Oxygen transport to skeletal muscle working at VO 2max in acute hypoxia: theoretical predictions

Abstract

The influence of acute hypoxia (30≤PaO 2≤100 mmHg) on the values of VO 2max and parameters of oxygen transport in muscle working at VO 2max was studied. We investigated muscle working under different values of blood flow F (60≤ F≤120 ml/min per 100 g), blood pH (7.0–7.6), and different diffusion conditions. Investigations were performed on a computer model of O 2 delivery to and O 2 consumption in the working muscle. VO 2max, PvO 2, pO 2- and VO 2-distribution in muscle fiber were calculated. It was shown that the greater the degree of arterial hypoxemia, the lower the muscle VO 2max and blood pO 2 values. When working at VO 2max, the average and minimal values of tissue pO 2 depend on PaO 2. The greater the blood flow through muscle, the greater the VO 2max. However, with an increasing degree of arterial hypoxemia, the effect of F and blood pH on the value of VO 2max is weakened. The diffusion conditions produced a powerful influence on the VO 2max value. At reduced PaO 2 they are the most important limiting factors of O 2 supply to muscle working at maximal effort.