TNOA Journal of Ophthalmic Science and Research

: 2019  |  Volume : 57  |  Issue : 3  |  Page : 231--232

Potentially life-threatening consequences of peribulbar anesthesia

Shahinur Tayab, Susmita Paul, Prafulla Sarma 
 Department of Glaucoma, Sri Sankaradeva Nethralaya, Guwahati, Assam, India

Correspondence Address:
Dr. Susmita Paul
Sri Sankaradeva Nethralaya, 96, Basistha Road, Guwahati - 781 028, Assam


Peribulbar anaesthesia is the most commonly used anaesthesia for intraocular surgeries, especially glaucoma and vitreoretinal surgeries. We present a case of a 70 years old man who became unconscious and developed other signs of brainstem anaesthesia following peribulbar block for a combined glaucoma and cataract surgery. Complications with peribulbar anaesthesia are remote but possible. Patients undergoing ocular surgeries under peribulbar anaesthesia should be closely monitored and facilities to tackle such life threatening complications must be available in the operation theatre.

How to cite this article:
Tayab S, Paul S, Sarma P. Potentially life-threatening consequences of peribulbar anesthesia.TNOA J Ophthalmic Sci Res 2019;57:231-232

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Tayab S, Paul S, Sarma P. Potentially life-threatening consequences of peribulbar anesthesia. TNOA J Ophthalmic Sci Res [serial online] 2019 [cited 2020 Jan 20 ];57:231-232
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Full Text


Ophthalmic surgeries are performed under a wide range of anesthesia technique. It started with Carl Koller using cocaine as topical anesthesia for ocular surgery in 1884. In the same year, Knapp introduced retrobulbar anesthesia. As late as 1980s, peribulbar anesthesia was discovered by Davis and Mandel,[1] and since then peribulbar anesthesia has been the most commonly used anesthesia for a variety of ocular surgeries. There are a number of advantages of peribulbar block over retrobulbar block such as less painful, less intraocular pressure rise, avoidance of facial block, and above all minimum risk of sight and life-threatening complications such as retrobulbar hemorrhage, optic nerve damage, oculocardiac reflex, and brainstem anesthesia.[2],[3],[4]

Although safe, peribulbar anesthesia can have potentially sight and life-threatening complications as reported by Davis and Mandel.[3] in a prospective multicenter study in 1994. The estimated incidence of brainstem anesthesia following peribulbar block is 0.020%.[5] Here, we report a case of brainstem anesthesia after peribulbar block for phacotrabeculectomy at a tertiary eye care center in March 2018.

 Case Report

A 70-year-old male presented with complaints of gradual dimness of vision in both the eyes. He underwent comprehensive ophthalmological examination and was advised to undergo phacotrabeculectomy surgery in the left eye. He was nondiabetic and nonhypertensive.

Peribulbar anesthesia was administered in the inferotemporal quadrant. A 24 gauge, 2.5 cm, sharp, disposable needle was used. The anesthetic agent used was a mixture of equal volume of 1% lignocaine and 0.5% bupivacaine with 50 IU/ml hyaluronidase. The periocular skin was cleaned with 10% W/V povidone-iodine. The patient was asked to maintain the primary gaze position. The needle was introduced through the skin of the lower lid sulcus at the inferotemporal part. The needle was inserted in a vertically downward direction along the orbital wall to a full depth of 2.5 cm. Aspiration was done to rule out intravascular injection. A total of 8 ml of the anesthetic mixture was injected and needle withdrawn. Within the next few minutes, the patient's speech slowly became incoherent, and nystagmus was noted in both the eyes. There was tachycardia (150 beats/min) and hypertension (190/120 mmHg).

The patient was immediately given oxygen mask. As there was no spontaneous respiration, he was intubated and put on with mechanical ventilation. Slow intravenous injection of esmolol (80 mg) was given and blood pressure (BP) gradually normalized. After that, BP started to fall, and injection atropine (1.0 mg) was given to control hypotension. Approximately 20 min later, the patient had grand mal seizure twice. Intravenous midazolam (2.0 mg) injection was given to control seizure. Finally, his vital parameters stabilized and he could be extubated approximately after 1 h. The patient was kept under observation before being discharged. Surgery was performed uneventfully after 2 weeks under peribulbar anesthesia.


Peribulbar anesthesia is a safe blocking technique with fewer perioperative complications than retrobulbar anesthesia, such as scleral perforation, retrobulbar hemorrhage, and brainstem anesthesia.[3],[4],[6],[7],[8] Attention should be given to maintain the ocular position in primary gaze in order to avoid these complications.[3]

The technique of peribulbar anesthesia used in our case is the standard practice followed by most practitioners. The blocker was at the head-end of the patient and injection was given while the patient was asked to maintain the primary gaze position. However, it is often noticed that patients have a tendency to look toward the doctor, and in this case, the eyeball rolls up exposing the optic nerve to a greater extent toward the advancing needle tip. However, if the blocker approaches the patient from the side and the patient attempts to look toward the doctor, it would mean rolling down of the eyeball minimizing the chance of damage to the optic nerve by the needle.

There are different mechanisms by which local anesthetic (LA) toxicity can occur.[9] In case of inadvertent intravenous injection of LA, the sequence of events are light-headedness, auditory and visual disturbances, facial muscle twitching, seizure followed by respiratory depression, and respiratory arrest. This is not possible in our case, as the volume of LA was too small to cause systemic toxicity. Second, in this case, respiratory arrest preceded the signs of central nervous system (CNS) excitement and or seizure.

In case of direct injection of LA into the meningeal coverings of the optic nerve and access to the subarachnoid space, respiratory depression is possible before CNS excitatory symptoms and or seizure but cannot explain the initial cardiovascular excitement.

Accidental intra-arterial injection can give rise to increased levels of LA in the brain via retrograde flow in the internal carotid artery. Only this mode of spread of LA to the brain can explain the initial cardiovascular excitement with shooting of pulse and BP. This excitement is highly transient which was also observed in our case. As the LA redistributes out of the brain quickly, the symptoms wear off.

Hence, the initial shooting of BP and pulse indicates an inadvertent intra-arterial injection of LA, whereas prolonged respiratory arrest and seizure can be explained only by injection of LA into the meningeal coverings.

Commonly, the onset of signs and symptoms of brainstem anesthesia have been reported within 5–10 min after retrobulbar block with complete recovery of consciousness within an hour, although wide variations exist.[5] In our case, the onset of respiratory depression occurred in <5 min with altered consciousness. The patient regained consciousness and vitals were stabilized approximately after 1 h. Even though there was a negative aspirate before injecting the anesthetic, the onset of grand mal seizure indicates that there must have an inadvertent intra-arterial injection.


Complications with peribulbar anesthesia are uncommon but may occur. Hence, the operation theatre should be equipped with appropriate instruments and trained personnel to deal with all kind of emergencies.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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