PROLONGED EPISODES OF HYPOXEMIA IN PRETERM INFANTS UNDETECTABLE BY CARDIORESPIRATORY MONITORS

Objective. To determine whether episodes of prolonged hypoxemia occur without prolonged apneic pauses (greater than or equal to 20 seconds) and without bradycardia (pulse rate, less than or equal to 100 beats p er minute) in apparently well preterm infants. Methods. Long-term reco rdings of arterial oxygen saturation as measured by pulse oximetry (Sp O(2)), photoplethysmographic (pulse) waveforms from the oximeter, and breathing movements were performed in 96 preterm infants (median gesta tional age at birth, 34 weeks; range, 28 to 36 weeks) who were breathi ng room air. Recordings started at a median age of 4 days (range, 1 to 60 days). Results. During a median duration of recording of 25 hours, 88 episodes in which SpO(2) fell to 80% or less and remained there fo r 20 seconds or longer were identified in 15 infants. The median durat ion of these prolonged desaturations was 27 seconds (range, 20 to 81 s econds). In 73 episodes (83%), SpO(2) continued to fall to 60% or less . Twenty-three desaturations were associated with prolonged apneic pau ses and 54 with bradycardia; 19 of these were associated with both apn ea and bradycardia. Thirty desaturations (34%; 10 infants) occurred wi thout bradycardia and without prolonged apnea. Conclusions. These resu lts indicate that a proportion of apparently well preterm infants exhi bit episodes of severe prolonged hypoxemia unaccompanied by prolonged apneic pauses or bradycardia. Such episodes, therefore, would be diffi cult to detect if only breathing movements and heart rate are monitore d. Indications for the use of oxygenation monitors in preterm infants should be reconsidered.