Repair of Retinal Detachment/Vitrectomy

What the Anesthesiologist Should Know before the Operative Procedure

The pathogenesis of retinal detachment is varied. Rhegmatogenous retinal detachment occurs upon formation of a tear or hole in the retina that allows vitreous cavity fluid to enter underneath the retina, causing displacement.

Exudative detachment is not associated with a tear or hole. Here, subretinal fluid accumulates secondary to inflammation, vascular anomaly, or injury. Tractional retinal detachment occurs when fibrovascular tissue, formed due to trauma or neovascularization, pulls the retina away from the underlying tissue. Myopia, diabetes, as well as history of cataract surgery are all risk factors for developing retinal detachment.

Vitreous hemorrhage can also occur, causing an acute reduction in quality of vision. Risk factors include diabetes, trauma, and retinal vein occlusion. The majority of patients presenting for retinal detachment surgery are adults. The strong association of diabetes with some forms of retinal pathology dictates that one must contend with the numerous systemic issues associated with that disease.

Surgery for retinal detachment is characterized by varying degrees of intraoperative surgical stimulation and an unpredictable procedural duration time.

1. What is the urgency of the surgery?

What is the risk of delay in order to obtain additional preoperative information?

The macula is a small, circular area (1-1.5 mm in diameter) of the retina that is responsible for central vision. It confers the ability for fine, sharp, central vision.

Procedural urgency depends, in part, on whether the macula is involved in the detachment. A “Macula-on” retinal detachment is urgent. If the macula has already detached, surgery is less urgent.

Emergent: Surgery is rarely emergent in nature. Traumatic eye injuries resulting in retinal detachment, vitreous hemorrhage, lens dislocation, or intraocular foreign bodies may be urgent/emergent.

Urgent: Repair of spontaneous retinal detachment is urgent when the macula is still attached. Urgent surgery is also indicated when a lens has dislocated and migrated into the vitreous during cataract surgery.

Elective: Ultimate visual outcome does not change if the macula has detached. While urgency is diminished, surgery needs to be accomplished within seven days.

2. Preoperative evaluation

Retinal detachment surgery patients are commonly elderly, myopic, and/or diabetic. Marfan’s syndrome is associated with a high incidence of retina disease as well. Preoperative evaluation should focus on ensuring that medical status is optimized to a level of acceptable risk. Preoperative evaluation of cardiovascular, pulmonary, neuromuscular, and endocrine status is vitally important.

• Medically unstable conditions warranting further evaluation include: Unstable or atypical angina, decompensated congestive heart failure, significant dysrhythmia, severe valvulopathy, malignant hypertension, active upper respiratory infection, decompensated COPD, Pickwickian obstructive sleep apnea, and uncontrolled diabetes.

• Delaying surgery may be indicated if: New onset of angina or change in characteristics of patient’s pain, angina at rest, dyspnea, inability to remain supine, new onset atrial fibrillation, supraventricular dysrhythmia with uncontrolled heart rate, ventricular dysrhythmia, complete heart block, ICD malfunction/frequent discharge/battery issues, pacer issues, poor oxygen saturation, moderate active cough, orthopnea, and severe hyper- or hypo-glycemia

3. What are the implications of co-existing disease on perioperative care?

N/A

b. Cardiovascular system

• Acute/unstable conditions: Geriatric patients may be at high risk for having preexisting cardiovascular disease. Acute issues, such as new onset or unstable or atypical angina, angina at rest, decompensated congestive heart failure, significant rhythm disturbance, severe valvulopathies, and malignant hypertension, typically require greater attention and may be of higher priority than immediate surgery.

• Baseline coronary artery disease or cardiac dysfunction – Goals of management: Ensure that there have been no recent changes in baseline cardiac status. Ideally, obtain recent evaluation of pacemaker and/or ICD function.

c. Pulmonary

Active URI, COPD, reactive airway disease (asthma), symptomatic postnasal drip

Retina surgery via regional anesthesia and MAC require that the patient remain relatively quiescent in the supine position for the duration of surgery. Length of time for the procedure is highly variable. If the patient moves excessively, whether due to severe cough, uncontrolled COPD/emphysema, asthma, or postnasal drip, the risk for poor ultimate visual outcome increases. Consider antitussives, bronchodilators, or nasal decongestants. Consider delaying surgery, if prudent, until pulmonary issues are optimized.

