Although overall survival at 28 days failed to reach statistical significance , 92 % ( 22 of 24 ) in the iNO group and 72 % ( 21 of 29 ) in the placebo group ( P = .07 ) , the rate of extracorporeal membrane oxygenation-free survival was significantly greater in those randomized to iNO 92 % ( 22 of 24 ) vs 52 % ( 15 of 29 ) for those receiving placebo ( P < .01 ) .