Cytogenetic studies on peripheral blood cultures of neonates treated in an intensive unit

The possible causes of an increased rate of structural chromosomal aberrations and sister chromatid exchange in peripheral blood cultures of mechanically ventilated newborns in an intensive care unit were investigated. No cytogenetic abnormalities were found in low-birth-weight babies affected by hypoxia and acidosis during their first week of life. The rate of chromosome breakage and sister chromatid exchange was increased in blood cultures of neonates continuously ventilated with 70-80 vol% oxygen for a long period of time. The incidence and degree of chromosomal damage, although showing wide individual variations, was related to the duration of oxygen treatment. In addition to high oxygen tension, other environmental factors of intensive care therapy like antibiotic and chemotherapeutic agents may be responsible for the mutagenic effect. The results indicate once again the importance of continuous pO2-monitoring of ventilated newborns.