Cervical Vagus Nerve Block Prevents Ocularvagal Reflex

Army Medical University of People's Liberation Army

Status: Unknown

Conditions: Reflex, Oculocardiac

Treatments: Drug: Bradycardia Treatment; Procedure: Ultrasound guided vagus nerve block

Study type: Interventional

Funder types: Other

Identifiers

NCT04950881

2021-55

Details and patient eligibility

About

In ophthalmic surgery, surgical operations such as pulling certain eye tissues or compressing the eyeball often leads to bradycardia, arrhythmia even cardiac arrest, bradypnea, nausea and vomiting and elevated blood sugar level. The condition is called the ocularvagal reflex (OVR). Traditionally, when the bradycardia or arrhythmia happens, the operation has to be suspended, and atropine or isoproterenol is given intravenously to treat the bradycardia. Vagus nerve block may be an effective way to prevent and alleviate this vagal reflex. However it is difficult to perform the nerve block with anatomical landmark (blind) methods. In this study, the investigators used ultrasound-guided right cervical vagus nerve block to reduce the incidence of the OVR. The researchers hypothesized that low concentrations of lidocaine or ropivacaine can block the right cervical vagus nerve and reduce the incidence of intraoperative OVR. Researchers evaluated the changes of heart rate, blood pressure, oxygen saturation, and airway pressure in patients undergoing high-risk OVR surgery.

Enrollment: 60 estimated patients

Sex: All

Ages: 16 to 70 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Patients received surgeries with high-risk OVR, including the strabismus surgery, the posterior scleral reinforcement, and the insertion of ocular implant.

Exclusion criteria

• Those who have pre-existed vocal cord damage before surgery (such as hoarseness, electronic laryngoscopy shows fixed vocal cords or arytenoid cartilage dislocation).
• Those with a history of surgery on the both sides of the neck (eg, thyroidectomy, carotid endarterectomy).
• American Society of Anesthesiologist (ASA) Grade > 3
• Patients with infection at the neck puncture site, or severe coagulation abnormalities before surgery, or a history of local anesthetic allergy, or who have a pacemaker.

Trial design

Primary purpose: Prevention

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Single Blind

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60 participants in 2 patient groups

Control group

Sham Comparator group

Description:

Conventional monitor and treatment The surgery is performed after patient is under general anesthesia. If patient's heart rate significantly slows down or bradycardia/arrhythmia happens, the surgeon will be asked to suspend the operation. Meanwhile, atropine (0.01-0.02mg/kg) is given intravenously to increase the heart rate. If atropine fails to increase the heart rate, isoproterenol (1-2 μg/per time) will be given intravenously to increase the heart rate.

Treatment:

Drug: Bradycardia Treatment

Nerve block group

Experimental group

Description:

After the patient is under general anesthesia, an attending physicians perform the ultrasound-guided cervical vagus nerve block (using a 50mm Braun nerve stimulation needle, and the patients were injected with 10ml of lidocaine or ropivacaine ). Then the operation starts. If patient's heart rate significantly slows down or bradycardia/arrhythmia happens, the surgeon will be asked to suspend the operation. Meanwhile, atropine (0.01-0.02mg/kg) is given intravenously to increase the heart rate. If atropine fails to increase the heart rate, isoproterenol (1-2 μg/per time) will be given intravenously to increase the heart rate. After endotracheal tube is removed, the patient will be followed up for next 24 hours.

Treatment:

Drug: Bradycardia Treatment

Procedure: Ultrasound guided vagus nerve block