Why do we wait 90 seconds to provide oxygen to a cyanotic baby?
There is some debate between experts on when to introduce supplemental oxygen. Animal studies, and limited human studies, suggest increased tissue injury when 100% oxygen is used during resuscitation. Human studies have also shown that onset of breathing is delayed in babies receiving 100% oxygen vs. 21% oxygen (room air) at birth. It has also been observed that healthy babies may take over 10 minutes to achieve saturations in excess of 90%. It is therefore felt that supplemental oxygen should only be provided if there is evidence of the need for greater than 21% oxygen (such as cyanosis at 90 seconds after birth, or a baby receiving chest compressions). This applies to supplemental oxygen administered by free flow and supplemental oxygen administered by manual ventilation. Ninety (90) seconds was chosen by the Canadian NRP Steering Committee as the time to start supplemental oxygen because 3 clinical trials (and more recently a fourth see references below) comparing 21% oxygen and 100
