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Treating Glaucoma with Drainage Devices and Pericardial Grafts
JUNE 2000, VOL 71, NO 6
Home Study Program mmmm~-yylcn DRAINAGE D M C E S AND PERlCARDlAL GRAFCS
he article “Treating glaucoma with drainage devices and pericardial grafts” is the basis for this AORN Journal independent study. The behavioral objectives and examination for this program were prepared by Jeanne F. Hately, RN, MSN, CNOR, clinical editor, with consultation from Eileen J. Ullmann, RN, MHS, CNOR, professional education specialist, Center for Perioperative Education. A minimum score of 70% on the multiple-choice examination is necessary to earn 2.5 contact hours for this independent study. Participants receive feedback on incorrect answers. Each applicant who successfully completes this study will receive a certificate of completion. The deadline for submitting this study is July 31, 2001. Send the completed application form, multiple-choiceexamination, learner evaluation, and appropriate fee to AORN Customer Service c/o Home Study Program 2170 S Parker Rd, Suite 300 Denver, CO 80231-5711 Or fax the information with a credit card number to (303) 750-3212
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After reading and studying the article on treating glaucoma with drainage devices and pencardial grafts, the nurse will be able to (I) identify treatment options for glaucoma, (2) identify the causes of glaucoma, and (3) identify the different types of glaucoma.
This program meets criteria for CNOR and CRNFA recertification, as well as other continuing education requirements.
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Treating Glaucoma with Drainage Devices and Pericardial Grafts
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which is located at the iridocorneal angle. The iridocorneal angle usually is a wide angle, is formed by the iris and the cornea, and encircles the anterior chamber. This watery fluid is then emptied at the canal of Schlemm, which is highly permeable and is adjacent to the trabecular meshwork. Aqueous humor is absorbed into the bloodstream through the canal of Schlemm.4 The ciliary body has three groups of ciliary muscles: the outer, middle, and circular muscles. The outer longitudinal parallel muscles are adjacent to the sclera. These muscles are important because when they contract, the canal of Schlemm opens, allowing drainage of the aqueous humor. The middle and circular muscles affect accommodation. The ciliary body ends in the ciliary processes, which join the retina at the ora serrata. The ciliary body also extends posteriorly to- the choroid, which joins the optic nerve at the optic disc.' A B S T R A C T The optic nerve, which transGlaucoma is caused by a sustained elevation of intraocu- fers images from the eye to the lar pressure due to the brain, enters the eye through the decreased drainage of aqueous optic disk, also known as the humor from the anterior chamber anatomic blind spot.' Aqueous of the eye. There are many types humor, which helps in lens of glaucoma, which, if left metabolism and nourishes the untreated, may have devastating lens and cornea, maintains normal results for the patient. Glaucoma intraocular pressure (ie, normal can remain uncontrolled after IOP is 10 to 22 mm Hg) by the medical and surgical intewen- rate of its secretion and the resisttions. Glaucoma drainage device ance to outflow by the trabecular implants with pericardial graft meshwork.' The posterior chamber is placements often are helpful in relieving the effects of glaucoma separated from the vitreous body and increasing the patient's by a transparent biconvex lens. quality of life. AORN J 71 (June The vitreous body is a jellylike substance approximately 4 mL to 2000) 1237-1251.
laucoma is a common eye disorder in which the optic nerve is damaged over time due to a sustained elevation of the intraocular pressure (IOP). Glaucoma affects approximately two million Americans, can lead to irreversible legal blindness, and is the second most common cause of legal blindness.' The legally blind patient's central vision may be 20120, but he or she can have less than 20% peripheral vision, which usually is the first to be lost.' The problem is compounded because the patient with glaucoma usually is asymptomatic until the disease is in an advanced stage. To understand this complex disease, it is necessary to know about the structure and function of the eye.
ANAtOMYAND PHVSIOLOGY
The eye is a spherical organ that is composed of three chambers: the anterior chamber, the posterior chamber, and the vitreous body. The anterior and posterior chambers are filled with a watery fluid called the aqueous humor. The anterior chamber is located behind the cornea and in front of the iris and is filled with approximately 0.2 mL of aqueous humor. The posterior chamber is found behind the iris and in front of the lens and ciliary bodies (Figure 1); Aqueous humor is secreted by the ciliary processes and flows from the posterior chamber through the pupil into the anterior chamber. It is then filtered through the trabecular meshwork,
DONNA HO-SHINC, H N
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5 mL in volume. It clings to the retina, the ciliary epithelium, and the margin of the optic nerve. In case of vitreous body degeneration or volume loss, the pulling action on the retina can result in a retinal tear.* TYPES OF GUUICOMA
The most common symptoms of glaucoma are increased IOP, a damaged optic nerve, and loss of vision. A higher than normal IOP does not always indicate glaucoma? Types of glaucoma include the following. Primary open angle. Primary open angle glaucoma, or chronic open angle glaucoma, is the most common type of glaucoma and is responsible for approximately 90% of the glaucoma cases. This type of glaucoma develops slowly and often is bilateral. Pigmentary glaucoma is a type of primary open angle glaucoma and is caused by pigments from the iris and other eye structures that obstruct the outflow of the Figure 1 Anatomy of the eye. (///ustrutionsby Murk aqueous humor. Kutnik, Denver' Low tension. Low tension, or normal tension, glaucoma causes damage to the optic nerve even though the IOP is normal or low. This is more comWarning signs that occur at an advanced stage of glaucoma include loss of peripheral vision, blurred mon in older adults." Closed angle. Closed angle glaucoma is less vision, difficulty focusing on close work, seeing colcommon and has severe symptoms. The drainage ored rings around lights, experiencing problems area is less visible on inspection and is blocked by the adjusting eyes to the dark, frequent changes of glassiris rotating toward the cornea and causing the folded es, headaches, and eye pain.I6 iris to block the outflow of aqueous humor. Intraocular pressure usually exceeds 60 mm Hg in DIAGNOSIS OF GUUICOMA closed angle glaucoma and produces symptoms of Glaucoma is diagnosed by a complete eye examnausea and vomiting, severe eye pain, redness, halos, ination performed by an ophthalmologist or blurred vision, and, in severe cases, sudden loss of optometrist. This includes examining the central vision, pupil reaction, retina, and optic nerve with an vision.'L Juvenile. Juvenile, or congenital, glaucoma ophthalmoscope; the IOP with a tonometer; cellular occurs in infants whose IOP is high at birth or during debris and adhesions in the anterior chamber with a gonioscope (ie, an instrument used to examine filtrathe first months of life." Seconakry. Secondary glaucoma occurs as a tion angle of the eye's anterior chamber); and visual field studies to determine scotomas, which frequentresult of eye deformities, inflammation, or trauma.I' Neovascular. Neovascular glaucoma occurs ly are seen in the presence of glaucoma." A scotoma when abnormal blood vessels grow into the anterior is an isolated area in the visual field in which vision chamber of the eye and block the drainage channel^.'^ is absent or depressed.I8A diagnosis is conclusive for Patients who are at high risk for glaucoma are glaucoma when scotomas exist in the visual field and patients older than 60 years of age, African- they become progressively worse and larger, the Americans, patients with a family history of glauco- patient's IOP is greater than 30 mm Hg, the appearma, diabetic patients, and patients with a high degree ance of the optic nerve is progressively worsened, of myopia (ie, near~ightedness).'~ Patients with any of and blind spots appear in other areas of the eye.I9 these risk factors should have a compIete eye exami- When the diagnosis for glaucoma is confiied, the nation every two years. Patients with severe glaucoma patient is medically treated and is reexamined every should be evaluated as frequently as every six months. three to four months. 1239 AORN JOURNAL
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Table 1 MEDICATIONS USED TO TREAT GLAUCOMA
Medlwtion Beta-Mockers Timolol maleate
Timolol maleate ophthalmic gel forming solution
Dosage
Action
0.25% or 0.5%, one drop twice daily
Reduces the production of aqueous humor.
