Shape changes in static V-P loops from children's lungs related to growth.

Fagan, D. G.

doi:10.1136/thx.32.2.198

Cited by 17 publications

(3 citation statements)

References 9 publications

(17 reference statements)

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“…This small shift occurred during a period when alveolar septae appeared to be thinning and elongating but it was not sustained during a subsequent period when septae appeared to be thickening and proliferating. Much greater growth-related PV shifts, albeit of the same type as detected here, have been measured in vivo from infants (Bryan and Wohl, 1986) and children (Zapletal et al, 1976;Mansell et al, 1977;DeTroyer et al, 1978;Kraemer et al, 1983), in postmortem lungs from infants (Fagan, 1977) and in saline-filled rat lungs (Nardell and Brody, 1982). The greatest PV change in the latter study of rat lungs was associated with accumulation of elastin and increase in volume per unit weight.…”

Section: Comparison With Previous Studiessupporting

confidence: 73%

Postnatal growth of lung parenchyma in the piglet: Morphometry correlated with mechanics

Mansell

Collins

Johnson³

et al. 1995

Anat. Rec.

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1) A relative stiffness to shape and volume change in freshly newborn piglet lungs is associated with relatively thick alveolar septal walls; 2) postnatal development of piglet lung parenchyma involves septal lengthening and thinning followed by septal proliferation; 3) the initial phase of septal lengthening, rather than the later phase of septal proliferation, is associated with increase in parenchymal recoil.

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Section: Comparison With Previous Studiessupporting

confidence: 73%

Postnatal growth of lung parenchyma in the piglet: Morphometry correlated with mechanics

Mansell

Collins

Johnson³

et al. 1995

Anat. Rec.

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“…Therefore, more compliant airways in the less mature subject should not contribute to proportionately higher flows in the younger infant. Similarly, limited data on lung elastic recoil pressure in infants suggest lower values in younger infants (9)(10)(11)(12)(13). This would also suggest that the faster rate of emptying in the younger infant should be related to relatively larger airways for the V L that is to be emptied.…”

Section: Discussionmentioning

confidence: 89%

Rate Constant for Forced Expiration Decreases with Lung Growth during Infancy

Tepper

Jones

Davis

et al. 1999

Am J Respir Crit Care Med

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Airway caliber and lung volume (VL) increase many fold between infancy and adulthood; however, these two components of the lung may not increase proportionately during lung growth and development. We evaluated in infants the rate of emptying during forced expiration from near total lung capacity to residual volume. From the flow-volume curves we calculated (1) a rate constant (k) as the change in flow divided by the change in volume between 50% and 75% of expired forced vital capacity (FVC), and (2) the fraction of the FVC expired in 0.5 s (FEV(0.5)/FVC). Seventeen normal healthy infants were evaluated twice; mean ages (ranges) at first and second tests were 30 (5 to 76) and 58 (28 to 98) wk. Analysis of cross-sectional and longitudinal data indicated that the rate of emptying during forced expiration measured by both parameters was greatest in the youngest infants and decreased during infancy. Our findings are consistent with the concept that younger infants have large airways relative to their VL and that VL increases more rapidly than airway caliber early in life.

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“…A similar consideration may also partly explain why adults have higher flows than children. The limited available data on developmental aspects of pressure-volume relationships in the respiratory system sug gest that the lungs increase in elasticity at least up to 18 years of age [Mansell et al, 1977;Fagan, 1977], Thus, the relatively compliant lungs of children should collapse more slowly than the adult lung and conse quently produce lower flows. If such differ ences in lung elasticity are a major factor in the adult sex effect on flow, then one would predict the disappearance of this effect among geriatric speakers, based on the data of Bode et al [1976], They found a dispro portionate loss of lung elasticity with aging among adult males, as compared to females, the result of which was comparable lung elas ticities across sex in older subjects.…”

Section: Oral Air Flowmentioning

confidence: 99%