Propofol-Only Versus Dexmedetomidine-Propofol in Children Undergoing Magnetic Resonance Imaging

A Randomized, Dose-Ranging Trial of Propofol-Only and Dexmedetomidine-Propofol in Children Undergoing Magnetic Resonance Imaging

The most common imaging procedure requiring sedation/anesthesia for the pediatric population is magnetic resonance imaging (MRI). However, the optimal anesthetic/sedation plan has not been determined for these procedures. Historically, common medications have included the use of pentobarbital and propofol, but in 2015, publication in the New England Journal of Medicine highlighted the accumulating evidence for the possible neurotoxic effects of these types of anesthetics in animal models and a collection of epidemiologic studies in humans. Although these initial possibilities have since been proven as less of a concern, in the interim, data has shown that alternative sedative agents, such as dexmedetomidine, may not have the same neurotoxic effect and could possibly even provide neuroprotection. Dexmedetomidine also possesses other beneficial traits such as reducing risks of pulmonary atelectasis or upper airway collapse, typically found with the administration of propofol.

A concern raised by previous studies has been the possibility that the addition of dexmedetomidine could increase recovery times, leading to disruptions in workflow. Although it has been shown that large doses of dexmedetomidine exposure may lead to longer PACU stays, it is uncertain whether a small dose of dexmedetomidine would have such a significant impact. Based on the investigators' pilot trial6, the investigators found that a bolus of 1 mcg/kg dose of dexmedetomidine with a bolus of titrated propofol of 2-3 mg/kg and an infusion of propofol of 100 mcg/kg/min provided adequate sedation for successful scans, reduced propofol (infusion) exposure by 60%, and did not significantly increase recovery times.

Finally, there is a paucity in literature for studies examining a range of doses subsequently; often, a control group is compared to a single, self-selected dose of choice. Here, the investigators hope to provide a range of doses to minimize selection bias in our study design and determine the dose that would provide the optimal sedation for these scans and minimize excess anesthetic exposure.

Study Overview

• Status: Recruiting
• Conditions: Dexmedetomidine; Propofol Dosage; Pediatric Sedation; Recovery Time; MRI Sedation; Emergence Delirium, Anesthesia
• Intervention / Treatment: Drug: Propofol (IV) 2-4 mg/kg; Drug: Propofol (IV) Infusion 250 mcg/kg/min; Drug: Dexmedetomidine (IV) 1 mcg/kg; Drug: Propofol (IV) 1-2 mg/kg; Drug: Propofol (IV) Infusion 150 mcg/kg/min; Drug: Dexmedetomidine (IV) 0.5 mcg/kg

• Study Type: Interventional
• Enrollment (Estimated): 105
• Phase: Phase 4

Contacts and Locations

• Study Contact: Name: Rachel Bernier, MPH; Phone Number: 857-218-5348; Email: rachel.bernier@childrens.harvard.edu
• Study Contact Backup: Name: Samuel Kim, BS; Phone Number: 617-919-3692; Email: samuel.kim@childrens.harvard.edu

Study Locations

• United States
  • Massachusetts
    • Boston, Massachusetts, United States, 02115
      • Recruiting
      • Boston Children's Hospital
      • Contact: Joseph Cravero, MD; Email: joseph.cravero@childrens.harvard.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Patients presenting as outpatients, scheduled to receive an anesthetic for MRI of brain, body (spine, chest, abdomen, and/or pelvis) and/or extremity (arm and/or leg).
• Patients must be a candidate for the sedation technique described in this study with a natural airway. This decision will be made by a staff member of the Department of Anesthesiology.
• Between 1 and 12 years of age.
• ASA status I, II, or III

Exclusion Criteria:

• Inpatient at BCH
• Diagnosis of a difficult airway, severe obstructive sleep apnea that is not compatible with spontaneous ventilation in a supine position, or requires an oral airway.
• Congenital heart disease or history of dysrhythmia.
• Taking digoxin or beta-blocker
• Anxiolytic medication is ordered before the MRI (e.g., midazolam or ketamine).
• History or a family (parent or sibling) history of malignant hyperthermia.
• Allergy to or has a contraindication to propofol, lidocaine, or dexmedetomidine.
• Tracheostomy or other mechanical airway device present
• Received within the past 12 hours an oral or intravenous alpha-adrenergic, beta-adrenergic agonist, or antagonist drugs (e.g., clonidine, propranolol, albuterol).
• Patient is not scheduled to receive anesthesia-sedation care or is noted to "try-without anesthesia" for the MRI
• Patient has significant developmental or psychological delays
• Patient scheduled for scan of duration <30 minutes or >90 minutes

Study Plan

How is the study designed?