0.25% or 0.5%, one drop daily
Reduces the production of aqueous humor.
Carbonic anhydmse inhibitors (CAI)
Dorzolamide hydrochloride
2%, one drop twice or three times daily
Lowers intraocular pressure.
MEDICALTllEATMENT OF GIAUCOMA
Medical treatment is aimed at controlling glaucoma to prevent optic nerve damage and loss of peripheral vision, as these cannot be restored.2O It is important that medications be used as prescribed and follow-up examinations are consistent. Medications (eg, eyedrops and/or tablets) that constrict the pupil (eg, miotics) and flatten the iris allow aqueous fluid to drain through the canal of Schlemm (Table I)?' SIDE EFFECTS FROM EVE DROPS
Beta-blocker combined with CAI
Dorzolamide hydrochloride/ timolol maleate
One drop of 0.25% twice daily or 0.5% once daily.
Reduces the productian af aqueous humor.
One drop in the evening.
Increasesthe ouiflow of aqueous humor; reduces intraocular pressure.
0.2%, one drop three times daily.
Reduces the production and increases the OMOW of aqueous humor.
Dichlorphenamide
25 mg to 50 mg orally, three times daily.
Inhibition of carbonic anhydrase in the eye, resulting in decreased aqueous humor.
Acetazotomide
250 rng to 1 g
Inhibition of corbonic anhydrase in the eye, resulting in decreased aqueous humor.
Prostaglandin
Latanoprost
Alpha-agonist
Brimonidine tartrate
Oral medication CAls
every 24 hours.
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Beta-blockers. The most common side effect from betablockers is burning and stinging when the medication is instilled in the eye. Timolol maleate can cause bronchospasms and is contraindicated in patients with bronchial asthma or severe chronic obstructive pulmonary disease. Depression of myocardial contractility by timolol maleate can lead to cardiac failure, causing this medication to be contraindicated in patients with sinus bradycardia and second- or third-degree atrioventricular block?* Carbonic anhydrase inhibitors (CAI). The most common side effect of this type of eyedrop is burning and stinging on instillation. This eyedrop has a sulfur base and it is contraindicated in patients with an allergy to sulfur.23 Beta-blockers combined with CAI. The side effect and contraindications noted for the previous two categories of eyedrops are the same for this group. Prostaglandins. Latanoprost can cause permanent changes to pigmented tissues, including the ins, eyelid, and eyelashes, and it also causes growth of the eyelashes. This information is especially
JUNE 2000, VOL 71, NO 6 Ho-Shing
important to patients who are receiving drops in only one e ~ e . 2 ~ Alpha-agonists. Side effects of this medication group include dryness of the mouth, redness of the eyes, burning and stinging on instillation, and allergic reactions of the eye. Alpha-agonists are contraindicated for patients taking monoamine oxidase inhibitor^.^^ SURGICAL TREATMEIYT
The surgical treatment for nonacute closed angle glaucoma is laser iridotomy (ie, a surgical incision into the iris). For acute closed angle glaucoma, a peripheral iridectomy (ie, surgical removal of a portion of the iris) is performed to create a hole in the iris that allows for an increased flow of aqueous humor within the eye. There are various types of surgical treatment for open angle glaucoma. Laser trabeculoplasty is a procedure in which the sur- Figure 2 The glaucoma drainage device. geon uses a laser to open the pores of the trabecular meshwork to permit drainage of the excess fluid. If laser trabeculo- chamber through the drainage device plate, through plasty does not control glaucoma, a trabeculectomy is which the fluid gets absorbed into the body.26 The pericardial graft (ie, allograft) is processed, performed; this is the most common type of surgery for primary open angle glaucoma. The surgeon dehydrated, preserved human pericardium, which is makes a partial thickness incision into the sclera and available in a wide range of sizes.*' The allograft is excises a segment of corneoscleral tissue. A fistula is cut and shaped to a desired size and is sutured in created, filtering aqueous humor from the anterior place over the drainage tube to prevent the tube from chamber to below the conjunctiva, forming a bleb (ie, eroding into the conjunctiva. an accumulation of fluid). If a trabeculectomy fails to control glaucoma, PREOPERATM pATlEwc CARE other surgical procedures are attempted. CycloThe evening before glaucoma drainage device surdestructive surgery is performed using a laser or cry- gery, the preoperative nurse telephones the patient and oprobe to damage the ciliary body to alter the produc- gives him or her instructions, which include advising tion of aqueous fluid. Another method to surgically the patient to remain "0after 10 PM. A patient with correct glaucoma includes the insertion of a glaucoma medication-controlled hypertension is advised to take drainage device into the anterior chamber to drain the medication as prescribed either the night before or aqueous humor from the eye to lower the IOP. A peri- the morning of surgery with a sip of water so that his or cardial graft also is used with this procedure. her blood pressure is controlled during the surgical proThe glaucoma drainage device is a silicone cedure. The patient also is given instructions about device with a drainage tube and a hole-filled plate what to expect the day of surgery and the time he or she that fits the normal curvature of the eye (Figure 2). is to arrive at the hospital the next morning. The morning of surgery, the patient is admitted The device regulates the buildup of aqueous humor in the eye. The tube drains the fluid from the anterior to the same day surgery unit (SDSU). The SDSU 1243 AORN JOURNAL
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nurse obtains and records the patient’s vital signs, and the anesthesia care provider and surgeon assess the patient and answer any questions he or she may have. The surgeon also obtains an informed consent that is signed by the surgeon and patient and witnessed by the SDSU nurse. An IV line is inserted by the SDSU nurse, and all preoperative test results are placed in the chart and reviewed. The tests that are performed are a complete blood count, blood chemistry, prothrombin time, partial thromboplastin time, electrocardiogram, and chest x-rays. The patient is given a gown to put on, and the SDSU nurse helps the patient onto an ophthalmology stretcher. An ophthalmology stretcher is a stretcher designed with a formed area for the patient’s head that allows the patient to remain on the stretcher and gives the surgeon better access to the surgical field. The SDSU nurse transports the patient on the ophthalmology stretcher to the surgical holding area and gives a patient report to the holding area nurse. The holding area nurse and the circulating nurse introduce themselves to the patient and venfy the patient’s identity, surgical eye, “0 status, allergies, and medical history. The circulating nurse checks the patient’s chart to ensure that all consents are signed and that preoperative test results and a completed medical history and physical examination results are present. The surgery does not involve entering the posterior chamber of the eye, so dilating drops are not necessary. A dilated pupil causes narrowing of the iridocomeal angle.
