Multifrequency Signals Identify Expiratory Flow Limitation Using Forced Oscillation Technique

Author(s):  
Sriram Mahadev ◽  
Gregory King ◽  
Cheryl M. Salome ◽  
Chris Htun ◽  
Robin Schoeffel
2004 ◽  
Vol 23 (2) ◽  
pp. 232-240 ◽  
Author(s):  
R.L. Dellacà ◽  
P. Santus ◽  
A. Aliverti ◽  
N. Stevenson ◽  
S. Centanni ◽  
...  

2014 ◽  
Vol 14 (1) ◽  
Author(s):  
Masashi Mikamo ◽  
Toshihiro Shirai ◽  
Kazutaka Mori ◽  
Yuichiro Shishido ◽  
Takefumi Akita ◽  
...  

2017 ◽  
Vol 49 (2) ◽  
pp. 1601270 ◽  
Author(s):  
András Lorx ◽  
Dorottya Czövek ◽  
Zoltán Gingl ◽  
Gergely Makan ◽  
Bence Radics ◽  
...  

Tracking of the within-breath changes of respiratory mechanics using the forced oscillation technique may provide outcomes that characterise the dynamic behaviour of the airways during normal breathing.We measured respiratory resistance (Rrs) and reactance (Xrs) at 8 Hz in 55 chronic obstructive pulmonary disease (COPD) patients and 20 healthy controls, and evaluated Rrs and Xrs as functions of gas flow (V′) and volume (V) during normal breathing cycles. In 12 COPD patients, additional measurements were made at continuous positive airway pressure (CPAP) levels of 4, 8, 14 and 20 hPa.The Rrs and Xrsversus V′ and V relationships displayed a variety of loop patterns, allowing characterisation of physiological and pathological processes. The main outcomes emerging from the within-breath analysis were the Xrsversus V loop area (AXV) quantifying expiratory flow limitation, and the tidal change in Xrs during inspiration (ΔXI) reflecting alteration in lung inhomogeneity in COPD. With increasing CPAP, AXV and ΔXI approached the normal ranges, although with a large variability between individuals, whereas mean Rrs remained unchanged.Within-breath tracking of Rrs and Xrs allows an improved assessment of expiratory flow limitation and functional inhomogeneity in COPD; thereby it may help identify the physiological phenotypes of COPD and determine the optimal level of respiratory support.


2006 ◽  
Vol 29 (2) ◽  
pp. 363-374 ◽  
Author(s):  
R. L. Dellaca ◽  
N. Duffy ◽  
P. P. Pompilio ◽  
A. Aliverti ◽  
N. G. Koulouris ◽  
...  

2020 ◽  
Vol 56 (3) ◽  
pp. 1902234 ◽  
Author(s):  
Eui-Sik Suh ◽  
Pasquale Pompilio ◽  
Swapna Mandal ◽  
Peter Hill ◽  
Georgios Kaltsakas ◽  
...  

BackgroundThe optimal noninvasive application of external positive end-expiratory pressure (EPAP) to abolish tidal-breathing expiratory flow limitation (EFLT) and minimise intrinsic positive end-expiratory pressure (PEEPi) is challenging in COPD patients. We investigated whether auto-titrating EPAP, using the forced oscillation technique (FOT) to detect and abolish EFLT, would minimise PEEPi, work of breathing and neural respiratory drive (NRD) in patients with severe COPD.MethodsPatients with COPD with chronic respiratory failure underwent auto-titration of EPAP using a FOT-based algorithm that detected EFLT. Once optimal EPAP was identified, manual titration was performed to assess NRD (using diaphragm and parasternal intercostal muscle electromyography, EMGdi and EMGpara, respectively), transdiaphragmatic inspiratory pressure swings (ΔPdi), transdiaphragmatic pressure–time product (PTPdi) and PEEPi, between EPAP levels 2 cmH2O below to 3 cmH2O above optimal EPAP.ResultsOf 10 patients enrolled (age 65±6 years; male 60%; body mass index 27.6±7.2 kg.m−2; forced expiratory volume in 1 s 28.4±8.3% predicted), eight had EFLT, and optimal EPAP was 9 (range 4–13) cmH2O. NRD was reduced from baseline EPAP at 1 cmH2O below optimal EPAP on EMGdi and at optimal EPAP on EMGpara. In addition, at optimal EPAP, PEEPi (0.80±1.27 cmH2O versus 1.95± 1.70 cmH2O; p<0.05) was reduced compared with baseline. PTPdi (10.3±7.8 cmH2O·s−1versus 16.8±8.8 cmH2O·s−1; p<0.05) and ΔPdi (12.4±7.8 cmH2O versus 18.2±5.1 cmH2O; p<0.05) were reduced at optimal EPAP+1 cmH2O compared with baseline.ConclusionAutotitration of EPAP, using a FOT-based algorithm to abolish EFLT, minimises transdiaphragmatic pressure swings and NRD in patients with COPD and chronic respiratory failure.


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