Design Details

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

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Propofol Only (P); 1 mg/kg (max 25 kg) of IV lidocaine (standard of care) will be given. 2-4 mg/kg titrated bolus of propofol will be administered, which can be repeated 2x until a Ramsay Sedation Score of 5-6 is achieved. After that, 250 mcg/kg/min infusion of propofol will be initiated and can be titrated up to a maximum of 300 mcg/kg/min to maintain a Ramsay Sedation Score of 5-6. If not sedated after 5 more minutes, record a technique failure and continue sedation at anesthesiologist's discretion. Per standard of care, the propofol infusion may be decreased if the blood pressure decreases by more than 30% from lowest expected norms or if there is any indication of possible airway obstruction.	Drug: Propofol (IV) 2-4 mg/kg; If patient is randomized to the P arm, patient will receive 2-4 mg/kg titrated, IV bolus of propofol until sleep is induced.; Other Names: Diprivan; Drug: Propofol (IV) Infusion 250 mcg/kg/min; If the patient is randomized to the P arm, following the bolus of propofol, the patient will be started on an IV propofol infusion of 250 mcg/kg/min.; Other Names: Diprivan
Active Comparator: Dexmedetomidine (high)-Propofol (DHP); 1 mcg/kg dexmedetomidine (DEX) bolus over 5-10 minutes will be delivered by fractionated doses or infusion. After the DEX bolus is complete, 1 mg/kg (max 25 mg) of IV lidocaine will be administered followed by a dose of 2-3 mg/kg titrated bolus of propofol (P), which can be repeated 2x until a Ramsay Sedation Score of 5-6 is achieved. After this, 150 mcg/kg/min infusion of P will be initiated. If the Ramsay Sedation score of 5-6 is not achieved within 2 minutes, 1-2 mg/kg bolus of P may be administered and P infusion will be increased to 200 mcg/kg/min. The P infusion can be titrated up to a maximum of 300 mcg/kg/min if needed to maintain a Ramsay Sedation Score of 5-6. If not sedated after 5 more minutes, record a technique failure and continue sedation at anesthesiologist's discretion. Per standard of care, the propofol infusion may be decreased if the blood pressure decreases by more than 30% from lowest expected norms or if there is any indication of possible airway obstruction.	Drug: Dexmedetomidine (IV) 1 mcg/kg; If patient is randomized to the DHP arm, patient will receive an IV bolus of 1 mcg/kg dexmedetomidine over 5 minutes.; Other Names: Precedex; Drug: Propofol (IV) 1-2 mg/kg; If the patient is randomized to the DLP or DHP arm, following the dexmedetomidine bolus, the patient will receive a titrated, IV bolus of 1-2 mg/kg propofol.; Other Names: Diprivan; Drug: Propofol (IV) Infusion 150 mcg/kg/min; If the patient is randomized to the DLP or DHP arm, following the titrated propofol bolus, the patient will be started on an IV propofol infusion of 150 mcg/kg/min.; Other Names: Diprivan
Active Comparator: Dexmedetomidine (low)-Propofol (DLP); 0.5 mcg/kg dexmedetomidine (DEX) bolus over 5-10 minutes will be delivered by fractionated doses or infusion. After the DEX bolus is complete, 1 mg/kg (max 25 mg) of IV lidocaine will be administered followed by a dose of 2-3 mg/kg titrated bolus of propofol (P), which can be repeated 2x until a Ramsay Sedation Score of 5-6 is achieved. After this, 150 mcg/kg/min infusion of P will be initiated. If the Ramsay Sedation score of 5-6 is not achieved within 2 minutes, 1-2 mg/kg bolus of P may be administered and P infusion will be increased to 200 mcg/kg/min. The P infusion can be titrated up to a maximum of 300 mcg/kg/min if needed to maintain a Ramsay Sedation Score of 5-6. If not sedated after 5 more minutes, record a technique failure and continue sedation at anesthesiologist's discretion. Per standard of care, the propofol infusion may be decreased if the blood pressure decreases by more than 30% from lowest expected norms or if there is any indication of possible airway obstruction.	Drug: Propofol (IV) 1-2 mg/kg; If the patient is randomized to the DLP or DHP arm, following the dexmedetomidine bolus, the patient will receive a titrated, IV bolus of 1-2 mg/kg propofol.; Other Names: Diprivan; Drug: Propofol (IV) Infusion 150 mcg/kg/min; If the patient is randomized to the DLP or DHP arm, following the titrated propofol bolus, the patient will be started on an IV propofol infusion of 150 mcg/kg/min.; Other Names: Diprivan; Drug: Dexmedetomidine (IV) 0.5 mcg/kg; If patient is randomized to the DLP arm, patient will receive an IV bolus of 0.5 mcg/kg dexmedetomidine over 5 minutes.; Other Names: Precedex

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total Propofol (mcg/kg/min) consumption	The total amount of propofol (mcg/kg/min) consumed will be measured for the duration of anesthesia time for the P, DLP, and DHP arms.	Up to 120 minutes or from induction of anesthesia/sedation to end of MRI scan

