S. Davis et al., EFFECT OF CONTINUOUS POSITIVE AIRWAY PRESSURE ON FORCED EXPIRATORY FLOWS IN INFANTS WITH TRACHEOMALACIA, American journal of respiratory and critical care medicine, 158(1), 1998, pp. 148-152
Citations number
15
Categorie Soggetti
Emergency Medicine & Critical Care","Respiratory System
Continuous positive airway pressure (CPAP) is used to minimize airway
collapse in infants with tracheomalacia. Forced expiratory flows (FEFs
) at functional residual capacity (FRC) increase with increasing CPAP
in infants with tracheomalacia, and it has been suggested that CPAP pr
events airway collapse by ''stenting'' the airway open. Since FEF is g
reater at higher than at lower lung volumes, we evaluated whether the
increase in flow measured at FRC ((V) over dot FRC) With CPAP could be
explained by the increase in FRC with CPAP. We measured full FEF-volu
me curves at CPAP levels of 0, 4, and 8 cm H2O in six infants with tra
cheomalacia and five healthy control infants. In both groups of infant
s, FVC did not change with CPAP; however, inspiratory capacity (IC) de
creased and thus FRC increased with increasing CPAP. FEFs at FRC incre
ased with increasing levels of CPAP; however, the FEFs at 50% and 75%
of expired volume were not different for the three levels of CPAP for
both groups of infants. Our finding that FEFs measured at the same lun
g volumes did not differ for the different levels of CPAP indicates th
at CPAP affects forced flows primarily by increasing lung volume.