G. Schmalisch et Rr. Wauer, PERCENTILE CURVES OF FUNCTIONAL RESIDUAL CAPACITY IN NEWBORN-INFANTS, Monatsschrift fur Kinderheilkunde, 141(9), 1993, pp. 714-720
Background: Helium dilution or nitrogen washout techniques are commonl
y used to measure the functional residual capacity (FRC) in newborn ba
bies. For both techniques equipment is available. Its clinical applica
tion, however, was difficult since there were no FRC reference ranges
for the different weight groups of newborn infants; reference studies
are very time consuming and cause several technical and ethical proble
ms. Methods: Statistical methods were used to evaluate several results
from the literature and to exclude significantly differing data of so
me authors. Measured values of FRC were related to body weight, and th
e percentiles of FRC/kg were estimated by the smoothed cumulative dist
ribution function of the pooled data. Results: No significant differen
ces were found between the results of helium dilution and nitrogen was
hout techniques. The distribution of 178 results showed a significant
skewedness (x5% = 18.3 ml/kg; x50% = 27.5 ml/kg x95% = 42.8 ml/kg), wh
ich could also be seen in the percentile curves calculated approximate
ly, assuming a linear development of functional residual capacity with
body weight. Conclusion: Percentile curves describe best the developm
ent and interindividual variability of FRC in newborn babies as our ev
aluation could show. We conclude that the nonparametric estimation of
percentiles is more adequate for the description than the use of simpl
e regression models.