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The circulating nurse and scrub person prepare the OR, instruments (ie, a basic cataract tray), and supplies for the surgery. A nonsterile camera is attached to the overhead microscope, and it is white balanced before the patient enters the room. The circulating nurse mixes vancomycin 500 mg in 10 mL normal sterile saline and pours the solution into a sterile container on the sterile field. The scrub person places the glaucoma drainage device implant and the pericardial graft into the vancomycin mixture until the surgeon is ready to implant them. Tetracaine hydrochloride drops (ie, O.S%)--an ophthalmic anesthetic-are given to the scrub person for placement on the sterile field to be used by the surgeon as needed. The circulating nurse transports the patient into the OR on the ophthalmology stretcher, which is placed in alignment with the overhead microscope. The circulating nurse ensures that the patient is in
proper body alignment in the supine position on the ophthalmology stretcher. The circulating nurse assists the anesthesia care provider in attaching the electrocardiogram leads, blood pressure cuff, and oxygen saturation sensor monitors to the patient. A round padded head support is placed under the patient’s head, a pillow is placed under the knees, and the arms are secured in place at the patient’s side with a warm blanket. The anesthesia care provider administers oxygen at 3 L/min via a nasal cannula and administers IV sedation to the patient so he or she can relax and be comfortable during the procedure. The surgeon administers a retrobulbar or a peribulbar block using lidocaine 2% plain mixed with 150 units of hyaluronidase. A retrobulbar block is administered to an area behind the eye. When a peribulbar block is used, the needle is directed to the inferior or superior aspect of the orbit, and the anesthetic agent is injected into the soft tissue of the globe. The anesthesia care provider increases the delivery of oxygen to 10 L/min and maintains the patient in a state of deep IV sedation, depending on the patient’s needs and medical condition. Prepping and draping. The circulating nurse instills tetracaine hydrochloride drops to decrease the burning sensation of the diluted povidone-iodine solution. The diluted povidone-iodine solution is instilled by a dropper into the surgical eye as an eye prep. The circulating nurse preps the eyelids, lid margins, lashes, eyebrows, and surrounding skin with povidoneiodine scrub solution, rinses the area with sterile water, and paints it with povidone-iodine solution. The area is dried to ensure that the eye drape adheres to the skin. The patient’s head is lifted for the placement of double-layered towels, which are draped around the patient’s head in turban style, covering the ears and hair. A towel clamp is secured to the towels to hold the towels in place. An eye drape with a fenestration for the surgical eye is placed over the eye, and the rest of the drape is unfolded, totally covering the patient. A tenting device is secured in place on either side of the patient’s face to keep the drape off the face. The drainage pouches, which are on either side of the drape fenestration, are opened to receive the irrigation fluid used during surgery. A plastic adhesive drape is placed over the lid margins to keep the eyelashes away from the surgical field. The surgeon and the surgical assistant place covers on the microscope lens. The microscope is positioned over the surgical
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eye, focused, and locked into position. Surgical procedure. The surgeon uses a wire speculum to retract the eyelids to expose the eyeball. The eye is irrigated with balanced salt solution delivered through an 18-g irrigation cannula during the procedure. There are various ways of performing this surgery, and the method varies according to the surgeon’s preference. For this procedure, the inferior and lateral rectus muscles are identified and marked with a sterile marking pen to maintain the orientation of the surgeon to the structure of the eye. The surgeon secures an 8-0 polyglactin traction suture in the peripheral comea to allow for manipulation of the globe supranasally. An incision is made in the conjunctiva at the limbus using a #57 ophthalmology blade. The conjunctiva is then reflected backward, allowing access to the sclera. The surgeon creates a scleral pocket by dissecting posteriorly, undermining the tissue with Wescott scissors. A caliper is set at 8 mm to 10 mm to mark the distance from the limbus to where the implant will be placed. The surgeon identifies the lateral and inferior rectus muscles and retracts them with muscle hooks (Figure 3). After the scleral pocket is created, the glaucoma drainage device is removed from the vancomycin antibiotic solution and flushed via the drainage tube with balanced salt solution using a 3 mL syringe attached to a 30-g imgating cannula. The tubing is tied to occlude the lumen with an 8-0 polyglactin suture to prevent rapid drainage of aqueous fluid, which may cause the anterior chamber to lose form during the procedure. Fitting the normal curvature of the eyeball, the body of the glaucoma drainage device is placed
Figure 3 The surgeon retracts the scleral pocket and conjunctiva with muscle hooks.
Figure 4
Limbus being pierced by a 23-g needle.
below the lateral and inferior rectus muscles, which are lifted off the sclera by muscle hooks. The surgeon secures the body of the glaucoma drainage device to the sclera using a 9-0 nylon suture on a spatulated needle. A corneal light shield is placed over the pupil to decrease pupil constriction from the amount of light entering the eye from the microscope. A 23-g needle is used to pierce the limbus (Figure 4) to create an opening through which the drainage tube is passed into the anterior chamber (Figure 5). The surgeon uses 9-0 nylon sutures to secure the tube to the sclera in two areas-one near the body of the glaucoma drainage device and the other near the limbus. The main purpose of securing the drainage tube near the body of the glaucoma drainage device is to prevent it from dislodging. The surgeon secures the tube at the limbus to prevent it from slipping out of the anterior chamber. An ophthalmology blade is used to make an incision at the limbus, through which sodium hyaluronate is injected into the anterior chamber to maintain the shape and depth of the anterior chamber. The pericardial graft is removed from the antibiotic solution and shaped to fit over the drainage tube of the glaucoma drainage device. The pericardial graft is used to cover the drainage tube to prevent it from eroding through the conjunctiva. The surgeon secures the pericardial graft in place by using a 9-0 nylon suture to anchor the comers to the sclera (Figure 6). The surgeon removes the 8-0 polyglactin suture that was placed to manipulate the eye, replaces the conjunctiva over the pericardial graft, and sutures it at the limbus using 9-0 polyglactin on a tapered needle.
