Abstract: An aortic cannula has an elongate generally tubular side wall defining a conduit with distal and proximal ends. The distal end is adapted for insertion into the aorta during heart surgery to provide blood to the aorta. The conduit is separated into plural elongate lumens having smooth uninterrupted side walls and substantially equal cross sections extending back from the distal end of the cannula. The distal end is configured to permit substantially unrestricted laminar flow from all lumens out the distal end of the cannula.