The effects of suctioning techniques on the distal tracheal mucosa in intubated low birth weight infants.

Microscopic pathology of the distal trachea at autopsy was retrospectively reviewed in 51 low birth weight infants (less than 1250 g). Twenty-six patients from 1977 who had nasal and/or orotracheal intubation and who underwent suctioning with uncontrolled deep suctioning technique were compared to 25 patients from 1980 who had orotracheal intubation with suctioning to the tube tip only. Clinical diagnoses, duration of intubation and number of intubations were correlated to degree of distal tracheal injury: absent (normal epithelium), mild (focal epithelial loss), moderate (diffuse epithelial loss/some inflammation), or severe (submucosal ulceration/squamous metaplasia). From 1977 to 1980 the mortality rate, mean gestational age and mean birth weight all decreased by 20% (P less than 0.05), 1.1 week (P less than 0.05) and 118 g (P less than 0.01) in both autopsied and non-autopsied infants. In 1977, 15 of 26 autopsies (58%) revealed mild (6), moderate (5) or severe (4) pathology. The mean duration of intubation was 71.3, 11.8, and 265 h. respectively. No history of intubation was obtained in two patients with mild injury. No significant tracheal pathology was seen in 11 patients (42%) in 1977. In 1980, fewer patients, 10 of 24 autopsies (42%), revealed mild (3), moderate (4) or severe (3) pathology. The mean duration of intubation was 19.3, 318.3 and 1391.3 h, respectively. One patient with no history of intubation had mild tracheal injury. No significant tracheal pathology was seen in 15 patients (58%) in 1980. The diagnoses of hyaline membrane disease, anemia, hyperbilirubinemia and coagulation disorder were seen more frequently in patients with moderate and severe tracheal pathology both in 1977 and 1980. Despite factors which should lead to greater tracheal injury--longer duration of intubation, lower birth weights and younger gestational age--less tracheal injury was seen in infants undergoing careful suctioning techniques. Clinical implications for the low birth weight neonate are discussed.