SHORT APNEAS AND THEIR RELATIONSHIP TO BODY MOVEMENTS AND SIGHS IN PRETERM INFANTS

To test the hypothesis that there is an association among short apneas (3-10 s), body movements, and sighs, we studied 11 preterm infants (b ody weight 1,500 +/- 200 g, mean +/- SE; gestational age 30 +/- 1 week s, postnatal age 28 +/- 5 days) using a flow-through system. A total o f 1,166 apneas, 1,024 movements, and 473 sighs were recorded. Of the 1 ,166 apneas, 460 (39%) were associated with movements, 91 (8%) with si ghs, and 226 (19%) with both movements and sighs. The rate of apneas a ssociated with movements and sighs was significantly greater than expe cted if only a random association had occurred. These differences rema ined in quiet, rapid eye movement, and indeterminate sleep. The freque ncy of each of the three events was similar in a given sleep state. Of the 460 movements associated with apnea, 26% preceded, 23% followed, and 51% occurred during apnea. Similarly, of the 315 sighs associated with apnea, 44% preceded and 56% followed apnea. Apneas preceded by mo vements were longer than those without movements (5.6 +/- 0.2 vs. 4.9 +/- 0.1 s; p = 0.01). Oxygen saturation before apnea with movement (94 +/- 0.1%) was lower than before apnea alone (96 +/- 0.6%; p = 0.02) a nd also lower than before movement alone (96 +/- 0.1%; p = 0.001). The se findings suggest: (1) there is a strong association among short apn eas, movements, and sighs in these infants; (2) sighs appear not to be an isolated event and are likely to be part of a Head reflex more gen eral motor discharge, and (3) these events are accompanied by mild des aturations and bradycardias. We conclude Sleep state that clusters of short apneas, movements and sighs are common in preterm infants and sp ectulate that they are probably mediated via a common central neurogen ic mechanism.