Obstructive sleep apnea

Assess patient’s ability to remain in the supine position without developing airway obstruction.

d. Renal-GI:

GERD

Determine if treated and asymptomatic or if active issues present.

PONV

Inquire about history of postoperative nausea and vomiting. Consider prophylactic antiemetic for the at-risk patient.

e. Neurologic:

Parkinson's disease

Mild tremors, particularly of the upper or lower extremities, may not have an impact on surgery. A moderate head tremor, however, may render surgery via regional anesthesia and MAC difficult. Assure that patients with Parkinson’s disease continue their medicines throughout the day of surgery.

Dementia

Assess patient’s ability to remain relatively still during surgery. Assure continuation of medications. Consider general anesthesia if patient is at greater risk for gross movement during surgery.

f. Endocrine:

Diabetes

Patients with diabetic vascular proliferative retinal disease are more likely to have poorly controlled blood sugar levels. Determine the adequacy of glucose control.

g. Additional systems/conditions which may be of concern in a patient undergoing this procedure and are relevant for the anesthetic plan (eg. musculoskeletal in orthopedic procedures, hematologic in a cancer patient)

Marfan's syndrome

More than half of those with this hereditable connective tissue disorder develop dislocation of one or both lenses, which can lead to subsequent retinal detachment. Patients are susceptible to aortic wall dilatation, dissection, valvulopathy, and sudden death.

Musculoskeletal

Arthritis and lower back pain may limit the patient’s ability to remain in the supine position for a prolonged period. Assure medications are continued on the morning of surgery. Assess regional/MAC patient ability to position properly and comfortably.

Ophthalmologic

Assess quality of vision in the non-operative eye. For the monocular patient having surgery on the sighted eye, consider shorter-acting local anesthetics if the clinician is relatively certain surgical duration will be brief. Otherwise, general anesthesia is a prudent choice. Blind care precautions will be needed postoperatively.

Ophthalmologic

Patients with a history of myopia (near-sightedness) may have a globe that is larger than is typical, rendering the eye at greater risk for unintentional penetration by a block needle. In addition to occupying more space, larger myopic eyes tend to have thinner walls and are thus more readily injured. Prior surgery with placement of a scleral buckle or band distorts the globe’s shape, increasing risk. Enophthalmia (recession of the globe into the orbit) also confers additional risk for globe penetration by the block needle.

4. What are the patient's medications and how should they be managed in the perioperative period?

Most medications should be continued on the day of surgery. Oral hypoglycemic agents may be omitted. Intermediate, combination, and long-acting insulin should be reduced, and regular insulin should not be administered on the morning of surgery.

Some herbals and supplements may interact with and augment anesthetic sedatives. Additionally, they may increase the propensity toward bleeding. For less urgent procedures, consider discontinuing these agents one to two weeks prior to scheduled surgery.

h. Are there medications commonly seen in patients undergoing this procedure and for which should there be greater concern?

Anticoagulant medications

Many patients for retinal detachment surgery take prescribed antiplatelet and/or anticoagulant medications due to coronary or vascular disease. Clopidogrel, coumadin, or aspirin may predispose towards perioperative bleeding, such as choroidal hemorrhage, hyphema, circumorbital bleeding, retrobulbar hemorrhage, and exacerbation of preexistent vitreous hemorrhage.

These agents have been traditionally discontinued upon diagnosis of retinal detachment or vitreous hemorrhage for fear of intraoperative bleeding and poor visual outcome. Withholding these medications, however, can place patients at risk for coronary hypoperfusion, myocardial ischemia, thrombosis of drug-eluting stents, cerebrovascular accident, and peripheral deep vein thrombosis.

Recent investigations suggest that surgery and regional anesthesia can be performed safely without discontinuation of said medications. Larger scale multicenter studies of cataract patients have not definitively proven the benefit of maintaining or discontinuing these agents.

Topical ophthalmic drops

These medications can be absorbed into the systemic circulation directly through the conjunctiva, or, more likely, via drainage through the nasolacrimal duct onto the nasal mucosa. For example, non-selective beta-adrenergic blocking agents for treatment of elevated intraocular pressure may produce severe bradycardia or exacerbate symptoms of bronchospasm.

