This invention relates to a venous cannula for use in conjunction with cardiovascular examinations, treatments and surgery. The venous cannula is configured for two-stage drainage of oxygen-depleted venous blood from a central venous location via a peripheral venous insertion site, such as a femoral vein. The venous cannula is optimized for use in a cardiopulmonary bypass system that includes a multichannel arterial perfusion catheter. The cardiopulmonary bypass system is advantageous for use in performing standard open chest or least invasive cardiac surgical procedures.