Two Intravenous Doses of Ketamine in Reducing the Oculocardiac Reflex in Adult Patients Undergoing Ophthalmic Surgery

Evaluation of Two Intravenous Doses of Ketamine in Reducing the Oculocardiac Reflex in Adult Patients Undergoing Ophthalmic Surgery: A Randomized Controlled Double-Blinded Trial

This study aims to evaluate whether a lower dose of ketamine (0.5 mg/kg IV) may be as effective as a higher dose (0.75 mg/kg IV) in reducing oculocardiac reflex (OCR) incidence in adult patients undergoing ophthalmic surgery.

Study Overview

• Status: Recruiting
• Conditions: Ketamine; Oculocardiac Reflex; Ophthalmic Surgery
• Intervention / Treatment: Drug: 0.5 mg/kg intravenous ketamine; Drug: 0.75 mg/kg intravenous ketamine

Detailed Description

The oculocardiac reflex (OCR) is a trigeminovagal reflex that can occur intraoperatively due to traction on extraocular muscles or pressure on the globe, resulting in bradycardia, arrhythmias, or asystole. Defined as a heart rate drop exceeding 20% from baseline, OCR is most frequently described in pediatric strabismus surgery, though its relevance persists in adult ophthalmic interventions involving similar stimuli.

Optimal ketamine dosing in adults remains underexplored. Higher doses may enhance OCR protection but could also prolong emergence or increase psychomimetic effects.

• Study Type: Interventional
• Enrollment (Estimated): 40
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Hebatullah S Abdelhamid, MD; Phone Number: 00201044512277; Email: drhebasalah593@gmail.com

Study Locations

• Egypt
  • Cairo, Egypt, 12613
    • Recruiting
    • Cairo University
    • Contact: Hebatullah S Abdelhamid, MD; Phone Number: 00201044512277; Email: drhebasalah593@gmail.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age from 18 to 65 years old.
• Both sexes.
• American Society of Anesthesiologists (ASA) physical status I, II.
• Scheduled for elective ophthalmic surgery involving extraocular muscle traction under general anesthesia.

Exclusion Criteria:

• Ketamine contraindications (e.g., hypersensitivity, uncontrolled hypertension)
• History of cardiac arrhythmia or conduction disorder
• Glaucoma or raised intraocular pressure
• ASA status greater than II
• Patient refusal.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Group A; Patients will receive 0.5 mg/kg intravenous ketamine hydrochloride.	Drug: 0.5 mg/kg intravenous ketamine; Patients will receive 0.5 mg/kg intravenous ketamine hydrochloride.
Experimental: Group B; Patients will receive 0.75 mg/kg intravenous ketamine hydrochloride.	Drug: 0.75 mg/kg intravenous ketamine; Patients will receive 0.75 mg/kg intravenous ketamine hydrochloride.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of oculocardiac reflex	Incidence of oculocardiac reflex (OCR) in each group [defined as ≥20% heart rate decrease from baseline or absolute bradycardia (HR<50 bpm)] sustained during extraocular muscles (EOMs) traction.	During extraocular muscle traction (intraoperative)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Lowest recorded intraoperative heart rate	The lowest recorded intraoperative heart rate will be recorded.	Intraoperatively
Incidence of use of atropine	If oculocardiac reflex (OCR) (defined as >20% drop in heart rate from the baseline or absolute bradycardia <50 bpm) occurs, the surgeon will be ordered to stop extraocular muscle traction, and atropine increments (0.3 mg IV) will be administered.	Intraoperatively
Mean arterial pressure	Mean arterial pressure (MAP) will be recorded throughout surgery, measured every 15 minutes.	Every 15 minutes till the end of surgery (Up to two hours)
Heart rate	Heart rate (HR) will be recorded throughout surgery, measured every 15 minutes.	Every 15 minutes till the end of surgery (Up to two hours)
Time to emergence	Time to emergence from anesthesia will be recorded from the conclusion of anesthesia to eye opening.	To eye opening (Up to one hour)
Incidence of postoperative complications	Incidence of postoperative complications such as nausea, vomiting, or hallucinations will be recorded.	24 hours postoperatively

Collaborators and Investigators

• Sponsor: Cairo University

Study record dates

Study Major Dates

• Study Start (Actual): July 1, 2026
• Primary Completion (Estimated): December 30, 2027
• Study Completion (Estimated): December 30, 2027

Study Registration Dates

• First Submitted: July 11, 2026
• First Submitted That Met QC Criteria: July 11, 2026
• First Posted (Actual): July 16, 2026

Study Record Updates

• Last Update Posted (Actual): July 16, 2026
• Last Update Submitted That Met QC Criteria: July 11, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: MS-139-2026 (20-6-2026)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: The data will be available upon a reasonable request from the corresponding author after the end of study for one year.
• IPD Sharing Time Frame: After the end of study for one year.
• IPD Sharing Access Criteria: The data will be available upon a reasonable request from the corresponding author.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL

Drug and device information, study documents

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