Morphologic changes and prognosis of the respiratory tract epithelium in inhalation injury and their relationship with clinical manifestations

Abstract

Background: We set out to observe the morphologic changes and determine prognosis based on airway epithelial injury after inhalation injury of varying severity using a fiberbronchoscope and to explore the relationship between the severity of epithelial injury and its clinical manifestation.

Methods: Sixty burn patients with an inhalation injury underwent fiberoptic bronchoscopy. Morphologic changes of the airway epithelium were observed, and the inhalation injury was divided into 3 categories based on the severity of the epithelial injury: first-degree injury, in which the airway epithelium had slight hyperemia and edema; second-degree injury, in which obvious epithelial hyperemia and edema, epithelial erosion, or petechial hemorrhage was observes; and third-degree, in which the airway epithelium had necrosis and exfoliation. For all groups, chest radiographs were examined. The duration of ventilation was recorded.

Results: Among 60 patients, 16 (27%) had first-degree injury, 33 (55%) had second-degree injury, and 11 (18%) had third-degree injury. Among this last group, 4 patients with epithelial exfoliation had airway hemorrhage. In this study, 38 of 60 (63%) patients presented with abnormal findings on lung radiographs and 9 of 60 (15%) developed pulmonary infections. The duration of ventilation averaged 2 days for second-degree injury and 14 days for third-degree injury. The recovery times for first-, second-, and third-degree injury were 7, 16, and 29 days, respectively.

Conclusion: Fiberoptic bronchoscopy contributes to the accurate evaluation of tracheal epithelial injury severity. As the severity of inhalation injury increased, the clinical symptoms also increased. Severe complications (eg, bleeding and asphyxia caused by epithelial slough) may occur in patients with third-degree injury and should be closely observed by clinicians. The airway epithelium has a substantial potential for repair. Even if the airway epithelial injury is severe, the damaged epithelium will recover.