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patient is given a light meal consisting of a sandwich and a glass of juice. The nurse gives the following discharge instructions to the patient. Leave the patch and shield in place for 24 hours. Do not rub or scratch the surgical eye. Sleep on the unaffected side. Leave the patch and shield on while sleeping. Use all medications as prescribed. Do not lift heavy items. Do not bend over. Call the surgeon if pain persists or increases or if the eye patch is soiled with drainage from the eye. The patient is discharged into the care of a family member, significant other, or friend. The patient is seen in the surgeon’s ofice the morning after surgery. The surgeon checks the wound and the TOP and gives the patient a prescription of tobramyciddexamethasone and antibiotic drops. If the IOP is high, the surgeon prescribes medication to reduce it. If the patient does not encounter any complications, he or she is seen in the surgeon’s oKice once each week for the first month to monitor the IOP.
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Figure 5 Arrow indicates shunt tubing in anterior chamber.
The surgeon removes the corneal light shield and places an absorbable collagen shield soaked in tobramyciddexamethasone ophthalmic suspension over the entire cornea. The lid speculum and drapes are removed, and the outer eye area is wiped with sterile water and dried. The surgeon places an eye patch and shield over the eye, and the circulating nurse secures the shield in place with tape. The circulating nurse removes the knee and head supports, places a pillow under the patient’s head, elevates the head of the stretcher, and covers the patient with a warm blanket. The anesthesia care provider removes the monitoring devices and nasal cannula and ensures patient stability. The circulating nurse and the anesthesia care provider transport the patient to the postanesthesia care unit (PACU).
PdSeoPERATlVE COMPLICATIONS
POSTOPERAT~VEPATI~CCCARE
The most common complication of a glaucoma drainage device and pericardial graft placement is high levels of IOP in the first few weeks due to the drainage tube’s having been tied off with the polyglactin suture during surgery. The suture used during the procedure to tie off the tube is absorbed slowly, causing gradual lowering of the IOP Another complication is erosion of the drainage tube, which is limited by placement of the pericardial graft. Other complications include suprachoroidal hemorrhage, infection, muscle imbalance due to the manipulation
In the PACU, an intraoperative patient report is given to the PACU nurses by the circulating nurse and the anesthesia care provider. The PACU nurse assesses the patient, connects the monitoring devices to the patient, and administers oxygen at 3 L/min. The PACU nurse monitors the patient’s vital signs every 15 minutes for one hour. Acetaminophen 325 mg is given by mouth as needed for pain. If the patient does not experience nausea, the PACU nurse gives the patient ice chips and discontinues the IV line when the patient is stable. The PACU nurse reports to the SDSU nurse who will be taking care of the patient and transports the patient to the SDSU. The SDSU nurse assesses the patient on return to the unit and records the patient’s vital signs. The
Figure 6
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Pericardiai graft being sutured into place.
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of the muscles when the glaucoma drainage device is implanted, hypotony (ie, decreased IOP), or increased IOP caused by either the drainage tube’s being blocked or by an overproduction of aqueous humor.
Surgical team members should be knowledgeable of the surgical procedure to be able to plan and provide the care needed for a successful surgical outcome. A
CONCLUSION
Donna Ho-Shing, RN, BSN, CNOR, is a level II nurse, OR educator at East Orange (NJ) General Hospital.
Glaucoma is a common but serious eye disorder that can be medically or surgically treated. The implantation of a glaucoma drainage device and placement of a pericardial graft is one of many SUrgical treatments that can be used to reduce IOP. NOTES
1. A Chandler, “Eye disorders: Glaucoma,” Eyesight Insight. Available from http://members.aol .com/insighteye/glau1.htm. Accessed 1 March 1998. 2. H D Jampel, Glaucoma: A Guidefor Patients (San Roman, Calif Health Information Network, Inc, 1997) 4. 3. “The eye,” in Mosbys Clinical Nursing, fourth ed, J M Thompson et al, eds (St Louis: Mosby-Year Book, Inc, 1997) 539. 4. Ibid. 5. Ihid, 538. 6. h i d , 539; V C Scanlon, “The senses,” in Essentials of Anatomy and Physiology, third ed, T Sanders, ed (Philadelphia: F A Davis Co, 1999) 194. 7. M Mawhinney, “Ophthalmic surgery,” in Alexander’s Care of the Patient in Surgery, 11th ed, M H
The author acknowledges Nahndi Williams, MD; Winston Scott, MD; and Gwendolyn Washingtonfor their help in the preparation of this article.
Meeker, J C Rothrock, eds (St Louis: Mosby-Year Book, Inc, 1999) 637. 8. “The eye,” 540. 9. Jampel, Glaucoma: A Guide for Patients, 7. 10. Chandler, “Eye disorders: Glaucoma.” 11. Ibid. 12. Jampel, Glaucoma: A Guide for Patients, 27. 13. “The eye,” 574. 14. Jampel, Glaucoma: A Guide for Patients, 26. 15. Chandler, “Eye disorders: Glaucoma.” 16. Glaucoma Research Foundation, “Facts about glaucoma,” InteliHealth. Available from www.intelihealth.com/IWhHH/ wsihwood/408/7 149/35736.html. Accessed 17 March 2000. 17. Ibid; “The eye,” 574. 18. Stedman’s Concise Medical Dictionary: Illustrated, second ed, J
T McDonough, Jr, ed (Baltimore: Williams & Wilkins, 1994) 913. 19. Chandler, “Eye disorders: Glaucoma.” 20. Ibid. 21. Scanlon, “The senses,” 194. 22. “Prescribing guide for the treatment of glaucoma patients,” in PDR 1999, second ed (Montvale, NJ: Medical Economics Co, Inc, 1999) 24-26. 23. Ibid, 50-51. 24. Ibid, 73. 25. Ibid, 79. 26. “How is glaucoma treated?” Cleveland Clinic Foundation. Available from http://ccf.org/ quality/OX-19/ 08-19c.htrn. Accessed 17 March 2000. 27. “Tutoplast processed pericardium description,” Products Pericardium. Available from http:// www.tutogen.com. Accessed 17 March 2000.
