Many hospitals are re-introducing these pieces of equipment into their ICU's. Thanks for this, but it really doesn't fully answer my question. Perhaps I can shed a bit of light on the subject. Apnea is not necessarily abnormal. In fact, it is usually a normal phenomenon that all babies and indeed all people exhibit.
All normal babies have apnea, which is to say, central apnea.
Therefore, by this definition, an apnea in that person would be any cessation of respiratory effort that lasted longer than 4 seconds. Having said that, it is well documented now that all normal babies have lots of apnea. Most of the apneas are less than 10 seconds duration but some are longer. Another important aspect of apnea is what happens to heart rate during the apnea. From studies of normals, both full term and preemies, we know also that normal infants have dips or drops in heart rate that are brief, self-limiting, and are not a sign of something wrong.