Lost without trace: oximetry signal dropout in preterm infants

Oxygen saturation (SpO2) signal dropout leaves caregivers without a reliable measure to guide oxygen therapy. We studied SpO2 dropout in preterm infants on continuous positive airway pressure, noting the SpO2 values at signal loss and recovery and thus the resultant change in SpO2, and the factors influencing this parameter. In 32 infants of median gestation 26 weeks, a total of 3932 SpO2 dropout episodes were identified (1.1 episodes/h). In the episodes overall, SpO2 decreased by 1.1%, with the SpO2 change influenced by starting SpO2 (negative correlation), but not dropout duration. For episodes starting in hypoxia (SpO2 <85%), SpO2 recovered at a median of 3.2% higher than at SpO2 dropout, with a downward trajectory in a quarter of cases. We conclude that after signal dropout SpO2 generally recovers in a relative normoxic range. Blind FiO2 adjustments are thus unlikely to be of benefit during most SpO2 dropout episodes.