The cardio-respiratory responses to asphyxia has been characterized
in the newborn monkey (Fig. 1).10 Thus during the initial
minute/s with apnea heart rate is greater than 60 beats per minute
and blood pressure is still compensated – a state referred to
as primary apnea. With intervention at this stage, and relief of
the asphyxial process, there is an immediate increase in heart
rate and blood pressure with initiation of spontaneous respirations.
However, if there are no interventions and the asphyxial
process is allowed to continue there is progressive bradycardia
and hypotension with final gasping (after approximately four to
five minutes) before secondary apnea develops. Once this state
evolves it becomes more difficult to resuscitate and restore cardiorespiratory
status and in those who do recover the likelihood for
hypoxic–ischemic brain injury is markedly increased.16,17 The findings
in this report are consistent with these observations. Thus
almost 50% of the apneic infants responded to stimulation and suctioning
only, and the outcome in this group was favourable (only
two deaths). On the other hand, although half of the infants administered
FMV initiated spontaneous respirations within four to five
minutes of delivery, death was significantly more likely in this