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NCT Number: NCT07708740

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

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.

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Key information

Conditions

Ketamine Oculocardiac Reflex Ophthalmic Surgery

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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.

Treatment and study plan

0.5 mg/kg intravenous ketamine

Drug

Patients will receive 0.5 mg/kg intravenous ketamine hydrochloride.

0.75 mg/kg intravenous ketamine

Drug

Patients will receive 0.75 mg/kg intravenous ketamine hydrochloride.

Primary outcomes

  1. Incidence of oculocardiac reflex

    Time frame: During extraocular muscle traction (intraoperative)

    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.

Secondary outcomes

  1. Lowest recorded intraoperative heart rate

    Time frame: Intraoperatively

    The lowest recorded intraoperative heart rate will be recorded.

  2. Incidence of use of atropine

    Time frame: Intraoperatively

    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.

  3. Mean arterial pressure

    Time frame: Every 15 minutes till the end of surgery (Up to two hours)

    Mean arterial pressure (MAP) will be recorded throughout surgery, measured every 15 minutes.

  4. Heart rate

    Time frame: Every 15 minutes till the end of surgery (Up to two hours)

    Heart rate (HR) will be recorded throughout surgery, measured every 15 minutes.

  5. Time to emergence

    Time frame: To eye opening (Up to one hour)

    Time to emergence from anesthesia will be recorded from the conclusion of anesthesia to eye opening.

  6. Incidence of postoperative complications

    Time frame: 24 hours postoperatively

    Incidence of postoperative complications such as nausea, vomiting, or hallucinations will be recorded.

Study contacts

Contact information is provided by the study sponsor or research team.

Hebatullah S Abdelhamid, MD

CONTACT

[email protected]

00201044512277

Sponsors and collaborators

Lead sponsor

Cairo University

Other

Registry information

Official study title

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

Important dates

Study start
2026
Primary completion
2027
Study completion
2027
First posted
Jul 16, 2026
Registry last updated
Jul 16, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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