Inspiratory Muscle Training in Mechanically Ventilated Patients in Intensive Care Unit

Inclusion Criteria: * ≥18 years of age * hemodynamic stability and alert * able to spontaneously trigger the ventilator and perform at least one command for activation of respiratory muscles * required mechanical ventilation support with continuous spontaneous ventilation mode or pressure- or volume-controlled intermittent mandatory ventilation (6 breaths/min) mode * required pressure support ≤ 15 cmH2O and PEEP ≤ 10 cmH2O * unable to breathe without support for 72 consecutive hours following the resolution of factors leading to respiratory failure * FiO2 of 0.5 or less * PaO2 greater than 60 mmHg and capable of sufficient gas exchange Exclusion Criteria: * cooperation disorder * trauma or deformity related to the thorax that affect respiration * progressive neuromuscular disease * excessive bronchial secretion (requiring more than one suctioning per hour) * need for continued sedative or analgesic agents * use of home-type mechanical ventilation before admission to the hospital * cardiac, pulmonary, or other conditions leading to impaired stability * impaired cooperation, compliance, and motivation