Echothiophate (phospholine iodide)

This is an anticholinesterase once commonly prescribed for the management of glaucoma. It can profoundly interfere with the metabolism of succinylcholine, resulting in prolonged neuromuscular paralysis following a single dose of succinylcholine. Normal pseudocholinesterase activity may not return for over a month after discontinuation of echothiophate.

Tamulosin

This agent is prescribed for symptomatic relief of benign prostratic hypertrophy. It may alter the tissue characteristics of the iris, rendering it floppy to manipulation by the surgeon. This may heighten the difficulty of performing surgery, warranting a denser block and/or deeper sedation for those patients having regional anesthesia and MAC.

i. What should be recommended with regard to continuation of medications taken chronically?

• Cardiac – continue

• Pulmonary – continue

• Renal – continue

• Neurologic – continue

• Anti-platelet – controversial (see above)

• Psychiatric – continue

j. How To modify care for patients with known allergies –

N/A

k. Latex allergy- If the patient has a sensitivity to latex (eg. rash from gloves, underwear, etc.) versus anaphylactic reaction, prepare the operating room with latex-free products.

Equipment and implant materials (scleral buckle or band) do not contain latex. Beware of latex-containing gloves.

l. Does the patient have any antibiotic allergies- – Common antibiotic allergies and alternative antibiotics]

Routine administration of prophylactic intravenous antibiotics is generally not indicated.

m. Does the patient have a history of allergy to anesthesia?

Local anesthetics/ muscle relaxants: Occasionally, patients will present with a purported history of local anesthetic allergy, particularly procaine. Amino-amide local anesthetics, such as lidocaine and bupivacaine, are the most commonly used agents for ophthalmic regional anesthesia, rendering use of amino-esters unnecessary. Note that topical analgesic drops are often amino-esters (tetracaine, for example).

5. What laboratory tests should be obtained and has everything been reviewed?

Routine preoperative laboratory testing has not been shown to improve outcome. The need for studies should be determined based upon the results of the preoperative history and physical examination. Patients may be elderly and have concomitant medical issues. In general, selective testing is best.

Common laboratory normal values will be same for all procedures, with a difference by age and gender.

• Hemoglobin levels: Not routine.

• Electrolytes: Check serum glucose in patients with diabetic vascular proliferative retinal disease.

• Coagulation panel: Consider INR. See discussion above.

• Axial length imaging: Some patients may have had ultrasound measurements of their eyes by the ophthalmologist prior to surgery. The axial length is the distance from the posterior retina to the anterior cornea. An eye with an elongated axis has greater size and volume than a globe of normal length, and thus may be at enhanced risk of penetration by a needle. A length of 25 mm or more is considered atypical.

• Other tests: As indicated by history and physical examination.

Intraoperative Management: What are the options for anesthetic management and how to determine the best technique?

Traditionally, due to the prolonged duration of surgery and the intensity of surgical stimulus, general anesthesia was considered optimal. Over the past few decades, surgical techniques have evolved to a point that allows a greater proportion of vitreoretinal procedures to be performed via regional anesthesia and monitored anesthesia care.

Anesthesia options for patients undergoing repair of retinal detachment and vitreous hemorrhage include general anesthesia, intraconal (retrobulbar) block, extraconal (peribulbar) injection, and sub-Tenon’s block. The majority of patients have monitored anesthesia care and some form of regional block.

Regional anesthesia

In addition to rendering the globe and surrounding eye insensate, ophthalmic regional anesthesia offers the benefit of an akinetic globe and a motionless surgical field for the surgeon to work in. Blocks are categorized as needle-based or cannula-based.

1. Peripheral nerve block: needle-based blocks

The anatomical basis of needle-based blocks rests upon the concept of the intraorbital muscle cone septum. This complex is comprised of the four ocular rectus muscles that have origin at the fibrous Annulus of Zinn and extend forward to their respective insertions into the globe. Taken together with their surrounding connective tissue, these muscles create a cone-like structure situated just posterior to the globe.

