SGEM#519: Don’t Let Pediatric Pulmonary Embolism Leave You Breathless

Reference: Ellison AM, et al. PERC-Peds rule for bedside exclusion of pulmonary embolism without radiation in children in the USA (BEEPER): a multicentre, prospective, observational, diagnostic accuracy study. Lancet Respir Med. July 2026. Date: August 13, 2026 Dr. Lauren Westafer Guest Skeptic: Dr. Lauren Westafer is an Associate Professor in the Department of Emergency Medicine at the University of Massachusetts Medical School, Baystate. She is the co-founder of FOAMcast and a researcher in pulmonary embolism and implementation science. Dr. Westafer serves as the research methodology editor for Annals of Emergency Medicine. Check out this FOAMcast episode on PERC-Peds as well! Case: A 15-year-old previously healthy teenage girl presents to the emergency department (ED) with pleuritic chest pain and feeling short of breath after a recent viral illness. On your exam, she is comfortable, has a heart rate of 88 beats/min and oxygen saturation of 99% throughout the visit. She denies hemoptysis, unilateral leg swelling, recent surgery, estrogen exposure, or previous venous thromboembolism. You are working with a trainee who gives you a fantastic differential diagnosis for the chief complaint, which includes a pulmonary embolism. The trainee thinks pulmonary embolism is unlikely and asks, “I have heard of PERC and Wells in adults, but can we apply these to pediatric patients?” Background: Pulmonary embolism (PE) represents a broad spectrum of disease with clinical history and presenting features that overlap with many other disease processes. Historically, venous thromboembolism (VTE) has been thought to be quite uncommon in pediatric patients, absent malignancy or indwelling lines. The gold standard diagnostic modality for PE, CT pulmonary angiography (CTPA), carries additional risk to children due to ionizing radiation. In adult patients, the epidemiology of VTE, validated diagnostic algorithms, and D-dimer testing can safely exclude PE in many patients without the need for CTPA. Previously, there were no prospectively validated bedside tools to identify children in whom we could feel comfortable safely stopping PE testing. Some clinicians extrapolated from adult Pulmonary Embolism Rule-Out Criteria (PERC). In adults, PERC can be used to exclude PE without need for additional blood work or imaging studies. The use and accuracy of D-dimer test to exclude PE in children is also unclear. The new PERC-Peds rule is a modified version of PERC that was created using retrospective data. There are 8 criteria. Many criteria are similar between the adult and pediatric PERC but there are some notable differences. Obviously, for children, PERC-peds has no age<50 criterion. Also, because of differences in vital signs in pediatric patients, the heart rate is age-adjusted rather than using a fixed HR >100. Rather than relying only on unilateral leg swelling, PERC-Peds asks whether deep vein thrombosis (DVT) is clinically suspected. There’s also a small change regarding the definition for surgery, which is a procedure requiring endotracheal intubation within the past 30 days. Clinical Question: In children aged 4-17 years in whom pulmonary embolism is being tested for or strongly considered, can a negative PERC-Peds rule safely exclude PE or proximal DVT within 45 days without laboratory testing or pulmonary vascular imaging? Reference: Ellison AM, et al. PERC-Peds rule for bedside exclusion of pulmonary embolism without radiation in children in the USA (BEEPER): a multicentre, prospective, observational, diagnostic accuracy study. Lancet Respir Med. July 2026. Population: Children aged 4-17 years at 21 pediatric EDs in the United States who had PE testing ordered (included D-dimer, CTPA, ventilation perfusion scan, magnetic resonance angiography, or other pulmonary vascular imaging) or in whom the senior clinician strongly considered PE (this could be when a D-dimer or CTPA were ordered or cancelled or there was an open verbal discussion about the possibility of ordering one of those tests but decided against it). Exclusion: Known pregnancy, current anticoagulation for VTE, intoxication, incarceration, inability to obtain consent/assent, and inability to complete 45-day contact Intervention: PERC-Peds Comparison: None Outcome: Performance of the PERC-Peds rule Primary: Safe exclusion of PE or proximal DVT, defined a priori as the upper bound of the 95% confidence interval for the false-negative rate not exceeding 1.5%. Secondary: Sensitivity, specificity, predictive values, likelihood ratios, inter-rater reliability, D-dimer performance, and potential reduction in CTPA use Trial: Multicentre, prospective, observational diagnostic accuracy study Authors’ Conclusions: “In this multicentre, prospective, observational, diagnostic accuracy study of children with suspected