Patients in critical condition, due to their prolonged stay in the Intensive Care Unit (ICU), the severity of the underlying disease, and potential adverse effects of hospitalization, may develop serious complications, such as muscle atrophy and weakness, which also affect the respiratory muscles. It is characteristic that within the first 18-69 hours of mechanical ventilation (MV), proteolytic processes occur that lead to rapid atrophy of the diaphragm. Diaphragmatic dysfunction acquired during the ICU stay thus appears to have an adverse effect on weaning from mechanical ventilation, length of ICU stay, length of hospital stay, functional status, quality of life, and mortality within the ICU and the hospital. Inspiratory muscle training (IMT) has been identified as an intervention that could augment weaning, preventing the dedtrimental effects of MV. The purpose of this study is to assess the effect of an IMT protocol in weaning success of ICU patients. Specifically, an electronic device will be used that incorporates a tapered flow resistive technique.

It is estimated that 40% of the duration of mechanical ventilation is devoted to the weaning process. A length of stay in the ICU of more than 7 days appears to be associated with a 27,9% risk of developing infections. Furthermore, the mortality rate is higher in patients with infections. Additionally, the daily cost of hospitalizing a patient on mechanical ventilation is estimated at €1,590-€1,657, while this varies depending on the interventions required. The burden on the National Health System from the prolonged stay of patients in the ICU, as well as from the complications that will arise, increases exponentially.

It has been found that implementing an IMT program can lead to rapid and successful extubation of the patient, while early mobilization can accelerate timely discharge from the ICU. This optimizes the cost-effectiveness ratio in intensive care units.

The investigators believe that implementing an IMT program will maximize the effectiveness of the early mobilization program for ICU patients. Thus, the investigators believe it will provide valuable insights into the rehabilitation needs of critically ill patients, contributing to earlier weaning from mechanical ventilation and transition to the next level of care. The investigators hypothesize that the implementation of such an intervention program will reduce the length of hospital stay, while also lowering the cost of daily care.

This is a randomized control trial that investigates the effectiveness of an inspiratory muscle training program in successful weaning of mechanically ventilated patients for at least 72 hours. Both experimental groups will receive a protocolised early mobilization program. IMT intervention will be applied till ICU discharge once a day for 5 days/week initiating with a load of 40% of maximal inspiratory pressure (MIP). Primary outcome will be a successful weaning from MV. And secondary includes MV duration, MIP, maximal expiratory pressure (MEP), ICU and hopsital length of stay.

Inclusion Criteria:

• ≥ 72h invasive mechanical ventilation
• adequate co-operativeness as assessed by 5SQ ≥ 3.

Exclusion Criteria:

• terminal condition or palliative care
• neuromuscular or neurological conditions prior to ICU admission