Derivation of VA/Q distribution from blood-gas tensions.
Gas exchange was modelled by a Fortran program. Arterial blood-gas tensions have higher resolution than inert gas retentions in terms of distinguishing a single VA/Q compartment from a progressively broadening lognormal distribution. The maximum number of compartments determinable by arterial blood-gas tensions is three; VA/Q distributions containing more compartments are non-unique. Without utilizing 100% inspired oxygen, arterial blood-gas tensions cannot resolve the relative perfusion in shunt and low-VA/Q compartments, but the total perfusion in these compartments is determinable. The way in which the arterial blood-gas tensions vary with the variables of two and three-compartment distributions is described. Two- and three-compartment VA/Q distributions are derivable from either arterial blood-gas tensions or inert gas retentions.
Kaufman
R D
RD
Department of Anesthesiology, University of California, Los Angeles 90024.
Patterson
R W
RW
Lee
A S
AS
D000465:Algorithms; D002245:Carbon Dioxide / Q000097:blood; D003198:Computer Simulation; D008954:Models, Biological; D005741:Noble Gases / Q000097:blood; D010100:Oxygen / Q000097:blood; D010313:Partial Pressure; D014692:Ventilation-Perfusion Ratio
D005741:Noble Gases; D002245:Carbon Dioxide; D010100:Oxygen