Download - Post Operative Visual Loss - Caleb Rogovin

POVL Postoperative Visual LossPOVL Postoperative Visual Loss

Caleb A. Rogovin, CRNA, MS, CCRN, CENTemple University Hospital

Philadelphia, PA

NJANA FALL MEETING

Sunday October 11, 2009

POVLPOVL

• A rare but devastating complication

• May involve one or both eyes with partial or complete visual loss

• May result in temporary, partial or complete permanent blindness

• 0.0008%-1% depending on surgical procedure (Non-ocular in nature)

Anatomy of the EyeAnatomy of the Eye

• The cornea and lens focus light on the retina

• Iris controls amount of light reaching the retina by altering size of pupil

http://images.google.com/imgres?imgurl=http://www.nlm.nih.gov/medlineplus/ency/images/ency/fullsize/1094.jpg&imgrefurl=http://www.nlm.nih.gov/medlineplus/ency/imagepages/1094.htm&h=320&w=400&sz=24&hl=en&start=14&tbnid=tNgltid1iIY_nM:&tbnh=99&tbnw=124&prev=/images%3Fq%3Deye%26gbv%3D2%26hl%3Den%26sa%3DG

Ocular AnatomyOcular Anatomy

• Eye has 3 chambers• Anterior

• Posterior

• Vitreous

• Ciliary Body produces aqueous humor

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• Aqueous humor flows through posterior chamber by way of pupil to anterior chamber and drains through Canal of Schlemm

http://www.mydr.com.au/content/images/categories/eyes/anatomy_of_eye.gif


• RETINA • Sensory portion of eye

• Optic Nerve• Axons are derived

from retinal ganglion cells

Ocular Blood SupplyOcular Blood Supply

• Blood supply to most of the eye is supplied by the Ophthalmic Artery• First intracranial branch of internal carotid

artery

• Increased Intraocular Pressure (IOP) decreases retinal blood flow

• IOP = (rate of aqueous humor production/facility of outflow) + EVP (episcleral venous pressure)

• Changes in HCT may alter ocular blood flow…anemia is bad!

Associated with…Associated with…

• Spine Surgery• Prone Position

• Neck Surgery• Cardiac Surgery• Nasal/Sinus Surgery

• Direct damage to the vascular system of the eye may cause spasm or thrombosis in arteries

• Compression of retinal artery by formation of a hematoma

• Intra-arterial injection of local anesthesia with epinepherine

POSTERIOR SPINE SURGERYPOSTERIOR SPINE SURGERY

• This is the major focus

• Majority of cases are related to this surgery

• ASA Postoperative Visual Loss Registry• Analysis of 93 spine cases with POVL• Anesthesiology 2006; 105:652-9 Lee et al.

• Majority of POVL (80%) was associated with Ischemic Optic Neuropathy (ION)

Spine SurgerySpine Surgery

• Associated Clinical Information

• Length of Surgery• >6 hours

• EBL• >1000 mL

• Deliberate Hypotension*• NOT a factor in POVL

• Prone Position

• Head Fixation*• NOT a factor

Deliberate HypotensionDeliberate Hypotension

• Autoregulation of blood flow in the cerebral vasculature is well documented and understood (???Well, maybe but not by me!)

• It is not clear whether the human optic nerve also has the ability to autoregulate in both the anterior and posterior regions

Central Venous Pressure (CVP)Central Venous Pressure (CVP)

• CVP is increased • Head down position• Head turned to one side• Direct abdominal pressure

Prone PositionProne Position

• Prone position itself, significantly increases intraocular pressure

• 10% Reverse Trendelenberg position reverses the increase

ION Ischemic Optic NeuropathyION Ischemic Optic Neuropathy

• Ischemic Optic Neuropathy• An ischemic insult to the optic nerve• Divided into ANTERIOR and POSTERIOR • Diagnosis depends on which part of the nerve is

affected…ANTERIOR and POSTERIOR sections have different blood supplies

IONION

• ANTERIOR • POSTERIOR• Main vascular supply

is Pial vessels derived from branches of the OA

• Farthest from an arterial supply

• Most commonly implicated with hemorrhagic hypotension

IONION

• Anterior Ischemia• Optic disc edema

• Occasional vision improvement

• Posterior Ischemia• Delayed edema

• Seldom vision improvement

IONION

• Posterior portion of optic nerve is farthest from arterial supply

• Main vascular supply from Pial vessels from branches of opthalmic artery

• NO autoregulatory control• Posterior portion is vulnerable to fall in

perfusion pressure and anemia

IONION

• Diagnosis of exclusion• No definitive opthalmoscopic findings

• Does not suggest that there was extrinsic pressure on the eye• Direct pressure yields

• Retinal Artery Thrombosis which exhibits retinal pallor and “cherry red spot”

Central Retinal Artery Occlusion CRAO

Central Retinal Artery Occlusion CRAO

• Unilateral visual loss

• Most commonly associated with an embolus

• Cherry red spot with retinal edema

• Vision occasionally improves

• Prolonged pressure on the globe

Additional AssociationsAdditional Associations

• Acute Glaucoma

• TURP• Glycine Toxicity

TreatmentTreatment

• There is no real treatment!

