Am. J. Respir. Crit. Care Med.,
Volume 164, Number 3, August 2001, 433-436
Effect of Maturity on Maximal Transdiaphragmatic
Pressure in Infants during Crying
GABRIEL
DIMITRIOU,
ANNE
GREENOUGH,
GERRARD F.
RAFFERTY,
and
JOHN
MOXHAM
Departments of Child Health and Respiratory Medicine, King's College Hospital, London, United Kingdom
The aim of this study was to determine the effect of maturation on
diaphragmatic function. In addition, we investigated whether noninvasive assessment yielded similar results to invasive measurement. Twenty-eight infants, median gestational age (GA) 35.5 wk (range, 25 to 42 wk) and postconceptional age (PCA), 37.6 wk
(range, 32 to 44 wk), were examined. Diaphragmatic function was
assessed by measuring the maximal transdiaphragmatic pressure
during crying (cPdi) using balloon catheters in the midesophagus
(Pes) and the stomach (Pgas). In 14 of the infants, a noninvasive
measurement of inspiratory muscle strength, maximal inspiratory
pressure (PImax), was also made. cPdi and PImax were recorded
during a crying effort with the airway occluded at end-expiration.
The median cPdi and Pes during crying (cPes), but not Pgas during crying (cPgas), were significantly lower in those studied at a
PCA of less than term compared with those studied at an older
age (p < 0.05). cPdi and cPes, but not cPgas, correlated significantly with PCA (r = 0.44, p < 0.02; r = 0.43, p < 0.03; respectively) and gestational age (r = 0.46, p < 0.02 and r = 0.56, p < 0.01; respectively). In the 14 infants, the median PImax was lower,
but it correlated significantly with cPdi (r = 0.79, p < 0.01). We
conclude maturation does affect diaphragm function, and PImax
may provide a noninvasive index of diaphragm strength.