WHAT IS POST OPERATIVE VISION LOSS
Post Operative Vision Loss (POVL) is exactly what it sounds like. A patient goes into surgery and after waking from the anesthesia the patient has reduced vision. It is surprisingly common. Studies estimate that it occurs somewhere between 0.05 percent and 4.5 percent of all surgical cases. Amazingly, few patients are aware of this risk of surgery and doctors rarely explain the risk to patients before surgery.
POVL is a permanent injury to the optic nerve. The injury causes the optic nerve to not function, or function but with reduced efficiency, thus resulting in vision loss.
CAUSES OF POST OPERATIVE VISION LOSS
POVL is caused by several factors. In a nut shell, it is caused by the doctor and anesthesiologist failing to maintain blood pressure and blood status during a long surgery. Because spinal surgeries tend to be long, it occurs during spinal surgery especially frequently. Three factors are known to increase the risk of POVL during surgery.
First, blood loss during surgery. The red blood cells in the blood stream are called Hemoglobin. They pick up oxygen in the lungs and carry that oxygen throughout the body. Oxygen is essential to the survival of all living tissue. When a patient bleeds during surgery the medical team typically replaces that lost blood with non blood fluids in order to maintain adequate blood pressure. Because the blood is being diluted (hemodilution), the ability of the blood to carry oxygen throughout the body is reduced.
Second, patient positioning during surgery. The heart pumps blood to all parts of the body. The heart does this using pressure. In order to pump blood, the heart must generate sufficient pressure to push the blood to tissues throughout the body. If the pressure on any tissues are increased, the heart is not as successful at pumping oxygen carrying blood to the tissues of the body. We've all experienced this effect when we sit improperly or lay on an arm and it goes to sleep. The sensation we experience is due to a lack of oxygen in the tissues that are "asleep." Blood returns to the heart through veins. The pressure in veins is typically lower. The lower pressure allows oxygenated blood to go the the tissues of the body and then return to the lungs to pick up more oxygen. When a patient's head is placed lower than the patient's head for a long period of time, tissue and venous pressure increase in the head and the heart may not be capable of delivering adequate oxygen to the optic nerve. This happens especially often in spinal surgery because a patient's head is frequently placed lower than the patient's heart during those surgeries.
Third, laying on your stomach. When a patient lies on his or her stomach, the pressure on the abdomen can cause the person to breath less efficiently and can reduce the amount of oxygen that the lungs deliver to the blood. Another problem with placing a patient on his or her stomach is that the abdominal pressure can push against the vena cava. The vena cava is a large vein running through the torso that returns blood to the heart. This pressure can force the blood to flow through peripheral veins to find its way back to the heart. During spinal surgery, this can increase the amount of bleeding, taking us back to the first risk factor.
In order to reduce bleedings, some surgeons request the anesthesiologist to reduce the patient's blood pressure. Some surgeons also place the patient head lower during spinal surgery to make it more comfortable for the surgeon to reach the spine.
POVL appears to be especially common in spinal surgeries lasting more than six hours and with more than one liter of blood loss. The type of anesthesia used does not appear to be a risk factor. Other risk factors are preexisting: vascular disease, high blood pressure, diabetes and a large belly.
COMMON DEFENSES
Sometimes doctors will claim during trial that the injury to the optic nerve could not have been caused by a lack of oxygenated blood during surgery. They argue that common sense would demand that any patient suffering such an injury would also have some sort of brain injury due to the decreased flow of oxygenated blood. In 2008, the journal Anesthesiology published a study performed on pigs. The study showed that in the scenario described above, the body protected the brain by increasing blood flow through the brain. The body did not protect the optic nerve in the same way. Therefore, the pigs suffered optic nerve damage without suffering any brain injury.11
WHAT WE CAN DO FOR YOU
Our attorneys are prepared to investigate your claim. If our investigation shows that your POVL was caused by the poor practices of the doctor or the anesthesiologist, we will make a medical malpractice claim for you and get you the compensation you deserve. Living a life without vision, or with reduced vision, is a devastating injury. Our attorneys are prepared to take on the medical industry on your behalf. If you or a loved one has suffered POVL, please call or click for a free consultation. Home and hospital visits are available.