Ischemic Stroke Risk Increases With Anesthesia and Surgery A new study shows that people who undergo surgery and anesthesia are more at risk for ischemic stroke, according to an April 12, 2000, news release from the Mayo Clinic, Rochester, Minn. Ischemic strokes are caused by blood supply obstructions. Researchers compared medical records of 1,455 Rochester residents who experienced ischemic strokes to 1,455 patients with no stroke experiences. They found surgery and anesthesia were independent risk factors for developing ischemic stroke within 30 days after surgery. This risk increased for all surgical procedures,
which may be important for patients to consider when deciding whether to undergo an elective procedure. The overall rates of strike, however, are low (ie, approximately 5% for high-risk procedures, greater than 1% for other), according to the release, and should not deter anyone from undergoing medically necessary surgery. Surgery and Anesthesia Increase Risk for Ischemic Stroke (press release, Rochester, Minn: Mayo Clinic, April 12, 2000) 1 . Available from hnp:/%ww.newsMMC.htrnt. wise.com/a~icIes/2000/4/SLIRGERY2. Accessed 13 April 2000. 1251
AORN JOURNAL
Home Study Program mmmm~-yylcn DRAINAGE D M C E S AND PERlCARDlAL GRAFCS
he article “Treating glaucoma with drainage devices and pericardial grafts” is the basis for this AORN Journal independent study. The behavioral objectives and examination for this program were prepared by Jeanne F. Hately, RN, MSN, CNOR, clinical editor, with consultation from Eileen J. Ullmann, RN, MHS, CNOR, professional education specialist, Center for Perioperative Education. A minimum score of 70% on the multiple-choice examination is necessary to earn 2.5 contact hours for this independent study. Participants receive feedback on incorrect answers. Each applicant who successfully completes this study will receive a certificate of completion. The deadline for submitting this study is July 31, 2001. Send the completed application form, multiple-choiceexamination, learner evaluation, and appropriate fee to AORN Customer Service c/o Home Study Program 2170 S Parker Rd, Suite 300 Denver, CO 80231-5711 Or fax the information with a credit card number to (303) 750-3212
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After reading and studying the article on treating glaucoma with drainage devices and pencardial grafts, the nurse will be able to (I) identify treatment options for glaucoma, (2) identify the causes of glaucoma, and (3) identify the different types of glaucoma.
This program meets criteria for CNOR and CRNFA recertification, as well as other continuing education requirements.
1234 AORN JOURNAL
JUNE 2000, VOL 7 1, NO 6 Ho-Shing
Treating Glaucoma with Drainage Devices and Pericardial Grafts
G
which is located at the iridocorneal angle. The iridocorneal angle usually is a wide angle, is formed by the iris and the cornea, and encircles the anterior chamber. This watery fluid is then emptied at the canal of Schlemm, which is highly permeable and is adjacent to the trabecular meshwork. Aqueous humor is absorbed into the bloodstream through the canal of Schlemm.4 The ciliary body has three groups of ciliary muscles: the outer, middle, and circular muscles. The outer longitudinal parallel muscles are adjacent to the sclera. These muscles are important because when they contract, the canal of Schlemm opens, allowing drainage of the aqueous humor. The middle and circular muscles affect accommodation. The ciliary body ends in the ciliary processes, which join the retina at the ora serrata. The ciliary body also extends posteriorly to- the choroid, which joins the optic nerve at the optic disc.' A B S T R A C T The optic nerve, which transGlaucoma is caused by a sustained elevation of intraocu- fers images from the eye to the lar pressure due to the brain, enters the eye through the decreased drainage of aqueous optic disk, also known as the humor from the anterior chamber anatomic blind spot.' Aqueous of the eye. There are many types humor, which helps in lens of glaucoma, which, if left metabolism and nourishes the untreated, may have devastating lens and cornea, maintains normal results for the patient. Glaucoma intraocular pressure (ie, normal can remain uncontrolled after IOP is 10 to 22 mm Hg) by the medical and surgical intewen- rate of its secretion and the resisttions. Glaucoma drainage device ance to outflow by the trabecular implants with pericardial graft meshwork.' The posterior chamber is placements often are helpful in relieving the effects of glaucoma separated from the vitreous body and increasing the patient's by a transparent biconvex lens. quality of life. AORN J 71 (June The vitreous body is a jellylike substance approximately 4 mL to 2000) 1237-1251.
laucoma is a common eye disorder in which the optic nerve is damaged over time due to a sustained elevation of the intraocular pressure (IOP). Glaucoma affects approximately two million Americans, can lead to irreversible legal blindness, and is the second most common cause of legal blindness.' The legally blind patient's central vision may be 20120, but he or she can have less than 20% peripheral vision, which usually is the first to be lost.' The problem is compounded because the patient with glaucoma usually is asymptomatic until the disease is in an advanced stage. To understand this complex disease, it is necessary to know about the structure and function of the eye.
ANAtOMYAND PHVSIOLOGY
The eye is a spherical organ that is composed of three chambers: the anterior chamber, the posterior chamber, and the vitreous body. The anterior and posterior chambers are filled with a watery fluid called the aqueous humor. The anterior chamber is located behind the cornea and in front of the iris and is filled with approximately 0.2 mL of aqueous humor. The posterior chamber is found behind the iris and in front of the lens and ciliary bodies (Figure 1); Aqueous humor is secreted by the ciliary processes and flows from the posterior chamber through the pupil into the anterior chamber. It is then filtered through the trabecular meshwork,
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5 mL in volume. It clings to the retina, the ciliary epithelium, and the margin of the optic nerve. In case of vitreous body degeneration or volume loss, the pulling action on the retina can result in a retinal tear.* TYPES OF GUUICOMA
The most common symptoms of glaucoma are increased IOP, a damaged optic nerve, and loss of vision. A higher than normal IOP does not always indicate glaucoma? Types of glaucoma include the following. Primary open angle. Primary open angle glaucoma, or chronic open angle glaucoma, is the most common type of glaucoma and is responsible for approximately 90% of the glaucoma cases. This type of glaucoma develops slowly and often is bilateral. Pigmentary glaucoma is a type of primary open angle glaucoma and is caused by pigments from the iris and other eye structures that obstruct the outflow of the Figure 1 Anatomy of the eye. (///ustrutionsby Murk aqueous humor. Kutnik, Denver' Low tension. Low tension, or normal tension, glaucoma causes damage to the optic nerve even though the IOP is normal or low. This is more comWarning signs that occur at an advanced stage of glaucoma include loss of peripheral vision, blurred mon in older adults." Closed angle. Closed angle glaucoma is less vision, difficulty focusing on close work, seeing colcommon and has severe symptoms. The drainage ored rings around lights, experiencing problems area is less visible on inspection and is blocked by the adjusting eyes to the dark, frequent changes of glassiris rotating toward the cornea and causing the folded es, headaches, and eye pain.I6 iris to block the outflow of aqueous humor. Intraocular pressure usually exceeds 60 mm Hg in DIAGNOSIS OF GUUICOMA closed angle glaucoma and produces symptoms of Glaucoma is diagnosed by a complete eye examnausea and vomiting, severe eye pain, redness, halos, ination performed by an ophthalmologist or blurred vision, and, in severe cases, sudden loss of optometrist. This includes examining the central vision, pupil reaction, retina, and optic nerve with an vision.'L Juvenile. Juvenile, or congenital, glaucoma ophthalmoscope; the IOP with a tonometer; cellular occurs in infants whose IOP is high at birth or during debris and adhesions in the anterior chamber with a gonioscope (ie, an instrument used to examine filtrathe first months of life." Seconakry. Secondary glaucoma occurs as a tion angle of the eye's anterior chamber); and visual field studies to determine scotomas, which frequentresult of eye deformities, inflammation, or trauma.I' Neovascular. Neovascular glaucoma occurs ly are seen in the presence of glaucoma." A scotoma when abnormal blood vessels grow into the anterior is an isolated area in the visual field in which vision chamber of the eye and block the drainage channel^.'^ is absent or depressed.I8A diagnosis is conclusive for Patients who are at high risk for glaucoma are glaucoma when scotomas exist in the visual field and patients older than 60 years of age, African- they become progressively worse and larger, the Americans, patients with a family history of glauco- patient's IOP is greater than 30 mm Hg, the appearma, diabetic patients, and patients with a high degree ance of the optic nerve is progressively worsened, of myopia (ie, near~ightedness).'~ Patients with any of and blind spots appear in other areas of the eye.I9 these risk factors should have a compIete eye exami- When the diagnosis for glaucoma is confiied, the nation every two years. Patients with severe glaucoma patient is medically treated and is reexamined every should be evaluated as frequently as every six months. three to four months. 1239 AORN JOURNAL
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Table 1 MEDICATIONS USED TO TREAT GLAUCOMA
Medlwtion Beta-Mockers Timolol maleate
Timolol maleate ophthalmic gel forming solution
Dosage
Action
0.25% or 0.5%, one drop twice daily
Reduces the production of aqueous humor.
