Analysis of variations in the pulse photo-plethysmogram and distribution of the reactivity index on polysomnographic recordings

Objectives :
Pulse photoplethysmography uses light absorbance technology to detect waves produced by heartbeats. This technique, is the basis for measuring SpO2 (1). The photoplethysmogram is one of the signals recorded during polysomnography. This signal can be considered as a good indicator of coronary pathology (2). It is easy to individualize amplitude variations of the photoplethysmographic signal in relation to events occurring during sleep (fig). We develop an algorithm and apply it to our polysomnographic recordings database to analyze Pulse Wave Reactivity according to associated sleep parameters.

Content :
Photoplethysmogram amplitude variations are calculated from a baseline developed on the moving average of the signal and filtered by a relaxation filter. Amplitude variations greater than 50% are counted and associated with the current epoch. This makes allow us to calculate a Pulse Wave Reactivity index. Results were validated visually.

Results :
The average PWR related to total sleep time is 53/h ± 29/h. There are significant differences reported to the sleep stage (SS : 54/h ± 33/h, SL : 44/h ± 32/h, SP : 67/h ± 35/h ; p < 0.001). There is a significant correlation (p < 0.07) between the reactivity index and sleep parameters.

Conclusion : The analysis of the PWR appear as a reliable sleep marker.

Bibliography :
1) Kirk H. Shelley, Photoplethysmography : beyond the calculation of arterial oxygen saturation and heart rate, Anesth Analg. 2007 Dec ;105(6 Suppl):S31-6
2) Brosh D, Assali A, Greenberg D, Kornowski R. Pulse wave analysis during instructed breathing as an indicator of significant coronary artery disease. Euro Intervention. 2010 Feb ;5(7):847-52.

Key words
Pulse Wave Reactivity, Sleep Recording, Sleep events, sleep apnoeas, periodic Limb Movmemt, Epworth Sleepiness Scale