Is this patient at risk for postoperative vision loss?

Is this patient at risk for postoperative vision loss?

Several techniques have been employed to reduce blood loss and limit the need for homologous transfusions: posi-tioning that reduces intra-abdominal pressure; surgical hemostasis; deliberate controlled hypotensive anesthesia; reinfusion of salvaged blood; normovolemic hemodilution. A devastating complication of these procedures is the development of ischemic optic neuropathy (ION). This has been reported with increasing frequency over the last decade. Postoperative vision loss is most often due to ante-rior or posterior ischemic optic neuropathy (AION, PION) and rarely due to less common perioperative complications such as central retinal artery or vein occlusion and occipi-tal lobe infarcts. Causes of ION include:

·  decreased perfusion pressure due to systemic hypoten-sion, increased venous pressure, or large vessel occlusive disease

·  increased resistance to blood flow due to increased blood viscosity, local arterial disease, or increased external pressure

·  decreased oxygen carrying capacity.

There are no identified effective treatments for ION and the vision loss is most often permanent. Prolonged surgery, large intraoperative blood loss, and large-volume fluid replacement have been reported to be associated with increased risk of ION. Patient risks are also noted in Table 21.2.

Maintenance of spinal cord perfusion is essential and must be maintained. Multiple-level surgery and fusion requires strict attention to replacement of intraoperative fluid losses and careful assessment before extubation of the trachea. This patient is relatively healthy but should be warned preoperatively of this potential complication.