Regional Anesthesia for Eye Surgery:

Convulsions during cataract surgery under peribulbar anesthesia: a case report

INTRODUCTION

Locoregional anesthesia techniques are increasingly used for cataract surgery. From these techniques, peribulbar anesthesia has been very successful over the retrobulbar anesthesia seen its effectiveness and safety. However, peribulbar anesthesia is not without risk.

CASE PRESENTATION

A 70-year-old African man was scheduled for cataract surgery and lens implant for his right eye. His medical history included hypertension, diabetes mellitus and gall bladder surgery. There were no personal or family antecedents of allergy, epilepsy or taking food or toxic drug. No abnormalities were detected in his preoperative evaluation. In the operating room, standard monitoring was installed and a peripheral venous catheter 18g was inserted. Peribulbar anesthesia was realized with two injections in primary gaze position. The anesthetic mixture contained lidocaine 2% and bupivacaine 0.5%. The needle used was 25GA, 19mm, ¾ inch. The first injection was performed in his lower temporal peribulbar space with 5mL of mixture; the second injection was performed with 3mL of mixture in his upper nasal peribulbar space. These injections were performed after a negative aspiration test and followed by manual compression of his globe for 5 minutes. Five minutes after peribulbar anesthesia, his blood pressure increased to 209/115mmHg requiring three bolus of nicardipine (3.0mg) to reduce his blood pressure to 134/56mmHg. One minute after, he had generalized tonic-clonic seizures. Tracheal intubation was performed. His capillary blood glucose was 170mg/dL, axillary temperature was 36.5°C, and his serum electrolytes were normal. He recovered spontaneous ventilation 1.5 hours later. A neurological examination noted no deficit. Extubation was performed 15 minutes later without incident. A brain computed tomography and electroencephalogram were unremarkable. He was discharged on the second day and operated on 1 month later under general anesthesia.

CONCLUSIONS

Various serious complications can occur during locoregional anesthesia techniques in ophthalmic surgery. The mastering and perfecting of these techniques by practitioners and compliance with safety standards in anesthesia are the only way to guarantee the prevention of such 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.

Peribulbar blockade with a short needle for phacoemulsification surgery

BACKGROUND

Peribulbar blockade is still widely used for phacoemulsification surgery. The potential complications of this technique include central spread, globe perforation and retrobulbar hemorrhage. The 25 mm needle is the most common needle used to perform the block. The aim of this study was to demonstrate the efficacy of a 12.5 mm needle in performing peribulbar blockade for phacoemulsification surgery.

METHODS

After obtaining the hospital research and the Human Ethics Committees' approval, 200 patients undergoing the phacoemulsification procedure under local anesthesia were enrolled in this descriptive study. Peribulbar blockade was performed with a 27 G, 12.5-mm-long needle. The needle was inserted transcutaneously through the lower eyelid into the inferotemporal quadrant. Digital pressure was applied by the thumb and index fingers around the needle hub during injection. After negative aspiration, a local anesthetic solution was injected until total drop of the upper eyelid was achieved. Ocular akinesia was assessed 10 min after the block using the simple akinesia score. A score of 3 or less was accepted to provide adequate analgesia for the surgical procedure to be performed. If the block was inadequate for surgery after 10 min, supplementary anesthesia was provided using the same needle.

RESULTS

Adequate analgesia after the first injection was reported in 90.5% of the patients while 9.5% required supplementary anesthesia. There were no major sight or life-threatening complications.

CONCLUSION

Using a 12.5-mm-long needle for peribulbar blockade produced satisfactory results. This technique is effective for phacoemulsification surgery.