0.25% or 0.5%, one drop daily
Reduces the production of aqueous humor.
Carbonic anhydmse inhibitors (CAI)
Dorzolamide hydrochloride
2%, one drop twice or three times daily
Lowers intraocular pressure.
MEDICALTllEATMENT OF GIAUCOMA
Medical treatment is aimed at controlling glaucoma to prevent optic nerve damage and loss of peripheral vision, as these cannot be restored.2O It is important that medications be used as prescribed and follow-up examinations are consistent. Medications (eg, eyedrops and/or tablets) that constrict the pupil (eg, miotics) and flatten the iris allow aqueous fluid to drain through the canal of Schlemm (Table I)?' SIDE EFFECTS FROM EVE DROPS
Beta-blocker combined with CAI
Dorzolamide hydrochloride/ timolol maleate
One drop of 0.25% twice daily or 0.5% once daily.
Reduces the productian af aqueous humor.
One drop in the evening.
Increasesthe ouiflow of aqueous humor; reduces intraocular pressure.
0.2%, one drop three times daily.
Reduces the production and increases the OMOW of aqueous humor.
Dichlorphenamide
25 mg to 50 mg orally, three times daily.
Inhibition of carbonic anhydrase in the eye, resulting in decreased aqueous humor.
Acetazotomide
250 rng to 1 g
Inhibition of corbonic anhydrase in the eye, resulting in decreased aqueous humor.
Prostaglandin
Latanoprost
Alpha-agonist
Brimonidine tartrate
Oral medication CAls
every 24 hours.
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Beta-blockers. The most common side effect from betablockers is burning and stinging when the medication is instilled in the eye. Timolol maleate can cause bronchospasms and is contraindicated in patients with bronchial asthma or severe chronic obstructive pulmonary disease. Depression of myocardial contractility by timolol maleate can lead to cardiac failure, causing this medication to be contraindicated in patients with sinus bradycardia and second- or third-degree atrioventricular block?* Carbonic anhydrase inhibitors (CAI). The most common side effect of this type of eyedrop is burning and stinging on instillation. This eyedrop has a sulfur base and it is contraindicated in patients with an allergy to sulfur.23 Beta-blockers combined with CAI. The side effect and contraindications noted for the previous two categories of eyedrops are the same for this group. Prostaglandins. Latanoprost can cause permanent changes to pigmented tissues, including the ins, eyelid, and eyelashes, and it also causes growth of the eyelashes. This information is especially
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important to patients who are receiving drops in only one e ~ e . 2 ~ Alpha-agonists. Side effects of this medication group include dryness of the mouth, redness of the eyes, burning and stinging on instillation, and allergic reactions of the eye. Alpha-agonists are contraindicated for patients taking monoamine oxidase inhibitor^.^^ SURGICAL TREATMEIYT
The surgical treatment for nonacute closed angle glaucoma is laser iridotomy (ie, a surgical incision into the iris). For acute closed angle glaucoma, a peripheral iridectomy (ie, surgical removal of a portion of the iris) is performed to create a hole in the iris that allows for an increased flow of aqueous humor within the eye. There are various types of surgical treatment for open angle glaucoma. Laser trabeculoplasty is a procedure in which the sur- Figure 2 The glaucoma drainage device. geon uses a laser to open the pores of the trabecular meshwork to permit drainage of the excess fluid. If laser trabeculo- chamber through the drainage device plate, through plasty does not control glaucoma, a trabeculectomy is which the fluid gets absorbed into the body.26 The pericardial graft (ie, allograft) is processed, performed; this is the most common type of surgery for primary open angle glaucoma. The surgeon dehydrated, preserved human pericardium, which is makes a partial thickness incision into the sclera and available in a wide range of sizes.*' The allograft is excises a segment of corneoscleral tissue. A fistula is cut and shaped to a desired size and is sutured in created, filtering aqueous humor from the anterior place over the drainage tube to prevent the tube from chamber to below the conjunctiva, forming a bleb (ie, eroding into the conjunctiva. an accumulation of fluid). If a trabeculectomy fails to control glaucoma, PREOPERATM pATlEwc CARE other surgical procedures are attempted. CycloThe evening before glaucoma drainage device surdestructive surgery is performed using a laser or cry- gery, the preoperative nurse telephones the patient and oprobe to damage the ciliary body to alter the produc- gives him or her instructions, which include advising tion of aqueous fluid. Another method to surgically the patient to remain "0after 10 PM. A patient with correct glaucoma includes the insertion of a glaucoma medication-controlled hypertension is advised to take drainage device into the anterior chamber to drain the medication as prescribed either the night before or aqueous humor from the eye to lower the IOP. A peri- the morning of surgery with a sip of water so that his or cardial graft also is used with this procedure. her blood pressure is controlled during the surgical proThe glaucoma drainage device is a silicone cedure. The patient also is given instructions about device with a drainage tube and a hole-filled plate what to expect the day of surgery and the time he or she that fits the normal curvature of the eye (Figure 2). is to arrive at the hospital the next morning. The morning of surgery, the patient is admitted The device regulates the buildup of aqueous humor in the eye. The tube drains the fluid from the anterior to the same day surgery unit (SDSU). The SDSU 1243 AORN JOURNAL
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nurse obtains and records the patient’s vital signs, and the anesthesia care provider and surgeon assess the patient and answer any questions he or she may have. The surgeon also obtains an informed consent that is signed by the surgeon and patient and witnessed by the SDSU nurse. An IV line is inserted by the SDSU nurse, and all preoperative test results are placed in the chart and reviewed. The tests that are performed are a complete blood count, blood chemistry, prothrombin time, partial thromboplastin time, electrocardiogram, and chest x-rays. The patient is given a gown to put on, and the SDSU nurse helps the patient onto an ophthalmology stretcher. An ophthalmology stretcher is a stretcher designed with a formed area for the patient’s head that allows the patient to remain on the stretcher and gives the surgeon better access to the surgical field. The SDSU nurse transports the patient on the ophthalmology stretcher to the surgical holding area and gives a patient report to the holding area nurse. The holding area nurse and the circulating nurse introduce themselves to the patient and venfy the patient’s identity, surgical eye, “0 status, allergies, and medical history. The circulating nurse checks the patient’s chart to ensure that all consents are signed and that preoperative test results and a completed medical history and physical examination results are present. The surgery does not involve entering the posterior chamber of the eye, so dilating drops are not necessary. A dilated pupil causes narrowing of the iridocomeal angle.
