Inspiratory muscle training in mechanical ventilation: suitable protocols and endpoints, the key to clear results - a critical review

Definitely, mechanical ventilation (MV) is a life-saving treatment in the intensive care unit (ICU), but it is also a double-edged sword. Forty percent of the overall time spent in the ICU was reported to be devoted to weaning of MV. The major cause of weaning failure is the imbalance between the imposed load on the respiratory system and its capacity to overcome that. Thus, since the 1980's numerous studies with inspiratory muscle training (IMT) have been conducted in an attempt to reduce weaning and MV time in prolonged mechanically ventilated patients. Despite dozens of published research, only 5 randomized controlled trial (RCT) were conducted to date. Nevertheless, it was not yet clear whether IMT led to a shorter duration of mechanical ventilation, improved weaning success, or improved survival. These RCT show considerable heterogeneity each other and possible bias that could have impaired their results. Thus, some questions may be made to highlight main points: What is the ideal prescription of IMT for patients on MV? What is the best time to measure treatment effect? Which kind of device should be used to IMT? What are the best endpoints to evaluate the effects of IMT on the process of discontinuing from MV? IMT on mechanically ventilated patients seems to be a promissory treatment despite controversial results. Therefore, RCT should be carried out to verify the efficacy of new protocols in different approaches