There was a significant decline in PaCO2 in the nCPAP group ( median of -4.6 mm Hg [ 10th-90th quantile , -14.55 to 3.85 ] ) as compared with the control group ( median of 0.95 mm Hg [ -4.75 to 9.85 ] ; P = 0.015 ; 95 % confidence interval [ CI ] for location shift = -9.5 to -1.3 ) .