J. L. MAUDERLY AND J. A. PICKRELL 
671 
The pulmonary function of 7 male and 6 female 
Beagle dogs, 12 to 14 months old, was meas- 
ured during treadmill exercise. Two or three 
measurements were performed on each dog, a 
mean was calculated for each dog, and these 
means were used to calculate the data given 
herein. 
RESULTS 
Table I lists the means, standard deviations, 
ranges, and 2.5 to 97.5 percentile ranges for 
pulmonary function parameters measured at 
rest on 12- to 14-month-old Beagle dogs. Table 
II lists the means, standard deviations, and 
ranges for the same parameters measured on 7- 
to 10-year-old Beagles. Differences between the 
two age groups significant at the 95% level 
were found in body weight, dynamic pulmonary 
compliance and resistance, arterial P02, the al- 
veolar-arterial O2 gradient, O2 saturation of 
hemoglobin, percent alveolar ventilation, and 
specific ventilation. Table III lists means, stand- 
ard deviations, and ranges for pulmonary func- 
tion parameters of 12- to 14-month-old Beagles 
measured on the treadmill at 0, 3.0, and 4.5 
mph. 
DISCUSSION/SUMMARY 
Experience in this laboratory had indicated 
the practicability of evaluating pulmonary 
function in the unanesthetized dog. The exami- 
nation of pulmonary function as described herein 
has been performed on a routine basis for 
over one year, with individual tests having been 
in use for various times up to six years. More 
than 550 dogs have been tested at least once 
during the past three years and multiple tests 
were performed on many of them. An esti- 
mated one percent of the dogs failed to complete 
their initial series of tests because of behavioral 
problems, but only one dog has been rejected 
for further study because of repeated failure to 
tolerate the manipulations. It must be recog- 
nized, however, that although the dogs in this 
colony receive no training for pulmonary func- 
tion testing, they are handled periodically by 
caretaker, clinical, and investigative personnel 
from birth until presented to the laboratory for 
evaluation. 
Although data from equal numbers of males 
and females were used in Tables I and II, no 
significant sex-related differences in pulmonary 
function were found in Beagle dogs. Calcula- 
tions performed on unpublished data have 
shown that differences apparently related to sex 
were actually related to body size. 
The data listed in Table I are similar to those 
previously reported^^ except for dynamic pul- 
monary compliance, for which a mean of 73 
ml/cm H2O was found as compared to the pre- 
vious mean of 48 ml/cm H2O. The reason for 
the difference has not been determined, but may 
relate to changes in the method of measure- 
ment. Compliance in the earlier report was de- 
termined graphically by the method of von 
Neergaard and Wirz,^'^ instead of the loop clos- 
ing method currently in use, and the pressure 
transducer connected to the esophageal catheter 
did not have a reference vent to the face mask. 
The values listed in Table I for alveolar and 
arterial P02 and Pco2, the alveolar-arterial gra- 
ients for O2 and COo, arterial pH, and specific 
ventilation are similar to values obtained from 
human subjects at approximately the same alti- 
tude. The results of measurements on Beagle 
dogs (Table I) and values obtained by similar 
methods from 10 normal, male human subjects 
with a mean age of 26.5 years (range = 17 to 
38 years) were compared (Table IV). The 
human measurements were performed in dupli- 
cate with the subjects breathing room air at 
rest at an altitude of approximately 1,620 me- 
ters (inspired P02 = approximately 122 mm 
Hg). While slight differences can be seen be- 
tween the human and dog values, especially in 
arterial pH where a human mean of 7.45 was 
found as compared to the dog mean of 7.38, the 
similarities are striking. 
The limited data obtained from older dogs 
(Table II) would seen to indicate certain age- 
related changes in pulmonary function similar 
to those reported for man. A reduction in the 
oxygen saturation of hemoglobin,^^ and an in- 
crease in the alveolar-arterial oxygen 
gradient^^'^o have also been observed in 
human subjects. A trend toward loss of diffus- 
ing capacity was observed in the older dogs, al- 
