Nitric oxide: platelet protectant properties during cardiopulmonary bypass/ECMO

Postoperative bleeding is a major complication in patients who have been placed on extracorporeal circulatory support for various cardiac procedures (1). The increase in hemorrhage is well documented and is associated with various factors, which include, high-dose systemic heparinization, thrombocytopenia, and impaired platelet function. Platelets activate when exposed to the large foreign surface of the extracorpeal circuit, with the largest area being the oxygenator. Despite adequate heparinization, platelet levels continue to decrease. This aggregation phenomenon has also been extensively studied, and it cannot be attributed to the use of aminocarproic acid, aprotinin, propofol, or amicar (2). Other factors found to be unrelated include, the brand or type of oxygenator, the use of heparin coatings (3), activated clotting time (ACT) levels while on bypass, the operative procedure, preoperative medications, or the types of anesthetic agents used (2). Therefore, it may be beneficial to add nitric oxide to the sweep gas to decrease platelet loss, platelet damage, postoperative bleeding, and lessening the need for post-operative blood transfusions.