Related Experiment Videos
Static compliance of the respiratory system in healthy infants
R S Tepper1, T Williams, J Kisling
1Department of Pediatrics, Indiana University Medical Center, James Whitcomb Riley Hospital for Children, Indianapolis, Indiana 46202-5225, USA. rtepper@iupui.edu
Insights
Static deflation pressure-volume curves reveal that respiratory compliance and volume increase with infant body length. Maternal smoking may lead to underdeveloped lungs in infants.
Area of Science:
- Pediatric Pulmonology
- Respiratory Physiology
- Neonatal Medicine
Background:
- Infant respiratory mechanics are crucial for understanding lung development and disease.
- Limited data exists on static lung compliance in spontaneously breathing infants across a wide age range.
Purpose of the Study:
- To record static deflation pressure-volume (PV) curves in healthy infants aged 1 to 104 weeks.
- To investigate the relationship between respiratory system compliance, lung volumes, and factors like age, sex, and maternal smoking.
Main Methods:
- Static deflation PV curves were obtained from total lung capacity (TLC) to functional residual capacity (FRC) in 49 sedated, spontaneously breathing infants.
- Respiratory activity was transiently inhibited to measure static recoil pressures.
- Compliance of the respiratory system (Crs) was calculated from the linear portion of the PV curve (5-15 cm H2O).
Main Results:
- Respiratory system compliance (Crs) and expired volume (V30E) increased with infant body length.
- Males exhibited greater Crs than females after adjusting for body length.
- V30E was smaller in female infants and those exposed to maternal smoking during pregnancy.
- Specific compliance (Crs/V30E) decreased with age but was not influenced by sex or maternal smoking.
Conclusions:
- Static deflation PV curves are feasible to record in infants from 1 to 104 weeks of age.
- Maternal smoking during pregnancy may be associated with hypoplastic lungs in infants.
- Infant lung function, including compliance and volume, is influenced by body size, sex, and prenatal exposures.
Abstract:
We recorded static deflation pressure-volume (PV) curves from near TLC to FRC in 49 healthy, sedated, spontaneously breathing infants of 1 to 104 wk of age. Respiratory activity was transiently inhibited by inflating the respiratory system several times to a volume at an airway pressure of 30 cm H2O (V30). Passive deflation from V30 to FRC was then interrupted by multiple brief occlusions at the airway opening, in order to measure static recoil pressures. The expired volume from V30 to FRC was defined as V30E. Compliance of the respiratory system (Crs) was calculated as the slope of the linear portion of the PV curve from 5 to 15 cm H2O. Crs and V30E increased with increasing body length (p < 0.001). After adjustment for body length, males had greater Crs values than did females (p < 0.01). V30E was smaller in female infants (p < 0.05) and in infants whose mothers smoked during pregnancy (p < 0.04). Specific compliance (Crs/V30E) declined with increasing age (p < 0.01), but there were no differences related to sex or maternal smoking. We conclude that static deflation PV curves can be recorded in the age range from 1 to 104 wk, and that maternal smoking may produce hypoplastic lungs.