Blood purification for perioperative management of cardiac surgery

Cardiopulmonary bypass (CPB) in cardiac surgery is closely associated with several adverse effects, including hemodilution, coagulopathy and activation of a systemic inflammatory response due to operative trauma, ischemia-reperfusion injury, endotoxemia and blood contact with synthetic surfaces of the circuit. This inflammatory response increased vascular permeability and interstitial oedema, leading to cardiac, respiratory, renal, hepatic, and even multiorgan dysfunction. One of the measures to counteract these CPB-related pathologic syndrome is perioperative blood purification, which is mandatory in patients with advanced renal failure. This review encompasses four roles of extracorporeal blood purification or renal replacement therapy (RTT) in perioperative management of cardiac surgery. (I) Simplified intermittent hemodialysis (HD) in the patients with chronic kidney disease dependent on HD. It consists of routine HD for 2 consecutive days before surgery, intraoperative ultrafiltration (UF) during CPB, and intermittent HD performed after the first day after surgery. (II) Continuous or intermittent RTT for postoperative acute kidney injury (AKI). (III) Aggressive dilution UF (DUF) during CPB for blood concentration to reduce systemic edema and to improve postoperative cardiopulmonary function. (IV) Continuous RTT after surgery to correct electrolyte disturbance and acidemia, fluid overload, and to improve hemodynamic stability in the patients with fluid overload and pulmonary edema induced by deep hypothermia and prolonged CPB, even if urine output is secured. We herein provide an overview of the methods and clinical impacts of these modalities of blood purification, which may an important role in in the current era of an increasing number of older patients with multiple comorbidities are undergoing cardiac surgery.