The present invention relates to priming solutions used during cardiopulmonary bypass procedures. In particular, the present invention relates to a cardiopulmonary bypass priming solution comprising a balanced salt solution and a combination of oncotic and non-oncotic dextran molecules. The present invention also relates to the use of the priming solution in a cardiopulmonary bypass method, a method of maintaining oncotic pressure in a patient during a cardiopulmonary bypass procedure, and a combination of cardiopulmonary bypass priming solution and cardiopulmonary bypass apparatus.
