We have reported series of four patients with respiratory failure and acidosis due to exacerbation of Chronic Obstructive Pulmonary Disease (COPD), hospitalized to University Hospital of Catania where they were treated with the Continuous Positive Airway Pressure (CPAP) and according to the literature, this treatment can generate high pressures in the nasal and paranasal sinus, so it can induce complications as rhinosinusitis, pneumosinusitis, pneumosinus, bones deformities, and according to our experience hemosinus; this is a rare condition and actually is not present in the scientific literature. We have collected a series of four cases of hemosinus after CPAP treatment occurred in a short period, about six months. The patient histories didn't show acute/sub-acute trauma or coagulation disorder in anamnesis before the hospital recovery. A CT brain study and coagulation factors assessment were performed in all patients. Our result confirmed the literature about effects of CPAP treatment in the coagulation state and identifies a new complication for patients undergoing this therapy.
