Mechanical insufflation-exsufflation to promote extubation success in critically ill adults on intensive care: protocol for a randomised controlled feasibility trial.

Background: Extubation failure, defined as reintubation within 48 h, is associated with increased intensive care unit (ICU) length of stay and higher mortality risk. One cause of extubation failure is secretion retention, resulting from an inability to cough effectively. Mechanical insufflation-exsufflation (MI-E) simulates a cough aiding secretion clearance. However, MI-E is not routinely used in the ICU for invasively ventilated patients. This study aims to determine feasibility and acceptability of a randomised controlled trial (RCT) examining MI-E use to promote extubation success in intubated, ventilated adults.

Methods: It is a single-centre, feasibility RCT with semi-structured interviews, economic scoping, and exploratory physiology study. The feasibility RCT (n = 50) will compare standard care to a MI-E protocol including a minimum of two MI-E sessions via the endotracheal tube prior to extubation. Post-extubation, MI-E will be delivered via facemask or mouthpiece up to two times/day for 48 h. MI-E settings will be individualised. All patients will receive standard care (no MI-E) in relation to mechanical ventilation, weaning, rehabilitation, physiotherapy techniques such as positioning, manual airway clearance techniques, manual/ventilator hyperinflation, endotracheal suctioning, and nebulisation. Clinical data collection will occur before, on completion, and 5-min post-physiotherapy sessions (intervention/control arms). Resource use will be calculated for each 24-h period. Analyses will be descriptive and address feasibility outcomes including participant recruitment and attrition, proportion of MI-E treatment sessions completed, dataset completeness, and frequency of adverse events and acceptability. Semi-structured online interviews informed by the Theoretical Framework of Acceptability (TFA) with patients, clinicians, and family members will explore the acceptability of the MI-E intervention and study processes. Interview data will be analysed using reflexive thematic analysis based on TFA domains through first-level coding. The embedded physiology study will use electrical impedance tomography and lung ultrasound to explore lung recruitment and de-recruitment during MI-E in a subset of 5-10 patients.

Discussion: This study will examine feasibility and acceptability of a RCT protocol of MI-E to promote extubation success. Study findings will inform design modification and conduct of a future adequately powered trial. Furthermore, the study will contribute and advance the understanding of MI-E use in critically ill intubated adults.

Trial Registration: ISRCTN 24603037; IRAS 303674.