Anesthesia for Ruptured Globe Repair

All content on Eyewiki is protected by copyright law and the Terms of Service. This content may not be reproduced, copied, or put into any artificial intelligence program, including large language and generative AI models, without permission from the Academy.

Article initiated by:

Jonathan (Eugene) Rho

All contributors:

Brian T. Fowler, MD, Grayson W Armstrong MD MPH, Stephen C. Dryden, M.D., Anna Murchison, MD, MPH, Grant A. Justin, MD, Grayson W Armstrong MD MPH

Assigned editor:

Grayson W Armstrong MD MPH

Review:

Assigned status Update Pending

 by Grayson W Armstrong MD MPH on January 6, 2024.

add
Contributing Editors:	add

Introduction

Open globe injuries are estimated to occur at 4.49/100,000 in the United States and require prompt surgery. For these injuries, the goal of anesthesia is to provide paralysis and insensitivity while minimizing increases in intraocular pressure (IOP). However, anesthetic management is multifaceted and can be challenging.

Classification

Ocular injuries are classified by extent of injury, mechanism, and location. Open globes involve a full thickness injury to the cornea and/or sclera. These injuries are divided into ruptures, which occur due to blunt trauma, and lacerations, which occur from sharp penetrating trauma. The location of damage is classified into three zones: Zone 1 = isolated to the cornea, Zone 2 = from the limbus up to 5mm posterior to the limbus, and Zone 3 = >5mm posterior to the limbus, respectively. For more information, see Ruptured Globe.

Timing of Repair

The timing of surgical repair requires a balance between the urgency to save vision, the need to close the eye to prevent infection, the need to address other concomitant potentially life threatening injuries, the risks of pulmonary aspiration, and avoiding the complications of delaying treatment. In healthy patients requiring general anesthesia, the minimum fasting recommendations for clear liquids, light meals, and heavy meals are 2, 6, and 8 hours, respectively. If a patient with ocular injury is deemed to have little chance of improving sight, surgery can usually be delayed to optimize the patient’s preoperative conditions. Literature has shown that within a 24 hour window, there is no difference in final visual acuity outcomes among patients who underwent immediate open globe repair as opposed to more delayed surgery. However, delays are carefully weighed with the increased risk of infection, endophthalmitis, and extrusion of intraocular content.

Physiology of Ocular Pressure

The eyeball can be viewed as a hollow sphere with a rigid shell, therefore increasing intraocular content or direct mechanical compression/decreasing the spherical volume can raise IOP. Coughing, vomiting, pain, and valsalva increases intraocular content by impeding the outflow of aqueous humor and increasing the volume of choroidal blood. On the other hand, administering inhaled anesthetics or using face masks can cause external compression and raise IOP. For more information on anesthetic medication effect on intraocular pressure, see Sedation for ER Ophthalmic Evaluation. In a patient with an open globe, it is vital to blunt these changes as the rigid eye wall has a full-thickness defect and any elevation in intraocular pressure greater than zero risks expulsion of intraocular contents and, thus, long term visual dysfunction.

Premedication

Preoperative medications can optimize conditions to reduce risk of elevation in IOP, restore vision, and provide necessary comfort. Midazolam is a good option for its anxiolytic, sedative properties, and lack of rise in IOP. Pain can be controlled with presurgical narcotics and postsurgical peribulbar blocks. Vomiting prevention can be addressed with antiemetics such as ondansetron. Specific situations can also necessitate premedication. For example, in general anesthesia (GA), lidocaine and remifentanil can be given before intubation and extubation to attenuate intraocular hypertension. Similarly, dexmedetomidine acts as a sympatholytic to blunt the increased IOP associated with succinylcholine, a common neuromuscular blocking agent used during intubation.

General vs. Regional Anesthesia

GA is typically performed with rapid sequence induction and intubation. GA is the predominant anesthetic method for open globe patients as it provides profound anesthesia and akinesia to perform safe microsurgery. General anesthesia is particularly useful in pediatric and uncooperative patients because they might not tolerate administration of regional anesthesia (RA) or remain immobilized during surgical operation. Additionally, there is a risk that injuries may be more extensive than anticipated, making GA safer and more comfortable for long drawn-out ocular repair. Furthermore, absorption of RA can transiently increase IOP and risk intraocular extrusion.

Succinolcholine is generally avoided with open globe surgery as it can raise the IOP by up to 10 mmHg. Inhalational and intravenous anesthetics generally lower the IOP, with the possible exception of ketamine. The surgeon should also communicate with the anesthesiologist for possibility of eliciting the oculocardiac reflex, which can result from manipulation of extraocular muscles and associated orbital tissues. In some cases, prophylactic medications are used in advance to suppress potential cardiac dysrhythmias.

Increases in systemic arterial pressure, ocular perfusion pressure, or sudden reduction in intraocular pressure can precipitate choroidal hemorrhage. While many ocular traumas will have already suffered this unfortunate complication, there is a risk during open globe repair of choroidal hemorrhage in otherwise uncomplicated cases or worsening of prior hemorrhage. The pathogenesis involves ocular decompression which reduces IOP and increases the pressure across the wall of all choroidal plexus vessels. In this setting, the transmural pressure is highly sensitive to arterial and/or venous pressure elevations such as are produced by the Valsalva maneuver, coughing, sneezing, or bucking on the endotracheal tube. An increase in vascular permeability (secondary to ocular inflammation) may also play a role. Surgical vigilance to prevent ocular hypotony and adequate anesthesia depth are important, as patient bucking or movement or Valsalva can result in complications.

Hypoperfusion and hypoxia are also rare causes of post-operative vision loss, associated with ischemic optic neuropathy, retinal vascular occlusion, and cortical blindness. Maintenance of systemic arterial pressure, monitoring systemic blood volume and adequate resuscitation, proper patient positioning, and anesthesia selection all play a critical role in avoiding these complications.

RA typically consists of retrobulbar or peribulbar blocks with facial nerve blocks as needed (see retrobulbar anesthesia). It is worth noting that injection of regional anesthesia in the orbit of a patient with an open globe injury will increase mechanical pressure on the globe and may expulse intraocular contents. Additionally, if the eye is macerated and proper anatomy cannot be identified, it is possible for the needle and/or anesthetic medication to directly penetrate and infiltrate ocular tissues. For these reasons, pre-operative orbital blocks are generally not recommended. Select cases may warrant the use of RA, however, particularly if the patient has a difficult anatomy for intubation. Furthermore, the severity and location of injury can affect the anesthetic method; one study found that smaller open globe injuries located in zones 1 or 2 were more likely to receive RA compared to GA. Some even found success in open globe repairs using topical anesthetics or a combination of RA with intracameral anesthesia.

Conclusion

Providing effective and safe anesthesia for open globe injury repair can be challenging particularly due to risks of extrusion of intraocular contents. The timing of repair, administration of premedication, and choice of anesthesia depends on several factors; however, GA, antiemetics, and analgesics are the most used to give patients an optimal outcome.