Mechanical Insufflation-Exsufflation to promote extubation success in critically ill adults on intensive care: Protocol for a randomised controlled feasibility trial

Abstract Background: Extubation failure, defined as reintubation within 48 hours 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 setting for invasively ventilated patients. This study aims to determine the feasibility and acceptability of a randomised controlled trial (RCT) examining MI-E use to promote extubation success in intubated, ventilated adults. Methods: Single centre, feasibility RCT with semi-structured interviews, economic scoping, and an 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 hours. MI-E settings will be individualised based on patient tolerance, chest expansion and secretion clearance. All patients will receive standard care 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 minutes after all physiotherapy sessions (intervention and control arms). Resource use will be calculated for each 24 hour period. Analyses will be descriptive and address feasibility outcomes. We will conduct semi-structured online interviews informed by the Theoretical Framework of Acceptability (TFA) with patients, clinicians and family members, exploring 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 the feasibility and acceptability of a RCT protocol of MI-E to promote extubation success. Study findings will inform further 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.