Inhaled Nitric Oxide May Reduce Surgical Complications

Administration of nitric oxide (NO) during and following heart surgery can decrease risk of developing acute and chronic kidney problems, claims a new study.

Researchers at Fourth Military Medical University (Xi’an, China), Brigham and Women’s Hospital (BWH; Boston, MA, USA), Massachusetts General Hospital (MGH; Boston, USA), and other institutions conducted a randomized, controlled trial involving 244 adults in Xi'an (China), who underwent multiple valve replacement surgery. The patients were randomized to receive 80 PPM of NO or of nitrogen alone, administered via a gas exchanger during cardiopulmonary bypass, and by inhalation for 24 hours post-operatively.

The results revealed that patients who received of NO during and for 24 hours after surgery were less likely to develop acute kidney injury (AKI), with a decrease from 64% in placebo-treated patients to 50% in those who received NO. Risk of progressing to stage 3 chronic kidney disease (CKD) was also reduced at 90 days, from 33% in placebo-treated patients to 21% in those who received NO. After one year, 31% of patients in the nitrogen placebo group had serious kidney disease, compared to 18% in the NO group. There was also a decrease in the overall one-year mortality rate, from 6% in the placebo group to 3% in the NO group. The study was published on June 22, 2018, in Journal of Respiratory and Critical Care Medicine.

“We tested whether administration of nitric oxide, a gas normally produced by cells in the lining of blood vessels, might render hemoglobin ‘inert’, thereby decreasing the risk of both acute and chronic kidney injury,” said co-lead author Lorenzo Berra, MD, medical director of respiratory care at MGH. “We believe that the older patients with an increased number of cardiovascular risk factors, including obesity, hypertension, and diabetes, may derive even greater benefit from nitric oxide administration during and after heart surgery.”

NO has been identified as an important molecule with versatile roles in human physiology, including selective pulmonary vasodilation, bronchodilator, and pulmonary surfactant activities to improve ventilation-perfusion mismatch and hence oxygenation. Clinical effects of nitric oxide gas include cardio-pulmonary vasodilation, reduction of right heart load, reduction of ischemia, reduction of hypoxemia, inhibition of platelet aggregation, and anti-inflammatory, fungicidal, virocidal, and bactericidal effects, among others.

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Fourth Military Medical University
Brigham and Women’s Hospital
Massachusetts General Hospital