224 
PULMONARY MODELS 
Table II. — Number of Vascular Components per Centimeter of Interalveolar Septum as Seen by Electron Microscopy 
in Normal and Emphysematous Horses 
Normal 
Emphysematous 
Endothelial 
Capillaries Nuclei 
RBC 
Capillaries 
Endothelial 
Nuclei 
RBC 
Mean 252.4 87.4 
Sx ' 25.0 3.68 
P< b ... 0.01 0.001 
384.4 
33.7 
0.05 
61.8 
13.3 
57.3 
4.7 
242.6 
29.0 
' Deviation from mean. •> Probability. 
Table III. — Blood-Gas Tension and pH Values at Rest and Immediately Following Exercise 
a 
Pao^ (mm Hg) 
P^COj 
(mm Hg) 
pHa 
Pre-exercise Post-exercise 
Pre-exercise 
Post-exercise 
Pre-exercise 
Post-exercise 
Horses Free of Respiratory Disease ^ 
X. 103 96 
Sx ±4.9 ±4.8 
Horse with Respiratory Disease * 
X 80 69 
Sx . -t-5.5 -*-6.4 
P< 0.01 0.01 
43 
±3.6 
46 
±12.1 
NSi" 
43 
±5.2 
49 
±17.8 
NS" 
7.47 
±.006 
7.45 
±.016 
NS" 
7.48 
±.016 
7.39 
±.035 
0.05 
" X, mean; Sx, deviation from mean; P, probability. 
Not statistically different from control group. 
with quantitative electron microscope tech- 
niques.^ The results are shown in Table II. The 
apparent loss of capillaries in the emphysema- 
tous lungs correlates well with the lower pul- 
monary diffusion capacity and hypoxemia in 
emphysematous horses (Tables III-V). 
More recently, Leith and Gillespie have ex- 
amined the flow-volume and flow pressure char- 
acteristics of the lungs of these horses.^ Aver- 
age values for six normals and values for a 
single horse with emphysema are shown in 
Table VI. 
Maximum expiratory flows at FRC were 65- 
90 L/sec in four normals and only 2 L/sec in 
the horse with emphysema. Figure 1 compares 
the volume-flow trace of a normal horse with 
that of the horse with emphysema (COLD). 
Our pulmonary function measurements show 
Table IV. — Pulmonary Vascular Shunt (QslQt) in 
Normal and Emphysematous Horses 
«3s/Qt (%) 
(ml/min/mm Hg) 
Normal 
Emphysematous 
Mean (%) 
5.24 
8.90 
Sx ° 
0.74 
1.21 
p< " 
0.02 
" Deviation from mean. 
" Probability. 
the horse to have proportional values to those 
in man and that there is similar loss in function 
when they are afflicted with emphysema. The 
more difficult task is the correlation of the loss 
of function with structural changes. New quan- 
titative techniques to evaluate the lung struc- 
Table V. — Pulmonary Diffusing Capacity for Carbon 
Monoxide (D^^^) Normal and Emphysematous 
Horses 
''CO 
Normal 
Emphasematous 
Mean.---.-.- - 
365.9 
236.4 
Sx " 
31.3 
17.5 
P< " 
0.01 
» Deviation from mean. 
>= Probability. 
Table VI. — Respiratory Mechanics of Normal Horses 
and One with Emphysema 
Normal Emphysematous 
Horses ° Horse 
Body Weight (Kg) _ - 452 363 
Lung Weight (Kg) - 4.1 5.9 
FRC (L) 18.9 37.8 
RV (L) - 9.1 16.1 
TLC (L) - 42.1 68.6 
Cl (L/cmHsO) - - 3.4 4.2 
Ccw (L/cmH20) 0.9 0.9 
Rl (cmHsO/L/sec) _. 0.2 0.15 
Row (cmH:0/L/sec) 0.16 0.10 
Rrs (cmHsO/L/sec) — _ 0.40 0.27 