mnmm
~ l y l ~ ~ o p l l uCAM ~ ~
The circulating nurse and scrub person prepare the OR, instruments (ie, a basic cataract tray), and supplies for the surgery. A nonsterile camera is attached to the overhead microscope, and it is white balanced before the patient enters the room. The circulating nurse mixes vancomycin 500 mg in 10 mL normal sterile saline and pours the solution into a sterile container on the sterile field. The scrub person places the glaucoma drainage device implant and the pericardial graft into the vancomycin mixture until the surgeon is ready to implant them. Tetracaine hydrochloride drops (ie, O.S%)--an ophthalmic anesthetic-are given to the scrub person for placement on the sterile field to be used by the surgeon as needed. The circulating nurse transports the patient into the OR on the ophthalmology stretcher, which is placed in alignment with the overhead microscope. The circulating nurse ensures that the patient is in
proper body alignment in the supine position on the ophthalmology stretcher. The circulating nurse assists the anesthesia care provider in attaching the electrocardiogram leads, blood pressure cuff, and oxygen saturation sensor monitors to the patient. A round padded head support is placed under the patient’s head, a pillow is placed under the knees, and the arms are secured in place at the patient’s side with a warm blanket. The anesthesia care provider administers oxygen at 3 L/min via a nasal cannula and administers IV sedation to the patient so he or she can relax and be comfortable during the procedure. The surgeon administers a retrobulbar or a peribulbar block using lidocaine 2% plain mixed with 150 units of hyaluronidase. A retrobulbar block is administered to an area behind the eye. When a peribulbar block is used, the needle is directed to the inferior or superior aspect of the orbit, and the anesthetic agent is injected into the soft tissue of the globe. The anesthesia care provider increases the delivery of oxygen to 10 L/min and maintains the patient in a state of deep IV sedation, depending on the patient’s needs and medical condition. Prepping and draping. The circulating nurse instills tetracaine hydrochloride drops to decrease the burning sensation of the diluted povidone-iodine solution. The diluted povidone-iodine solution is instilled by a dropper into the surgical eye as an eye prep. The circulating nurse preps the eyelids, lid margins, lashes, eyebrows, and surrounding skin with povidoneiodine scrub solution, rinses the area with sterile water, and paints it with povidone-iodine solution. The area is dried to ensure that the eye drape adheres to the skin. The patient’s head is lifted for the placement of double-layered towels, which are draped around the patient’s head in turban style, covering the ears and hair. A towel clamp is secured to the towels to hold the towels in place. An eye drape with a fenestration for the surgical eye is placed over the eye, and the rest of the drape is unfolded, totally covering the patient. A tenting device is secured in place on either side of the patient’s face to keep the drape off the face. The drainage pouches, which are on either side of the drape fenestration, are opened to receive the irrigation fluid used during surgery. A plastic adhesive drape is placed over the lid margins to keep the eyelashes away from the surgical field. The surgeon and the surgical assistant place covers on the microscope lens. The microscope is positioned over the surgical
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eye, focused, and locked into position. Surgical procedure. The surgeon uses a wire speculum to retract the eyelids to expose the eyeball. The eye is irrigated with balanced salt solution delivered through an 18-g irrigation cannula during the procedure. There are various ways of performing this surgery, and the method varies according to the surgeon’s preference. For this procedure, the inferior and lateral rectus muscles are identified and marked with a sterile marking pen to maintain the orientation of the surgeon to the structure of the eye. The surgeon secures an 8-0 polyglactin traction suture in the peripheral comea to allow for manipulation of the globe supranasally. An incision is made in the conjunctiva at the limbus using a #57 ophthalmology blade. The conjunctiva is then reflected backward, allowing access to the sclera. The surgeon creates a scleral pocket by dissecting posteriorly, undermining the tissue with Wescott scissors. A caliper is set at 8 mm to 10 mm to mark the distance from the limbus to where the implant will be placed. The surgeon identifies the lateral and inferior rectus muscles and retracts them with muscle hooks (Figure 3). After the scleral pocket is created, the glaucoma drainage device is removed from the vancomycin antibiotic solution and flushed via the drainage tube with balanced salt solution using a 3 mL syringe attached to a 30-g imgating cannula. The tubing is tied to occlude the lumen with an 8-0 polyglactin suture to prevent rapid drainage of aqueous fluid, which may cause the anterior chamber to lose form during the procedure. Fitting the normal curvature of the eyeball, the body of the glaucoma drainage device is placed
Figure 3 The surgeon retracts the scleral pocket and conjunctiva with muscle hooks.
Figure 4
Limbus being pierced by a 23-g needle.
below the lateral and inferior rectus muscles, which are lifted off the sclera by muscle hooks. The surgeon secures the body of the glaucoma drainage device to the sclera using a 9-0 nylon suture on a spatulated needle. A corneal light shield is placed over the pupil to decrease pupil constriction from the amount of light entering the eye from the microscope. A 23-g needle is used to pierce the limbus (Figure 4) to create an opening through which the drainage tube is passed into the anterior chamber (Figure 5). The surgeon uses 9-0 nylon sutures to secure the tube to the sclera in two areas-one near the body of the glaucoma drainage device and the other near the limbus. The main purpose of securing the drainage tube near the body of the glaucoma drainage device is to prevent it from dislodging. The surgeon secures the tube at the limbus to prevent it from slipping out of the anterior chamber. An ophthalmology blade is used to make an incision at the limbus, through which sodium hyaluronate is injected into the anterior chamber to maintain the shape and depth of the anterior chamber. The pericardial graft is removed from the antibiotic solution and shaped to fit over the drainage tube of the glaucoma drainage device. The pericardial graft is used to cover the drainage tube to prevent it from eroding through the conjunctiva. The surgeon secures the pericardial graft in place by using a 9-0 nylon suture to anchor the comers to the sclera (Figure 6). The surgeon removes the 8-0 polyglactin suture that was placed to manipulate the eye, replaces the conjunctiva over the pericardial graft, and sutures it at the limbus using 9-0 polyglactin on a tapered needle.
