Lung function in toddlers with chronic lung disease in infancy (BPD etiologically from the perinatal period). Pilot study using infant pulmonary function tests, IPFT)
Abstract
Chronic lung disease in infancy (CLDI) develops frequently as a consequence of perinatal/neonatal lung injury. Bronchopulmonary dysplasia (BPD) derived from perinatal burden is one of the most important sequelae of premature birth.
Morphological lung changes in preterm infgints with BPD have functional consequences on airway potence, lung volumes and respiratory mechanics. Methods of infant pulmonary function testing (IPFT) represent an important diagnostic tool for an assessment of severity of CLDI.
We assessed lung function in 74 infants and toddlers with a perinatal burden and CLDI (birth weight 1.47 +- 1.11 kg (mean +- SD); body length at birth 30.8 +- 16.3 cm). Age at testing was 1.38 +- 0.69 (median 1.35) yrs; body weight 9.0 +- 2.2 kg, body length 76.0 +- 9.7 cm.
The whole-body plethysmography (to measure functional residual capacity, FRCp and specific effective flow resistance, sReff), tidal breathing analysis (to assess the time to peak tidal expiratory flow to total duration of expiration, tPTEF%tE), baby resistance/compliance (to test specific compliance of the respiratory system, Crs) and rapid thoraco-abdominal compression method (to measure maximum expiratory flow at end-tidal volume level, V'maxFRc) were performed. MS Baby Body, VIASYS, USA, standard protocols and proper reference values were used.
FRCp equals 115.3 +- 41.2 % pred. (P < 0.02), sReff reached 134.6 +- 93.8 % pred. (P < 0.005). A parameter of tpTEF%tE decreased (23.5 +- 10.6 %).
Specific compliance rs (Crs/kg) was 14.4 +- 3.9 ml/kPa/kg; V'maxFRc reached 136 +- 69 ml/sec only. In infants and toddlers with a perinatal burden peripheral and central airway obstruction with mild (secondary) hyperinflation was found.
Mildly increased specific compliance of the respiratory system was also found. Restrictive pattern was detected in 12,5 % patients only.
Serial assessments in our cohort is required to validate present data and to assess future development of IPFT.