Study of pulse transit time oscillations during obstructive sleep apnoea by using a distributed model

Area of Science:

• Biomedical Engineering
• Cardiovascular Physiology
• Pediatric Sleep Medicine

Background:

• Arterial compliance is crucial for understanding the systemic arterial tree's properties.
• Existing mathematical models link arterial phenomena to wall properties, but few address pediatric sleep breathing disorders.
• Pulse transit time (PTT) oscillations during sleep offer insights into cardiovascular dynamics.

Purpose of the Study:

• To develop and validate a mathematical model for PTT oscillations in sleeping children.
• To differentiate PTT patterns during tidal breathing versus obstructive sleep apnea (OSA).
• To assess the model's ability to capture cardiovascular responses to respiratory events.

Main Methods:

• Utilized data from 20 children undergoing overnight polysomnography (PSG).
• Employed a modified Windkessel model incorporating physiological parameters to simulate PTT fluctuations.
• Compared model predictions with actual PSG recorded data for tidal breathing and OSA events.

Main Results:

• The model accurately predicted PTT oscillations during tidal breathing, with predicted values (3.89 s) closely matching actual data (3.72 ± 0.79 s).
• For OSA, the model indicated under-damping PTT responses, with an estimated Q factor of 4.23 compared to actual data of 3.86 ± 0.64.
• Model trends aligned with recorded PSG data for both breathing conditions.

Conclusions:

• The proposed mathematical model demonstrates potential in illustrating PTT dynamics during tidal breathing and OSA in sleeping children.
• This model can aid in understanding the cardiovascular system's response to different respiratory states during sleep.
• Further research can refine the model for clinical applications in pediatric sleep and cardiovascular health.