Modified haemoglobins as oxygen-transporting blood substitutes.

Haemoglobin solutions have been developed as red cell substitutes from various sources, e.g. outdated human blood, and bovine and recombinant haemoglobins. Haemoglobins have been modified to reduce their high oxygen affinity, oncotic activity and to prolong their intravascular half-life. Aside from oxygen carriage, modified haemoglobin solutions have other interesting properties, including vasopressor effects and improvements in regional blood flow.