Intraocular Pressure During Spine Surgery

The Effect of Lactated Ringer's Solution Versus Albumin and the Alpha-2 Agonist Brimonidine Versus Placebo on Intraocular Pressure During Prone Spine Surgery

This study will compare the effect of two intravenous solutions on eye pressure during spine surgery in the following groups:

Group A - Lactated Ringer's replacement for blood loss and placebo eye drops

Group B - Lactated Ringer's replacement for blood loss and brimonidine eye drops

Group C - Albumin replacement for blood loss and placebo eye drops

Group D - Albumin replacement for blood loss and brimonidine eye drops

Patients will be administered either brimonidine eye drops, or placebo eye drops, preoperatively, on the day of surgery and during surgery. Eye pressure will be measured before surgery, every 30 minutes throughout your surgery and every hour for 4 hours following surgery. Subjects will be evaluated before surgery and on days 5, 8, 15 after surgery. During these evaluations, the subject will be asked questions about recovery and his/her eyes will be checked by an ophthalmologist and vision will be tested.

Inclusion Criteria:

• Spine surgery with instrumentation in prone position expected to last at least 5 hours;
• Anticipated blood loss ≥ 1L
• Age 18-80 years old;
• ASA physical status I-III.

Exclusion Criteria:

• History of increased intraocular pressure or glaucoma;
• Diabetic retinopathy;
• Heart failure or serious left ventricular dysfunction;
• Abnormal preoperative fundus examination;
• Creatinine > 2 mg/dL;
• Patient refuses blood transfusion or albumin administration