Comparison Between Peribulbar And Sub-tenon Blocks on Oculocardiac Reflex (OCR) During Pediatric Strabismus Surgery

A Comparison Between The Effects Of Peribulbar And Sub-tenon Blocks Combined With General Anesthesia On The Incidence Of Oculocardiac Reflex (OCR) During Pediatric Strabismus Surgery: A Double Blinded Randomised Control Study

The aim of this study is to compare between peribulbar block and subtenon block as an adjunct to general anesthesia in children undergoing strabismus surgery on oculocardiac reflex (OCR), post-operative analgesia and postoperative vomiting. Both techniques will be compared to intra-operative intravenous (IV) paracetamol combined with general anesthesia as a sole anesthetic technique.

Study Overview

• Status: Recruiting
• Conditions: Anesthesia, Local; Strabismus; Pediatric ALL; Ophthalmopathy
• Intervention / Treatment: Procedure: peribulbar block; Procedure: sub-tenon block; Drug: Paracetamol

Detailed Description

120 children, American Society of Anaesthesiology (ASA) I or II, aged 6 to 13 years, scheduled for elective squint surgery under GA will be included in the study. Children with tumors or infections of the orbit, raised intraocular pressure, eye injury, airway abnormalities or who are blind in the eye other than that which will to be operated, will be excluded. Other exclusion criteria will include known allergy to local anaesthetics or nonsteroidal anti-inflammatory drugs (NSAIDS), steroid therapy, those with significant cardiac, respiratory, renal, hepatic, or neurological disorders, mentally challenged children, or parental refusal to participate.

All children will undergo a detailed preanesthetic evaluation including previous history of operations, drug history, physical examination (cardiovascular and respiratory systems, blood pressure, oxygen saturation, airway and dentition, body weight and height). During the pre-anesthesia evaluation, children will be encouraged to report postoperative pain, if present. All children will be fasted for a minimum of 4 hours and premedicated with oral midazolam 0.5 mg/kg 30 minutes before anaesthesia. Anesthesia will be induced with sevoflurane 6% in oxygen or intravenous (i.v.) propofol (2mg/kg), as appropriate for the child's age and preference. Following inhalational induction, an intravenous line will be placed. The airway will be secured using an appropriately sized endotracheal tube (ETT) following intravenous atracurium(0.5 mg.kg) and 1 to 3 min of mask ventilation using isoflurane 1.5% in oxygen.Anesthesia will then be maintained with isoflurane in air-oxygen and end tidal minimal alveolar concentration maintained at 1 to 1.3. ventilation will be established at 6-8ml per kg with a target PECO2 of 32 - 34 and will be adjusted accordingly.

Children will then be randomly allocated to one of three groups; by a nurse who will not participate in the study, reads the number contained in the envelope and makes group assignment.

Children in the control group (group C, n_20) will receive IV paracetamol (20mg/kg).

Children in the sub-tenon group (sub-tenon group (S), n _ 20) will receive a sub-tenon block. Sub-Tenon's anesthesia will be performed with 5% bupivacaine (0.08 ml/kg). Under sterile conditions, a 19-gauge curved, blunt metallic cannula (25 mm) will be inserted into sub-Tenon's space and the local anesthetic will be injected by the ophthalmologist.

The peribulbar group (P group _ 20) will receive peribulbar block with 0.25 mL/kg of a 1:1 mixture of 0.5% bupivacaine and 2% lignocaine containing hyaluronidase (500 IU hyaluronidase has been premixed with 30 mL 2% lignocaine). Peribulbar block using a two-injection technique will be performed by a second anaesthetist.

The children will not be aware to as which group they will be allocated into. Digital oculopression will be performed for 5 minutes. All blocks will be performed by one of the investigators. LAM will be injected both inferotemporallly and superonasally using a 26-G needle. Haemodynamic variables; electrocardiography (ECG), pulse oximetry, noninvasive blood pressure (NIBP) and end tidal carbon dioxide (PECO2); will be monitored continuously and Occurrence of oculocardiac reflex (OCR) will be recorded (either in the form of bradyarrhythmias mostly sinus bradycardia or o) . bradyarrhythmias which is the most common presentation of Oculocardiac reflex (OCR) will be considered as an acute decrease in heart rate below 60 beats/min and will be treated by asking the surgeon to stop stimulation and giving intravenous atropine (0.01 mg.kg), whereas other less common presentations of oculocardiac reflex (OCR) will be managed accordingly. All children will receive Dexamethasone (0.125mg/kg) 30 minutes before the end of surgery. At the end of the procedure, the ETT will be removed after reversing residual neuromuscular blockade with 50 μg·kg-1 neostigmine and 20 μg·kg-1 atropine and adequate spontaneous ventilation established.

Children will then be transferred to the recovery room, where they will be kept for 2 to 3 hours. On arrival in the recovery room, the child's' behavior and postoperative pain level will be assessed at 30 min by the recovery room nurse who will not be aware of the block using the modified objective pain scale (MOPS) [10] which assess pain via 5 points (crying, facial expressions, posture of the trunk, posture of the legs, and motor restlessness) with a minimum score of 0 and a maximum score of 10. 0-1 (no pain), 2-5 (mild), 6-7 (moderate), and 8-10 (severe) out of 10.

