Congenital cystic adenomatoid malformation: Initial lung function test predicts respiratory impairment

Background: Congenital cystic adenomatoid malformations of the lung (CCAM) are increasingly being detected by prenatal ultrasound. Postnatal management of CCAM remains controversial. Aims and objectives: To investigate the effect of CCAM on postnatal lung function test (LFT) parameters, and to elucidate whether LFTs help identify infants who would benefit from early surgery. Methods: LFTs were performed in 26 CCAM infants at a median (interquartile range) postmenstrual age of 42.4 (39.6 – 44.0) weeks and compared with LFT from 30 healthy matched controls. LFTs included measurement of tidal breathing, functional residual capacity by body plethysmography (FRCpleth), respiratory mechanics (respiratory compliance (Crs), and respiratory resistance (Rrs) by occlusion test, and blood gas analysis. Results: CCAM infants showed a breathing pattern typical for restrictive ventilation disorders with increased respiratory rate (p=0.006) and marginally decreased tidal volume (p=0.043). The Crs was significantly reduced, compared to controls (p=0.007). Particularly CCAM infants who had surgery in the first two years of life had markedly reduced Crs on initial LFT (p<0.001). No statistically significant differences were seen in the Rrs, FRCpleth and capillary blood gases. Conclusion: CCAM can cause restrictive ventilation disorders, which can be detected and monitored by postnatal LFT. Thus, LFT represents an additional tool to support the decision for or against surgery.