Related Experiment Video
Updated: Aug 25, 2025
Breath Collection from Children for Disease Biomarker Discovery
Published on: February 14, 2019
Breath detection algorithms affect multiple-breath washout outcomes in pre-school and school age children
Marc-Alexander Oestreich1,2, Florian Wyler1, Bettina S Frauchiger1
1Division of Paediatric Respiratory Medicine and Allergology, Department of Paediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
Insights
A new breath detection algorithm improves multiple-breath washout (MBW) outcomes in children by accurately identifying breaths, unlike commercial software that rejected many breaths, especially in young children.
Area of Science:
- Pediatric Pulmonology
- Respiratory Physiology
- Medical Device Technology
Background:
- Accurate breath detection is critical for multiple-breath washout (MBW) technique outcomes.
- Irregular breathing patterns in children pose challenges for distinguishing inspirations and expirations.
Purpose of the Study:
- Compare a commercial breath-detection algorithm with a novel custom algorithm.
- Evaluate the impact of breath detection on MBW outcomes in pediatric populations.
Main Methods:
- Replicated Spiroware software algorithm and developed a novel custom breath detection algorithm.
- Compared algorithms using 2,455 nitrogen (N2) and 325 sulfur hexafluoride (SF6) trials in infants, children, and adolescents.
Main Results:
- The commercial algorithm rejected 83% of N2 and 32% of SF6 breaths.
- The custom algorithm uses flow reversal and CO2 elevation, analyzing all breaths.
- In preschool children, the custom algorithm detected more breaths, preventing underestimation of lung clearance index by up to 21%.
Conclusions:
- Breath detection in young children is challenging, necessitating algorithms that minimize breath rejection.
- An improved custom algorithm accurately detects breaths using flow reversal and CO2 data.
- This enhances the reliability of MBW technique outcomes in pediatric studies.
Background:
Accurate breath detection is essential for the computation of outcomes in the multiple-breath washout (MBW) technique. This is particularly important in young children, where irregular breathing is common, and the designation of inspirations and expirations can be challenging.
Aim:
To investigate differences between a commercial and a novel breath-detection algorithm and to characterize effects on MBW outcomes in children.
Methods:
We replicated the signal processing and algorithms used in Spiroware software (v3.3.1, Eco Medics AG). We developed a novel breath detection algorithm (custom) and compared it to Spiroware using 2,455 nitrogen (N2) and 325 sulfur hexafluoride (SF6) trials collected in infants, children, and adolescents.
Results:
In 83% of N2 and 32% of SF6 trials, the Spiroware breath detection algorithm rejected breaths and did not use them for the calculation of MBW outcomes. Our custom breath detection algorithm determines inspirations and expirations based on flow reversal and corresponding CO2 elevations, and uses all breaths for data analysis. In trials with regular tidal breathing, there were no differences in outcomes between algorithms. However, in 10% of pre-school children tests the number of breaths detected differed by more than 10% and the commercial algorithm underestimated the lung clearance index by up to 21%.
Conclusion:
Accurate breath detection is challenging in young children. As the MBW technique relies on the cumulative analysis of all washout breaths, the rejection of breaths should be limited. We provide an improved algorithm that accurately detects breaths based on both flow reversal and CO2 concentration.
Related Concept Videos
01:23Assessment of Respiration
Subjective Assessment: Nurses interview the patient to gather information directly during the subjective assessment. It includes questions about the individual's medical history, medications, and symptoms, focusing on past respiratory conditions like...
01:27Physical Assessment of the Respiratory Tract II: Inspection
Chest Configuration
The chest configuration...
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:
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: