Can a mini-bypass circuit improve perfusion in cardiac surgery compared to conventional cardiopulmonary bypass?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether the 'mini-bypass technique' can give a reduction in complications after cardiac surgery compared to the conventional cardiopulmonary bypass circuit. Altogether 144 papers were found using the reported search, of which 14 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. We conclude that 10 out of these 14 studies show reduced hemodilution, 7 show reduced red blood cell transfusion, 2 show reduced fresh frozen plasma use (one showing increased use), and 2 show reduced platelet use. Three studies show reduced postoperative blood loss, but one shows increased blood loss. Three studies show better renal function. Four studies show a better cardiac index and 2 show shorter intensive care unit stay. One study found an increased minute volume and reduced oxygenation for one hour post-mini-bypass. Six studies find significantly reduced inflammatory markers, and 5 measure superior myocardial protection. There are several anecdotal references to a 'learning curve' with this technique but no significant morbidity with complications arising from this were found. Mini-bypass seems to be a promising technique with many documented benefits in studies reporting as many as 1000 patients undergoing this technique.