Digital illustration of lungs with data streams representing respiratory monitoring.

Breathe Easier: New Algorithm Improves Oxygen Therapy Monitoring

Mira Elwood in Health & Wellness December 2025 • 4 min read.

"A flow-leak correction algorithm enhances the accuracy of work-of-breathing measurements during high-flow nasal cannula oxygen therapy, ensuring better respiratory support."

High-flow nasal cannula (HFNC) therapy is a prevalent method for treating respiratory failure, delivering a heated and humidified oxygen/air mixture at high flow rates to improve ventilatory efficiency and reduce the work of breathing (WOB). However, accurately measuring WOB during HFNC therapy has been technically challenging due to the continuous unidirectional flow toward the patient.

A recent study introduces a novel method for measuring WOB based on a differential pneumotachography (DP) system, which uses pneumotachographs inserted into the HFNC circuit and connected to a monitoring facemask. The key innovation is a leak correction algorithm (LCA) that addresses flow measurement errors caused by leakage around the monitoring facemask. This algorithm ensures more precise readings of respiratory flow and volume, essential for calculating WOB.

The study's findings suggest that this new system, combining DP with LCA, offers a reliable way to monitor respiratory effort during HFNC therapy, potentially leading to more personalized and effective respiratory support strategies. This article delves into the specifics of the algorithm, its validation, and its potential impact on patient care.

How the Flow-Leak Correction Algorithm Works

Digital illustration of lungs with data streams representing respiratory monitoring.

The core challenge in measuring WOB during HFNC therapy lies in the constant flow of air, which can throw off traditional pneumotachography measurements. The LCA is designed to correct these inaccuracies by accounting for leaks around the monitoring facemask. The system uses two pneumotachographs: one in the HFNC circuit (PNT-A) and another in the monitoring facemask (PNT-B).

The algorithm leverages the pressure inside the facemask (PMask) to estimate and correct for flow leaks. By applying principles of fluid dynamics, specifically Ohm's law for fluidic circuits, the LCA calculates the leak flow and adjusts the respiratory flow measurements accordingly. This ensures that the final respiratory flow (VResp) accurately reflects the patient's breathing effort.

The LCA incorporates two main approaches:

Pressure-based Leak Correction (P-LCA): Uses the pressure inside the facemask to estimate and correct for flow leaks. This method is more robust to changes in mask position or breathing patterns.
Flow-based Leak Correction (F-LCA): Relies on flow measurements to estimate leaks, simplifying the algorithm by avoiding the need for pressure measurements.

Both P-LCA and F-LCA demonstrated high accuracy in correcting flow measurements, as validated through mechanical lung model and in vivo studies. The corrected data allows for a more precise calculation of WOB and pressure-time product (PTP), key indicators of respiratory muscle workload.

The Future of Respiratory Monitoring

The development and validation of this flow-leak correction algorithm represent a significant step forward in respiratory monitoring during HFNC therapy. By accurately measuring work of breathing, clinicians can better assess the effectiveness of respiratory support and make more informed decisions regarding flow rate adjustments.

While the study demonstrates the algorithm's effectiveness in controlled settings, further research is needed to evaluate its performance in diverse patient populations and clinical scenarios. Future studies could also explore the integration of this technology into user-friendly monitoring devices, making it more accessible to healthcare providers.

Ultimately, this advancement paves the way for more personalized and effective respiratory care, optimizing patient outcomes and improving the management of respiratory failure. With precise monitoring of patients in need, medical practitioners would have greater insight and a more optimized respiratory plan.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1016/j.medengphy.2018.02.004, Alternate LINK

Title: A Flow-Leak Correction Algorithm For Pneumotachographic Work-Of-Breathing Measurement During High-Flow Nasal Cannula Oxygen Therapy

Subject: Biomedical Engineering

Journal: Medical Engineering & Physics

Publisher: Elsevier BV

Authors: Francesco Montecchia, Fabio Midulla, Paola Papoff

Published: 2018-04-01

Everything You Need To Know

What is high-flow nasal cannula (HFNC) therapy?

The **high-flow nasal cannula (HFNC)** therapy is a method for treating respiratory failure, where a heated and humidified oxygen/air mixture is delivered at high flow rates. This is to improve ventilatory efficiency and reduce the work of breathing (WOB) for patients. The treatment uses the continuous unidirectional flow to the patient.

Why is the flow-leak correction algorithm (LCA) so important?

The **flow-leak correction algorithm (LCA)** is significant because it enhances the accuracy of **work-of-breathing (WOB)** measurements during **HFNC** therapy. By correcting the flow measurement errors caused by leaks around the monitoring facemask, the **LCA** allows for more precise readings of respiratory flow and volume. This, in turn, leads to more accurate calculation of WOB and **pressure-time product (PTP)**, which are key indicators of respiratory muscle workload. This precision is crucial for optimizing respiratory support strategies.

How does the Differential Pneumotachography (DP) system work with the flow-leak correction algorithm (LCA)?

The **Differential Pneumotachography (DP)** system combines with the **flow-leak correction algorithm (LCA)** to provide a reliable way to monitor respiratory effort. The system uses two **pneumotachographs** (PNT-A and PNT-B) and the **LCA** to correct the flow measurements. The **LCA** leverages the pressure inside the monitoring facemask (**PMask**) to estimate and correct for flow leaks. This is essential in accurately calculating the **WOB** and, ultimately, in assessing the effectiveness of **HFNC** therapy.

How does the flow-leak correction algorithm (LCA) work?

The **flow-leak correction algorithm (LCA)** functions by correcting inaccuracies in **HFNC** therapy measurements. The core innovation is the use of a leak correction algorithm (**LCA**) that addresses flow measurement errors, specifically leaks around the monitoring facemask. It uses the pressure inside the facemask (**PMask**) to estimate and correct for flow leaks. There are two main approaches: **Pressure-based Leak Correction (P-LCA)** uses pressure, while **Flow-based Leak Correction (F-LCA)** uses flow measurements to estimate leaks. Both approaches correct flow measurements, which allows for precise calculation of **WOB** and **PTP**.

What is the difference between Pressure-based Leak Correction (P-LCA) and Flow-based Leak Correction (F-LCA)?

The **Pressure-based Leak Correction (P-LCA)** and **Flow-based Leak Correction (F-LCA)** are two methods used within the **flow-leak correction algorithm (LCA)** to correct flow measurements in **HFNC** therapy. **P-LCA** uses the pressure inside the facemask (**PMask**) to estimate and correct for flow leaks. **F-LCA** relies on flow measurements to estimate leaks, thereby simplifying the algorithm. Both methods have demonstrated high accuracy in correcting flow measurements. The corrected data from both methods leads to a more precise calculation of **WOB** and **PTP**.