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Peak Pediatric Anesthesia Emergence Delirium (PAED) Score	The peak (highest) PAED score will be obtained in the post-anesthesia recovery area (PACU).	Up to 180 minutes or duration of PACU stay
Incidence of Adverse Events	Arterial desaturation, airway obstruction, hypotension and bradycardia	Up to 240 minutes or from induction of anesthesia/sedation to immediately during recovery
Incidences of Patient Movements/MRI Interruptions	If patient moved during their MRI and caused an interruption of the scan.	Up to 90 minutes or duration of MRI scan
Incidence of Technique Failure	Lack of adequate sedation for MRI scan in spite of the sedation as described above (based on anesthesiologist's discretion or PSSS)	Up to 120 minutes or from induction of anesthesia/sedation to end of MRI scan
Case Duration	Total number of minutes in the MRI scanner	Up to 90 minutes or duration of MRI scan
Post Anesthesia Care Unit (PACU) Duration	Total number of minutes in the PACU	Up to 180 minutes or duration of PACU stay
Ramsay Sedation Score	Average Ramsay Sedation Score	10 minutes or from anesthesia induction to MRI scan start

Collaborators and Investigators

• Sponsor: Boston Children's Hospital
• Investigators: Principal Investigator: Joseph Cravero, MD, Boston Children's Hospital

Publications and helpful links

General Publications

• Rappaport BA, Suresh S, Hertz S, Evers AS, Orser BA. Anesthetic neurotoxicity--clinical implications of animal models. N Engl J Med. 2015 Feb 26;372(9):796-7. doi: 10.1056/NEJMp1414786.
• Nagoshi M, Reddy S, Bell M, Cresencia A, Margolis R, Wetzel R, Ross P. Low-dose dexmedetomidine as an adjuvant to propofol infusion for children in MRI: A double-cohort study. Paediatr Anaesth. 2018 Jul;28(7):639-646. doi: 10.1111/pan.13400. Epub 2018 Jun 7.
• Boriosi JP, Eickhoff JC, Klein KB, Hollman GA. A retrospective comparison of propofol alone to propofol in combination with dexmedetomidine for pediatric 3T MRI sedation. Paediatr Anaesth. 2017 Jan;27(1):52-59. doi: 10.1111/pan.13041. Epub 2016 Oct 25.
• Ramaprasannakumar SK, Bhadrinarayan V, Venkataramaiah S. The Effectiveness of Three Regimens of Sedation for Children Undergoing Magnetic Resonance Imaging: A Clinical Study. Anesth Essays Res. 2022 Jul-Sep;16(3):345-352. doi: 10.4103/aer.aer_45_22. Epub 2022 Dec 9.
• Vinson AE, Peyton J, Kordun A, Staffa SJ, Cravero J. Trends in Pediatric MRI sedation/anesthesia at a tertiary medical center over time. Paediatr Anaesth. 2021 Sep;31(9):953-961. doi: 10.1111/pan.14225. Epub 2021 Jun 22.
• Kim SY, Booth JM, Staffa SJ, Kordun A, Yu J, Cravero JP. A dose-ranging pilot trial of dexmedetomidine-propofol in children undergoing magnetic resonance imaging. J Anesth. 2025 Dec;39(6):989-994. doi: 10.1007/s00540-025-03511-z. Epub 2025 May 11.
• Mallory MD, Travers C, Cravero JP, Kamat PP, Tsze D, Hertzog JH. Pediatric Sedation/Anesthesia for MRI: Results From the Pediatric Sedation Research Consortium. J Magn Reson Imaging. 2023 Apr;57(4):1106-1113. doi: 10.1002/jmri.28392. Epub 2022 Aug 12.

Study record dates

Study Major Dates

• Study Start (Estimated): June 1, 2026
• Primary Completion (Estimated): December 1, 2027
• Study Completion (Estimated): March 1, 2028

Study Registration Dates

• First Submitted: January 24, 2026
• First Submitted That Met QC Criteria: January 26, 2026
• First Posted (Actual): January 27, 2026

Study Record Updates

• Last Update Posted (Actual): May 29, 2026
• Last Update Submitted That Met QC Criteria: May 27, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: MRI; pediatrics; dexmedetomidine; sedation; propofol
• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Mental Disorders; Postoperative Complications; Pathologic Processes; Confusion; Neurobehavioral Manifestations; Neurocognitive Disorders; Delirium; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Emergence Delirium; Organic Chemicals; Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds; Azoles; Hydrocarbons; Hydrocarbons, Cyclic; Hydrocarbons, Aromatic; Imidazoles; Phenols; Benzene Derivatives; Dexmedetomidine; Propofol
• Other Study ID Numbers: IRB-P00052391

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: Yes