Peak Expiratory Flow During Mechanical Insufflation-Exsufflation: Endotracheal Tube Versus Facemask

Background: Mechanical insufflation-exsufflation (MI-E) applied through the endotracheal tube (ET) can effectively eliminate airway secretions in intubated patients. However, the effect of the interface (ET vs. facemask) on expiratory airflow generated by MI-E has not been investigated. This study aimed to investigate the effect of the ET on peak expiratory flow (PEF), along with other associated factors that could influence PEF generated by MI-E. Methods: Intubated participants received two sessions of MI-E via ET therapy per day for two consecutive days. One MI-E session consisted of five sets of either constant (+40/-40 cmH2O) or incremental (+30/-30 to +50/-50 cmH2O) pressure applications. Following extubation, MI-E sessions were repeated using facemask. Expiratory airflow during MI-E therapy was measured, and repetitive PEF measurements during each session were analysed using linear mixed-effect and generalised linear mixed models. Results: A total of 12 participants (9 [75.0%] men; mean [SD] age, 74.0 [10.2] years) completed all MI-E sessions with both ET and facemask interfaces. The PEF generated during MI-E treatment was influenced by the pressure gradient, number of session repetitions, and interface (ET vs. facemask). Adjusted mean PEF values for MI-E via ET and facemask at +40/-40 cmH2O were -2.521 and -3.114 L/s, respectively, and -2.956 and -3.364 L/s at +50/-50 cmH2O, respectively. At a pressure gradient of +40/-40 cmH2O, only 172 of 528 MI-E trials via ET (32.6%) achieved a PEF faster than -2.7 L/s, whereas 304 of 343 MI-E trials via facemask (88.6%) exceeded the PEF cut-off value.Conclusions: MI-E via ET generated slower PEF than via facemask, suggesting that a higher-pressure protocol should be prescribed for intubated patients. An insufflation-exsufflation pressure of at least +50/-50 cmH2O should be considered to produce a PEF faster than 2.7 L/s, and the applications were safe and feasible for patients under invasive mechanically ventilation.