Impact of Home Non Invasive Ventilation in Patients With Chronic Obstructive Pulmonary Disease Discharged From Assiut University Hospital

Inclusion Criteria: * Patients more than 18 year old. * Severe COPD (classified as GOLD stage Ⅲ and IV), confirmed by FEV₁/FVC \< 70% and FEV₁ \< 50% of the predicted value. (9) * Persistent hypercapnia (PaCO₂ ≥ 60 mmHg ≥2 weeks after resolution of acute exacerbation and compliant on optimal medical therapy with or without long term oxygen therapy Exclusion Criteria: * Other significant respiratory disorders (e.g,history suggestive OSA, Body Mass Index more than 30, pneumothorax, bullous lung disease, advanced interstitial lung diseases , restrictive thoracic wall diseases , neuromuscular disease). * Undergone intubation or tracheostomy prior to NIV initiation during the last 2 months. * Those using addictive narcotic medications. * Comorbidities and diseases that might confound survival outcomes (e.g., malignancy, advanced hepatic or renal diseases). * Pregnancy * Refusal or Inability to tolerate NIV during initiation and adaptation phase. * Expected Poor compliance (patients deemed unlikely to adhere to nightly NIV use such as no family support, severe frailty). * Withdrawal criteria: stopping bipap or medical treatment, voluntary withdrawal by the participant, failure to attend scheduled visits, and significant clinical deterioration requiring alternative management during the study period