Sleep apnea is a sleep disorder characterized by abnormal pauses in breathing while you sleep. When there are breathing pauses, the level of oxygen in the blood decreases. Oxygen is needed to repair wounds and build new tissue, which is critical to surgical patients. These abnormal pauses in breathing can move you out of a deep sleep and into a lighter sleep. As a result, your quality of sleep is poor, and the system that carries your blood throughout your body (cardiovascular system) experiences stress. Patients with sleep apnea are at an increased risk for developing respiratory and cardiovascular complications following surgery. These complications can include irregular heart rhythms, oxygen deficiency, high blood pressure, diabetes, stroke, heart attack and even death.