A retrobulbar block consists of placing a needle tip behind (“retro”) the globe (“bulbar”). A more descriptive and anatomically proper term, intraconal block, relates to the position of the needle tip inside of the muscle cone. Injection of a low volume of local anesthetic (1-3 mL) via a steeply angled and somewhat deeply placed needle will produce swift onset of analgesia and akinesia. For patients who are prone to blepharospasm (tight eyelid squeezing), a separate injection seeking to block a branch of the facial nerve leading to the orbicularis oculi may be warranted.

Numerous studies have shown that the intraorbital septum is porous in nature. Local anesthetics deposited outside of the complex diffuse inward. Thus, anesthesia of the eye and orbit can be achieved by instilling local anesthetics exterior to the muscle cone. The extraconal block is also known by the less descriptive term, peribulbar anesthesia (“around” the “globe”).

An extraconal block is achieved by directing a minimally angled, short needle to a shallow depth such that the tip becomes situated outside of the muscle cone. Larger volumes of local anesthetic are required to obtain sufficient ingress into the cone. Onset of anesthesia and analgesia are more gradual. A separate facial nerve block is usually not required, as some portion of the local anesthetic diffuses forward and creates lid akinesia.

Complications associated with needle-based blocks include superficial or retrobulbar hemorrhage, precipitation of the oculocardiac reflex (bradyarrhythmia), postoperative diplopia, puncture or penetration of the globe, intraocular injection of local anesthetics and subsequent poor visual outcome, optic nerve trauma, central retinal artery occlusion, and blindness.

Due to the proximity of the central nervous system, intravascular injection of local anesthetics can produce immediate onset of seizure activity, abrupt loss of consciousness, apnea, and cardiac instability. The optic nerve is covered by dura, so dispersal of local anesthetic along the optic nerve sheath can induce brainstem anesthesia, characterized by delayed-onset loss of consciousness, respiratory depression, and cardiovascular instability.

A differential diagnosis of altered physiologic status after needle-based eye block includes oversedation, intravascular injection of local anesthetics, and brainstem anesthesia. All three may present with varying levels of consciousness, apnea, and cardiac issues. The diagnosis of oversedation may be confirmed upon response to administration of narcotic and/or benzodiazepine reversal agents. The reaction to intravascular injection is quick and seizure activity is common. Brainstem anesthesia tends to have a longer latency of onset. Mydriasis (pupil dilation) and akinesia of the contralateral eye are diagnostic and indicates travel of local anesthetic across the optic chiasm.

An intraconal block is theoretically safer, as the needle is not directed deeply or towards the apex of the orbit where the optic nerve, muscle origins, and vasculature ingress are located. This distance from key structures decreases the likelihood of causing optic nerve injury, dural sheath penetration, orbital epidural injection, and brainstem anesthesia.

• Drawbacks: Diffusion of local anesthetics may be impinged by presence of scar tissue in those patients who have had prior scleral buckle placement. This is more of a concern with sub-Tenon’s bocks. The in situ scleral buckle may distort the globe’s shape, increasing the risk of needle penetration.

• Issues: In myopic patients, their larger eyes and thinner sclera render myopes more prone to needle penetration.

2. Peripheral nerve block: cannula-based blocks

The anatomical basis of cannula-based blocks rests upon the key structure, Tenon’s capsule. The capsule overlays and surrounds the sclera, the globe’s tough outer layer, providing a smooth frictionless environment for globe movement. Tenon’s capsule originates near the limbal margin, where it is fused to the conjunctiva. It extends posteriorly towards the optic nerve, encompassing the globe as well as portions of the extraocular muscles.

A sub-Tenon’s block consists of placing a cannula (or needle) into the episcleral space underneath Tenon’s capsule. Local anesthetics instilled into this potential space will flow posteriorly to the optic nerve as well as to the ciliary nerves that penetrate the capsule en route to the globe.

Common, minor complications include subconjunctival hemorrhage, conjunctival chemosis (swelling with local anesthetic), and incomplete akinesia or anesthesia. Case reports of rare, serious complications include postoperative diplopia, puncture or penetration of the globe by the cannula or scissors, intraocular injection of local anesthetics, optic nerve trauma, central retinal artery occlusion, and brainstem anesthesia.

