Clinical charts, autopsy records, and slides of the larynx, trachea, and bronchi in 172 cases of newborn infants with respiratory distress syndrome (RDS) were reviewed for acute lesions induced by endotracheal intubation. Mild lesions (mucosal or submucosal necrosis) were seen in 63.3% and relatively severe lesions showing inflammatory changes in 15.8% of the cases. No lesions were seen in the remaining cases. Vocal cords with or without the subglottic region of larynx and trachea were the commonest lesion sites. Lesion severity was directly related to duration of intubation and subsequent bacterial infection. In seven (4.3%) cases Pseudomonas pneumonia with or without septicemia extending from acute diffuse laryngotracheobronchitis was a major factor in infant death. Comparable focal lesions in RDS survivors may result in residual permanent damage to upper respiratory tract. Endotracheal intubation with posi¬ tive pressure mechanical venti¬ lation is now frequently used in the management of severe cases of res¬ piratory distress syndrome (RDS).1 The pathological features of lesions induced by endotracheal intubation in adults.-' and in experimental ani¬ mals4 has been adequately described. However, only brief descriptions of acute lesions of the larynx, trachea, and bronchi in intubated newborn in¬ fants are available in the literature.59It is the purpose of this paper to de¬ scribe and analyze these lesions seen at autopsy on RDS patients who died within seven days of birth and to dis¬ cuss their role in the mortality of some patients with RDS and their possible implications for future mor¬ bidity in the survivors.
Materials and MethodsClinical charts, autopsy protocols, and slides from all patients dying of RDS dur¬ ing the period 1961 to 1970 were reviewed. A total of 1,250 cases of patients whose conditions were clinically diagnosed as Hospital during this period. Out of 220 pa¬ tients dying within seven days with defi¬ nite histologie evidence of RDS, 48 cases were excluded because of inadequacy of data, leaving a total of 172 cases for the present study. At least one slide each of a longitudinal section of the larynx and cross sections of the trachea and mainstem bronchi were available in these cases.Types of Lesions.-The lesions noted in the slides of larynx, trachea, and bronchi were classified as follows in increasing or¬ der of severity: type 1, mucosal necrosis (Fig 1); type 2, mucosal and submucosal necrosis (Fig 2); and type 3, mucosal and submucosal necrosis with mild to moderate inflammation (3m) (Fig 3) or severe in¬ flammation (3s) (Fig 4 and 5). Other changes, such as edema, vascular engorge¬ ment, and hemorrhage, were also noted. In assigning cases to various types described above, the severest lesion in each case, seen in either the larynx, trachea, or bronchi, was considered. The distribution of the lesions, ie, whether focal or diffuse, was also assessed. Reports of bacterial cul¬ tures taken at autopsy from the trachea, lungs, and heart blood or spleen were ob¬ tained from the autopsy prot...