Nitric Oxide during Cardio Pulmonary Bypass during surgery for congenital heart defects: A Randomised Controlled Trial.

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Each year, over 2000 children are born with congenital heart disease in Australia, of which the majority requires surgical intervention. Congenital heart disease ranks still within the top causes of infant mortality in industrialized countries. Despite considerable advances over the past decade, the exposure to cardiopulmonary bypass (CPB), which is needed for most surgeries, remains responsible for major side effects: The exposure of patient blood to large artificial surfaces in the CPB circuit triggers a very strong systemic inflammatory syndrome, which leads in a third of patients to low cardiac output syndrome (LCOS). LCOS is defined as a condition with a reduced oxygen delivery to end organs due the postoperative heart not being able to meet the circulatory demand. LCOS manifests with severe organ dysfunction such as respiratory and renal failure, and can lead to brain hypoperfusion, cardiac arrest, and death. Survivors are at increased risk for long term neurological impairment. Patients with LCOS require increased length of respiratory support, prolonged length of stay in intensive care and hospital, resulting in significantly increased health care costs, and translating into lifelong costs due to neurological impairment. Previous attempts to reduce the detrimental inflammatory effects of CPB using immunomodulating drugs such as corticosteroids have failed to show a demonstrable benefit. Nitric oxide is a endogenous anti-inflammatory mediator, with direct actions on endothelial bed and immunologically active cells. Previous studies suggest that the delivery of gaseous nitric oxide (NO) to bypass circuits results in myocardial protection and in a reduction in bypass-induced inflammation. We have therefore performed a randomised controlled single centre pilot trial and showed that the delivery of gaseous nitric oxide (NO) to the oxygenator of the CPB circuit for children undergoing cardiac surgery for congenital heart defect resulted in a twofold reduced incidence of LCOS, and improved patient-centred outcomes including less need for extracorporeal life support post surgery, and shorter duration of mechanical ventilation, with a trend to improved mortality. In order to confirm these single centre pilot data we aim to investigate in a multicentre randomised controlled trial if NO reduces length of mechanical ventilation as a primary outcome, and reduced LCOS/ECLS/death as secondary outcomes.