Clinical

Inhaled nitric oxide has benefits in liver transplantation

Last Updated: 2007-09-17 11:45:17 -0400 (Reuters Health)

By Megan Rauscher

NEW YORK (Reuters Health) - Inhaled nitric oxide (NO) administered during orthotopic liver transplantation inhibits hepatic ischemia-reperfusion injury, resulting in improved liver function, preliminary results of a small study indicate.

"The key observations in this study were that inhaled nitric oxide had effects beyond the lung in humans and specifically protective effects in the context of liver transplantation," Dr. Rakesh P. Patel of the University of Alabama at Birmingham noted in comments to Reuters Health.

As Dr. Patel and colleagues explain in the September issue of the Journal of Clinical Investigation, "Ischemia/reperfusion injury in transplanted livers contributes to organ dysfunction and failure and is characterized in part by loss of NO bioavailability."

In a prospective, blinded, placebo-controlled study, 20 adults undergoing orthotopic liver transplantation were randomized to inhaled NO at 80 ppm or inhaled placebo during the operative period only.

Evaluation of serum transaminases and coagulation times showed that inhaled NO "improved the rate at which liver function was restored after transplantation," the authors report.

"This effect, our data suggested, was related to prevention of liver cell death," Dr. Patel noted.

"The study also provided data suggesting that inhaled nitric oxide may protect extrapulmonary organs from ischemia-reperfusion injury by increasing levels of the anion, nitrite," the researcher said.

"Importantly," the team notes, "use of inhaled NO at 80 ppm for the duration of surgery was well tolerated" with no undesirable change in cardiopulmonary performance or subsequent complications.

Inhaled NO, relative to placebo, also significantly decreased time spent in the hospital by about 10%, the investigators found.

While larger clinical trials are needed, they conclude, the current study "supports the clinical use of inhaled NO as an extrapulmonary therapeutic to improve organ function following transplantation."

J Clin Invest 2007;117:2583-2591.