Human serum albumin induced hypotension in the postoperative phase of cardiac surgery.

Hypotension associated with the rapid infusion of human serum albumin products was first recognised in Australasia in the early 1970s. An association with the angiotensin converting enzyme inhibitor class of drugs (ACE-I) followed, leading to a proposed mechanism involving bradykinin generation through pre-kallikrein activator (PKA) presence in the infused fluid. The newer generation albumin products (Albumex) contain very low concentrations of PKA and are generally thought safe to use in most patient populations. Anecdotal reports of paradoxical hypotension with rapid infusion of 4% albumin in our department led to an audit of practice over three months. Four out of 36 patients (11%) who received 4% albumin intravenously experienced paradoxical hypotension. Three of these patients were taking ACE-I preoperatively (P=0.04). There was no observed hypotension associated with intravenous infusion of crystalloid fluid. We believe 4% albumin should be used with caution, particularly in those patients receiving ACE-I preoperatively.