Xenon Ventilation-Perfusion Lung Scans

To the Editor.—  Schall and associates have emphasized the importance of early and accurate diagnosis of inhalation injury and have advocated the use of xenon ventilation-perfusion lung scans to achieve this end. Their data, however, do require careful interpretation. Contrary to the authors' claims in the text (their Table 2), patients with abnormal scans do not have a higher incidence of closed space vs open space burns. Three patients with intraoral burns and four patients with carbonaceous sputum, signs almost pathognomonic of inhalation injury, had normal scans. For reasons not immediately evident, the authors have equated the presence of an early normal xenon perfusion scan to the absence of inhalation injury and a classification that we believe is inappropriate. We have revised their Table.In effect, 4+23, or 27 patients had clinical evidence of an inhalation injury, and the xenon scan substantiated it in 85% (23 of 27) of patients.