It is of course interesting and valuable for perfusionists to study every aspect that applies to their craft.  However, to be blunt, it seems that pursuing a master's degree in perfusion would be a waste of time and money.  Although it would be a way to display how much of an expert one is in the profession, it would not translate into greater professional success for the vast majority of perfusion positions in the U.S.  The possible exception is for a clinical and classroom instructor at a perfusion school, but those are also shrinking in number.  I hate to sound overly pessimistic; I love being a perfusionist and love my job.  But the truth is even if  you had a Phd in perfusion, you would still have trouble finding and keeping a decent job that would pay you what it is worth to work in a specialized field in a stressful environment.