Eye Protection during General Anaesthesia

Literature Review

Background

Approximately 6 out of 10 patients will experience lagophthalmos, or incomplete eye closure, during a general anaesthetic

Eye injuries account for 2% of claims against anaesthetists in Australia1 2 and 3% in the USA7

These injuries include: Corneal injury, visual loss, painful eyes, and local inflammation.1

Corneal Abrasions

Corneal abrasions are the most common form of ocular injury associated with general anaesthesia.2

They are often linked to:

Exposure Keratitis

General anaesthesia causes a reduction in tear production as well as an inhibition of the reflex in which the eye turns upwards to protect it during sleep. Therefore there is an increased chance of the epithelium of the cornea drying out.2 3 5 When the cornea dries out it may stick to the eyelid and cause an abrasion when the eye reopens.4

Chemical Injury.

Facemasks and other equipment are cleaned with detergents that may spill into the eye causing chemical damage. Antiseptic skin preparations such as chlorhexidine and alcoholic antiseptic solutions are commonly used to prepare the area to be operated on. The risk of it spilling into the eyes is much higher when the procedure is being performed on the face or neck.2 8

Direct Trauma.

Facemasks, laryngoscopes, stethoscopes, surgical drapes, surgical instruments, and removal of tape used for shutting the eyes can all cause direct trauma. The chances of them resulting in corneal abrasions increase significantly when the cornea is suffering from exposure keratopathy.2

Current Methods

Current methods of protecting the eyes during general anaesthesia are inadequate and include:

Manual Closure of the Eyelids

This method is ineffective in 59% of patients due to the patients inability to maintain eye closure while affected by a general anaesthetic.2

Taping the Eyelids Closed

Medical tapes are not designed to be used on the delicate skin of the eyelids, especially in the elderly. Therefore, removal of the tape may result in bruising or tearing of the eyelid, as well as significant eyelash removal. Inadequate taping may result in exposure keratitis. There is also a possibility of causing corneal abrasions by placing the tape directly onto the cornea.2

Ophthalmic Ointment

Ointments may cause chemical injuries to eyes. Blurred vision has been reported in up to 75% of patients. Ointments can cause eyelid oedema and/or conjunctival hyperaemia. They also do not protect from direct trauma or chemical spills.2 6

Negative outcomes of intraoperative eye injuries

Any intraoperative injuries have a negative effect on the patient, personnel, and hospital. The negative outcomes associated with intraoperative eye injuries include:

Increased length of stay

This can be due to ophthalmology consults required, associated infections and treatment.5

Increased costs

This is due to increased length of stay, cost of additional consults, and the cost of treating the complications.5

Pain and discomfort for patient.

Corneal abrasions and exposure keratitis can be extremely painful for the patient. The treatment required consists of drops and ointments applied in the eye which may cause discomfort for the patient.5 6

Summaries of Individual Articles

Tarmey & White 2009, 'Damage to the eye during general anaesthesia'

"What is the most common type of damage?

The most common damage to the eye which can occur during or after general anaesthesia is a corneal abrasion.

What is a corneal abrasion?

The cornea is one of the outer clear layers of the eye. An abrasion is a tear or graze of this layer. The abrasion can cause pain, blurred vision and considerable irritation for a few days. Almost all corneal abrasions heal without long-term effects on vision.

How do corneal abrasions happen?

Most abrasions happen because the eye does not close fully during the anaesthetic. Approximately 6 out of 10 people (60%) do not close their eyes naturally when they have a general anaesthetic. The cornea is then exposed to the air and becomes dry. Fewer tears are produced during an anaesthetic which also causes dryness in the eyes. The dry cornea can then stick to the inside of the eyelid and the abrasion occurs when the eye opens again at the end of the anaesthetic. Corneal abrasion can also occur because something rubs against the exposed cornea during the anaesthetic. This may be one of the sheets used during surgery to cover the patient and keep the operation area sterile, or other equipment. Anaesthetists take care to ensure the eyes are closed during a general anaesthetic and to protect the eyes.

What is done to prevent corneal abrasions?

Corneal abrasions can usually be prevented by careful protection of the eyes. Small pieces of sticking tape are commonly used to keep the eyelids fully closed during the anaesthetic. This has been shown to reduce the chance of a corneal abrasion occurring. However, bruising of the eyelid can occur when the tape is removed, especially if you have thin skin and bruise easily. Sometimes, the anaesthetist may use a gel, an ointment or eye drops to moisten the eyes during your anaesthetic. These may be helpful if tape cannot be used or for certain operations in which the eyes need to be opened briefly during the operation. Eye ointments can sometimes cause temporary eye irritation or blurring of vision following an anaesthetic. Anaesthetists are trained to take care that nothing rubs against the eyes. If your surgery requires you to be positioned lying on your front, your anaesthetist will use goggles, cushions and/or eyepads to protect your eyes.

