Pediatric ARDS continues to be a management challenge in the ICU with prolonged hospitalizations and high mortality. Thromboembolic pulmonary embolism and in situ pulmonary artery thrombosis might represent underappreciated thrombotic processes for a subset of these patients. Although well described in the adult literature, descriptions of pulmonary thromboses with pediatric ARDS are limited to case reports. However, many risk factors for pulmonary thromboses are present in children with ARDS (eg, coagulopathy, endothelial injury, central venous catheters, concomitant inflammatory diseases), suggesting a much higher incidence is plausible. Based on an interpretation of animal, pediatric, and adult data, we propose a diagnostic algorithm to facilitate a timely and accurate diagnosis. Observing an alveolar dead space fraction ≥ 0.25, or either a 50% increase in physiologic dead space/tidal volume or a central venous saturation ≤ 60% over 24 h, triggers the algorithm. Together with targeted heparin treatment and right ventricular afterload reduction, clinical outcomes might improve if this particular patient subgroup can be identified early. While anticoagulation is recommended in adults with confirmed pulmonary embolism and low early mortality risk, data for children are limited., Competing Interests: The authors have disclosed no conflicts of interest., (Copyright © 2019 by Daedalus Enterprises.)