Related Experiment Video
Updated: Aug 14, 2026
Measuring Cardiac Autonomic Nervous System (ANS) Activity in Children
Published on: April 29, 2013
Estimation of breathing interval from the photoplethysmographic signals in children
Jong Yong A Foo1, Stephen J Wilson
1School of Information Technology and Electrical Engineering, The University of Queensland, St Lucia Campus, Brisbane 4072, Australia. jong@ieee.org
Insights
Photoplethysmography (PPG) signals can accurately derive breathing intervals (BI) in children, offering a less intrusive alternative to traditional methods. This non-invasive technique is promising for pediatric respiratory sleep studies.
Area of Science:
- Biomedical Engineering
- Respiratory Physiology
- Pediatric Sleep Medicine
Background:
- Clinical monitoring often tracks heart rate (HR) variability and breathing interval (BI).
- Current BI monitoring in pediatric sleep studies uses uncomfortable nasal cannulas.
- Photoplethysmography (PPG) is typically used for HR and blood oxygen saturation.
Purpose of the Study:
- To investigate the feasibility of deriving breathing intervals (BI) from photoplethysmography (PPG) signals in children.
- To compare the accuracy of PPG-derived BI with a calibrated air pressure transducer.
- To assess the potential of PPG as a less intrusive method for pediatric respiratory monitoring.
Main Methods:
- Employed a two-stage zero-phase digital filtering technique to extract BI from PPG signals.
- Recruited eight children (7 male, aged 8.6 ± 2.6 years) for the study.
- Collected breathing data during tidal breathing and with inspiratory resistive loading (IRL).
Main Results:
- Mean BI derived from PPG signals showed significant correlation with the air pressure transducer during tidal breathing (r² = 0.76) and IRL (r² = 0.79).
- Accuracy was maintained in the absence of motion artifacts.
- The PPG-derived BI demonstrated strong agreement with the gold standard measurement.
Conclusions:
- PPG signals can be effectively utilized to derive breathing intervals (BI) in children.
- This non-invasive PPG-based method offers a promising alternative to intrusive techniques like nasal cannulas for pediatric respiratory monitoring.
- PPG technology can potentially enhance comfort and compliance during prolonged clinical monitoring in children.
Abstract:
Two important parameters that are generally under continual observation during clinical monitoring are heart rate (HR) variability and breathing interval (BI) of patients. Current HR monitoring during night-long childhood respiratory sleep studies is well tolerated but BI monitoring requires instrumentation, like nasal cannula, that can be less accommodating for children. In this study, BI was extracted from the photoplethysmographic (PPG) signals using a two-stage signal processing technique termed zero-phase digital filtering. Eight children (7 male) aged 8.6 +/- 2.6 years were recruited to perform two breathing activities: during tidal and with customized externally applied inspiratory resistive loading (IRL). The accuracy of BI derived from the PPG signals was compared with that estimated by a calibrated air pressure transducer in children. Statistical analysis revealed that mean BI attained from the PPG signals were significantly related during tidal breathing (r(2) = 0.76; range 0.61-0.83; p < 0.05) and with the IRL (r(2) = 0.79; range 0.68-0.85; p < 0.05) in the absence of motion artefacts. Preliminary findings herein suggest that besides having the capability to monitor HR and arterial blood oxygen saturation measurements, the PPG signals can be used to derive BI for children. This can be an attractive alternative for children who are more disturbed by intrusive techniques in prolonged clinical monitoring.
Related Concept Videos
01:19Special considerations while measuring oxygen saturation
Ensuring accuracy in vital sign recordings while prioritizing patient comfort and minimizing anxiety is important.
01:27Physical Assessment of the Respiratory Tract II: Inspection
Chest Configuration
The chest configuration can...
01:20Assessment of Ventilation I: Respiratory Rate
A Ventilation assessment is critical for monitoring a patient's health status. Respiration, one of the most accessible vital signs, provides insights into the function of numerous body systems and can indicate serious health issues, such as brainstem injuries from head trauma.
Critical Guidelines for Assessing Ventilation:
01:26Respiratory Volumes and Capacities I
01:29Assessment of Ventilation II: Respiratory Depth and Rhythm
Respiratory depth measures the volume of air inhaled or exhaled during a breath. It can vary from shallow to deep and typically remains consistent when a person is at rest or asleep. Occasionally, individuals will automatically inhale deeply, known as sighing, which inflates the lungs with more air than normal breathing.
To assess respiratory depth, observe the degree of chest excursion or movement: