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Corneal Protection during General Anesthesia for Nonocular Surgery
Clinical Practice Corneal Protection during General Anesthesia for Nonocular Surgery ANDRE GRIXTI, MD, 1 MAZIAR SADRI, MD, MRCS, DOHNS, FRCA MARK T. WATTS, MBCHB, DO, FRCOPHTH 3
ABSTRACT Corneal abrasion is the most common ophthalmologic complication that occurs during general anesthesia for nonocular surgery. Such abrasions can be caused by a variety of mechanisms and can lead to sightthreatening microbial keratitis and permanent scarring. There is no standard mode of protecting the cornea during general anesthesia for nonocular surgery. Methods described in the literature are not entirely effective and may be associated with unwanted side effects. Taping alone provides protection that is equivalent or superior to other interventions and has fewer side effects. Petroleum gel is flammable and is best avoided when electrocautery and open oxygen are to be used around the face. Preservativefree eye ointment is preferred, as preservative can cause corneal epithelial sloughing and conjunctival hyperemia. Recently, the application of Geliperm and bio-occlusive dressings has been advocated. Geliperm may be particularly useful during endonasal surgery when continuous perioperative observation of the eye is required. In this article, the literature on the etiology of perioperative corneal abrasions is reviewed and various protection strategies are compared in order to identify the best methods to prevent corneal abrasions during general anesthesia. KEY WORDS corneal abrasions, general anesthesia
Accepted for publication October 2012. From the 1Department of Ophthalmology, Royal Liverpool University Hospital, Liverpool, 2Department of Anaesthesia, Cambridge University Hospital, Cambridge, and 3Department of Ophthalmology, Wirral University Teaching Hospital, Wirral, United Kingdom. The authors have no proprietary or commercial interest in any concept or product discussed in this article. The authors declare that they have no research grants or financial support. Single-copy reprint requests to Andre Grixti, MD (address below). Corresponding author: Andre Grixti, MD, Department of Ophthalmology, Royal Liverpool University Hospital, Prescot Street, Liverpool, UK, L7 8XP. Tel: 07783974823. E-mail address: [email protected] © 2013 Elsevier Inc. All rights reserved. The Ocular Surface ISSN: 15420124. Grixti A, Sadri M, Watts MT. Corneal protection during general anesthesia for nonocular surgery. 2013;11(2):109-118.
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I. INTRODUCTION orneal abrasion is the most common ophthalmologic complication in patients undergoing general anesthesia for nonocular surgery.1-9 Because the cornea is the most densely innervated tissue in the body, the postoperative pain resulting from abrasion of the cornea may be more severe than that arising from the surgical procedure itself.6,10,11 Moreover, the cornea serves as a mechanical barrier to infection, and corneal damage facilitates penetration of pathogenic organisms, which may lead to sight-threatening microbial keratitis and permanent scarring.6 Various methods of corneal protection have been advocated to eliminate or decrease the rate of this potentially avoidable complication. In this review, the etiology of perioperative corneal abrasions is discussed and various protection strategies are compared in order to identify the best methods to prevent corneal abrasions following general anesthesia.
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II. METHOD OF LITERATURE SEARCH A literature search was performed using the keywords general anesthesia; eye; cornea; abrasion. The search engines of CINAHL, MEDLINE and EMBASE were all used in the initial search. A manual search was also performed on the reference lists of all papers relevant to the topic. A total of 557 hits were provided through the search engines. The abstracts of these papers were reviewed by the first and second authors separately, and 107 papers were considered relevant to the topic. Of the 107 selected articles, 52 papers focused on the etiology and prevention of perioperative corneal abrasions and were included in this review. The remaining 55 papers consisted of case reports or studies on uncommon ophthalmological complications following general anesthesia and did not meet the criteria for inclusion. The studies included in this review had significant heterogeneity and lack of raw data in the papers, which made it impossible to perform a meta-analysis. However, we identified studies with a higher level of evidence which compare corneal protection strategies during general anesthesia for elective nonophthalmic surgery. These include randomized controlled trials (RCTs) and a historical controlled study. They are summarized in table format with their main conclusions.
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CORNEAL PROTECTION IN GENERAL ANESTHESIA / Grixti, et al
OUTLINE I. II. III. IV.
Introduction Method of Literature Search General Findings Pathogenesis of Corneal Abrasions A. Risk Factors B. Mechanical Injury C. Chemical Injury D. Exposure Keratopathy E. Reduced Tear Production V. Methods of Ocular Surface Protection A. Passive Eyelid Closure B. Eyelid Taping C. Ocular Lubricants D. Tarsorrhaphy E. Protective Goggles and Bandage Contact Lenses F. Geliperm G. Bio-occlusive Dressings VI. Summary and Conclusions
III. GENERAL FINDINGS The incidence of perioperative corneal injury reported in the literature varies significantly depending on the design of the study, type of surgical population, method of assessment, and protection used.3,8,12 Its prevalence ranges from as low as 0% with adequate protection up to 44% when no prophylactic measures were employed.1,3-5,7,13-22 Corneal abrasion sustained during general anesthesia was the most common type of eye injury reported in the American Society of Anesthesiologists Closed Claims Project, accounting for 35% of all ocular injuries.2 However, claims for corneal abrasion were characterized by a lower incidence of permanent injury and a lower level of compensation than other ocular injuries. Only 16% of corneal abrasions resulted in permanent ocular sequelae, the nature of which was not specified.2 Consistent with this report, two large retrospective studies have also identified corneal abrasion as the most prevalent form of ocular injury in 61.8%3 and 59%5 of subjects who sustained an eye injury during general anesthesia for nonophthalmic surgery. All patients were treated in the immediate postoperative period without permanent ocular morbidity. Most corneal abrasions heal without complications; however, visual loss secondary to direct trauma10 or irreversible corneal opacification following chemical injury23,24 during general anesthesia have been reported. No cases of blindness from infection or scarring as a direct result of anesthesia-induced abrasion were identified in the literature. Various methods of perioperative ocular surface protection have been proposed.5,13,17,25 These include manual closure of the eyelids,7 taping the eyelids closed with or without the use of an eye ointment,4,7,13,14,19 application of petroleum-based lubricant ointments,6 aqueous solutions such as methylcellulose15,26 or viscous gels,27 wearing of protective goggles, insertion of hydrophilic contact lenses,28 tarsorrhaphy sutures,6 Geliperm dressings,29 and, most
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recently, the use of bio-occlusive dressings such as Tegaderm (3M, St Paul, MN) and Opsite (Smith & Nephew, Largo, FL).5,16,17 In our literature review, we identified eight RCTs 4,7,13,15,18,19,21,26 and one historical controlled study16 comparing different methods of corneal protection following general anesthesia for nonocular surgery. The results of these studies together with their main conclusions are summarized in Table 1. Taping alone was found to be superior or equivalent to other interventions in preventing corneal abrasions in five RCTs4,7,13,14,18 and was associated with side effects in two RCTs.13,18 Methylcellulose was utilized in four RCTs and produced fewer untoward side effects than paraffin-based ointments during general anesthesia.13,15,18,26 A historical controlled study conducted by Lavery et al identified a significantly lower incidence of perioperative corneal abrasions with the use of bio-occlusive dressings (Tegaderm) compared to a combination of lubricant ointment and lid taping (P<.001).16 IV. PATHOGENESIS OF CORNEAL ABRASIONS A. Risk Factors Several independent risk factors have been associated with an increased incidence of corneal injury during general anesthesia.30 These include long surgical procedures,1,3 operations on the head or neck,3,5 lateral or prone positioning,3,5 lower American Society of Anesthesiologists physical status,1 anesthesia provided by a student nurse anesthetist,1 surgery on a Monday,3 sustained intraoperative deliberate hypotension and preoperative anaemia.5 Although the mechanism of corneal injury was recognized in only 20% of claims for corneal abrasion in the American Society of Anesthesiologists Closed Claims Analysis,2 a variety of mechanisms can cause perioperative corneal abrasions. B. Mechanical Injury Corneal abrasions can occur as a result of direct trauma to the unprotected eye from the anesthesiologists’ equipment or personal items, such as watches, identification badges, stethoscopes or the laryngoscope during intubation.6,12,15,25,31,32 Mechanical injury from surgical drapes, anesthetic masks, patient repositioning or pressure from the surgeon’s hands and instruments has also been documented.2,4,6,10,12,15,25,33 Cucchiara et al identified a significantly higher incidence of corneal epithelial defects in subjects undergoing lumbar laminectomy in the prone position with the head turned to the side as compared to other neurosurgical procedures (P¼.005).14 All abrasions occurred in the lower positioned eye. Similarly, Grover et al19 noted that all eyes showing corneal abrasions in the lateral position were dependent, ie, lying at a lower point with respect to the other eye. Subjects lying in the lateral or prone position as well as those undergoing operations on the head or neck are more susceptible to direct trauma and globe compression.3
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Table 1.
Ocular surface protection during general anesthesia Method/ Design
Batra and Bali, 19777
BoggildMadsen et al, 198126
Sample Description
Results and Prevalence Rates
Comments/Conclusion
Randomized controlled trial
200 patients undergoing elective surgery under general anesthesia. The participants were randomized in two equal groups of 100 subjects each: Group A (eyes uncovered); Group B (eyes covered: 75/100 lid taping and 25/100 vaseline gauze).
Corneal abrasion was identified in 26% (26/ 100) of subjects in Group A and none (0/100) of the subjects in Group B. Lagophthalmos occurred in 59% (59/100) of patients in Group A, and 44% (26/59) of these patients developed corneal erosions.
Eyelid closure by taping or vaseline gauze is effective in preventing exposure keratopathy during general anesthesia.
Doubleblinded, randomized controlled trial
120 patients undergoing general anesthesia of >90 minutes in the supine position. Null Group: 12 randomly selected subjects received the same ointment in both eyes. Main Group: 108 patients randomly received water-based methylcellulose 4% ointment in one eye (Group A), and paraffin-based ointment, oculentum simplex, Ph Nord.63 in the other eye (Group B). Patients were further subclassified into a group that received anesthesia with halothane or without halothane.
The incidence of complications with each eye ointment are detailed in Table 1 of the paper. Perioperatively (at 90 mins): Periorbital edema (edema1) was identified in 1.9% (2/108) of subjects in Group A and 72% (78/108) subjects in Group B. Conjunctival injection (pink eye1) was observed in 2.8% (3/108) of subjects in Group A and 38% (41/108) of subjects in Group B. In the latter group, a conjunctival reaction occurred in 83% (34/41) of patients with halothane anesthesia and 17% (7/41) of patients without halothane. At 1 hour post-anesthesia: Periorbital edema (edema2) was recorded in 3.7% (4/108) of subjects in Group A and 44% (48/108) of subjects in Group B. Conjunctival injection (pink eye2) was observed in 6.5% (7/108) of subjects in Group A and 19% (20/108) of subjects in Group B. In the latter group, a conjunctival reaction occurred in 60% (12/20) of patients with halothane anesthesia and 40% (8/20) of patients without halothane. Blurred vision was documented in 0.9% (1/108) of subjects in Group A and 15% (16/108) of subjects in Group B.
