Early prediction of chronic lung disease by tracheal aspirate cytology in ventilated newborns

We assessed the specificity of squamous metaplasia in tracheal aspirates of 69 ventilated newborns (gestational age 25-41 weeks) between days 3 and 7 of life for prediction of chronic lung disease (CLD). CLD was diagnosed whe n the patient was still requiring ventilation or supplementary oxygen at th e postconceptional age of 36 weeks (or postnatal age of 28 days for babies born after 32 weeks gestation) and showed X-ray changes compatible with CLD . In the total population the presence of squamous metaplasia had a sensiti vity of 59% and a specificity of 74% for the early diagnosis of CLD. The co mbination of squamous metaplasia and very lon birth weight (VLBW) had a muc h higher specificity (94%), but a lower sensitivity (45%). Our results show that the presence of sqaumous metaplasia in VLBW babies during the Ist wee k of life predicts development of CLD with a specificity of 94% and may be helpful for entering patients into early treatment protocols or trials when a high risk population needs to be identified. as sensitivity of this appr oach is only 45%. further studies are needed to evaluate the predictive val ue of the combination of cytology with other markers in tracheal aspirate s pecimens. Conclusion The presence of squamous metaplasia in tracheal aspirates of VLB W babies between days 3 and 7 of life is significantly associated with the development of chronic lung disease. Simple microscopic evaluation of fresh tracheal aspirates enables us to identify patients at high risk of CLD at a very early stage.