The effect of age and increasing head-up tilt on pre-oxygenation times in children: a randomised exploratory study

We conducted a randomised exploratory trial in children aged between one and sixteen years old to establish the time to achieve an end-tidal oxygen fraction ≥ 0.9 in three different positions: supine, and 30 and 45° head up. We recruited 120 children analysed in two age groups: 1-8 years and 9-16 years. The median (IQR [range]) time to reach the end point was 80 (59-114 [41-295]) s in the younger group and 150 (107-211 [44-405]) s in the older group, regardless of position (p = 0.0001). The end point was reached in 90% of children in approximately 160 s in the younger, and 271 s in the older, groups, respectively. There was no statistical difference between the three positions within each age group in the time to reach the endpoint (p = 0.59). Only two patients in the older age group could not reach the end point, due to poorly fitting facemasks. We conclude that pre-oxygenation can therefore be achieved effectively in most children, and that tilting children head up by 30 or 45° does not significantly reduce the time taken to achieve an end-tidal oxygen fraction of ≥ 0.9. The recommended period for pre-oxygenation in both groups should remain at 3 min but it should be noted that this may be insufficient for many older patients.