Effect of Parallel Oxygen Delivery Through a Tracheal Gas Insufflation (TGI) and a T-piece, on Blood Gases and Respiratory Rate, in ICU Tracheostomized Patients

Inclusion Criteria: * Tracheostomized haemodynamically stable patients, without the need of vasopressors or inotrope medications, without symptoms of pulmonary edema, or interstitial lung diseases. Stable blood gasses (no bigger changes than 15-20% in Oxygen and Carbon dioxide during last 24 hours) Exclusion Criteria: * Peripheral body temperature \< 38 C, White blood cells (WBCs) \< 15 x 109/L * Respiratory rate \>35 * Paradoxical breathing * Abdominal muscle recruitment * Dyspnoea, SaO2 \< 94, without evidence of angina, cyanosis or arrhythmia. * Chest circumferences no bigger than 110 cm (for the larger belt of impedance tomograph)