If you have a symptom of shortness of breath or a known lung or heart condition, your doctor may use a pulse oximeter. The pulse oximeter, or Pulse Ox, is an electronic device that measures the saturation of oxygen carried in your red blood cells. Pulse oximeters can be attached to your fingers, forehead, nose, foot, ears or toes. The device may then be reused or disposed of. If using this in a home setting, you should ask your healthcare provider before disposing of a pulse ox device, as it can be expensive and reusable.