There were no significant differences between oral and nasal interfaces for the on-CPAP frequency of apneas and hypopneas ( mean difference , nasal-oral [ 95 % CI ] = -4.6 [ -10.1 -1.0 ] / h ; P = 0.06 ) or arousals ( -3.0 [ -7.8 -1.8 ] / h ; P = 0.23 ) .
