Oxygen Cylinder for Home.  Oxygen cylinder content home use Oxygen cylinders are commonly used at home by patients with respiratory illnesses who require supplemental oxygen therapy. The content of an oxygen cylinder varies depending on its size and pressure. The most common size of oxygen cylinder used for home use is the E cylinder, which contains approximately 680 liters of oxygen when full. This amount of oxygen is usually enough to last for a few days or a week, depending on the flow rate prescribed by the patient's doctor. It is important to note that oxygen cylinders should be used and handled with care. They should be stored in a cool, dry place away from heat and open flames. It is also important to ensure that the cylinder is properly secured to prevent it from falling or tipping over. Patients using oxygen cylinders at home should also be aware of the signs and symptoms of oxygen toxicity, which can occur if too much oxygen is administered for an extended period of time. Symptoms of oxygen toxicity may include chest pain, shortness of breath, and coughing. If these symptoms occur, the patient should contact their doctor or seek medical attention immediately.