Water-based methylcellulose 4% has less untoward effects than paraffin-based ointment during general anesthesia. A conjunctival reaction was most distinct when both paraffin-based ointment and halothane anesthesia were used, suggestive of a drug interaction. Reviewers’ comment: This paper does not have robust statistical measurements and therefore is acceptable only as an observational study.
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Ocular surface protection during general anesthesia (continued from previous page ) Method/ Design
Sample Description
Results and Prevalence Rates
Comments/Conclusion
Doubleblinded, randomized controlled trial
47 patients undergoing general anesthesia of < 90 minutes in the supine position. Each patient randomly received water-based methylcellulose 4% ointment in one eye (Group A), and paraffin-based neutral eye ointment Ph Nord.63 in the other eye (Group B).
Corneal abrasion occurred in 2.1% (1/47) of eyes in Group A and none (0/47) of the eyes in Group B. Overall, 66% (31/47) of subjects reported subjective complaints as detailed in Table 1 of the paper.The most prevalent complaint was ‘sticking’ of the eyes together. It occurred in 32% (15/47) of eyes in Group A and 2.1% (1/47) of eyes in Group B. Overall, 55.3% (26/47) of subjects showed objective signs of ocular surface staining, red eyes, or chemosis, as detailed in Table 2 of the paper.The most common sign was conjunctival staining. It occurred in 10.6% (5/47) of eyes in Group A and 21.3% (10/47) of eyes in Group B.
Water-based methylcellulose ointment produced more firm adhesion of the eyelids than paraffin-based ointment. This reduces evaporation and protects the eyes against trauma or foreign bodies. No unintended drug side effects were observed in either group. Limitations of the study: The short duration of anesthesia may have resulted in fewer objective signs compared to other studies. Reviewers’ comment: The paper lacks statistical analysis including sample size calculation.
Siffring and Poulton, 198713
Randomized controlled trial.
127 patients undergoing general anesthesia of 30 to 180 minutes duration in the supine position. Subjects were randomly divided into four equal groups. Group A received Lacrilube (paraffin-based) ointment (Allergan; Irvine, CA) and taping; Group B, Duratears (paraffinbased) ointment (Alcon; Forth Worth, TX) and tape; Group C, IsoptoAlkaline methylcellulose (water-based) drops (Alcon; Forth Worth, TX) and tape; and Group D, hypoallergenic paper tape (3M; St. Paul, MN) alone.
No corneal abrasions were identified in any of the patients studied. Blurred vision was recorded in 75% of subjects (mean -1.9 Snellen lines) in Group A and 55% of subjects (mean -1.3 Snellen lines) in Group B. This was statistically significant compared to groups C and D (P<.05). Foreign body sensation occurred in 62.5% of patients in Group A and 42% of patients in Group B. This was statistically significant compared to groups C and D (P<.05). Scleral erythema was observed in 20% of subjects in Group B (no statistical test was conducted).
Ocular morbidity was significantly greater in groups treated with paraffin-based ointments. During general anesthesia of short duration (<180 minutes) for procedures distant from the head and neck in the supine position, lid taping with or without methylcellulose appears to be most effective.
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Schmidt et al, 198115
Randomized controlled trial
4652 patients undergoing elective neurosurgical procedures under general anesthesia over a 13-month period were randomized into two groups. 2439 subjects received a combination of eye ointment and lid taping (Intervention Group) and 2213 subjects were treated with lid taping alone (Control Group).
Overall, the prevalence of corneal abrasion was 0.17% (8/4652). Corneal erosions developed in 0.16% (4/2439) of subjects in the Intervention Group and 0.18% (4/2213) of subjects in the Control Group. 0.73% (5/681) of patients undergoing lumbar laminectomy in the prone position with the head turned to the side developed a corneal abrasion of the lower eye (Table 1 of the paper). This was statistically significant (P¼.005; Chi-square with Fisher exact test) when compared to all other neurosurgical procedures as a group.
No difference was noted in the incidence of corneal abrasion between patients who received a combination of eye ointment and lid taping and lid taping alone. The risk of corneal abrasion during lumbar laminectomy was higher than with other neurosurgical procedures. Reviewers’ comment: High quality study with good randomization.
Orlin et al, 19894
Doubleblinded, randomized controlled trial.
76 subjects undergoing general anesthesia for nonocular surgery of 45 to 385 minutes duration. Each patient randomly received lubricating ointment, white petrolatum 55% (Lacrilube) followed by lid taping to one eye (Group A), and lid taping alone to the other eye (Group B).
No corneal abrasions were identified in any of the subjects studied. Only 1.3% (1/76) of eyes in Group B showed transient conjunctival staining (X2 > 0.7). 6.6% (5/76) of eyes in Group A had a worse postoperative visual acuity (2 to 6 lines) in the first 24 hours after surgery. No significant difference was identified between the two forms of eye care
Lid taping with or without lubricating ointment significantly reduces the incidence of corneal injury during general anesthesia. Limitations: Small sample size.
Grover et al, 199819
Randomized controlled trial
150 ASA type 1 patients (300 eyes) undergoing general anesthesia of >90 minutes for nonophthalmic surgery were randomized in three equal groups of 50 subjects (100 eyes) each: Group C (no treatment); Group T (lid Taping); Group O (eye ointment).
The overall incidence of corneal epithelial defects was 10% (30/300 eyes). Corneal erosions occurred in 27% (27/100) of eyes in Group C; 2% (2/100) of eyes in Group T and 1% (1/100) of eyes in Group O. Basal tear production was reduced postoperatively in all groups compared to preoperative values (P<.0001); (Table 1 of the paper). The maximum reduction in basal tear production was seen in Group C, followed by Group T and Group O (P<.0008). The incidence of corneal abrasions in relation to surgical positioning is described in Table 2 of the paper. Supine posture, 9.67% (24/248) of eyes; Right lateral, 19.2% (5/26) of eyes and Left lateral, 3.84% (1/26) of eyes. All 6 eyes showing corneal erosions in the lateral posture were dependent eyes.
This study showed that inadequate eyelid closure was the main cause of corneal abrasions in unprotected eyes. Therefore, during general anesthesia, eye protection by lid taping or lubricating ointment should be provided. General anesthesia reduced basal tear production irrespective of the method of ocular protection used. In patients undergoing surgery in the lateral position, the dependent eye was more prone to develop corneal injuries.
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Cucchiara and Black, 198814
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Table 1.
Ocular surface protection during general anesthesia (continued from previous page ) Method/ Design
Ganidagli et al, 200418
Lavery et al, 201016
Sample Description
Results and Prevalence Rates
Comments/Conclusion
Single-blinded, randomized controlled trial
200 ASA type1 or 2 adult subjects undergoing elective nonophthalmic surgery under general anesthesia were divided into 4 equal groups of 50 patients each. Group 1, Hypoallergenic tape (Hypafix; Smith and Nephew, France); Group 2, Paraffin-based ointment including terramycine (Terramycine; Pfizer, Turkey); Group 3, Polyacrylic acid liquid gel (Viscotears; Novartis, Turkey) and Group 4, Artificial tears including hydroxypropyl methylcellulose (Tears Naturale II; Alcon, Turkey).
The overall prevalence of corneal defects at 12 hours after surgery was 9% (18/200). Corneal lesions (at 12 hours) occurred in 10% (5/50) of Group 1; 8% (4/50) of Group 2; 12% (6/50) of Group 3 and 6% (3/50) of Group 4. There was no significant difference in size or intensity of corneal staining between the four groups; (Table 1 of the paper). Conjunctival hyperemia scores in Group 3 at 12 hours [16% (8/50)] and 24 hours [12% (6/ 50)] were significantly higher than those of other groups (P<.05); (Table 2 of the paper). Blurred vision in Group 4 [42% (21/50)] was significantly higher than in Group 1 [12% (6/ 50)]; Group 2 [30% (15/50)] or Group 3 [34% (17/50)] (P<.05). Photophobia in Group 2 [26% (13/50)] was significantly more frequent than in Group 1 [12% (6/50)]; Group 3 [4% (2/50)] or Group 4], [8% (4/50)] (P<.01).
All 4 methods of eye protection were equally effective in the prevention of corneal abrasions. Methylcellulose was associated with more blurred vision and polyacrylic acid liquid gel with more conjunctival hyperemia. Subjects treated with paraffin-based ointment experienced more photophobia. The authors postulate a drug interaction between the inhalational anesthetic (isoflurane) and paraffin-based ointment resulting in ocular irritation.
Historical controlled study
1028 subjects undergoing robotic prostatectomy in the steep Trendelenburg position under general anesthesia. Phase 1 (May 2007 e October 2007): 214 patients received lubricating ointment and lid taping (Group A). Phase 2 (October 2007 e October 2009): 814 subjects received a sterile, transparent occlusive dressing (Tegaderm 3M, St Paul, MN), (Group B).
During phase 1, 2.3% (5 /214) of patients in Group A developed a corneal abrasion. During phase 2, none (0/814) of the subjects in Group B suffered a corneal abrasion. This difference was statistically significant (P<.001). The mean operative time was 117 minutes in Group A and 116 minutes in Group B (P¼NS).
The use of a sterile, transparent bio-occlusive dressing (Tegaderm) is effective in reducing the incidence corneal abrasion during general anesthesia.
ASA, American Society of Anesthesiologists. Type 1: Normal healthy patients. Type 2: Patients with mild systemic disease.
