Journal of Applied Physiology, Vol 55, Issue 1 254-257, Copyright © 1983 by American Physiological Society
Technique for making hollow central airway casts
C. J. Pedersen, J. W. Watson and A. C. Jackson
We have developed a method for producing rigid hollow casts of the central
airways. Woods metal (melting point 70 degrees C) was poured into the
airways at the trachea of an excised canine lung air-dried at a
transpulmonary pressure of 30 cmH2O. The tissue was dissolved and removed,
and the resulting negative cast was carefully trimmed leaving only airways
with a diameter of 2 mm or greater. The cast was then electroplated with
copper that provided a rigid jacket encasing the Woods metal. Heating this
structure to 100 degrees C liquefied the Woods metal allowing the majority
of it to flow out. Residual amounts were readily removed by a high-pressure
steam hose attached to the trachea. Comparisons were made between airway
diameters from in vivo radiographic bronchograms (DB) and direct
measurements of the resulting trimmed Woods metal cast (DC). Linear
regression analysis of these data indicated a high degree of correlation
(DC = 0.98 DB + 0.03, r = 0.99). We concluded that this technique produces
positive casts which provide a good representative model of the central
airways.
