Effects of nCPAP and FmCPAP on expired tidal volume. Each box represents the interquartile range between the 25th and the 75th percentiles, with the median value shown as a horizontal line within the box. Vertical bars represent the maximum and minimum values except for outliers. Outliers identified with a star are any data which lie more than 3.0 times the box length beyond the lower or higher edges of the box. FmCPAP, continuous positive airway pressure via a full face mask and ventilation; nCPAP, continuous positive airway pressure via a nasal mask and ventilation; Vte, expired tidal volume (in milliliters per kilogram of ideal body weight).