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Author
CORNEAL PROTECTION IN GENERAL ANESTHESIA / Grixti, et al Care should be taken to avoid inadvertent pressure on the eyeball, as this reduces the choroidal blood supply to the peripheral cornea, leading to corneal anoxia, edema, and epithelial cell loss.5,25 Decreased venous return from the head and raised intraocular pressure secondary to lateral or prone positioning and mechanical ventilation can also produce corneal edema and ulceration.5,25 In the recovery period, ocular injury has been reported from the bedclothes, oxygen face mask, and the patient’s fingers with or without a pulse oximeter probe.6,8,34,35 Loss of pain perception and inhibition of protective corneal reflexes following induction of anesthesia further increase the risk of corneal injury.6,8,11,19,26 Because of their reduced corneal sensitivity and tear production, diabetic patients are particularly prone to corneal damage.1,5 C. Chemical Injury Chemical injury can result from spillage of antimicrobial solutions into the eyes during skin preparation,2,3,6,7,13,15,32,36 contact with cleaning solutions retained on the anesthetic mask,37 or ocular hypersensitivity to inhaled anesthetic agents, such as halothane.6,7,15,26,38 Antiseptic solutions containing detergents that disrupt the precorneal tear film or alcohol are well documented to trigger adverse corneal reactions, causing edema, desquamation of the epithelial layer, opacification, and possibly permanent blindness.23,24,39,40 D. Exposure Keratopathy Corneal abrasions during general anesthesia can occur secondary to exposure keratopathy.1,2,4,6,7,10,17,25,32 Sedatives and neuromuscular blocking agents utilized during mechanical ventilation inhibit active contraction of the orbicularis oculi muscle, resulting in incomplete eyelid closure (lagophthalmos), corneal exposure, and dryness.6,12,15 Batra and Bali stained and examined the eyes of 200 patients who underwent general anesthesia. Of 59 patients whose eyes had been partly open during surgery, 26 (44%) showed positive staining, while none of the 141 patients whose eyes were naturally closed or protected during surgery developed exposure keratitis.7 The risk of keratopathy correlates with the duration of anesthesia and, consequently, corneal exposure.1,10 A peak incidence of corneal abrasion was observed between 90 and 150 minutes of anesthesia.7,28 Subjects with anatomically prominent eyes, proptosis, or exophthalmos in the presence of Graves’ disease are more susceptible to incomplete eyelid closure and corneal desiccation.1,6,10 Facial nerve injury during mastoidectomy, tympanoplasty or parotidectomy, and facial burns can also impair complete lid closure.6 Lagophthalmos facilitates inoculation of debris and noxious particles on the cornea, predisposing to injury and infection.41 E. Reduced Tear Production General anesthesia suppresses the autonomic nerve supply to the lacrimal gland, which is responsible for reflex
tear secretion.42,43 Krupin et al observed a significant decrease in basal tear production at 10, 30, and 60 minutes following induction of anesthesia (P<.001), further contributing to ocular surface desiccation.43 Moreover, specific drugs, such as beta blockers and the diuretic agent hydrochlorothiazide, are known to inhibit tear production.5 Ocular hypoperfusion secondary to deliberate hypotension and anemia have been suggested to cause a decrease in basal tear production and corneal hypoxia.5 Anesthetic gases delivered via face mask add to corneal dehydration.4,41 In addition, certain preoperative conditions such as dry eyes or recurrent corneal erosion syndrome may predispose to perioperative corneal lesions.5,44 General anesthesia abolishes the blink reflex and redistribution of the tear film over the ocular surface.8,25,45 Bell’s phenomenon, in which upward rotation of the eyeball protects the cornea during sleep, is absent in the anesthetized patient.8,25,35 V. METHODS OF OCULAR SURFACE PROTECTION A. Passive Eyelid Closure Simple manual closure of the eyelids without the application of lubricant ointment or adhesive tape to maintain shut eyelids has been reported by Batra and Bali to afford adequate corneal protection.7 However, in a study of 150 patients (300 eyes), Grover et al identified a higher incidence of corneal epithelial defects in the group whose eyes were unprotected (27%) compared to eyes that received lid taping (2%) or eye ointment (1%).19 Passive closure of the eyelids should be discouraged because of the risk of corneal damage and also because an unprotected eye requires constant vigilance by the anesthesiologist to prevent reopening of the lids, posing a distraction from other duties.13 This method is often impractical during certain types of surgical procedures, due to placement of the drapes or positioning of the patient.12,17 B. Eyelid Taping Taping the eyelids closed with adhesive or cellophane tape is one of the most popular methods to prevent lagophthalmos and exposure keratopathy during general anesthesia.13 Batra and Bali7 and Orlin et al4 observed no corneal abrasions in any of the patients whose eyes were taped closed. Taping also provides ocular surface protection from chemical injury and trauma.2 Horizontal lid taping is recommended to achieve complete closure, by allowing proper apposition of the upper and lower eyelids. Vertical lid taping is not helpful, because the lids may open under the tape.35 Lid taping is advised immediately after induction of anesthesia as soon as the eyelid reflex disappears and before tracheal intubation to reduce the risk of mechanical corneal trauma, unless rapid-sequence induction is being performed.1,14,25,31 Although lid taping provides protection, it impedes direct perioperative observation of the eye and assessment of pupillary reactions, which may be necessary during endonasal surgery to identify signs of orbital injury.29 Moreover, lid taping has potential hazards. Mechanical trauma to the
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CORNEAL PROTECTION IN GENERAL ANESTHESIA / Grixti, et al cornea or exposure keratopathy can occur if the tape is placed improperly.13 Ocular surface contact with the adhesive substance or rubbing against the edge of the tape can denude the exposed cornea.6,32 Periodic perioperative eye checks are required to ensure that the tape has not become displaced.8,11 Undesirable effects also include allergic reaction to the tape material, breakdown of the eyelid skin, and trauma to the eyelashes.12 During the recovery period, ocular injury can occur if patients open their eyes prematurely beneath the tape.6 Therefore, it is suggested that the tape be removed before emergence from anesthesia.5 The tape should be removed from the upper to the lower eyelid to prevent corneal injury or exposure.12 C. Ocular Lubricants Because general anesthesia significantly reduces tear production,19,43 lid taping alone may not provide adequate corneal protection to prevent mechanical damage. Replacement of the deficient tear film by artificial tear substitutes may also be necessary.42,43 In one RCT, Grover et al observed a lower incidence of corneal epitheliopathy and a lesser reduction in basal tear secretion with the use of eye ointment than with lid taping alone.19 Eye ointment is advocated for patients with facial burns or facial bone injuries that preclude taping of the lids.5 This technique also facilitates continuous perioperative eye monitoring.12,29 A wide variety of ocular lubricants are available. Conventionally, fat-based ointments have been preferred to aqueous solutions, as they are retained in the eye longer. The half-lives for ocular retention of petroleum ointments, methylcellulose, and saline in the closed human eye are 32, 12, and 6.6 minutes, respectively.25,46 During prolonged general anesthesia, repeated application of lubricant ointment every 90 minutes has been suggested to compensate for diminished tear production,42 but published studies substantiating this statement are lacking. Reapplication also presents an increased risk of corneal abrasion.47 Several RCTs showed no significant reduction in corneal abrasion with the use of lubricating ointment with or without lid taping, as compared to lid taping alone.4,13,14,18 Therefore, overall, evidence from the literature suggests that decreased tear production associated with general anesthesia is not detrimental to the normal ocular surface, provided that the eyelids are taped closed. This may not apply to patients with pre-existing dry eye syndrome or other ocular surface disorders associated with tear film deficiency.4 No significant difference was reported in the incidence of corneal abrasions during general anesthesia of short to long duration with either paraffin-based ointments or aqueous solutions, such as methylcellulose.13,15,18 However, petroleum ointments disrupt the stability of the precorneal tear film by reducing the breakup time, which may result in corneal exposure and dryness.48,49 Paraffin-based ointments have also been associated with significant ocular morbidity, such as blurred vision, local allergic reactions, 116
photophobia, and foreign body sensation.13,18,26 Drug interactions can occur between petroleum ointments and the inhalational anesthetic halothane. Halothane is up to 35 times more soluble in paraffin-based ointments compared to water-based methylcellulose 4% ointment. The resultant high concentration of halothane in lipid-based ointments can cause ocular surface inflammation, and this combination should be prohibited.26,41 A similar reaction was also noted with isoflurane.18 Ocular lesions can be prevented by using less soluble agents, such as sevoflurane or desflurane.18 Petroleum ointments are also flammable and are contraindicated during facial surgery.13 Water-based methylcellulose solutions have a low complication rate.26 Methylcellulose increases stability of the tear film by prolonging the tear film breakup time.50 The use of methylcellulose 4% ointment has been advocated, as it does not absorb halothane while producing firm adhesion of the upper and lower eyelids.15,26,41 This reduces tear film evaporation and provides mechanical protection against trauma and foreign bodies.15,41 Methylcellulose 0.5% may be less efficient, particularly during long procedures, as it has a relatively short ocular retention time and tends to run out of the eyes more rapidly.41 Visidic, a clear gelatinous artificial tear substitute, stabilizes the precorneal tear film, is well tolerated, and allows a more permanent, reliable judgement of pupillary reactions compared to dexpanthenol-based ointment.27 The use of other protective agents, such as artificial tears including hydroxypropyl methylcellulose (Tears Naturale II) and polyacrylic acid liquid gel (Viscotears), has also been described. However, occasional side effects such as blurred vision and conjunctival hyperemia have been reported. This was mainly attributed to the preservatives contained in these agents.18 More severe chemical injury resulting in complete bilateral sloughing of the corneal epithelium has also been reported secondary to the application of preservativecontaining eye lubricants.51 Thus, preservative-free preparations are recommended. D. Tarsorrhaphy In subjects with anatomically prominent eyes or exophthalmos, temporary suturing of the eyelids may be required to prevent lagophthalmos and exposure keratopathy during anesthesia.6,10,32 However, suture tarsorrhaphy causes trauma to the eyelids and provides limited ocular surface protection against chemical or mechanical injury.12,17 Furthermore, it restricts compensatory proptosis of the globe in the presence of periorbital edema or raised intraorbital pressure.12,29 E. Protective Goggles and Bandage Contact Lenses Protective goggles provide mechanical protection against ocular surface trauma. However, they are ineffective in preventing corneal desiccation and may hinder skin preparation as well as periorbital access during facial surgery.17 Goggles can also become displaced and cause pressure on the globe resulting in blindness.52 Corneal protection with
