RADS (Radiologist’s Score) for Smoke Inhalation Injury
Why Use
Currently, no single tool accurately and reliably risk-stratifies and prognosticates patients with smoke inhalation injury. Can be a useful adjunct to determine severity of inhalational injury to the lungs. A multicenter prospective cohort study to develop a scoring system for inhalation injury based on clinical, radiographic, bronchoscopic, and biochemical parameters is underway by the American Burn Association.
When to Use
Patients with suspected or diagnosed inhalation injury. Best used in conjunction with flexible bronchoscopy.
Formula
Pearls / Pitfalls
Score derived from sheep model and validated retrospectively in human cohorts, with limited validation in prospective human clinical trials. Requires assessment of each CT slice, which can be time-consuming. Higher RADS 24 hours after smoke inhalation seems to correlate with greater smoke exposure and severity of lung injury. Using chest CT in the evaluation of inhalation injury has limitations, including questionable optimal timing of CT and interpretation of abnormal CT findings in the setting of a negative bronchoscopy.
Management
Supportive treatment is the primary means of inhalation injury management, as there is very little in the way of pharmacologic treatment once the inhalation injury has occurred. Bronchoscopy can play a therapeutic role in airway clearance as necrotic tissue and eschar can form pseudomembranes, sloughing of mucosa, and bronchial obstruction. Other measures include intensive bronchial hygiene, including bronchodilators (e.g. inhaled β2 agonists), frequent chest physiotherapy, and early patient ambulation). Upper airway edema can progress, particularly over the first 24 hours after injury, necessitating intubation. If mechanical ventilation is required, a high frequency percussive mode of ventilation can be considered, as some studies have shown benefit to this patient population. A lung-protective, low tidal volume ventilation strategy (6-8 cc/kg of predicted body weight) is preferred in adults. Other supportive measures have been used with varied success, including prone positioning, extracorporeal membrane oxygenation (ECMO), inhaled anticoagulants (e.g. heparin, antithrombin), and inhaled N-acetylcysteine (NAC). Additionally, referral to a designated burn center should be considered if any inhalation injury is present, according to American Burn Association guidelines .
Critical Actions
As always, clinical judgment is paramount. Management decisions should not be made based solely on RADS.
Advice
Should be used with clinical history, examination, bronchoscopy, and arterial blood gas data to determine the full clinical picture.
More Information
Interpretation: RADS Risk >8 per slice 12.7x increased risk of composite endpoint (pneumonia, acute lung injury/ARDS, and death)