Red blood cells have been reported to shrink and become stiffer under hypoxic conditions leading to a downward spiral in oxygen transport and delivery. So, “Early detection and correction of tissue hypoxia is essential if progressive organ dysfunction and death are to be avoided. However, hypoxia in individual tissues or organs caused by disordered regional distribution of oxygen delivery or disruption of the processes of cellular oxygen uptake and utilisation cannot be identified from global measurements. Regional oxygen transport and cellular utilisation have an important role in maintaining tissue function. When tissue hypoxia is recognised, treatment must be aimed at the primary cause,” write Drs. R M Leach, D F Treacher.