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CORNEAL PROTECTION IN GENERAL ANESTHESIA / Grixti, et al soft contact lenses was found to be as effective as occlusion bandage, viscous drops, or eye ointments, as it promotes tear film stability during long-term anesthesia.28 Yet, their use is not practical, as corneal abrasion can occur during application and removal of the lens.12,25 F. Geliperm Hydrogel dressings such as Geliperm (Geistlich Pharma AG, Ch-6110 Wolhusen, Switzerland) have been recently utilized for corneal protection during endonasal surgery. Geliperm is a transparent, nonallergenic, pliant, polyacrylamide hydrogel substance originally designed as a woundcare dressing. Its high water content prevents desiccation of the ocular surface, while its transparency allows direct perioperative observation of the eye. This is particularly important during nasolacrimal and functional endoscopic sinus surgery to detect signs of traumatic orbital complications. Following induction of anesthesia, a small sheet of Geliperm can be cut and placed over the closed eyelids. Alternatively, to allow continuous perioperative visualization of the eye, an eye speculum can be inserted and the Geliperm sheet can be placed directly over the ocular surface. The pliancy of Geliperm allows complete coverage of the cornea, as it conforms easily to the shape of the eyeball. It also acts as a mechanical barrier to bacterial infection. However, corneal abrasions can occur if the gel is allowed to dry. Therefore, irrigation with sterile water is advocated during long procedures.29 Cuddihy et al observed no corneal abrasions in over 300 procedures employing this method.29 G. Bio-occlusive Dressings Recently, the application of bio-occlusive transparent wound dressings, such as Tegaderm (3M, St Paul, MN) or Opsite (Smith Nephew United, Largo, FL), has been proposed as a means of corneal protection during general anesthesia.5,16,17 Once in position, these polymer films maintain complete uniform lid closure and create a moist environment by reducing tear film evaporation, thus preventing corneal desiccation. In addition, their conformity to the skin allows sealing of the periphery, reducing the risk of displacement, and inhibits spillage of various contaminants into the eye. Thus, it acts as a mechanical barrier to trauma, chemical injury, and infection.5,17 Anderson et al identified ocular injuries in only 12 of 40,089 patients (0.03%) undergoing general anesthesia for head and neck surgery with the use of this technique.17 This rate is comparable to or less than that observed with lid taping and/or ocular lubricants in other smaller reported studies.4,7,13-15,18,19 Moreover, Lavery et al reported no corneal abrasions with the use of Tegaderm alone during robotic prostatectomy in the steep Trendelenburg position, compared to an abrasion rate of 2.3% in patients who received lid taping and ocular lubricants (P <.001). In general, the use of bio-occlusive dressings may be considered in patients who are particularly at risk of corneal pathology, whereby protection by lid taping or lubricant
ointment may not be optimal. These include patients undergoing head and neck operations, prolonged surgery, or procedures in the prone or lateral position.5 Similarly, polyethylene covers were proven to be effective in the prevention of exposure keratopathy in patients in the intensive care unit.53 However, skin inflammatory reactions and trauma to the eyelids, lashes, or cornea itself can occur during application or removal of the dressing.12 Martin et al reported a significant reduction in the prevalence of perioperative corneal injuries from 1.51 per 1000 surgeries to 0.79 per 1000 surgeries following the introduction of an educational initiative to improve perioperative eye care (P¼.008). This emphasizes the importance of continuous standardized education and increased awareness among anesthesia providers, including recovery room nursing staff, regarding the risk of perioperative corneal abrasions. VI. SUMMARY AND CONCLUSIONS None of the available methods of corneal protection for patients undergoing anesthesia is completely effective, and they may be associated with unwanted side effects. Lid taping is the single best protective measure, but other interventions, eg, use of ointments, gels, or dressings, may provide additional or alternative means of protection. Aqueous-based ointments, such as methylcellulose 4%, are better tolerated than paraffin ointments, and preservativefree ointments are preferred. Geliperm hydrogel dressings may be particularly useful during endonasal surgery when continuous perioperative observation of the eye is required. Recent studies have recommended the application of bio-occlusive dressings instead of lid taping, particularly during head and neck surgery, prolonged procedures, and operations in the prone or lateral position. Further research, particularly large RCTs, are necessary to determine the efficacy of these novel treatment strategies. REFERENCES 1. Martin DP, Weingarten TN, Gunn PW, et al. Performance improvement system and postoperative corneal injuries: incidence and risk factors. Anesthesiology 2009;111:320-6 2. Gild WM, Posner KL, Caplan RA, Cheney FW. Eye injuries associated with anesthesia. A closed claims analysis. Anesthesiology 1992;76:204-8 3. Roth S, Thisted RA, Erickson JP, et al. Eye injuries after nonocular surgery. A study of 60,965 anesthetics from 1988 to 1992. Anesthesiology 1996;85:1020-7 4. Orlin SE, Kurata FK, Krupin T, et al. Ocular lubricants and corneal injury during anesthesia. Anesth Analg 1989;69:384-5 5. Yu HD, Chou AH, Yang MW, Chang CJ. An analysis of perioperative eye injuries after nonocular surgery. Acta Anesthesiol Taiwan 2010;48: 122-9 6. Snow JC, Kripke BJ, Norton ML, et al. Corneal injuries during general anesthesia. Anesth Analg 1975;54:465-7 7. Batra YK, Bali IM. Corneal abrasions during general anesthesia. Anesth Analg 1977;56:363-5 8. Moos DD, Lind DM. Detection and treatment of perioperative corneal abrasions. J Perianesth Nurs 2006;21:332-8
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CORNEAL PROTECTION IN GENERAL ANESTHESIA / Grixti, et al 9. Duncalf D, Rhodes DH. Anesthesia in clinical ophthalmology. Baltimore, Williams and Wilkins, 1963. pp 143-5 10. Terry Jr HR, Kearns TP, Love JG, Orwoll G. Untoward ophthalmic and neurologic events of anesthesia. Surg Clin North Am 1965;45:927-38 11. Yanagidate F, Dohi S. Corneal abrasion after the wake-up test in spinal surgery. J Anesth 2003;17:211-2 12. White E, David DB. Care of the eye during anesthesia and intensive care. Anesthesia Intensive Care Med 2010;11(10):418-22 13. Siffring PA, Poulton TJ. Prevention of ophthalmic complications during general anesthesia. Anesthesiology 1987;66:569-70 14. Cucchiara RF, Black S. Corneal abrasion during anesthesia and surgery. Anesthesiology 1988;69:978-9 15. Schmidt P, Boggild-Madsen NB. Protection of the eyes with ophthalmic ointments during general anesthesia. Acta Ophthalmol (Copenh) 1981;59:422-7 16. Lavery HJ, Samadi DB, Gainsburg DM. Preventing ocular injuries during robotic prostatectomy: A simple technique (Abstract of poster presentation at the 25th Annual Congress of the European Association of Urology in Barcelona, April 2010). Eur Urol Suppl 2010;9:257 17. Anderson DA, Braun TW, Herlich A. Eye injury during general anesthesia for oral and maxillofacial surgery: etiology and prevention. J Oral Maxillofac Surg 1995;53:321-4 18. Ganidagli S, Cengi M, Becerik C, et al. Eye protection during general anesthesia: comparison of four different methods. Eur J Anesthesiol 2004;21:665-7 19. Grover VK, Kumar KV, Sharma S, et al. Comparison of methods of eye protection under general anesthesia. Can J Anesth 1998;45:575-7 20. Aders A, Aders H. Anesthetic adverse incident reports: an Australian study of 1,231 outcomes. Anesth Intensive Care 2005;33:336-44 21. Fassoulaki A, Sarantopoulos C. Minor complications of general anesthesia in a series of 1220 patients: the influence of mode of ventilation. Acta Anesthesiol Belg 1991;42:157-63 22. Duncan PG, Cohen MM, Tweed WA, et al. The Canadian four-centre study of anesthetic outcomes: III. Are anesthetic complications predictable in day surgical practice? Can J Anesth 1992;39:440-8 23. Tabor E, Bostwick DC, Evans CC. Corneal damage due to eye contact with chlorhexidine gluconate. JAMA 1989;261:557-8 24. Hamed LM, Ellis FD, Boudreault G, et al. Hibiclens keratitis. Am J Ophthalmol 1987;104:50-6 25. White E, Crosse MM. The aetiology and prevention of peri-operative corneal abrasions. Anesthesia 1998;53:157-61 26. Boggild-Madsen NB, Bundgarrd-Nielsen P, Hammer U, Jakobsen B. Comparison of eye protection with methylcellulose and paraffin ointments during general anesthesia. Can Anesth Soc J 1981;28:575-8 27. Marquardt R, Christ T, Bonfils P. Gelatinous tear substitutes and nonspecific eye ointments in the critical care unit and in perioperative use. Anasth Intensivther Notfallmed 1987;22:235-8 28. Hrazdirová V, Navrátilová B, Ventrubová R. Use of contact lenses during general anesthesia. Cesk Oftalmol 1990;46:223-9 29. Cuddihy PJ, Whittet H. Eye observation and corneal protection during endonasal surgery. J Laryngol Otol 2005;119:556-7 30. Brooks GZ. Ocular injury during anesthesia. Anesthesia Rev 1978;5:22-4
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31. Watson WJ, Moran RL. Corneal abrasion during induction. Anesthesiology 1987;66:440 32. Rosenberg M. Ocular injuries during general anesthesia. J Oral Surg 1981;39:945-7 33. Ho AM, Lam GC, Karmakar MK. Potential eye injury due to protective face shields. Anesthesiology 2004;100:201 34. Brock-Utne JG. The aetiology and prevention of peri-operative corneal abrasion. Anesthesia 1998;53:829 35. Herbert L. Ophthalmology in anesthesia and intensive care. Anesthesia Intensive Care Med 2004;5:304-7 36. Duncalf D, Rhodes DH. Anaesthesia in clinical ophthalmology. Baltimore, Williams and Wilkins, 1963. pp143-5 37. Murray WJ, Ruddy MP. Toxic eye injury during induction of anesthesia. South Med J 1985;78:1012-3 38. Boyd CH. Ophthalmic hyper-sensitivity to anesthetic vapour. Anesthesia 1972;27:456-7 39. Morgan 3rd JP, Haug RH, Kosman JW. Antimicrobial skin preparations for the maxillofacial region. J Oral Maxillofac Surg 1996;54: 89-94 40. Mac Rae SM, Brown B, Edelhauser HF. The corneal toxicity of presurgical skin antiseptics. Am J Ophthalmol 1984;97:221-32 41. Bundgaard-Nielsen P, Boggild-Madsen NB, Hammer U. The development of an ophthalmic ointment for the protection of eyes during anesthesia. Arch Pharm Chemi Sci Ed 1978;6:121-6 42. Cross DA, Krupin T. Implications of the effects of general anesthesia on basal tear production. Anesth Analg 1977;56:35-7 43. Krupin T, Cross DA, Becker B. Decreased basal tear production associated with general anesthesia. Arch Ophthalmol 1977;95:107-8 44. Fayers T, Simcock DE, Wilkins MR. Reactivation of recurrent corneal erosion syndrome by continuous positive pressure ventilation. Cornea 2007;26:1292 45. Smith RM. Anesthesia for infants and children. ed 3. London, CV Mosby, 1968. p 349 46. Hardberger R, Hanna C, Boyd CM. Effects of drug vehicles on ocular contact time. Arch Ophthalmol 1975;93:42-5 47. Siffring PA. On the use of ophthalmic ointment to prevent corneal abrasions during general anesthesia. Anesthesiology 1988;68:639-40 48. Norn MS. Tear-film and cornea wetting time [proceedings]. Acta Ophthalmol Suppl 1975;125:42-3 49. Norn MS. Desiccation of the precorneal film. I. Corneal wetting-time. Acta Ophthalmol (Copenh) 1969;47:865-80 50. Norn MS, Opauszki A. Effects of ophthalmic vehicles on the stability of the precorneal film. Acta Ophthalmol (Copenh) 1977;55:23-34 51. Manecke Jr GR, Tannenbaum DP, McCoy BE. Severe bilateral corneal injury attributed to a preservative-containing eye lubricant. Anesthesiology 2000;93:1545-6 52. Roth S, Tung A, Ksiazek S. Visual loss in a prone-positioned spine surgery patient with the head on a foam headrest and goggles covering the eyes: An old complication with a new mechanism. Anesth Analg 2007;104:1185-7 53. Grixti A, Sadri M, Edgar J, Datta AV. Common ocular surface disorders in patients in intensive care units. Ocul Surf 2012;10:26-42
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ABSTRACT Corneal abrasion is the most common ophthalmologic complication that occurs during general anesthesia for nonocular surgery. Such abrasions can be caused by a variety of mechanisms and can lead to sightthreatening microbial keratitis and permanent scarring. There is no standard mode of protecting the cornea during general anesthesia for nonocular surgery. Methods described in the literature are not entirely effective and may be associated with unwanted side effects. Taping alone provides protection that is equivalent or superior to other interventions and has fewer side effects. Petroleum gel is flammable and is best avoided when electrocautery and open oxygen are to be used around the face. Preservativefree eye ointment is preferred, as preservative can cause corneal epithelial sloughing and conjunctival hyperemia. Recently, the application of Geliperm and bio-occlusive dressings has been advocated. Geliperm may be particularly useful during endonasal surgery when continuous perioperative observation of the eye is required. In this article, the literature on the etiology of perioperative corneal abrasions is reviewed and various protection strategies are compared in order to identify the best methods to prevent corneal abrasions during general anesthesia. KEY WORDS corneal abrasions, general anesthesia
Accepted for publication October 2012. From the 1Department of Ophthalmology, Royal Liverpool University Hospital, Liverpool, 2Department of Anaesthesia, Cambridge University Hospital, Cambridge, and 3Department of Ophthalmology, Wirral University Teaching Hospital, Wirral, United Kingdom. The authors have no proprietary or commercial interest in any concept or product discussed in this article. The authors declare that they have no research grants or financial support. Single-copy reprint requests to Andre Grixti, MD (address below). Corresponding author: Andre Grixti, MD, Department of Ophthalmology, Royal Liverpool University Hospital, Prescot Street, Liverpool, UK, L7 8XP. Tel: 07783974823. E-mail address: [email protected] © 2013 Elsevier Inc. All rights reserved. The Ocular Surface ISSN: 15420124. Grixti A, Sadri M, Watts MT. Corneal protection during general anesthesia for nonocular surgery. 2013;11(2):109-118.
PRIMARY,
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AND
I. INTRODUCTION orneal abrasion is the most common ophthalmologic complication in patients undergoing general anesthesia for nonocular surgery.1-9 Because the cornea is the most densely innervated tissue in the body, the postoperative pain resulting from abrasion of the cornea may be more severe than that arising from the surgical procedure itself.6,10,11 Moreover, the cornea serves as a mechanical barrier to infection, and corneal damage facilitates penetration of pathogenic organisms, which may lead to sight-threatening microbial keratitis and permanent scarring.6 Various methods of corneal protection have been advocated to eliminate or decrease the rate of this potentially avoidable complication. In this review, the etiology of perioperative corneal abrasions is discussed and various protection strategies are compared in order to identify the best methods to prevent corneal abrasions following general anesthesia.
C
II. METHOD OF LITERATURE SEARCH A literature search was performed using the keywords general anesthesia; eye; cornea; abrasion. The search engines of CINAHL, MEDLINE and EMBASE were all used in the initial search. A manual search was also performed on the reference lists of all papers relevant to the topic. A total of 557 hits were provided through the search engines. The abstracts of these papers were reviewed by the first and second authors separately, and 107 papers were considered relevant to the topic. Of the 107 selected articles, 52 papers focused on the etiology and prevention of perioperative corneal abrasions and were included in this review. The remaining 55 papers consisted of case reports or studies on uncommon ophthalmological complications following general anesthesia and did not meet the criteria for inclusion. The studies included in this review had significant heterogeneity and lack of raw data in the papers, which made it impossible to perform a meta-analysis. However, we identified studies with a higher level of evidence which compare corneal protection strategies during general anesthesia for elective nonophthalmic surgery. These include randomized controlled trials (RCTs) and a historical controlled study. They are summarized in table format with their main conclusions.
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CORNEAL PROTECTION IN GENERAL ANESTHESIA / Grixti, et al
OUTLINE I. II. III. IV.
Introduction Method of Literature Search General Findings Pathogenesis of Corneal Abrasions A. Risk Factors B. Mechanical Injury C. Chemical Injury D. Exposure Keratopathy E. Reduced Tear Production V. Methods of Ocular Surface Protection A. Passive Eyelid Closure B. Eyelid Taping C. Ocular Lubricants D. Tarsorrhaphy E. Protective Goggles and Bandage Contact Lenses F. Geliperm G. Bio-occlusive Dressings VI. Summary and Conclusions
III. GENERAL FINDINGS The incidence of perioperative corneal injury reported in the literature varies significantly depending on the design of the study, type of surgical population, method of assessment, and protection used.3,8,12 Its prevalence ranges from as low as 0% with adequate protection up to 44% when no prophylactic measures were employed.1,3-5,7,13-22 Corneal abrasion sustained during general anesthesia was the most common type of eye injury reported in the American Society of Anesthesiologists Closed Claims Project, accounting for 35% of all ocular injuries.2 However, claims for corneal abrasion were characterized by a lower incidence of permanent injury and a lower level of compensation than other ocular injuries. Only 16% of corneal abrasions resulted in permanent ocular sequelae, the nature of which was not specified.2 Consistent with this report, two large retrospective studies have also identified corneal abrasion as the most prevalent form of ocular injury in 61.8%3 and 59%5 of subjects who sustained an eye injury during general anesthesia for nonophthalmic surgery. All patients were treated in the immediate postoperative period without permanent ocular morbidity. Most corneal abrasions heal without complications; however, visual loss secondary to direct trauma10 or irreversible corneal opacification following chemical injury23,24 during general anesthesia have been reported. No cases of blindness from infection or scarring as a direct result of anesthesia-induced abrasion were identified in the literature. Various methods of perioperative ocular surface protection have been proposed.5,13,17,25 These include manual closure of the eyelids,7 taping the eyelids closed with or without the use of an eye ointment,4,7,13,14,19 application of petroleum-based lubricant ointments,6 aqueous solutions such as methylcellulose15,26 or viscous gels,27 wearing of protective goggles, insertion of hydrophilic contact lenses,28 tarsorrhaphy sutures,6 Geliperm dressings,29 and, most
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recently, the use of bio-occlusive dressings such as Tegaderm (3M, St Paul, MN) and Opsite (Smith & Nephew, Largo, FL).5,16,17 In our literature review, we identified eight RCTs 4,7,13,15,18,19,21,26 and one historical controlled study16 comparing different methods of corneal protection following general anesthesia for nonocular surgery. The results of these studies together with their main conclusions are summarized in Table 1. Taping alone was found to be superior or equivalent to other interventions in preventing corneal abrasions in five RCTs4,7,13,14,18 and was associated with side effects in two RCTs.13,18 Methylcellulose was utilized in four RCTs and produced fewer untoward side effects than paraffin-based ointments during general anesthesia.13,15,18,26 A historical controlled study conducted by Lavery et al identified a significantly lower incidence of perioperative corneal abrasions with the use of bio-occlusive dressings (Tegaderm) compared to a combination of lubricant ointment and lid taping (P<.001).16 IV. PATHOGENESIS OF CORNEAL ABRASIONS A. Risk Factors Several independent risk factors have been associated with an increased incidence of corneal injury during general anesthesia.30 These include long surgical procedures,1,3 operations on the head or neck,3,5 lateral or prone positioning,3,5 lower American Society of Anesthesiologists physical status,1 anesthesia provided by a student nurse anesthetist,1 surgery on a Monday,3 sustained intraoperative deliberate hypotension and preoperative anaemia.5 Although the mechanism of corneal injury was recognized in only 20% of claims for corneal abrasion in the American Society of Anesthesiologists Closed Claims Analysis,2 a variety of mechanisms can cause perioperative corneal abrasions. B. Mechanical Injury Corneal abrasions can occur as a result of direct trauma to the unprotected eye from the anesthesiologists’ equipment or personal items, such as watches, identification badges, stethoscopes or the laryngoscope during intubation.6,12,15,25,31,32 Mechanical injury from surgical drapes, anesthetic masks, patient repositioning or pressure from the surgeon’s hands and instruments has also been documented.2,4,6,10,12,15,25,33 Cucchiara et al identified a significantly higher incidence of corneal epithelial defects in subjects undergoing lumbar laminectomy in the prone position with the head turned to the side as compared to other neurosurgical procedures (P¼.005).14 All abrasions occurred in the lower positioned eye. Similarly, Grover et al19 noted that all eyes showing corneal abrasions in the lateral position were dependent, ie, lying at a lower point with respect to the other eye. Subjects lying in the lateral or prone position as well as those undergoing operations on the head or neck are more susceptible to direct trauma and globe compression.3
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Table 1.
Ocular surface protection during general anesthesia Method/ Design
Batra and Bali, 19777
BoggildMadsen et al, 198126
Sample Description
Results and Prevalence Rates
Comments/Conclusion
Randomized controlled trial
200 patients undergoing elective surgery under general anesthesia. The participants were randomized in two equal groups of 100 subjects each: Group A (eyes uncovered); Group B (eyes covered: 75/100 lid taping and 25/100 vaseline gauze).
Corneal abrasion was identified in 26% (26/ 100) of subjects in Group A and none (0/100) of the subjects in Group B. Lagophthalmos occurred in 59% (59/100) of patients in Group A, and 44% (26/59) of these patients developed corneal erosions.
Eyelid closure by taping or vaseline gauze is effective in preventing exposure keratopathy during general anesthesia.
Doubleblinded, randomized controlled trial
120 patients undergoing general anesthesia of >90 minutes in the supine position. Null Group: 12 randomly selected subjects received the same ointment in both eyes. Main Group: 108 patients randomly received water-based methylcellulose 4% ointment in one eye (Group A), and paraffin-based ointment, oculentum simplex, Ph Nord.63 in the other eye (Group B). Patients were further subclassified into a group that received anesthesia with halothane or without halothane.
The incidence of complications with each eye ointment are detailed in Table 1 of the paper. Perioperatively (at 90 mins): Periorbital edema (edema1) was identified in 1.9% (2/108) of subjects in Group A and 72% (78/108) subjects in Group B. Conjunctival injection (pink eye1) was observed in 2.8% (3/108) of subjects in Group A and 38% (41/108) of subjects in Group B. In the latter group, a conjunctival reaction occurred in 83% (34/41) of patients with halothane anesthesia and 17% (7/41) of patients without halothane. At 1 hour post-anesthesia: Periorbital edema (edema2) was recorded in 3.7% (4/108) of subjects in Group A and 44% (48/108) of subjects in Group B. Conjunctival injection (pink eye2) was observed in 6.5% (7/108) of subjects in Group A and 19% (20/108) of subjects in Group B. In the latter group, a conjunctival reaction occurred in 60% (12/20) of patients with halothane anesthesia and 40% (8/20) of patients without halothane. Blurred vision was documented in 0.9% (1/108) of subjects in Group A and 15% (16/108) of subjects in Group B.
