Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7237386 | Medical Engineering & Physics | 2018 | 12 Pages |
Abstract
Measuring work of breathing (WOB) is an intricate task during high-flow nasal cannula (HFNC) therapy because the continuous unidirectional flow toward the patient makes pneumotachography technically difficult to use. We implemented a new method for measuring WOB based on a differential pneumotachography (DP) system, equipped with one pneumotachograph inserted in the HFNC circuit and another connected to a monitoring facemask, combined with a leak correction algorithm (LCA) that corrects flow measurement errors arising from leakage around the monitoring facemask. To test this system, we used a mechanical lung model that provided data to compare LCA-corrected respiratory flow, volume and time values with effective values obtained with a third pneumotachograph used instead of the LCA to measure mask flow leaks directly. Effective and corrected volume and time data showed high agreement (Bland-Altman plots) even at the highest leak. Studies on two healthy adult volunteers confirmed that corrected respiratory flow combined with esophageal pressure measurements can accurately determine WOB (relative errorâ¯<â¯1%). We conclude that during HFNC therapy, a DP system combined with a facemask and an algorithm that corrects errors due to flow leakages allows pneumotachography to measure reliably the respiratory flow and volume data needed for calculating WOB.
Keywords
Respiratory flowMFLWOBPneumotachographyPTPVTECPAPZFLPNTPEEPHFNCExpiratory tidal volumeLCAAlgorithmstandard deviationanalysis of varianceANOVATidal volumerelative errorinspiratory timeexpiratory timeCoefficient of VariationPositive end expiratory pressureContinuous positive airway pressureAtmospheric pressureEsophageal pressureFacemaskrespiratory ratePesoVtiPatmpneumotachographWork of breathingHigh-flow nasal cannula
Related Topics
Physical Sciences and Engineering
Engineering
Biomedical Engineering
Authors
Francesco Montecchia, Fabio Midulla, Paola Papoff,