Computer Modeling of Relationship Between Critical PVO₂, VO₂max and Blood Supply of Skeletal Muscle at Working with a Right-Shifted Blood O₂ Dissociation Curve

Abstract

Investigations were performed on a computer model of O₂ delivery and O₂ consumption in the one working muscle. At working with increasing power and achieving the critical value of VO₂ (VO₂crit), the muscle VO₂ began to lag behind the oxygen demand qO₂ .The model permits to find critical pO₂ in effluent venous blood Pvcrit at VO2crit as well as to calculate VO2max and PvO₂ at VO₂max under exercise with changing muscle blood flow F and blood pH.Pvcrit was computed from the condition VO₂crit=0.9qO₂, and VO₂max— from the condition (dVO₂/dgO₂) = 0.1. VO₂max, Pv at VO₂max, Pvcrit, and VO₂crit were calculated for: 40 ≤ F ≤ 120 ml/min/ 100g; 6.8 ≤ pH ≤ 7.4. It was shown that the faster is F and the lesser is blood pH, the greater were the Pvcrit and VO₂max values. With decreasing F and blood pH, the influence of F on Pvcrit and VO₂max increases, whereas the influence of blood pH on these values decreases. With increasing F and, hence, an increasing VO₂max, the blood supply efficiency decreases due to the important limiting factor - tissue oxygen diffusion.