Water-based methylcellulose 4% has less untoward effects than paraffin-based ointment during general anesthesia. A conjunctival reaction was most distinct when both paraffin-based ointment and halothane anesthesia were used, suggestive of a drug interaction. Reviewers’ comment: This paper does not have robust statistical measurements and therefore is acceptable only as an observational study.
Table 1. continues on the next page
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Author
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Ocular surface protection during general anesthesia (continued from previous page ) Method/ Design
Sample Description
Results and Prevalence Rates
Comments/Conclusion
Doubleblinded, randomized controlled trial
47 patients undergoing general anesthesia of < 90 minutes in the supine position. Each patient randomly received water-based methylcellulose 4% ointment in one eye (Group A), and paraffin-based neutral eye ointment Ph Nord.63 in the other eye (Group B).
Corneal abrasion occurred in 2.1% (1/47) of eyes in Group A and none (0/47) of the eyes in Group B. Overall, 66% (31/47) of subjects reported subjective complaints as detailed in Table 1 of the paper.The most prevalent complaint was ‘sticking’ of the eyes together. It occurred in 32% (15/47) of eyes in Group A and 2.1% (1/47) of eyes in Group B. Overall, 55.3% (26/47) of subjects showed objective signs of ocular surface staining, red eyes, or chemosis, as detailed in Table 2 of the paper.The most common sign was conjunctival staining. It occurred in 10.6% (5/47) of eyes in Group A and 21.3% (10/47) of eyes in Group B.
Water-based methylcellulose ointment produced more firm adhesion of the eyelids than paraffin-based ointment. This reduces evaporation and protects the eyes against trauma or foreign bodies. No unintended drug side effects were observed in either group. Limitations of the study: The short duration of anesthesia may have resulted in fewer objective signs compared to other studies. Reviewers’ comment: The paper lacks statistical analysis including sample size calculation.
Siffring and Poulton, 198713
Randomized controlled trial.
127 patients undergoing general anesthesia of 30 to 180 minutes duration in the supine position. Subjects were randomly divided into four equal groups. Group A received Lacrilube (paraffin-based) ointment (Allergan; Irvine, CA) and taping; Group B, Duratears (paraffinbased) ointment (Alcon; Forth Worth, TX) and tape; Group C, IsoptoAlkaline methylcellulose (water-based) drops (Alcon; Forth Worth, TX) and tape; and Group D, hypoallergenic paper tape (3M; St. Paul, MN) alone.
No corneal abrasions were identified in any of the patients studied. Blurred vision was recorded in 75% of subjects (mean -1.9 Snellen lines) in Group A and 55% of subjects (mean -1.3 Snellen lines) in Group B. This was statistically significant compared to groups C and D (P<.05). Foreign body sensation occurred in 62.5% of patients in Group A and 42% of patients in Group B. This was statistically significant compared to groups C and D (P<.05). Scleral erythema was observed in 20% of subjects in Group B (no statistical test was conducted).
Ocular morbidity was significantly greater in groups treated with paraffin-based ointments. During general anesthesia of short duration (<180 minutes) for procedures distant from the head and neck in the supine position, lid taping with or without methylcellulose appears to be most effective.
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Schmidt et al, 198115
Randomized controlled trial
4652 patients undergoing elective neurosurgical procedures under general anesthesia over a 13-month period were randomized into two groups. 2439 subjects received a combination of eye ointment and lid taping (Intervention Group) and 2213 subjects were treated with lid taping alone (Control Group).
Overall, the prevalence of corneal abrasion was 0.17% (8/4652). Corneal erosions developed in 0.16% (4/2439) of subjects in the Intervention Group and 0.18% (4/2213) of subjects in the Control Group. 0.73% (5/681) of patients undergoing lumbar laminectomy in the prone position with the head turned to the side developed a corneal abrasion of the lower eye (Table 1 of the paper). This was statistically significant (P¼.005; Chi-square with Fisher exact test) when compared to all other neurosurgical procedures as a group.
No difference was noted in the incidence of corneal abrasion between patients who received a combination of eye ointment and lid taping and lid taping alone. The risk of corneal abrasion during lumbar laminectomy was higher than with other neurosurgical procedures. Reviewers’ comment: High quality study with good randomization.
Orlin et al, 19894
Doubleblinded, randomized controlled trial.
76 subjects undergoing general anesthesia for nonocular surgery of 45 to 385 minutes duration. Each patient randomly received lubricating ointment, white petrolatum 55% (Lacrilube) followed by lid taping to one eye (Group A), and lid taping alone to the other eye (Group B).
No corneal abrasions were identified in any of the subjects studied. Only 1.3% (1/76) of eyes in Group B showed transient conjunctival staining (X2 > 0.7). 6.6% (5/76) of eyes in Group A had a worse postoperative visual acuity (2 to 6 lines) in the first 24 hours after surgery. No significant difference was identified between the two forms of eye care
Lid taping with or without lubricating ointment significantly reduces the incidence of corneal injury during general anesthesia. Limitations: Small sample size.
Grover et al, 199819
Randomized controlled trial
150 ASA type 1 patients (300 eyes) undergoing general anesthesia of >90 minutes for nonophthalmic surgery were randomized in three equal groups of 50 subjects (100 eyes) each: Group C (no treatment); Group T (lid Taping); Group O (eye ointment).
The overall incidence of corneal epithelial defects was 10% (30/300 eyes). Corneal erosions occurred in 27% (27/100) of eyes in Group C; 2% (2/100) of eyes in Group T and 1% (1/100) of eyes in Group O. Basal tear production was reduced postoperatively in all groups compared to preoperative values (P<.0001); (Table 1 of the paper). The maximum reduction in basal tear production was seen in Group C, followed by Group T and Group O (P<.0008). The incidence of corneal abrasions in relation to surgical positioning is described in Table 2 of the paper. Supine posture, 9.67% (24/248) of eyes; Right lateral, 19.2% (5/26) of eyes and Left lateral, 3.84% (1/26) of eyes. All 6 eyes showing corneal erosions in the lateral posture were dependent eyes.
This study showed that inadequate eyelid closure was the main cause of corneal abrasions in unprotected eyes. Therefore, during general anesthesia, eye protection by lid taping or lubricating ointment should be provided. General anesthesia reduced basal tear production irrespective of the method of ocular protection used. In patients undergoing surgery in the lateral position, the dependent eye was more prone to develop corneal injuries.
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Table 1.
Ocular surface protection during general anesthesia (continued from previous page ) Method/ Design
Ganidagli et al, 200418
Lavery et al, 201016
Sample Description
Results and Prevalence Rates
Comments/Conclusion
Single-blinded, randomized controlled trial
200 ASA type1 or 2 adult subjects undergoing elective nonophthalmic surgery under general anesthesia were divided into 4 equal groups of 50 patients each. Group 1, Hypoallergenic tape (Hypafix; Smith and Nephew, France); Group 2, Paraffin-based ointment including terramycine (Terramycine; Pfizer, Turkey); Group 3, Polyacrylic acid liquid gel (Viscotears; Novartis, Turkey) and Group 4, Artificial tears including hydroxypropyl methylcellulose (Tears Naturale II; Alcon, Turkey).
The overall prevalence of corneal defects at 12 hours after surgery was 9% (18/200). Corneal lesions (at 12 hours) occurred in 10% (5/50) of Group 1; 8% (4/50) of Group 2; 12% (6/50) of Group 3 and 6% (3/50) of Group 4. There was no significant difference in size or intensity of corneal staining between the four groups; (Table 1 of the paper). Conjunctival hyperemia scores in Group 3 at 12 hours [16% (8/50)] and 24 hours [12% (6/ 50)] were significantly higher than those of other groups (P<.05); (Table 2 of the paper). Blurred vision in Group 4 [42% (21/50)] was significantly higher than in Group 1 [12% (6/ 50)]; Group 2 [30% (15/50)] or Group 3 [34% (17/50)] (P<.05). Photophobia in Group 2 [26% (13/50)] was significantly more frequent than in Group 1 [12% (6/50)]; Group 3 [4% (2/50)] or Group 4], [8% (4/50)] (P<.01).
All 4 methods of eye protection were equally effective in the prevention of corneal abrasions. Methylcellulose was associated with more blurred vision and polyacrylic acid liquid gel with more conjunctival hyperemia. Subjects treated with paraffin-based ointment experienced more photophobia. The authors postulate a drug interaction between the inhalational anesthetic (isoflurane) and paraffin-based ointment resulting in ocular irritation.
Historical controlled study
1028 subjects undergoing robotic prostatectomy in the steep Trendelenburg position under general anesthesia. Phase 1 (May 2007 e October 2007): 214 patients received lubricating ointment and lid taping (Group A). Phase 2 (October 2007 e October 2009): 814 subjects received a sterile, transparent occlusive dressing (Tegaderm 3M, St Paul, MN), (Group B).
During phase 1, 2.3% (5 /214) of patients in Group A developed a corneal abrasion. During phase 2, none (0/814) of the subjects in Group B suffered a corneal abrasion. This difference was statistically significant (P<.001). The mean operative time was 117 minutes in Group A and 116 minutes in Group B (P¼NS).
The use of a sterile, transparent bio-occlusive dressing (Tegaderm) is effective in reducing the incidence corneal abrasion during general anesthesia.
ASA, American Society of Anesthesiologists. Type 1: Normal healthy patients. Type 2: Patients with mild systemic disease.