How often do corneal abrasions occur?

Studies have been done using a microscope to examine the eyes following an anaesthetic. These show that small corneal abrasions occur commonly. Around 1 in 25 patients may have a small corneal abrasion, which the patient does not notice. This occurs even when protective eye tape or ointment is used. You are more likely to suffer from a corneal abrasion if your surgery requires you to be positioned lying on your front or your side, if your operation lasts a long time, or if you are having surgery on your head or neck.

What happens if I have a corneal abrasion?

Corneal abrasions may be very painful. Healing usually takes a few days, after which the pain will stop completely. Treatment during this time can reduce pain and aims to prevent an eye infection developing. Eye drops, ointments and an eye patch may be used, as well as pain-relieving medicines. No surgical treatment is necessary. Almost all corneal abrasions heal with no visible scar and no long-term effect on vision. An eye specialist may be able to see a scar through a microscope. Contact lens users should take advice before using contact lenses again." 4

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Weed & Syed 2012, Perioperative Corneal Abrasions: Systems-based Review and Analysis'

"In our experience, two different types of perioperative abrasions predominate. The first type is the classic corneal abrasion; this occurs with mechanical trauma to the cornea, and results in abrasions of varying shapes and sizes depending on the nature of the insult. The second type occurs due to exposure of the cornea during or after surgery, and produces a horizontal fusiform or linear staining pattern in the interpalpebral area.

Various mechanisms have been posited which may contribute to perioperative corneal abrasions. Analgesia and anesthesia inherently mask the natural pain response, preventing the patient from sensing and reacting to the noxious stimulus of ongoing corneal exposure. Lagophthalmos (incomplete eyelid closure) has been reported to occur in over half of patients under general anesthesia, increasing corneal exposure and surface drying. This is exacerbated by the fact that general anesthetic agents also abolish Bell's phenomenon, further risking corneal exposure. Also, general anesthetics cause a significant decrease in tear production. In addition to exposure, the cornea may be traumatized by inadvertent pressure, or by chemicals such as the sterile prep. Finally, direct mechanical trauma may occur from myriad means, including the oxygen facemask, laryngoscope, sterile drape, nasal cannula, low-hanging identification badges, or patient attempts to rub the eyes with a pulse-oximetered finger. The exact mechanism of injury in these cases remains unknown more often than not.

Prevention

There are several reasons why the prevention of perioperative corneal abrasions is important. From a patient perspective, they are significantly painful injuries. It is our experience that patients with these injuries will frequently describe the pain of the abrasion as more severe than the pain from their operative site. They often recall the pain of the abrasion vividly as part of their immediate postoperative memory. Patients are often concerned they were mishandled in some way. Ophthalmologic evaluation may result in a delay in discharge, and most patients end up with the expense and inconvenience of an ophthalmology consultation, extra medication and a follow-up eye visit. Finally, there is a small risk of corneal ulcer or recurrent erosion.

The health care system also stands to benefit by reducing the incidence of perioperative corneal abrasions. Ophthalmology consults have an associated cost. At our facility, they also necessitate a provider leaving his or her other responsibilities and patients in order to perform the urgent consult. The topical medication and bandage contact lenses that are often dispensed also have a cost. In addition, from a medicolegal perspective, ocular injuries are reported to account for between three and 8% of anesthesia malpractice claims, with 35% stemming from perioperative corneal abrasions.

An oft-employed preventative strategy involves the preoperative application of lubricating ointment to the eyes following induction of anesthesia. Interestingly, this practice has not been shown to decrease incidence of corneal abrasions, as documented by a large, prospective trial.

Current best-practice recommendations include a review of eye problems between the provider and patient prior to surgery, as well as removal of contact lenses pre-operatively. Eyes should be closed and securely taped immediately after induction of anesthesia. During long procedures, the eyes should be periodically checked to make sure that they are staying closed." 5

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Nair & White 2014, 'Care of the eye during anaesthesia and intensive care'

Aetiology of perioperative corneal abrasions

"The most common ocular complication associated with general anaesthesia is corneal abrasion. Patients having prolonged surgery, lateral or prone positioning and operations on the head and neck are most at risk. It is most commonly caused by exposure keratopathy, chemical injury or direct trauma.

General anaesthesia reduces the tonic contraction of the orbicularis oculi muscle, which causes lagophthalmos in up to 59% of patients. If the anaesthetist does not ensure that the eyes are fully closed, exposure keratopathy occurs in 27–44% of patients. Anaesthesia decreases production of tears the film stability plus inhibits the protective mechanism afforded by Bell's phenomenon (in which the eyeball turns upwards during sleep, protecting the cornea). The combination of these may lead to corneal epithelial drying.

