Background: The selection of the optimal airway clearance technique is difficult due to the lack of appropriate evaluation tools. To date, little is known about the lung aeration of different oscillating devices on patients undergoing mechanical ventilation. This study protocol outlines an investigation into the feasibility and effectiveness of two different oscillating devices evaluated by electrical impedance tomography (EIT) in hypersecretive mechanically ventilated patients on lung aeration and ventilation distribution, and provides a feasible approach for developing an optimal airway clearance protocol.
Methods: This single-center, single-blind, randomised crossover study employed a parallel-group design. All participants will use high-frequency chest wall oscillation (HFCWO) and oscillation and lung expansion (OLE), with the order of assignment randomized; HFCWO or OLE was applied for 10 min. After baseline recording (T0), EIT data were subsequently recorded for 10 minutes at the end of treatment (T1) and at 1 hour (T2). The vital parameters and ABGs were recorded 1 min later. The primary endpoint was the between-group comparison of relative end-expiratory lung impedance (ΔEELI) at T1 following interventions with High-Frequency Chest Wall Oscillation (HFCWO) and Oscillating Positive Expiratory Pressure (OPEP). ΔEELI was defined as the difference between end-expiratory lung impedance at T1 (immediately post-airway clearance) and T0 (5 minutes pre-clearance), normalized to the T0 value. Secondary endpoints included additional EIT-derived indices and physiological monitoring parameters such as arterial partial pressure of oxygen (PaO₂) at 30% ± 9% FiO₂, heart rate, and respiratory rate variations across groups. Sputum samples were also collected and analyzed.
Conclusions: This study protocol will compare two oscillating devices on lung aeration, potentially endorsing the adoption of EIT. If successful, this approach could enhance accessibility for targeted populations.
Trial registration: This study was prospectively registered at the National Library of Medicine (https://clinicaltrials.gov/; Reference: NCT06675942; Date of registration: 5th November 2024)
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