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patient is given a light meal consisting of a sandwich and a glass of juice. The nurse gives the following discharge instructions to the patient. Leave the patch and shield in place for 24 hours. Do not rub or scratch the surgical eye. Sleep on the unaffected side. Leave the patch and shield on while sleeping. Use all medications as prescribed. Do not lift heavy items. Do not bend over. Call the surgeon if pain persists or increases or if the eye patch is soiled with drainage from the eye. The patient is discharged into the care of a family member, significant other, or friend. The patient is seen in the surgeon’s ofice the morning after surgery. The surgeon checks the wound and the TOP and gives the patient a prescription of tobramyciddexamethasone and antibiotic drops. If the IOP is high, the surgeon prescribes medication to reduce it. If the patient does not encounter any complications, he or she is seen in the surgeon’s oKice once each week for the first month to monitor the IOP.
.
Figure 5 Arrow indicates shunt tubing in anterior chamber.
The surgeon removes the corneal light shield and places an absorbable collagen shield soaked in tobramyciddexamethasone ophthalmic suspension over the entire cornea. The lid speculum and drapes are removed, and the outer eye area is wiped with sterile water and dried. The surgeon places an eye patch and shield over the eye, and the circulating nurse secures the shield in place with tape. The circulating nurse removes the knee and head supports, places a pillow under the patient’s head, elevates the head of the stretcher, and covers the patient with a warm blanket. The anesthesia care provider removes the monitoring devices and nasal cannula and ensures patient stability. The circulating nurse and the anesthesia care provider transport the patient to the postanesthesia care unit (PACU).
PdSeoPERATlVE COMPLICATIONS
POSTOPERAT~VEPATI~CCCARE
The most common complication of a glaucoma drainage device and pericardial graft placement is high levels of IOP in the first few weeks due to the drainage tube’s having been tied off with the polyglactin suture during surgery. The suture used during the procedure to tie off the tube is absorbed slowly, causing gradual lowering of the IOP Another complication is erosion of the drainage tube, which is limited by placement of the pericardial graft. Other complications include suprachoroidal hemorrhage, infection, muscle imbalance due to the manipulation
In the PACU, an intraoperative patient report is given to the PACU nurses by the circulating nurse and the anesthesia care provider. The PACU nurse assesses the patient, connects the monitoring devices to the patient, and administers oxygen at 3 L/min. The PACU nurse monitors the patient’s vital signs every 15 minutes for one hour. Acetaminophen 325 mg is given by mouth as needed for pain. If the patient does not experience nausea, the PACU nurse gives the patient ice chips and discontinues the IV line when the patient is stable. The PACU nurse reports to the SDSU nurse who will be taking care of the patient and transports the patient to the SDSU. The SDSU nurse assesses the patient on return to the unit and records the patient’s vital signs. The
Figure 6
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Pericardiai graft being sutured into place.
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of the muscles when the glaucoma drainage device is implanted, hypotony (ie, decreased IOP), or increased IOP caused by either the drainage tube’s being blocked or by an overproduction of aqueous humor.
Surgical team members should be knowledgeable of the surgical procedure to be able to plan and provide the care needed for a successful surgical outcome. A
CONCLUSION
Donna Ho-Shing, RN, BSN, CNOR, is a level II nurse, OR educator at East Orange (NJ) General Hospital.
Glaucoma is a common but serious eye disorder that can be medically or surgically treated. The implantation of a glaucoma drainage device and placement of a pericardial graft is one of many SUrgical treatments that can be used to reduce IOP. NOTES
1. A Chandler, “Eye disorders: Glaucoma,” Eyesight Insight. Available from http://members.aol .com/insighteye/glau1.htm. Accessed 1 March 1998. 2. H D Jampel, Glaucoma: A Guidefor Patients (San Roman, Calif Health Information Network, Inc, 1997) 4. 3. “The eye,” in Mosbys Clinical Nursing, fourth ed, J M Thompson et al, eds (St Louis: Mosby-Year Book, Inc, 1997) 539. 4. Ibid. 5. Ihid, 538. 6. h i d , 539; V C Scanlon, “The senses,” in Essentials of Anatomy and Physiology, third ed, T Sanders, ed (Philadelphia: F A Davis Co, 1999) 194. 7. M Mawhinney, “Ophthalmic surgery,” in Alexander’s Care of the Patient in Surgery, 11th ed, M H
The author acknowledges Nahndi Williams, MD; Winston Scott, MD; and Gwendolyn Washingtonfor their help in the preparation of this article.
Meeker, J C Rothrock, eds (St Louis: Mosby-Year Book, Inc, 1999) 637. 8. “The eye,” 540. 9. Jampel, Glaucoma: A Guide for Patients, 7. 10. Chandler, “Eye disorders: Glaucoma.” 11. Ibid. 12. Jampel, Glaucoma: A Guide for Patients, 27. 13. “The eye,” 574. 14. Jampel, Glaucoma: A Guide for Patients, 26. 15. Chandler, “Eye disorders: Glaucoma.” 16. Glaucoma Research Foundation, “Facts about glaucoma,” InteliHealth. Available from www.intelihealth.com/IWhHH/ wsihwood/408/7 149/35736.html. Accessed 17 March 2000. 17. Ibid; “The eye,” 574. 18. Stedman’s Concise Medical Dictionary: Illustrated, second ed, J
T McDonough, Jr, ed (Baltimore: Williams & Wilkins, 1994) 913. 19. Chandler, “Eye disorders: Glaucoma.” 20. Ibid. 21. Scanlon, “The senses,” 194. 22. “Prescribing guide for the treatment of glaucoma patients,” in PDR 1999, second ed (Montvale, NJ: Medical Economics Co, Inc, 1999) 24-26. 23. Ibid, 50-51. 24. Ibid, 73. 25. Ibid, 79. 26. “How is glaucoma treated?” Cleveland Clinic Foundation. Available from http://ccf.org/ quality/OX-19/ 08-19c.htrn. Accessed 17 March 2000. 27. “Tutoplast processed pericardium description,” Products Pericardium. Available from http:// www.tutogen.com. Accessed 17 March 2000.
Ischemic Stroke Risk Increases With Anesthesia and Surgery A new study shows that people who undergo surgery and anesthesia are more at risk for ischemic stroke, according to an April 12, 2000, news release from the Mayo Clinic, Rochester, Minn. Ischemic strokes are caused by blood supply obstructions. Researchers compared medical records of 1,455 Rochester residents who experienced ischemic strokes to 1,455 patients with no stroke experiences. They found surgery and anesthesia were independent risk factors for developing ischemic stroke within 30 days after surgery. This risk increased for all surgical procedures,
which may be important for patients to consider when deciding whether to undergo an elective procedure. The overall rates of strike, however, are low (ie, approximately 5% for high-risk procedures, greater than 1% for other), according to the release, and should not deter anyone from undergoing medically necessary surgery. Surgery and Anesthesia Increase Risk for Ischemic Stroke (press release, Rochester, Minn: Mayo Clinic, April 12, 2000) 1 . Available from hnp:/%ww.newsMMC.htrnt. wise.com/a~icIes/2000/4/SLIRGERY2. Accessed 13 April 2000. 1251
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