Atelectasis: small air pockets within the lung collapse Complications that arise from treatment in a hospital: blood clots formed by lying down for long periods of time, weakness in muscles that are used for breathing, stress ulcers, and even depression or other mental illnesses. Failure of multiple organs Pulmonary hypertension or increase in blood pressure in the main artery from the heart to the lungs. This complication typically occurs due to the restriction of the blood vessel due to inflammation of the mechanical ventilation