P041: POST OPERATIVE VISUAL LOSS: CAN WE DO ANYTHING ABOUT IT?
Scott Wasilko; University of Florida College of Medicine
Introduction: Post operative visual loss (POVL) is a rare but devastating perioperative complication. First described in 1950, more cases began to appear in the literature over the following half century. While rates vary based on the literature referenced, it is most commonly reported in patients following prone spine surgery and cardiac surgery. Nevertheless, the etiology of POVL remains complex. Here we utilize a recent case of post operative visual loss to review the pathophysiology of the disorder, identify risk factors associated with POVL, and discuss what we can do as anesthesiologists to help prevent this dreaded complication.
Case Description: A 67-year-old Caucasian male with a past medical history of peptic ulcer disease presented from an outside hospital with chest pain and shortness of breath. A chest CT performed in the ER was negative for pulmonary embolism but showed pneumomediastinum with a dilated abnormal appearing esophagus. Follow up CT esophagram revealed a large 1.2cm perforation from the anterior esophagus just distal to the carina. He was subsequently intubated and taken to the operating room where he underwent emergent Ivor Lewis esophagectomy that took roughly 10 hours to complete. Postoperatively he was transported to the intensive care unit intubated and sedated. Immediately following extubation on post operative day 9, he complained of “dark blurry vision” and only seeing shadows. Ophthalmologic exam revealed a normal appearing optic disc, no light perception, fixed and nonreactive pupils, and total visual field deficiencies in both eyes. An orbital MRI revealed edema and hyper-enhancement of the intraorbital segment of the optic nerve bilaterally, confirming the diagnosis of posterior ischemic optic neuropathy (ION).
Discussion: The etiology of POVL remains complex and identifying definitive risk factors is problematic. Incidence after nonocular surgery ranges from 0.002% of all surgeries to as high as 0.2% of cardiac and spine surgery. Visual loss can occur anywhere along the visual pathway, including the anterior segment (corneal abrasions), retina (central retinal artery occlusion), retrochiasmal pathways (cortical blindness), and the optic nerve (anterior or posterior ION). The most common site of permanent injury to the visual pathways in the setting of general anesthesia for nonocular surgery is the optic nerve, and the most often presumed mechanism of injury in this location is ischemia. Identified risk factors for ION include: male gender, case duration, estimated blood loss, obesity, fraction of colloids given, and Wilson frame use. Unfortunately at this time there are no effective treatments for central retinal artery occlusion or ION. As such, it is crucial that we focus on prevention. Possible preventative strategies may include eliminating Wilson frame use, substituting colloid for crystalloid, and maintaining the patient’s head in neutral position and higher than the heart.