Respiratory Failure -- Exacerbations of COPD: The Role of Invasive Mechanical Ventilation -- Acute Respiratory Failure after Abdominal Surgery -- Tracheostomy in Critically Ill Patients: The Right Technique in the Right Patient -- Percutaneous Tracheostomy: Past, Present, and Future Perspectives -- Acute Lung Injury -- Role of iNOS-derived Excessive Nitric Oxide in the Pathogenesis of Acute Lun…