Does 133 Xenon washout measured by external monitoring accurately reflect blood flow in isolated cat gastrocnemius muscle?
The study experimentally verified Zierler's equation for measuring blood flow using inert gas diffusion (133 Xenon washout) in skeletal muscle.
The isolated cat gastrocnemius preparation was used to study the relation between the washout of 133 Xenon measured by external monitoring and blood flow measured directly by a dropcounter. The experimental possibility was thereby tested of recording the total tracer bolus and its subsequent washout by external monitoring, using the height H and the corresponding area A of the washout curve. The partition coefficient λ, and the amount of recirculation were evaluated in separate experiments. According to Zierler, the blood flow per gram of tissue should equal λ • H/A . This relation was verified experimentally. Exponential analysis was carried out but the results of it were not considered to support the hypothesis of a two compartment inparallel model in skeletal muscle. The shape of the washout curve did not suggest the existence of A-V shunts.
Tønnesen et al. (Mon,) studied this question.