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Author
CORNEAL PROTECTION IN GENERAL ANESTHESIA / Grixti, et al Care should be taken to avoid inadvertent pressure on the eyeball, as this reduces the choroidal blood supply to the peripheral cornea, leading to corneal anoxia, edema, and epithelial cell loss.5,25 Decreased venous return from the head and raised intraocular pressure secondary to lateral or prone positioning and mechanical ventilation can also produce corneal edema and ulceration.5,25 In the recovery period, ocular injury has been reported from the bedclothes, oxygen face mask, and the patient’s fingers with or without a pulse oximeter probe.6,8,34,35 Loss of pain perception and inhibition of protective corneal reflexes following induction of anesthesia further increase the risk of corneal injury.6,8,11,19,26 Because of their reduced corneal sensitivity and tear production, diabetic patients are particularly prone to corneal damage.1,5 C. Chemical Injury Chemical injury can result from spillage of antimicrobial solutions into the eyes during skin preparation,2,3,6,7,13,15,32,36 contact with cleaning solutions retained on the anesthetic mask,37 or ocular hypersensitivity to inhaled anesthetic agents, such as halothane.6,7,15,26,38 Antiseptic solutions containing detergents that disrupt the precorneal tear film or alcohol are well documented to trigger adverse corneal reactions, causing edema, desquamation of the epithelial layer, opacification, and possibly permanent blindness.23,24,39,40 D. Exposure Keratopathy Corneal abrasions during general anesthesia can occur secondary to exposure keratopathy.1,2,4,6,7,10,17,25,32 Sedatives and neuromuscular blocking agents utilized during mechanical ventilation inhibit active contraction of the orbicularis oculi muscle, resulting in incomplete eyelid closure (lagophthalmos), corneal exposure, and dryness.6,12,15 Batra and Bali stained and examined the eyes of 200 patients who underwent general anesthesia. Of 59 patients whose eyes had been partly open during surgery, 26 (44%) showed positive staining, while none of the 141 patients whose eyes were naturally closed or protected during surgery developed exposure keratitis.7 The risk of keratopathy correlates with the duration of anesthesia and, consequently, corneal exposure.1,10 A peak incidence of corneal abrasion was observed between 90 and 150 minutes of anesthesia.7,28 Subjects with anatomically prominent eyes, proptosis, or exophthalmos in the presence of Graves’ disease are more susceptible to incomplete eyelid closure and corneal desiccation.1,6,10 Facial nerve injury during mastoidectomy, tympanoplasty or parotidectomy, and facial burns can also impair complete lid closure.6 Lagophthalmos facilitates inoculation of debris and noxious particles on the cornea, predisposing to injury and infection.41 E. Reduced Tear Production General anesthesia suppresses the autonomic nerve supply to the lacrimal gland, which is responsible for reflex
tear secretion.42,43 Krupin et al observed a significant decrease in basal tear production at 10, 30, and 60 minutes following induction of anesthesia (P<.001), further contributing to ocular surface desiccation.43 Moreover, specific drugs, such as beta blockers and the diuretic agent hydrochlorothiazide, are known to inhibit tear production.5 Ocular hypoperfusion secondary to deliberate hypotension and anemia have been suggested to cause a decrease in basal tear production and corneal hypoxia.5 Anesthetic gases delivered via face mask add to corneal dehydration.4,41 In addition, certain preoperative conditions such as dry eyes or recurrent corneal erosion syndrome may predispose to perioperative corneal lesions.5,44 General anesthesia abolishes the blink reflex and redistribution of the tear film over the ocular surface.8,25,45 Bell’s phenomenon, in which upward rotation of the eyeball protects the cornea during sleep, is absent in the anesthetized patient.8,25,35 V. METHODS OF OCULAR SURFACE PROTECTION A. Passive Eyelid Closure Simple manual closure of the eyelids without the application of lubricant ointment or adhesive tape to maintain shut eyelids has been reported by Batra and Bali to afford adequate corneal protection.7 However, in a study of 150 patients (300 eyes), Grover et al identified a higher incidence of corneal epithelial defects in the group whose eyes were unprotected (27%) compared to eyes that received lid taping (2%) or eye ointment (1%).19 Passive closure of the eyelids should be discouraged because of the risk of corneal damage and also because an unprotected eye requires constant vigilance by the anesthesiologist to prevent reopening of the lids, posing a distraction from other duties.13 This method is often impractical during certain types of surgical procedures, due to placement of the drapes or positioning of the patient.12,17 B. Eyelid Taping Taping the eyelids closed with adhesive or cellophane tape is one of the most popular methods to prevent lagophthalmos and exposure keratopathy during general anesthesia.13 Batra and Bali7 and Orlin et al4 observed no corneal abrasions in any of the patients whose eyes were taped closed. Taping also provides ocular surface protection from chemical injury and trauma.2 Horizontal lid taping is recommended to achieve complete closure, by allowing proper apposition of the upper and lower eyelids. Vertical lid taping is not helpful, because the lids may open under the tape.35 Lid taping is advised immediately after induction of anesthesia as soon as the eyelid reflex disappears and before tracheal intubation to reduce the risk of mechanical corneal trauma, unless rapid-sequence induction is being performed.1,14,25,31 Although lid taping provides protection, it impedes direct perioperative observation of the eye and assessment of pupillary reactions, which may be necessary during endonasal surgery to identify signs of orbital injury.29 Moreover, lid taping has potential hazards. Mechanical trauma to the
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CORNEAL PROTECTION IN GENERAL ANESTHESIA / Grixti, et al cornea or exposure keratopathy can occur if the tape is placed improperly.13 Ocular surface contact with the adhesive substance or rubbing against the edge of the tape can denude the exposed cornea.6,32 Periodic perioperative eye checks are required to ensure that the tape has not become displaced.8,11 Undesirable effects also include allergic reaction to the tape material, breakdown of the eyelid skin, and trauma to the eyelashes.12 During the recovery period, ocular injury can occur if patients open their eyes prematurely beneath the tape.6 Therefore, it is suggested that the tape be removed before emergence from anesthesia.5 The tape should be removed from the upper to the lower eyelid to prevent corneal injury or exposure.12 C. Ocular Lubricants Because general anesthesia significantly reduces tear production,19,43 lid taping alone may not provide adequate corneal protection to prevent mechanical damage. Replacement of the deficient tear film by artificial tear substitutes may also be necessary.42,43 In one RCT, Grover et al observed a lower incidence of corneal epitheliopathy and a lesser reduction in basal tear secretion with the use of eye ointment than with lid taping alone.19 Eye ointment is advocated for patients with facial burns or facial bone injuries that preclude taping of the lids.5 This technique also facilitates continuous perioperative eye monitoring.12,29 A wide variety of ocular lubricants are available. Conventionally, fat-based ointments have been preferred to aqueous solutions, as they are retained in the eye longer. The half-lives for ocular retention of petroleum ointments, methylcellulose, and saline in the closed human eye are 32, 12, and 6.6 minutes, respectively.25,46 During prolonged general anesthesia, repeated application of lubricant ointment every 90 minutes has been suggested to compensate for diminished tear production,42 but published studies substantiating this statement are lacking. Reapplication also presents an increased risk of corneal abrasion.47 Several RCTs showed no significant reduction in corneal abrasion with the use of lubricating ointment with or without lid taping, as compared to lid taping alone.4,13,14,18 Therefore, overall, evidence from the literature suggests that decreased tear production associated with general anesthesia is not detrimental to the normal ocular surface, provided that the eyelids are taped closed. This may not apply to patients with pre-existing dry eye syndrome or other ocular surface disorders associated with tear film deficiency.4 No significant difference was reported in the incidence of corneal abrasions during general anesthesia of short to long duration with either paraffin-based ointments or aqueous solutions, such as methylcellulose.13,15,18 However, petroleum ointments disrupt the stability of the precorneal tear film by reducing the breakup time, which may result in corneal exposure and dryness.48,49 Paraffin-based ointments have also been associated with significant ocular morbidity, such as blurred vision, local allergic reactions, 116
photophobia, and foreign body sensation.13,18,26 Drug interactions can occur between petroleum ointments and the inhalational anesthetic halothane. Halothane is up to 35 times more soluble in paraffin-based ointments compared to water-based methylcellulose 4% ointment. The resultant high concentration of halothane in lipid-based ointments can cause ocular surface inflammation, and this combination should be prohibited.26,41 A similar reaction was also noted with isoflurane.18 Ocular lesions can be prevented by using less soluble agents, such as sevoflurane or desflurane.18 Petroleum ointments are also flammable and are contraindicated during facial surgery.13 Water-based methylcellulose solutions have a low complication rate.26 Methylcellulose increases stability of the tear film by prolonging the tear film breakup time.50 The use of methylcellulose 4% ointment has been advocated, as it does not absorb halothane while producing firm adhesion of the upper and lower eyelids.15,26,41 This reduces tear film evaporation and provides mechanical protection against trauma and foreign bodies.15,41 Methylcellulose 0.5% may be less efficient, particularly during long procedures, as it has a relatively short ocular retention time and tends to run out of the eyes more rapidly.41 Visidic, a clear gelatinous artificial tear substitute, stabilizes the precorneal tear film, is well tolerated, and allows a more permanent, reliable judgement of pupillary reactions compared to dexpanthenol-based ointment.27 The use of other protective agents, such as artificial tears including hydroxypropyl methylcellulose (Tears Naturale II) and polyacrylic acid liquid gel (Viscotears), has also been described. However, occasional side effects such as blurred vision and conjunctival hyperemia have been reported. This was mainly attributed to the preservatives contained in these agents.18 More severe chemical injury resulting in complete bilateral sloughing of the corneal epithelium has also been reported secondary to the application of preservativecontaining eye lubricants.51 Thus, preservative-free preparations are recommended. D. Tarsorrhaphy In subjects with anatomically prominent eyes or exophthalmos, temporary suturing of the eyelids may be required to prevent lagophthalmos and exposure keratopathy during anesthesia.6,10,32 However, suture tarsorrhaphy causes trauma to the eyelids and provides limited ocular surface protection against chemical or mechanical injury.12,17 Furthermore, it restricts compensatory proptosis of the globe in the presence of periorbital edema or raised intraorbital pressure.12,29 E. Protective Goggles and Bandage Contact Lenses Protective goggles provide mechanical protection against ocular surface trauma. However, they are ineffective in preventing corneal desiccation and may hinder skin preparation as well as periorbital access during facial surgery.17 Goggles can also become displaced and cause pressure on the globe resulting in blindness.52 Corneal protection with