• Drawbacks: Diffusion of local anesthetics may be impinged by the presence of scar tissue in those patients who have had prior scleral buckle placement. This is more of a concern with sub-Tenon’s blocks. The in situ scleral buckle may distort the globe’s shape, increasing the risk of needle penetration.

• Issues: In myopic patients, the sub-Tenon’s block-thinner sclera is more readily injured by dissection scissors.

General anesthesia

• Benefits: General anesthesia is more suitable for younger patients and those undergoing prolonged, complex surgical procedures. Not all patients have the capacity to remain quiescent during surgery. Infants, children, the developmentally delayed or challenged, patients with movement disorders, and those with certain psychiatric issues, such as profound claustrophobia, for example, may benefit from the use of a general anesthetic.

• Drawbacks: Prolonged recovery, the need for phase I recovery, and the potential for an abrupt spike of intraocular pressure upon emergence and extubation. Following intravitreous gas bubble injection (see section 6 below) to tamponade posterior retinal breaks, patients must remain prone for therapy to be effective. Patients must recover sufficiently following general anesthesia in order to be capable of adopting the face-down position.

• Other issues: Intravitreous gas may be used in order to tamponade the retina. Nitrous oxide diffuses into the bubble, causes it to expand, increasing pressure on surrounding structures, potentially causing ischemia with subsequent postoperative visual compromise. Administering general anesthesia without nitrous oxide obviates this issue.

• Airway concerns: By definition, with the surgeon, assistant, and microscope at the head of the OR table, intraoperative access to the patient’s airway is limited. Confirm the position and security of the endotracheal tube/supraglottic airway and all monitoring lines prior to draping.

Endotracheal tube vs. supraglottic airway: Unless contraindicated, a supraglottic airway offers advantages over traditional endotracheal intubation. Intraocular pressure is increased by laryngoscopy and intubation upon induction of anesthesia, and by bucking, coughing, or straining on the tube during emergence from anesthesia. In contrast, with a supraglottic airway, there is minimal-to-zero change in intraocular pressure upon placement, maintenance, or emergence from general anesthesia.

Side of surgery: Tape the non-operative eye shut. During the time-out, reconfirm that the appropriate eye is exposed and not taped or draped! Intraocular pressure can be reduced by decreasing arterial carbon dioxide levels via controlled mechanical ventilation, avoidance of constricting materials around the neck, reverse Trendelenburg positioning, and intravenous agents, such as acetazolamide.

Oculocardiac reflex: This manifests as an abrupt bradycardic or asystolic response to orbit or globe manipulation. It is more commonly encountered with light planes of general anesthesia, hypoxia, and hypercarbia. Assure adequate depth of anesthesia as well as oxygenation and ventilation. Administration of anticholinergics preoperatively in order to prevent the oculocardiac reflex is a dubious strategy with variable effectiveness. Tachycardia secondary to anticholinergics may precipitate cardiac ischemia, and thus have greater adverse consequences than a transiently induced bradycardia.

Treatment of the oculocardiac reflex entails cessation of the causative stimulus and stopping further surgical manipulation until restoration of adequate rate and rhythm. The reflex tends to wane in response to repeated elicitations. If not, or in the face of asystole, consider administration of intravenous anticholinergic agents.

Movement: Untoward gross patient movement during intraocular surgery can result in an unfavorable ultimate visual outcome. Note that the placement of the scleral buckle itself is extraocular; however, other aspects of the repair are intraocular. General anesthesia may be inappropriate for the patient with an active cough, as there is an enhanced risk of laryngospasm, bronchospasm, and/or bucking and straining upon emergence.

Emergence: Consider endotracheal tube extubation under a deep plane of general anesthesia in order to avoid emergence hypertension, coughing, bucking, or straining, which may dramatically raise intraocular pressure. Consider administering intravenous lidocaine (1 mg/kg) or a small dose of remifentanil or propofol prior to extubation.

Postoperative pain management: Intraoperative supplementation of anesthesia with a regional eye block decreases the need for deeper planes of general anesthesia and provides effective postoperative pain management.

Monitored anesthesia care

includes administration of anxiolytics, sedative-hypnotics, analgesics, and anesthetic agents; monitoring and support of vital functions; and diagnosis and management of any medical issues during the surgical procedure and perioperative period. It also includes provision of psychological support and assurance of physical comfort.