pulmonary embolism in the emergency department, we found a 6·3% prevalence of pulmonary embolism or proximal DVT; in this population, the PERC-Peds negative rule can safely rule out pulmonary embolism. Use of PERC-Peds might reduce low-value diagnostic testing for pulmonary embolism in children and adolescents.” Quality Checklist for A Diagnostic Study: The clinical problem is well defined. Yes The study population represents the target population that would normally be tested for the condition (ie no spectrum bias). Yes The study population included or focused on those in the ED. Yes The study patients were recruited consecutively (ie no selection bias). Unsure The diagnostic evaluation was sufficiently comprehensive and applied equally to all patients (ie no evidence of verification bias). No All diagnostic criteria were explicit, valid and reproducible (ie no incorporation bias). Yes The reference standard was appropriate (id no imperfect gold-standard bias). Yes All undiagnosed patients underwent sufficiently long and comprehensive follow-up (ie no double gold-standard bias) Yes The likelihood ratio(s) of the test(s) in question is presented or can be calculated from the information provided. Yes The precision of the measure of diagnostic performance is satisfactory. Yes Who funded the trial? National Institutes of Health. Did the authors declare conflicts of interest? At least one author, T Charles Casper, reported payments to his institution. Results: From July 2020 through September 2024, 4,039 children were enrolled. The median age was 15 years (IQR 13-16), 64% were female, and 17% were younger than 12 years. A final VTE outcome was adjudicated for 4,011, and 3,988 had complete PERC-Peds data for the diagnostic accuracy analysis. Among the adjudicated cohort, 254 children (6%) met the criterion standard: 122 had PE only 56 had PE plus DVT 76 had isolated proximal DVT. The false negative rate was 0.1% (95% CI 0.0-0.8). Below the threshold of 1.5% they had set at the beginning of the trial. PERC-Peds was negative in 734 of 3,988 children (18.4%). But there was one false negative. One child with a negative rule was adjudicated as having PE. This was a 16-year-old female with cough, recent positive SARS-CoV-2 test, chest pain, dyspnea. But she also had normal vital signs and a normal D-dimer test. She had a CTPA ordered that had a filling defect in a peripheral pulmonary arterial branch of the left lower lobe. Key Results: The PERC-Peds rule had high sensitivity and a very low false-negative rate, but low specificity. Apply it carefully as indiscriminate use could increase downstream testing and potentially unnecessary imaging. Verification Bias: This is sometimes called work-up bias and can occur when only some participants receive the definitive reference-standard test (often those who appear higher risk) while the remainder are classified using a less intensive method. This can make a diagnostic test appear more accurate because disease is more likely to be detected in test-positive or clinically concerning patients, while disease in lower-risk, untested patients may be missed. In this study, pulmonary vascular imaging was performed in only around a third (36.6%) of participants, and all diagnostic testing was left to the treating clinician. Children with concerning symptoms, abnormal vital signs, or other risk factors were more likely to undergo imaging, whereas lower-risk or PERC-Peds-negative children were considered disease-free based on medical-record review and 45-day follow-up rather than direct imaging. An occult PE that caused no return visit or diagnosis during follow-up could therefore have been missed, potentially inflating sensitivity and lowering the observed false-negative rate. The authors did take meaningful steps to reduce this bias. The PERC-Peds variables were collected prospectively but were not used as a mandated clinical management pathway, all adjudicated participants had complete 45-day follow-up, and an independent committee reviewed imaging, follow-up responses, and outside records. This makes the study stronger than one in which un-imaged patients simply were assumed not to have PE, but follow-up is still not equivalent to applying the same definitive imaging reference standard to everyone. Given the harms of imaging thousands of children solely for research, this was a pragmatic and ethically reasonable compromise, but some residual partial verification bias remains. PE and Proximal DVT: The study’s criterion standard was broader than pulmonary embolism alone. A patient was considered positive if they developed either imaging-confirmed PE or proximal DVT within 45 days. Of the 254 patients classified as having venous thromboembolism, 76 (~30%) had proximal DVT without a verified PE. Among those 76, 42 had a negative CTPA and 33 never underwent pulmonary vascular imaging. ...