1288 DIMINISHED METABOLIC RESPONSE OF PREMATURE INFANTS TO A THERMAL STRESS WHILE PERIODIC BREATHING DURING SLEEP

Abstract

Periodic breathing (PB) occurs frequently in premature infants and may represent immaturity of central chemoreceptors. We postulate that other regulated functions such as temperature might be altered during episodes of PB. Six premature infants were studied under radiant warmers for 6-8 hours while simultaneous measurements of oxygen consumption (VO2), skin (Tabd) and core (Trec) temperature, EEG, EOG, EMG, and respiration were made. After periods of stabilization (Tabd=36.5 ± 0.5 and Trec=37.0 ± 0.2°C.), Tabd was allowed to fall slowly for short periods 4-10 times during the study period. For each of the 907 minutes of total sleep time (TST), breathing pattern (PB or non-PB), state, and VO2 were assessed. PB occurred in all but one subject and accounted for 11-60% of the TST. PB was distributed equally between REM and NREM sleep. The values for VO2 were then compared during sleep for warm and cool periods by breathing pattern. These data support our hypothesis and suggest that PB during sleep is associated with a decreased metabolic response to thermal stress.