Airway/Ventilation

Patient airway status may become compromised due to regional anesthesia (brainstem anesthesia, intravascular injection of local anesthetics) or sedation. See discussion above for differential diagnosis. Airway obstruction, hypoventilation, and hypercarbia may predispose towards abrupt patient movement.

Movement

Untoward movement during ophthalmic block or surgery can result in unfavorable ultimate visual outcome. About 20% of MAC closed claims cases in the ASA database occurred with patients having eye surgery. The most common causes were attributed to block issues and/or perioperative patient movement.

The preoperative evaluation should seek to determine if there is an increased potential for gross movement during retina surgery, which has potential to be of prolonged duration. Factors that increase likelihood include cough, post nasal drip, obstructive sleep apnea, pathologic anxiety, severe claustrophobia, fluctuating levels of consciousness during surgery, and rebreathing of carbon dioxide under closely occluded surgical drapes. Consider postponing less urgent retina surgery until the patient is capable of remaining relatively motionless during the procedure. Patients should be made aware of these risks.

Awareness

Ideally, patients should remain sufficiently alert during surgery in order to retain the ability to remain relatively still. Light planes of sedation will likely promote intraoperative awareness and recall. Consider preoperative consultation with the patient to create appropriate expectations of the surgical experience.

Oculocardiac reflex

The oculocardiac reflex is an abrupt bradyarrhythmic or asystolic response to orbit or globe manipulation. It can occur during administration of a regional anesthetic or during surgery. Administration of anticholinergics preoperatively in order to prevent the oculocardiac reflex is a dubious strategy with variable effectiveness.

Tachycardia secondary to anticholinergics may precipitate cardiac ischemia and thus have greater adverse consequences than a transiently induced bradyarrhythmia. Treatment of the oculocardiac reflex entails cessation of the causative stimulus and stopping further surgical manipulation until restoration of adequate rate and rhythm. This reflex tends to wane in response to repeated elicitations. If not, or in the face of asystole, consider administration of anticholinergic agents.

Malignant hypertension

Phenylephrine drops are commonly administered prior to retina surgery in order to dilate the pupils, creating greater surgical access. Drops can be absorbed systematically via drainage through the puncta into the nasal mucosa, producing a moderate spike in arterial blood pressure. Malignant hypertension, dysrhythmias, myocardial ischemia, and myocardial infarction have occurred following the use of 10% phenylephrine drops. The use of 2.5% phenylephrine, as well as limited application of total volume, is recommended.

6. What is the author's preferred method of anesthesia technique and why?

What prophylactic antibiotics should be administered?

Prophylactic antibiotics are not indicated for routine cataract surgery.

What do I need to know about the surgical technique to optimize my anesthetic care?

The vitreoretinal surgeon has a host of procedural options, including vitrectomy, scleral buckling, injection of intravitreous gas or silicone oil, laser treatment, and cryotherapy. Most of these are intraocular procedures; however, scleral buckles are placed external to the globe. Intravitreous gases and silicone oil are used to internally tamponade the retina. Gas agents commonly employed include sulfa hexafluoride (SF6) and perfluoropropane (C3F8). Resorption takes ten days for the former and six weeks or longer for the latter. Silicone oil does not resorb and must be removed during an operation at a later date.

What can I do intraoperatively to assist the surgeon and optimize patient care?

Notify the surgeon if nitrous oxide is being used as part of general anesthesia, and ask to be informed when/if a decision to use intravitreous agents is made. Discontinue nitrous oxide prior to injection of the gas bubble.

Inform the surgeon if there are any unusual risks for anesthesia, such that he/she may factor that into the decision of whether or not to use silicone oil (which will mandate a follow-up surgical procedure).

One must appreciate the limited physiologic reserve and associated comorbidities that may be present in many geriatric patients scheduled for retina surgery. A reduction in the standard dosing of hypnotics/sedatives due to decreased MAC may be prudent. Large intermittent doses of propofol may produce fluctuating levels of consciousness and/or airway obstruction and result in gross patient movement.

What are the most common intraoperative complications and how can they be avoided/treated?

