Delayed Convulsions and Brief Contralateral Hemiparesis After Retrobulbar Block

Brainstem Anesthesia after Retrobulbar Block: A Case Report and Review of Literature

Background

Retro-bulbar anesthesia is one of the most common regional blocks used for intraocular surgeries. Complications associated with regional blocks may be limited to the eye or may be systemic.

Case Report

After a retro-bulbar block for glaucoma surgery, a 60-year-old man developed loss of consciousness, apnea with hypotension and bradycardia-features of brainstem anesthesia. We present the clinical features, treatment and comments on how to prevent the problem as well as a review of the literature on reported cases.

Conclusion

Although it is rare, treating physicians should be aware of the potentially lethal consequences of retro-bulbar block, understand measures to reduce the risks and early recognition and treatment. Facilities where ophthalmic surgeries are performed under local anesthesia should be properly equipped and staffed for advanced resuscitation.

Generalized seizures and transient contralateral hemiparesis following retrobulbar anesthesia: a case report

BACKGROUND

Retrobulbar block is a local anesthetic technique widely used for intraocular surgery. Although retrobulbar anesthesia is considered to be relatively safe, a number of serious adverse events have been reported. To our knowledge, immediate onset of generalized seizures with contralateral hemiparesis after retrobulbar anesthesia has not been reported.

CASE PRESENTATION

A 62-year-old Caucasian healthy male with a right eye retinal detachment was admitted for pars plana vitrectomy. During retrobulbar anesthesia with ropivacaine and before needle withdrawal, the patient developed twitching of the face which rapidly progressed to generalized tonic-clonic seizures. Arterial oxygen saturation decreased to 75 %. Chin lift was performed and 100 % oxygen was administrated via face mask, which increased saturation to 99 %. Midazolam 2 mg was administrated intravenously to control seizures. After cessation of seizures, left-sided hemiparesis was evident. Brain computed tomography and electroencephalogram were normal 3 h later. The patient underwent pars plana vitrectomy under general anesthesia 4 days later.

CONCLUSION

Serious complications of local anesthesia for ophthalmic surgery are uncommon. We present a case in which generalized tonic-clonic seizures developed during retrobulbar anesthesia, followed by transient contralateral hemiparesis. The early onset of seizures indicated intra-arterial injection of the anesthetic. Our case suggested the need for close monitoring during the performance of retrobulbar anesthesia and the presence of well-trained personnel for early recognition and immediate management of the complications.

Pulmonary oedema in a patient undergoing vitreo-retinal surgery under peribulbar block

A 42-year-old diabetic and hypertensive male with good effort tolerance was administered peribulbar block for vitreo-retinal surgery. Ten millilitres of an equal mixture of 2% lignocaine and 0.5% bupivacaine was administered for the block after ascertaining negative aspiration for blood. Inadequate akinesia of the eye necessitated further supplementation with 4 mL of local anaesthetic (LA) mixture. Thirty minutes later, the patient complained of uneasiness, respiratory distress and desaturated despite oxygen supplementation. He was found to be in pulmonary oedema. He subsequently developed a weak thready pulse, became unresponsive, apnoeic and had generalized tonic clonic convulsions. Immediately, atropine 0.6 mg, followed by midazolam, intubation, mechanical ventilation, morphine and furosemide, were administered intravenously. Spontaneous respiration returned in 20 minutes and he started responding to verbal commands 90 minutes later. He was weaned off the ventilator the next morning. There was no evidence of an ischemic myocardial event and non-contrast computerized tomography scan of the head was normal. The reversible cardiorespiratory arrest, associated convulsions and loss of consciousness were suggestive of LA toxicity. Pulmonary oedema manifesting as respiratory distress and desaturation can be the initial manifestation of LA toxicity in patients with pre-existing cardiovascular disease undergoing eye surgery under peribulbar block.

Death potentially secondary to sub-Tenon's block

An 82-year-old ASA 2 patient underwent routine sub-Tenon's block for cataract surgery. One minute after injection of the local anaesthetic, the patient had a generalised tonic-clonic seizure and developed refractory ventricular fibrillation; subsequent resuscitation was unsuccessful. With no evidence for intravascular injection, the lack of structural brain abnormalities, and the most striking feature on post mortem examination being severe triple vessel coronary artery disease, it was concluded that this was primarily cardiac in origin; however, the possibility of brainstem anaesthesia should also be considered.