An investigation on pulse transit time in respiratory sleep studies for infants.

The main objective of this study was to assess the capability of pulse transit time (PTT) to identify obstructive and/or central apnoeas from normal breathing patterns in sleeping infants. Clinical trials were conducted with PTT being monitored as an adjunct measure in routine overnight polysomnography (PSG) studies. Standard PSG scorings of events were performed by two blinded observers to evaluate PTT accuracy. Data from eight infants (six male; aged 8.5 +/- 2.1 months; apnoea-hypopnoea index of 12.1 +/- 8.4 events per hour) were collected. Obstructive events were not successfully identified by PTT due to their low occurrence. However, PTT scored positive and negative predictive values of 0.803 and 0.788 for central events, respectively. Preliminary findings suggest that PTT has the potential to differentiate normal breathing from central events only in sleeping infants.