Apnea in premature infants: recording by arterial catheter.

Respirations and apnea were recorded through an arterial catheter and observed simultaneously in 13 premature infants. Based on simultaneous clinical observation and characteristic recordings of preapneic and apneic periods, three distinct mechanisms of evolution of apneic spells were noted. Studies to elucidate pathophysiologic changes during apnea should recognize varied mechanisms of their origin.