DELIVERED OXYGEN (DO2)
Whilst global delivered oxygen is an important principal to be considered as part of cardiovascular management, the various causes of a reduced global oxygen delivery (haemorrhage, anaemia, hypoxia) can result in different haemodynamic effects.
Changes in the individual components of the DO2 calculation and the subsequent effects on haemodynamic, tissue oxygenation, and stress hormone responses were studied by Dyson et al. :
- Haemorrhage resulted in the largest decrease in CO and the greatest stress hormone response
- Haemodilution had the largest effect on MAP
- Hypoxaemia induced the largest decrease in tissue oxygenation but only had a minor haemodynamic impact
As a result, the authors concluded “not all oxygen delivery is the same; this disparity should be emphasized in classical teaching and re-evaluated in patient management.”
- Dyson, A., N. Ekbal, M. Stotz, S. Barnes, J. Carre, S. Tully, S. Henderson, L. Barrett, and M. Singer, Component reductions in oxygen delivery generate variable haemodynamic and stress hormone responses. Br J Anaesth, 2014. 113(4): p.708-16.