PhD Scientific Days 2024

Poster Session P - Conservative Medicine

Investigating the Effects of Positive Pressure and Body Posture on the Respiratory Mechanics in Obese Children

Text of the abstract

Introduction: Continuous positive airway pressure (CPAP) support can be used in obese patients with respiratory failure to compensate for the increased mechanical load on the respiratory system and the decreased lung volumes.

Aims: To assess how positive pressure support and body posture affects respiratory mechanics in overweight and obese children.

Method: We conducted our prospective study between 2021 and 2024 at the Pediatric Center of Semmelweis University. Overweight and obese children (BMI z-score ≥1) between 6-18 years were recruited voluntarily from the endocrinology outpatient clinic. Intrabreath oscillometry (IB-Osc) was performed at 10 Hz in sitting and supine positions using a custom-made setup. Following the baseline measurements, measurements were conducted at increasing CPAP levels (no-5-10 cmH2O). From the 10-Hz IB-Osc data resistance (R) and reactance (X) at various points of the respiratory cycle (end-expiration [ReE and XeE], end-inspiration [ReI and XeI]), and the corresponding tidal differences (deltaR and deltaX) were estimated. The effects of body posture and CPAP support on the IB-Osc measures were assessed.

Results: 47 children were enrolled in the study, out of them 38 (20 boys; age:10,9±3.8 yrs; BMI Z-score: 2.3±0.4) had successful measurements in both positions. In general, lung mechanics were worse in supine position that improved with CPAP support. ReE (4,81±1,82→3,98±1,4→3,52±1,2 H2Ocm.s/l, p<0,001) and ReI (3,76±1,26→3,28±1,24→3,01±1,05 H2Ocm.s/l, p<0,001) were the most sensitive to changes in pressure, while ReE and XeE were the most sensitive to changes in position although with great inter-individual differences.

Conclusion: IB-Osc during CPAP support is feasible in children. Pressure support affects the measured respiratory parameters in different ways. These inter-individual differences might be helpful later in clinical practice in the setting of non-invasive ventilation. Further research is needed to determine the exact benefits.

Funding:
Hungarian Scientific Research Fund grants FK 129237 and K 128701; János Bolyai Research Scholarship of the Hungarian Academy of Sciences; Semmelweis 250+ Excellence PhD Scholarship