Am. J. Respir. Crit. Care Med., Vol 157, No. 1, 01 1998, 237-245.
Intrapulmonary gas mixing in panacinar- and centriacinar-induced emphysema in rats [In Process Citation]
ML Rubio, MV Sanchez-Cifuentes, G Peces-Barba, S Verbanck, M Paiva and N Gonzalez Mangado
Laboratorio Fisiopatologia Respiratoria Experimental, Fundacion Jimenez Diaz, Universidad Autonoma, Madrid, Spain.
We studied ventilation distribution using the single-breath washout
technique in rats with two types of induced emphysema: panacinar-like (by
instilled elastase) and centriacinar-like (by inhaled CdCl2 combined with
oral intake of beta-aminopropionitrile). Morphologically, panacinar and
centriacinar groups presented a similar degree of airspace enlargement,
which was irregularly distributed and also accompanied by fibrosis only in
the centriacinar group. In terms of mechanical properties, the centriacinar
group presented lower end- expiratory flows and lower compliance than the
panacinar group. The ventilation distribution patterns were also different
between both groups. Single-breath washout phase III slopes, reflecting
mainly diffusion-convection-dependent inhomogeneities in rat lungs, were
largest in the centriacinar group. The SF6-He slope difference, which was
reversed in both emphysema groups with respect to the control group, could
be attributed mainly to He slope changes in the panacinar group and to SF6
slope changes in the centriacinar group. In addition, the respective He and
SF6 slope decrease as a function of end- inspiratory breath-hold time, was
only different from the control group in the centriacinar group. The
observed ventilation distribution patterns can be explained by interacinar
elastic changes in the panacinar group and severe interacinar structural
alterations in the centriacinar group.
