1796 FUNCTIONAL RESIDUAL CAPACITY (FRC), DYNAMIC AND SPECIFIC LUNG COMPLIANCE IN INFANTS

Abstract

This study was designed to obtain normative data for FRC, dynamic (CLd) and specific lung compliance (CLs) during the first years of life. Thirteen boys and 9 girls free of respiratory disease were studied. Age, height, weight and ventilatory rate respectively ranged from 2 – 52 months, 55 – 96 cm, 4.9 – 16 Kg and 22 – 55/min. Studies were performed during chloral hydrate induced sleep. Infants breathed through a mouth piece or a face mask. FRC was determined by the closed circuit helium dilution technique using a 2.2 1 water sealed spirograph. Added dead space was subtracted from the measured volume and values were converted to BTPS. Measurement of tidal flow and volume through a heated pneumotachograph and of esophageal pressure with an air filled balloon catheter allowed for calculation of CLd as Δ V/ Δ P at zero flow. FRC, CLd and CLs respectively ranged from 110 – 430 ml, 8.1 – 34.7 ml/cm H2O and .051 – .110 ml/cm H2O/ml FRC. FRC and CLd were significantly correlated with height, age, weight and ventilatory rate while CLs was not. CLd was also significantly correlate with FRC. Multiple linear regression analysis showed that: 1– the only significant predictive variable for FRC was height: FRC = 6.2 × height – 200 (r=.83); 2– CLd was best predicted from FRC and age: CLd = .05 × FRC + .24 × age + 2.24 (r=.84); 3– CLs (.073 ± .004*) was independent of growth parameters. CLs would thus appear useful for evaluation of lung elastic properties in infancy. *(Mean ± SEM)

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Marchal, F., Gross, P., Crance, J. et al. 1796 FUNCTIONAL RESIDUAL CAPACITY (FRC), DYNAMIC AND SPECIFIC LUNG COMPLIANCE IN INFANTS. Pediatr Res 19, 410 (1985). https://doi.org/10.1203/00006450-198504000-01814

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