Abstract | BACKGROUND: METHODS: We aimed to examine the viability of intra-breath oscillometry in optimizing CPAP therapy for OHS. We performed intra-breath oscillometry at 10 Hz in the sitting and supine positions, followed by measurements at increasing CPAP levels (none-5-10-15-20 cmH2O) in awake OHS patients. We plotted intra-breath resistance and reactance (Xrs) values against flow (V') and volume (V) to identify tidal expiratory flow limitation (tEFL). RESULTS: Thirty-five patients (65.7% male) completed the study. We found a characteristic looping of the Xrs vs V' plot in all patients in the supine position revealing tEFL: Xrs fell with decreasing flow at end-expiration. Intra-breath variables representing expiratory decrease of Xrs became more negative in the supine position [end-expiratory Xrs (mean ± SD): -1.9 ± 1.8 cmH2O·s·L- 1 sitting vs. -4.2 ± 2.2 cmH2O·s·L- 1 supine; difference between end-expiratory and end-inspiratory Xrs: -1.3 ± 1.7 cmH2O·s·L- 1 sitting vs. -3.6 ± 2.0 cmH2O·s·L- 1 supine, p < 0.001]. Increasing CPAP altered expiratory Xrs values and loop areas, suggesting diminished tEFL (p < 0.001). 'Optimal CPAP' value (able to cease tEFL) was 14.8 ± 4.1 cmH2O in our cohort, close to the long-term support average of 13.01(± 2.97) cmH2O but not correlated. We found no correlation between forced spirometry values, patient characteristics, apnea-hypopnea index and intra-breath oscillometry variables. CONCLUSIONS: tEFL, worsened by the supine position, can be diminished by stepwise CPAP application in most patients. Intra-breath oscillometry is a viable method to detect tEFL during CPAP initiation in OHS patients and tEFL is a possible target for optimizing therapy in OHS patients.
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Authors | Szabolcs Baglyas, Luca Valkó, Vivien Móró, Eszter Podmaniczky, Dorottya Czövek, Gergely Makan, Zoltán Gingl, János Gál, Zoltán Hantos, András Lorx |
Journal | BMC pulmonary medicine
(BMC Pulm Med)
Vol. 23
Issue 1
Pg. 477
(Nov 28 2023)
ISSN: 1471-2466 [Electronic] England |
PMID | 38017501
(Publication Type: Journal Article)
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Copyright | © 2023. The Author(s). |
Topics |
- Humans
- Male
- Female
- Continuous Positive Airway Pressure
- Obesity Hypoventilation Syndrome
(therapy)
- Oscillometry
(methods)
- Exhalation
- Respiratory Mechanics
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