Abstract
Eight dogs were exposed to isopropyl methyl phosphonofluoridate (sarin) by inhalation, at rest and while running on a treadmill at 6 mph. Five of the dogs were also exposed to sarin by intravenous injection at rest and while running, in doses nearly equal to those given by inhalation. The doses were such as to produce a depression of activity of cholinesterase of the erythrocytes amounting to from 9 to 78 % of the initial activity. The activity was given time to recover fully between exposures. The average loss of activity was 9% per γg of dose per kg of dog; differences associated with exercise and route of entry were not significant statistically. Other effects of sarin were minimal.
The respiratory ventilation in 1/min averaged 8 at rest and 20 in exercise. The dog inhaled sarin from a mask whose effective dead space was not determined.
If this dead space mvas assunmed to be zero, the percentage of retention averaged 90 for rest and 72 for exercise. If the retention was assumed to be 100%, the effective dead space of the mask averaged 25 ml at rest and 103 ml in exercise. In view of the small size of these dead spaces and the likelihood of an increase in effective dead space in exercise the second assumption is regarded as the more probable. It is concluded that the retention in dogs must be nearly complete at rest and only slightly, if any, less with the increased respiratory ventilation encountered in moderate exercise.
Footnotes
- Received January 26, 1959.
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