The Effects of Increased Cardiac Output, Surgical Isolation and Countercurrent Exchange at the Femoral Artery on the Residence Time of Xenon in Muscle
Abstract
This report describes a series of pilot experiments performed to guide the planning of NMRI's inert gas exchange research work unit after 1990. We conducted 5 experiments to examine the relationship of xenon residence time in tissue to cardiac output. In these experiments xenon mean residence time was not reduced when we increased the cardiac output using intravenous infusions of drugs. We found mean residence times to be generally longer in intact versus isolated muscle preparations, possibly due to differences in lipid content. In a 6th experiment, we recorded the profile of xenon radioactivity in the femoral artery and found that any countercurrent exchange above this level could account for a maximum of 4% of the mean residence time observed in the muscle. We modified the fitting routine to include the switching times as parameters to be estimated by the data. The mean transit times estimated using this model were more consistent with the time course of xenon observed on visual inspection of the curves. The results of these experiments produced a modification of the gas exchange project work unit and 5-year plan for Fiscal Year 1990. Inert gas, Xenon, Tissue gas exchange.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1993
- Accession Number
- ADA275337
Entities
People
- E. C. Parker
- E. D. Thalmann
- J. A. Novotny
Organizations
- Naval Medical Research Center