Detection of central respiratory events using pulse transit time in infants

The prevalence of sudden infant death syndrome (SIDS) has been well studied and central sleep apnea is deemed as one of the possible causes. Current gold standard for its diagnosis is nocturnal polysomnography (PSG). However, this procedure is complex and generally needs to be performed in a sleep laboratory. Pulse transit time (PTT) shows its potential to indicate abrupt blood pressure (BP) changes during the occurrences of upper airway obstruction. The main objective of this study was to assess the capability of PTT to differentiate central respiratory events from tidal breathing in infants. This study involved 5 infants (4 male) with mean age of 7.8 months. 50 valid central respiratory events were randomly selected. These events were free from motion artifacts and pre-scored in the corresponding PSG studies by two blinded observers. PTT measurements from these events were then evaluated against the PSG scorings. Using a two-tailed F-test for variance, it was observed that central events differed from tidal breathing in a significant manner (p<0.05). Furthermore, PTT has showed its sensitivity to monitor marginal BP fluctuations during tidal breathing. Hence, the results herein suggest that PTT can be a valuable non-invasive technique to monitor central apneic events in sleeping infants.