Chemical injury can result from cleaning materials on the facemask and inadvertent spillage of antiseptic skin preparations onto the eye. The only antiseptic skin preparation that is not toxic to the cornea is preservative-free povidone–iodine 10% in aqueous solution. It is the agent of choice when antimicrobial skin preparation of the face is required.

Antiseptic solutions with detergent readily penetrate the corneal epithelium causing damage to the underlying iris, ciliary body, lens and blood vessels leading to ischaemia. Chlorhexidine, cetrimide, aqueous povidone–iodine containing phenol and alcoholic antiseptic solutions cause oedema and de-epithelialization of the cornea.

Trauma to the eyes can occur at anytime during the perioperative period. During induction of anaesthesia it can be caused by ill-fitting facemasks, the laryngoscope, the anaesthetist's fingers, watchstrap, identification badge or stethoscope. After induction of anaesthesia trauma to the eyes by surgical drapes, surgical instruments and during patient repositioning have all been reported. In the recovery unit, the patient's fingers, pulse oximeter probe, pillow, Hudson mask and removal of the occlusive tape from the eyelid may injure the eye.

Patients often rub their eyes on emergence from anaesthesia. Placing the pulse oximeter probe on either the little or ring finger of the non-dominant hand can reduce the risk of trauma to the eye. Removal of tape from the eyelid at the end of surgery should be from the upper eyelid to the lower to prevent exposure." 2

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J Anson, 'Perioperative Corneal Abrasions: Etiology, Prevention, and Management'

"Corneal abrasions are the most frequent ocular complications following general anesthesia, and are a painful burden to the recovering postoperative patient. The most recent ASA closed claim analysis showed that eye injury occurred in 3 percent of all claims in the database. Of these claims, 35 percent represented corneal abrasions with a 16 percent incidence of permanent eye injury.

Corneal abrasions can occur during general anesthesia, monitored anesthesia care, and regional anesthesia. Several strategies are widely used to try and prevent corneal abrasions, although there is a paucity of recent studies to support one method over another. This review will discuss common causes of peri-operative corneal abrasions and review the literature supporting various approaches to prevention. The basic management of this painful condition will also be discussed." 7

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Contractor & Hardman 2006, 'Injury during anaesthesia'

"Many injuries sustained during anaesthesia are due to human error and may be avoided through high standards of clinical practice.

Dental injury occurs during 1% of general anaesthetics and is the commonest cause for litigation against anaesthetists.

Peripheral nerve injury is usually due to poor patient positioning during general anaesthesia or to intra-neural injection during regional anaesthesia.

Ocular injury occurs during 0.1% of general anaesthetics, and is usually corneal. Blindness occurs following 1 in 125 000 (0.0008%) general anaesthetics.

Muscular and cutaneous injuries are commonest in the elderly and debilitated; they may be fatal in these patients." 3

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References

1 A. Aders & H. Aders 2005, 'Anaesthetic Adverse Incident Reports: An Australian Study of 1,231 Outcomes', Anaesthesia and Intensive Care, vol. 33, no. 3, pp. 336-344, Read Article

2 Priya N Nair & Emert White 2014, 'Care of the Eye During Anaesthesia and Intensive Care', Anaesthesia and Intensive Care Medicine, vol. 15, no. 1, pp. 40-43, Read Article

3 S Contractor & JG Hardman 2006, 'Injury During Anaesthesia', Continuing Education in Anaesthesia, Critical Care & Pain, vol. 6, no. 2, pp. 67-70, Read Article

4 N Tarmey & LA White 2009, 'Section 5: Damage to the eye during General Anaesthesia', Risk Associated with your Anaesthetic, Royal College of Anaesthetists website, Read Article

5 M Weed & N Syed 2012, 'Perioperative Corneal Abrasions: Systems-based review and analysis', EyeRounds.org, Read Article

6 S Prakash 2013, 'Perioperative Eye Protection under General Anaesthesia', Journal of Anaesthesiology Clinical Pharmacology, vol. 29, no. 1, pp. 138-139, Read Article

7 J Anson, 'Perioperative Corneal Abrasions: Etiology, Prevention, and Management', Pennsylvania Society of Anesthesiologists, Read Article

8 Sawyer M, Danielson D, Degnan B, Dickson E, Doty S, Hamlin C, Harder K, Harper C, Matteson M, Moes R, Roemer R, Schuller-Bebus G, Swanson C, Terrell C, Webb B, Weisbrod C 2012, 'Perioperative Protocol', Institute for Clinical Systems Improvement, Read Article

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