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Noninvasive method for measuring respiratory system compliance during pressure support ventilation.
Zhanqi Zhao1, Marcus Eger, Thomas Handzsuj
1Department of Biomedical Engineering, Furtwangen University, D-78054 VS-Schwenningen, Germany. zhanqi.zhao@hs-furtwangen.de
Summary
The adaptive time slice method (ATSM) accurately and noninvasively calculates respiratory system compliance (Crs) in patients on assisted ventilation. This robust method offers a reliable bedside assessment without extra equipment.
Area of Science:
- Pulmonary Medicine
- Critical Care
- Respiratory Physiology
Background:
- Assessing respiratory system compliance (Crs) in ventilated patients at the bedside is challenging.
- Existing methods for Crs measurement are limited in clinical application.
Purpose of the Study:
- To evaluate the efficacy of the adaptive time slice method (ATSM) for continuous Crs calculation.
- To determine if ATSM provides accurate and reliable Crs measurements in patients under assisted ventilation.
Main Methods:
- The ATSM divides breaths into adaptive time slices to calculate C(i) values.
- Outliers are removed, and Crs is determined as the mean of remaining C(i) values.
- The method was tested on seven Chronic Obstructive Pulmonary Disease patients during pressure support ventilation, comparing results with transdiaphragmatic pressure (Pdi) measurements.
Main Results:
- ATSM successfully analyzed 95 ± 4% of recorded data.
- In 6 of 7 patients, ATSM results showed similar variation and accuracy (<20% difference) compared to Pdi.
- A strong correlation (r=0.86, p<10(-5)) was observed between ATSM and Pdi, with a mean difference of 3.22 ml/mbar.
Conclusions:
- ATSM is a robust and accurate method for noninvasive Crs assessment.
- The technique is suitable for spontaneously breathing patients on pressure support ventilation.
- ATSM requires no extra instrumentation or complex maneuvers, making it practical for bedside use.
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