiagnosed are at significant risk for additional inflicted injuries.
- When will doctors apply the CDR? At or near the time of a young child’s PICU admission for treatment of their acute, closed head trauma.
- How will doctors apply the CDR? To minimize missed cases of AHT, doctors will be encouraged to apply the CDR as clinical decision rule that will provide specific practice recommendations. Its recommendations should be considered directive, but not mandatory.
- What are the CDR’s specific recommendations? The CDR reads as follows: “To minimize missed cases, every acutely head-injured infant or young child hospitalized for intensive care who presents with one or more of these four predictor variables should be considered “high risk” and thoroughly evaluated for abuse  acute respiratory compromise;  bruising of the torso, ear(s) or neck;  bilateral or interhemispheric subdural hemorrhage(s) or fluid collection(s); and  any skull fracture(s) other than an isolated, unilateral, non-diastatic, linear, parietal skull fracture.”
- What about patients who present for PICU admission with none of the CDR’s four predictor variables? The CDR makes no specific recommendations regarding abuse evaluations in these “low risk” patients. For these patients, doctors should launch an abuse evaluation only if and when their clinical intuition tells them to do so.
- What are the screening tool’s sensitivity and specificity? Its sensitivity is high. Applied accurately and consistently, the CDR would have correctly identified (categorized as “high risk”) 96% of our derivation and validation study patients (N=500) who met a priori criteria for AHT, 98% of patients who were ultimately diagnosed with AHT, and 99% of patients whose completed skeletal survey and/or retinal examination revealed additional findings of abuse. The CDR’s specificity was mediocre. Only 46% of “high risk” patients were ultimately diagnosed with AHT.
- Should we be using an AHT screening tool whose specificity in only 46%? When doctors explain that their decisions to launch a workup for abuse are based on the recommendation of a validated AHT screening tool designed specifically to cast a very broad net, and that many abuse evaluations reveal no corroborating findings of abuse, some parents and caregivers will feel less specifically targeted for additional scrutiny.
- Can doctors apply the screening tool as a clinical prediction rule? Yes. Doctors can use the AHT screening tool to calculate an evidence-based, patient-specific, estimate of the probability of abuse based on their patient’s unique combination of the CDR’s four predictor variables. We call this funtionality our AHT Probability Calculator.
- Are the prediction tool’s patient-specific estimates of abuse probability good predictors of the results of abuse evaluations? Yes. The correlation between its patient-specific estimates of abuse probability and the overall diagnostic yields of patients’ completed abuse evaluations was positive and very strong (Pearson R =.708).
- What will be the CDR’s impact on AHT screening accuracy when doctors begin to apply it in PICU settings? We don’t know. Many obstacles could limit physicians’ application of the CDR and/or their acceptance of its recommendations. Measuring its real impact on AHT screening accuracy is the overall goal of our current "CDR Implementation Trial.”
- What could be the CDR’s potential clinical impact? Our theoretical analyses suggest that—applied accurately and consistently—the CDR could  increase AHT detection from 87% to 96% (P <.001),  increase the overall diagnostic yield of completed abuse evaluations (skeletal surveys and retinal exams) from 49% to 56% (P =.058), and  decrease total abuse evaluations from 78% to 76% (P =.408).
- What’s next for PediBIRN? Having derived and validated an effective CDR, we are ready to see how well it performs as an AHT screening tool in actual PICU settings. This is the purpose of this "CDR Implementation Trial".
- How will you do this? PediBIRN investigators will conduct a randomized clinical trial at eight U.S. PICUs randomly assigned to intervention (n=4) or control conditions (n=4). Our “CDR Implementation Trial” will compare AHT screening accuracy after the deployment of active, multifaceted, CDR implementation strategies designed to promote CDR acceptance and application at the four intervention sites.
- What are your primary hypotheses for this ‘CDR implementation trial’? We hypothesize that, in comparison to control sites, deployment of our CDR implementation strategies at the intervention sites will result in higher percentages of “high risk” patients evaluated thoroughly for abuse, and lower percentages of “low risk” patients evaluated (even partially) for abuse.
- What PICU sites will participate in the ‘CDR implementation trial’? Texas Children’s Hospital, Primary Children’s Hospital, Children’s Mercy Hospital, Connecticut Children’s Medical Center, The University of Texas Health Sciences Center at San Antonio, The Children’s Hospital at Richmond, Wesley Medical Center, and The Children’s Hospital of Omaha.
- Where can I learn more about the PediBIRN screening tool for AHT? The most relevant, peer-reviewed references are…
- Hymel KP, Willson DF, Boos SC, Pullin DA, Homa K, Lorenz DJ, et al, for the PediBIRN investigators. Derivation of a clinical prediction rule for pediatric abusive head trauma. Pediatr Crit Care Med 2013;14:210-220
- Hymel KP, Armijo-Garcia V, Foster R, Frazier TN, Stoiko M, Christie LM, et al, for the PediBIRN investigators. Validation of a clinical prediction rule for pediatric abusive head trauma. Pediatrics 2014;134(6):e1537-e1544
- Hymel KP, Herman BE, Narang SK, Graf JM, Frazier TN, Stoiko M, et al, for the PediBIRN investigators. Potential impact of a validated screening tool for pediatric abusive head trauma. J Pediatr 2015;167:1375-1381