Mechanical Insufflation-Exsufflation: The Good, the Bad, and the Ugly.

Mechanical insufflation-exsufflation is a vital component in the management of respiratory symptoms in individuals with neuromuscular disease.1,2 This therapy is often the primary treatment modality long before additional support such as ventilator assistance is indicated. Although there are only 2 devices approved in the United States, there are several devices that have been approved in Europe. The existence of different devices raises the question of whether they should be used interchangeably or not. A previous study comparing 2 commercially available mechanical in-exsufflation devices in Europe found differences in peak expiratory flow (PEF).3 In this issue of RESPIRATORY CARE, Frigerio et al4 reported the findings of an in vitro comparison of 5 mechanical in-exsufflation devices available in Europe. They found discrepancies between the preset and actual inspiratory and expiratory pressures and time. Tidal volume and PEF were also affected by different simulated conditions. A reduction in tidal volume resulted in a lower pre-tussive volume, potentially leading to a less effective artificial cough. A decrease in PEF could potentially have similar effects. The authors also found that air leaks negatively impacted the performance of the devices. The clinical implication is that practitioners should verify that caregivers can correctly operate the device while minimizing the presence of air leaks. Although the reported differences are statistically significant, new studies are necessary to establish whether they are clinically important as well. A clinical trial with a crossover design utilizing the best and worse in vitro performer could be used to determine the impact of using different devices on frequency of respiratory infections and hospitalizations in a population with neuromuscular disease. It also important to point out that the reported findings should be confined to the testing conditions that were utilized in the study. Namely, these results cannot be extrapolated to either pediatric patients/models or different settings. In addition to performance of mechanical in-exsufflation devices, the authors also evaluated ease of use by ICU physicians. They found that the device with an analog interface resulted in more errors. User-friendliness is a characteristic that should not be overlooked when respiratory devices are prescribed for home. Home caregivers with no medical background are often trained in a short period of time to provide care at home.