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CORNEAL PROTECTION IN GENERAL ANESTHESIA / Grixti, et al soft contact lenses was found to be as effective as occlusion bandage, viscous drops, or eye ointments, as it promotes tear film stability during long-term anesthesia.28 Yet, their use is not practical, as corneal abrasion can occur during application and removal of the lens.12,25 F. Geliperm Hydrogel dressings such as Geliperm (Geistlich Pharma AG, Ch-6110 Wolhusen, Switzerland) have been recently utilized for corneal protection during endonasal surgery. Geliperm is a transparent, nonallergenic, pliant, polyacrylamide hydrogel substance originally designed as a woundcare dressing. Its high water content prevents desiccation of the ocular surface, while its transparency allows direct perioperative observation of the eye. This is particularly important during nasolacrimal and functional endoscopic sinus surgery to detect signs of traumatic orbital complications. Following induction of anesthesia, a small sheet of Geliperm can be cut and placed over the closed eyelids. Alternatively, to allow continuous perioperative visualization of the eye, an eye speculum can be inserted and the Geliperm sheet can be placed directly over the ocular surface. The pliancy of Geliperm allows complete coverage of the cornea, as it conforms easily to the shape of the eyeball. It also acts as a mechanical barrier to bacterial infection. However, corneal abrasions can occur if the gel is allowed to dry. Therefore, irrigation with sterile water is advocated during long procedures.29 Cuddihy et al observed no corneal abrasions in over 300 procedures employing this method.29 G. Bio-occlusive Dressings Recently, the application of bio-occlusive transparent wound dressings, such as Tegaderm (3M, St Paul, MN) or Opsite (Smith Nephew United, Largo, FL), has been proposed as a means of corneal protection during general anesthesia.5,16,17 Once in position, these polymer films maintain complete uniform lid closure and create a moist environment by reducing tear film evaporation, thus preventing corneal desiccation. In addition, their conformity to the skin allows sealing of the periphery, reducing the risk of displacement, and inhibits spillage of various contaminants into the eye. Thus, it acts as a mechanical barrier to trauma, chemical injury, and infection.5,17 Anderson et al identified ocular injuries in only 12 of 40,089 patients (0.03%) undergoing general anesthesia for head and neck surgery with the use of this technique.17 This rate is comparable to or less than that observed with lid taping and/or ocular lubricants in other smaller reported studies.4,7,13-15,18,19 Moreover, Lavery et al reported no corneal abrasions with the use of Tegaderm alone during robotic prostatectomy in the steep Trendelenburg position, compared to an abrasion rate of 2.3% in patients who received lid taping and ocular lubricants (P <.001). In general, the use of bio-occlusive dressings may be considered in patients who are particularly at risk of corneal pathology, whereby protection by lid taping or lubricant
ointment may not be optimal. These include patients undergoing head and neck operations, prolonged surgery, or procedures in the prone or lateral position.5 Similarly, polyethylene covers were proven to be effective in the prevention of exposure keratopathy in patients in the intensive care unit.53 However, skin inflammatory reactions and trauma to the eyelids, lashes, or cornea itself can occur during application or removal of the dressing.12 Martin et al reported a significant reduction in the prevalence of perioperative corneal injuries from 1.51 per 1000 surgeries to 0.79 per 1000 surgeries following the introduction of an educational initiative to improve perioperative eye care (P¼.008). This emphasizes the importance of continuous standardized education and increased awareness among anesthesia providers, including recovery room nursing staff, regarding the risk of perioperative corneal abrasions. VI. SUMMARY AND CONCLUSIONS None of the available methods of corneal protection for patients undergoing anesthesia is completely effective, and they may be associated with unwanted side effects. Lid taping is the single best protective measure, but other interventions, eg, use of ointments, gels, or dressings, may provide additional or alternative means of protection. Aqueous-based ointments, such as methylcellulose 4%, are better tolerated than paraffin ointments, and preservativefree ointments are preferred. Geliperm hydrogel dressings may be particularly useful during endonasal surgery when continuous perioperative observation of the eye is required. Recent studies have recommended the application of bio-occlusive dressings instead of lid taping, particularly during head and neck surgery, prolonged procedures, and operations in the prone or lateral position. Further research, particularly large RCTs, are necessary to determine the efficacy of these novel treatment strategies. REFERENCES 1. Martin DP, Weingarten TN, Gunn PW, et al. Performance improvement system and postoperative corneal injuries: incidence and risk factors. Anesthesiology 2009;111:320-6 2. Gild WM, Posner KL, Caplan RA, Cheney FW. Eye injuries associated with anesthesia. A closed claims analysis. Anesthesiology 1992;76:204-8 3. Roth S, Thisted RA, Erickson JP, et al. Eye injuries after nonocular surgery. A study of 60,965 anesthetics from 1988 to 1992. Anesthesiology 1996;85:1020-7 4. Orlin SE, Kurata FK, Krupin T, et al. Ocular lubricants and corneal injury during anesthesia. Anesth Analg 1989;69:384-5 5. Yu HD, Chou AH, Yang MW, Chang CJ. An analysis of perioperative eye injuries after nonocular surgery. Acta Anesthesiol Taiwan 2010;48: 122-9 6. Snow JC, Kripke BJ, Norton ML, et al. Corneal injuries during general anesthesia. Anesth Analg 1975;54:465-7 7. Batra YK, Bali IM. Corneal abrasions during general anesthesia. Anesth Analg 1977;56:363-5 8. Moos DD, Lind DM. Detection and treatment of perioperative corneal abrasions. J Perianesth Nurs 2006;21:332-8
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CORNEAL PROTECTION IN GENERAL ANESTHESIA / Grixti, et al 9. Duncalf D, Rhodes DH. Anesthesia in clinical ophthalmology. Baltimore, Williams and Wilkins, 1963. pp 143-5 10. Terry Jr HR, Kearns TP, Love JG, Orwoll G. Untoward ophthalmic and neurologic events of anesthesia. Surg Clin North Am 1965;45:927-38 11. Yanagidate F, Dohi S. Corneal abrasion after the wake-up test in spinal surgery. J Anesth 2003;17:211-2 12. White E, David DB. Care of the eye during anesthesia and intensive care. Anesthesia Intensive Care Med 2010;11(10):418-22 13. Siffring PA, Poulton TJ. Prevention of ophthalmic complications during general anesthesia. Anesthesiology 1987;66:569-70 14. Cucchiara RF, Black S. Corneal abrasion during anesthesia and surgery. Anesthesiology 1988;69:978-9 15. Schmidt P, Boggild-Madsen NB. Protection of the eyes with ophthalmic ointments during general anesthesia. Acta Ophthalmol (Copenh) 1981;59:422-7 16. Lavery HJ, Samadi DB, Gainsburg DM. Preventing ocular injuries during robotic prostatectomy: A simple technique (Abstract of poster presentation at the 25th Annual Congress of the European Association of Urology in Barcelona, April 2010). Eur Urol Suppl 2010;9:257 17. Anderson DA, Braun TW, Herlich A. Eye injury during general anesthesia for oral and maxillofacial surgery: etiology and prevention. J Oral Maxillofac Surg 1995;53:321-4 18. Ganidagli S, Cengi M, Becerik C, et al. Eye protection during general anesthesia: comparison of four different methods. Eur J Anesthesiol 2004;21:665-7 19. Grover VK, Kumar KV, Sharma S, et al. Comparison of methods of eye protection under general anesthesia. Can J Anesth 1998;45:575-7 20. Aders A, Aders H. Anesthetic adverse incident reports: an Australian study of 1,231 outcomes. Anesth Intensive Care 2005;33:336-44 21. Fassoulaki A, Sarantopoulos C. Minor complications of general anesthesia in a series of 1220 patients: the influence of mode of ventilation. Acta Anesthesiol Belg 1991;42:157-63 22. Duncan PG, Cohen MM, Tweed WA, et al. The Canadian four-centre study of anesthetic outcomes: III. Are anesthetic complications predictable in day surgical practice? Can J Anesth 1992;39:440-8 23. Tabor E, Bostwick DC, Evans CC. Corneal damage due to eye contact with chlorhexidine gluconate. JAMA 1989;261:557-8 24. Hamed LM, Ellis FD, Boudreault G, et al. Hibiclens keratitis. Am J Ophthalmol 1987;104:50-6 25. White E, Crosse MM. The aetiology and prevention of peri-operative corneal abrasions. Anesthesia 1998;53:157-61 26. Boggild-Madsen NB, Bundgarrd-Nielsen P, Hammer U, Jakobsen B. Comparison of eye protection with methylcellulose and paraffin ointments during general anesthesia. Can Anesth Soc J 1981;28:575-8 27. Marquardt R, Christ T, Bonfils P. Gelatinous tear substitutes and nonspecific eye ointments in the critical care unit and in perioperative use. Anasth Intensivther Notfallmed 1987;22:235-8 28. Hrazdirová V, Navrátilová B, Ventrubová R. Use of contact lenses during general anesthesia. Cesk Oftalmol 1990;46:223-9 29. Cuddihy PJ, Whittet H. Eye observation and corneal protection during endonasal surgery. J Laryngol Otol 2005;119:556-7 30. Brooks GZ. Ocular injury during anesthesia. Anesthesia Rev 1978;5:22-4
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31. Watson WJ, Moran RL. Corneal abrasion during induction. Anesthesiology 1987;66:440 32. Rosenberg M. Ocular injuries during general anesthesia. J Oral Surg 1981;39:945-7 33. Ho AM, Lam GC, Karmakar MK. Potential eye injury due to protective face shields. Anesthesiology 2004;100:201 34. Brock-Utne JG. The aetiology and prevention of peri-operative corneal abrasion. Anesthesia 1998;53:829 35. Herbert L. Ophthalmology in anesthesia and intensive care. Anesthesia Intensive Care Med 2004;5:304-7 36. Duncalf D, Rhodes DH. Anaesthesia in clinical ophthalmology. Baltimore, Williams and Wilkins, 1963. pp143-5 37. Murray WJ, Ruddy MP. Toxic eye injury during induction of anesthesia. South Med J 1985;78:1012-3 38. Boyd CH. Ophthalmic hyper-sensitivity to anesthetic vapour. Anesthesia 1972;27:456-7 39. Morgan 3rd JP, Haug RH, Kosman JW. Antimicrobial skin preparations for the maxillofacial region. J Oral Maxillofac Surg 1996;54: 89-94 40. Mac Rae SM, Brown B, Edelhauser HF. The corneal toxicity of presurgical skin antiseptics. Am J Ophthalmol 1984;97:221-32 41. Bundgaard-Nielsen P, Boggild-Madsen NB, Hammer U. The development of an ophthalmic ointment for the protection of eyes during anesthesia. Arch Pharm Chemi Sci Ed 1978;6:121-6 42. Cross DA, Krupin T. Implications of the effects of general anesthesia on basal tear production. Anesth Analg 1977;56:35-7 43. Krupin T, Cross DA, Becker B. Decreased basal tear production associated with general anesthesia. Arch Ophthalmol 1977;95:107-8 44. Fayers T, Simcock DE, Wilkins MR. Reactivation of recurrent corneal erosion syndrome by continuous positive pressure ventilation. Cornea 2007;26:1292 45. Smith RM. Anesthesia for infants and children. ed 3. London, CV Mosby, 1968. p 349 46. Hardberger R, Hanna C, Boyd CM. Effects of drug vehicles on ocular contact time. Arch Ophthalmol 1975;93:42-5 47. Siffring PA. On the use of ophthalmic ointment to prevent corneal abrasions during general anesthesia. Anesthesiology 1988;68:639-40 48. Norn MS. Tear-film and cornea wetting time [proceedings]. Acta Ophthalmol Suppl 1975;125:42-3 49. Norn MS. Desiccation of the precorneal film. I. Corneal wetting-time. Acta Ophthalmol (Copenh) 1969;47:865-80 50. Norn MS, Opauszki A. Effects of ophthalmic vehicles on the stability of the precorneal film. Acta Ophthalmol (Copenh) 1977;55:23-34 51. Manecke Jr GR, Tannenbaum DP, McCoy BE. Severe bilateral corneal injury attributed to a preservative-containing eye lubricant. Anesthesiology 2000;93:1545-6 52. Roth S, Tung A, Ksiazek S. Visual loss in a prone-positioned spine surgery patient with the head on a foam headrest and goggles covering the eyes: An old complication with a new mechanism. Anesth Analg 2007;104:1185-7 53. Grixti A, Sadri M, Edgar J, Datta AV. Common ocular surface disorders in patients in intensive care units. Ocul Surf 2012;10:26-42
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