• Acetazolamide• Decreases IOP

• Diuretics (Mannitol, Furosemide)• Decrease swelling

• Corticosteroids• Decrease axonal swelling

DevicesDevices

• No specific product has been shown to be more effective

Mayfield Pins…Tell San Francisco Story

IONION

• ASA Visual Loss Registry• ION was associated with 83 of 93 spine cases• Mean Anesthetic Duration: 9.8 +/- 3.1 hours• Mean Age: 50 +/- 14 years• Mayfield Pins: 16/83 cases• EBL: 2.0L (range: 0.1-25L)• ION was most common cause of visual loss after

spine surgery

Case ReportsCase Reports

• ION after spinal surgery• Canadian Journal of Anesthesia 1998

• Cortical blindness secondary to cyclosporine after orthotopic heart transplantation: a case report and review of the literature• J Heart Lung Transplant 1996

• CRAO after scoliosis surgery with a horseshoe headrest • Spine 1993

• Amaurosis secondary to massive blood loss after lumbar spine surgery• Spine 1994

CASE REPORTSCASE REPORTS

• Transient postoperative blindness as a possible effect of glycine toxicity• Arthroscopy 1990

• Anterior ischemic optic neuropathy: a complication after extracorpreal circulation• Ann Thorac Cardiovasc 1998

• Blindness after intranasal ethmoidectomy• Rhinology 1993

• Unilateral blindness after prone spine surgery• Anesthesiology 2001

The Effects of Steep Trendelenburg Positioning on Intraocular Pressure During Robotic Radical Prostatectomy


• Awad, H., Santilli, S., Ohr, M., Roth, A., Yan, W., Fernandez, S., Roth, A., Patel. International Anesthesia Research Society, 109 (2), August 2009.

• IOP increases significantly in anesthetized patients undergoing robotic prostatectomy in steep t-burg position

• Quantified changes in IOP throughout the procedure



• This increase in IOP may be related to the occurrence of Ischemic Optic Neuropathy

• Peak Airway Pressure

• MAP

• EtCO2

• Surgical duration• PREDICTORS OF IOP INCREASE IN T-BURG

OK…OK…

• So what do we know?• POVL is a rare but tragic complication• Majority of cases are related to ION• Factors:

• Length of surgical procedure• EBL• Direct compression on eye• Prone Position• Pre-existing Medical Conditions• Hemorrhagic Anemia

OK…OK…

• Deliberate Hypotensive Techniques• NOT associated with >

incidence of POVL

• No specific transfusion threshold to eliminate risk

• Colloids should be used along with crystalloids to maintain intravascular homeostasis in patients with large blood loss

Anesthetic PlanningAnesthetic Planning

• Head should be level with or higher than the heart when possible (10% Reverse T-Berg)

• Head should be maintained in a neutral position

• Consider staging procedure• For those very long (>6 hr) procedures when

feasible

• Discuss POVL with anesthesia risks and complications

POVLPOVL

• A rare, unexpected, devastating complication

• Anesthetic vigilance!• Awareness of associated factors• Proper positioning• Anemia• Crystalloids and Colloids• Blood Pressure

NEW INFORMATIONNEW INFORMATION

• APSF Newsletter• Volume 23, No. 1, 1-20 Spring 2008

• If my spine surgery went fine, why can’t I see?• Postoperative Visual Loss and Informed Consent

• Anthony Lehner, MD

New InformationNew Information

• Current Reviews for Nurse Anesthetists• Lesson 5 Volume 31 7/17/2008• C. Phillip Larson Jr., M.D.C.M.

• A Rational Approach for Preventing Blindness During Posterior Spinal Surgery

What do “I” do?What do “I” do?

• Careful pre-op assessment and anesthesia risks and complications

• Consider Arterial Line and Central Line

• Limit surgical time to <6 hours• Stage Procedures

• Monitor HCT• <26% consider transfusion

What do “I” do?What do “I” do?

• Keep head in neutral position or slightly higher than heart

• Limit Crystalloids to 5cc/kg/hr• Current Reviews

• BE VIGILANT!

REFERENCESREFERENCES

• A report by the American Society of Anesthesiologists Task Force on Perioperative Blindness. Practice Advisory for Perioperative Visual Loss Associated with Spine Surgery. Anesthesiology 2006; 104:1319-28.

• Lee, L., Roth, S., Posner, K., et al. The american society of anesthesiologists postoperative visual loss registry. Anesthesiology 2006; 105:652-9.


• Warner, M. Postoperative visual loss experts, data and practice. Anesthesiology 2006;105:641-2.

• Chaudhry, T., Chamberlain, M., Vila, H. Unusual cause of postoperative blindness. Anesthesiology 2007; 106:869-79.

• Roth, S., Barach, P. Postoperative visual loss: still no answers-yet. Anesthesiology 2001; 95:575-77.


• Ochroch, E., Fleisher, L. Retrospective analysis: looking backward to point the way forward. Anesthesiology 2006; 105:643-44.

• Katz, D., Karlin, L. Visual field defect after posterior spine fusion. Spine 2005; 30:E83-85.