Slings are placed around the extraocular rectus muscles in order to facilitate placement of an external scleral buckle. Traction upon these muscles and surgical rotation of the globe can precipitate an oculocardiac reflex, resulting in profound bradycardia or asystole. Ensure adequate ventilation, oxygenation, and depth of anesthesia. There may be significant surgical stimulation at this point of the procedure, so additional sedation may be warranted for the awake patient or deepening of anesthesia for those under general anesthesia.

Movement and oculocardiac reflex are complications, as described above. An uncomfortable patient, blepharospasm, and/or a roving globe can be problematic for all involved. Compensation via increasing the depth of sedation may result in airway obstruction, hypoventilation, and predisposition toward gross patient movement. Preoperative assessment with deliberate patient selection and judicious choice of the type of anesthetic (regional vs. general) is requisite in order to provide optimal anesthesia care.

Studied positioning of the patient on the operating room table is essential in order to maximize the patient’s ability to tolerate a potentially prolonged procedure. Positioning may need to be modified for patients with significant scoliosis, lumbar or cervical spine pathology, or advanced arthritis. Pad bony areas and place pillows underneath the knees to relieve spine and lower back strain. Intravenous access should ideally be placed on the extremity that will be nearest the anesthesia provider.

For MAC patients, surgical drapes should be tented such that they are not tightly adherent to the patient’s face. Rebreathing may manifest as anxiety, hypertension, tachycardia, and diaphoresis. Consider placing a suction catheter by the patient’s chin or blowing air underneath the drapes.

For general anesthesia patients, orient the endotracheal tube or supraglottic airway away from the upper face. Oral Rae tubes or flexible LMAs are ideal. Tape the airway firmly in place to avoid accidental dislodgement during surgery or upon removal of drapes at the conclusion of the case. Assure sufficient space between the patient’s head and the surgical ring wrist-rest.

For laser treatment, take care to use appropriate protective eyewear when the laser is in use.

a. Neurologic:

N/A

b. If the patient is intubated, are there any special criteria for extubation?

Coughing or bucking upon emergence may increase intraocular pressure.

c. Postoperative management

What analgesic modalities can I implement?

Mild to moderate pain may be suitably treated with oral or intravenous nonsteroidal antinflammatory agents. The use of long-acting local anesthetics for regional anesthesia markedly reduces postoperative pain.

What level bed acuity is appropriate?

Surgery is most commonly performed on an ambulatory basis.

What are common postoperative complications, and ways to prevent and treat them?

Postoperative nausea, retching, or vomiting can produce a dramatic increase in intraocular pressure and result in significant visual complications, including intraocular hemorrhage, vitreous loss, iris prolapse, and wound rupture. It may also interfere with postoperative prone positioning for those patients who have received an intravitreous gas bubble injection. Postoperative nausea, retching and/or vomiting may be due to a surgically-related increase in intraocular pressure. Consultation with the opthalmologist may be warranted.

What's the Evidence?

Gayer, S, Zuleta, J. “Perioperative management of the elderly undergoing eye surgery”. Clinics in Geriatric Medicine.. vol. 24. 2008. pp. 687-700.

Charles, S, Rosenfeld, PJ, Gayer, S. “Medical consequences of stopping anticoagulants prior to intraoculat surgery or intravitereal injections”. Retina.. vol. 27. 2007. pp. 813-815.

Schein, OD, Katz, J, Bass, EB. “The value of routine preoperative medical testing beofre cataract surgery”. New England Journal of Medicine. vol. 342. 2000. pp. 168

Gayer, S, Kumar, CM. “Ophthalmic regional anesthesia techniques”. MInerva Anesthesiologica. vol. 74. 2008. pp. 23-33.

Gayer, S. “Ophthalmic anesthesia: More than meets the eye”. American Society of Anesthesiologists Refresher Courses in Anesthesiology.. vol. 34. 2006. pp. 55-63.

Bhananker, SM, Posner, KL, Cheney, FW, Caplan, RA, Lee, LA, Domino, KB. “Injury and liability associated with monitored anestheisa care”. Anesthesiology. vol. 104. 2006. pp. 228-234.

Gayer, S. “Key components of risk associated with ophthalmic anesthesia”. Anesthesiology. vol. 105. 2006. pp. 859

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