For pain judged as moderate or severe (MOPS > 5), ibuprofen 10mg/kg will be administered orally. After 2 hours in the recovery area, the children's pain will be assessed by Modified objective pain scale (MOPs) at 2 and 4 hours. Requirement of postoperative analgesia will be recorded. The incidence of PONV will be recorded. Numeric scoring will be used for PONV (0 = no nausea; 1 = nausea is present, but no vomiting; 3 = vomiting once within 30 min; 4 = vomiting two or more times within 30 min). Ondansetron (0.1 mg/kg, i.v.) will be given in cases of vomiting. The data collector will not be aware of the intervention the child will receive

• Study Type: Interventional
• Enrollment (Estimated): 140
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Essam Nossair, Masters; Phone Number: 0201002014809; Email: e.nossair92@gmail.com

Study Locations

• Egypt
  • Cairo, Egypt, 11559
    • Recruiting
    • Cairo University faculty of medicine
    • Contact: Essam Nossair, Masters degree; Phone Number: 0201002014809; Email: e.nossair92@gmail.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Participants were children (6-13 years), ASA I-II patients, scheduled to undergo strabismus surgery.

Exclusion Criteria:

• Children with tumors or infections of the orbit, raised intraocular pressure more than 20 mm Hg, axial length more than 28 mm, eye injury, airway abnormalities or who were blind in the eye other than that which was to be operated on were excluded. Other exclusion criteria included patients undergoing revision surgery, known allergy to local anesthetics or non-steroidal antiinflammatory drugs (NSAIDs), steroid therapy, parental refusal to participate and patients with INR more than 1.5 or with platelets less than 100.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Peribulbar group (Group P); The peribulbar group (P group _ 40) received a peribulbar block with 0.25 mL/kg of a 1:1 local anesthetic mixture (LAM) of 0.5% bupivacaine and 2% lignocaine. Peribulbar block using a two-injection technique was performed by a second anesthetist under sterile conditions and before the application of surgical drapes. LAM was injected both infratemporal and superonasally using a 26-G needle, in contrast to the single infratemporal injection approach.	Procedure: peribulbar block; Peribulbar block using a two-injection technique was performed by a second anesthetist under sterile conditions and before the application of surgical drapes. LAM was injected both infratemporal and superonasally using a 26-G needle, in contrast to the single infratemporal injection approach. Gentle digital oculopression was performed for 5 minutes
Experimental: sub-tenon group (group S); Children in the sub-Tenon group (sub-Tenon group (S), n _ 40) received a sub-Tenon block. Sub-Tenon's anesthesia was performed with 0.5% bupivacaine (0.08 ml/kg), bearing in mind not to exceed the maximum dose. Under sterile conditions, a 19- gauge curved blunt metallic cannula (25 mm) was inserted into sub-Tenon's space and the local anesthetic was injected by the ophthalmologist after the application of surgical drapes.	Procedure: sub-tenon block; Children in the sub-Tenon group received a sub-Tenon block. Sub-Tenon's anesthesia was performed with 0.5% bupivacaine (0.08 ml/kg), bearing in mind not to exceed the maximum dose. Under sterile conditions, a 19- gauge curved blunt metallic cannula (25 mm) was inserted into sub-Tenon's space and the local anesthetic was injected by the ophthalmologist after the application of surgical drapes.
Active Comparator: paracetamol (group C); Children in the paracetamol group received IV paracetamol (15 mg/kg) after induction of anesthesia before any surgical intervention.	Drug: Paracetamol; Children in the control group received IV paracetamol (15 mg/kg) after induction of anesthesia before any surgical intervention.; Other Names: paracetamol iv

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The incidence of intraoperative oculocardiac reflex (OCR)	drop in heart rate below 60 bpm	2 hours

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
blood pressure	blood pressure in mmhg will be recorded preop, after induction, and every 15 minutes.	2 hours
heart rate	heart rate as beats per minute will be recorded preop, after induction, and every 15 minutes.	2 hours

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Post-operative pain using the MOPS	pain assessed using the MOPS	4 hours
Post-operative analgesia requirements	pethidine 0.5 mg/kg was administered IV	4 hours
The incidence of POV using numeric scoring	using Numeric scoring at 30 minutes and 2h post-operative	2 hours
Complications resulting from orbital regional anesthesia were recorded	e.g.: subconjunctival hemorrhage, local anesthetic toxicity, chemosis, optic neuropathy, extra-ocular muscle paresis	2 hours
Total intraoperative atropine requirements	Brady arrhythmias intraoperatively which are the most common presentation of OCR was considered when an acute decrease in heart rate below 60 beats/min and was treated by asking the surgeon to stop stimulation and giving intravenous atropine (0.01 mg. kg)	2 hours

Collaborators and Investigators

• Sponsor: Cairo University

Study record dates

Study Major Dates

• Study Start (Actual): December 1, 2023
• Primary Completion (Estimated): March 30, 2024
• Study Completion (Estimated): March 30, 2024

Study Registration Dates

• First Submitted: February 20, 2024
• First Submitted That Met QC Criteria: February 27, 2024
• First Posted (Estimated): March 5, 2024

Study Record Updates

• Last Update Posted (Estimated): March 5, 2024
• Last Update Submitted That Met QC Criteria: February 27, 2024
• Last Verified: February 1, 2024

More Information

Terms related to this study

• Keywords: paracetamol; oculocardiac reflex; peribulbar block; sub-tenon block; pediatric strabismus surgery
• Additional Relevant MeSH Terms: Nervous System Diseases; Cranial Nerve Diseases; Ocular Motility Disorders; Eye Diseases; Strabismus; Physiological Effects of Drugs; Peripheral Nervous System Agents; Analgesics; Sensory System Agents; Analgesics, Non-Narcotic; Antipyretics; Acetaminophen
• Other Study ID Numbers: MD-11-2022

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No