NCT02481791

Study to Evaluate the Optimal Dose of Remifentanil During MRI of the Heart Under General Anaesthesia

Study to Evaluate the Optimal Dose of Remifentanil Required to Ensure Apnoea During Magnetic Resonance Imaging of the Heart Under General Anaesthesia

• Status: Unknown
• Phase: Phase 3
• Study type: Interventional
• Enrollment: 35 (estimated)
• Sponsor: Alder Hey Children's NHS Foundation Trust · Academic / Other
• Sex: All
• Age: 1 Year – 7 Years
• Healthy volunteers: Not accepted

Summary

What is the optimal maintenance dose of remifentanil to ensure apnoea, during breath hold episodes in children having cardiac MR imaging with general anaesthesia?

Detailed description

The management of congenital heart disease depends upon accurate imaging of the heart to define anatomical abnormalities. The use of magnetic resonance imaging has grown in response to this need. Young children, however, are unable to cooperate sufficiently to allow the scan to occur; this necessitates the use of general anaesthesia. The optimal anaesthetic management of children in this situation is complex. Imaging of an acceptable quality depends on a low (normal) heart rate which is relatively constant during the scan and frequent breath holds to avoid respiratory artefacts. Children undergoing such scans commonly have significant cardiac and non-cardiac disease. A technique, currently used at Alder Hey Hospital, is to use intravenous agents to provide anaesthesia: commonly a mixture of the intravenous anaesthetic propofol and the potent opiate remifentanil. The patient's own ventilation is suppressed by the use of remifentanil which also reduces heart rate and heart rate variability. Controlled ventilation is provided via a ventilator and endotracheal tube. Adequate doses of remifentanil are required to ensure suppression of the patient's ventilation whilst excess doses are avoided to reduce the risk of adverse effects (primarily arterial hypotension) and ensure rapid recovery. Remifentanil dose has been studied during surgery(3-6), however this is a unique indication and optimal dosage has not been formally studied. In particular the absence of any stimulation from surgery is likely to mean that substantially lower doses of remifentanil will be required.

Conditions

• Children
• Heart Diseases
• Anaesthesia
• Magnetic Resonance Imaging

Interventions

Type	Name	Description
DRUG	Remifentanil and/or propofol	Induction Phase: A dose of remifentanil 1mcg/kg by slow bolus, will be given to facilitate endotracheal intubation. Further doses of either remifentanil (0.5 mcg/kg) or propofol (1-2mg/kg) may be given to ensure an anaesthetised patient.
DRUG	Remifentanil and/or propofol	Settling Period: An infusion of the test dose of remifentanil will be commenced from an infusion prepared prior to the patient being anaesthetised. 1mg of Remifentanil (one vial) will be diluted to a volume of 50mls in normal saline 0.9% in a 50ml syringe. Maintenance dose of propofol 130 mcg/Kg/min for the first 5 minutes reduced to 100 mcg/kg/min thereafter. 40mls of propofol 1% (10mg/ml) will be drawn undiluted into a 50ml syringe. During the settling period further doses of either remifentanil (0.5 mcg/kg) or propofol (1-2mg/kg) may be given.
DRUG	propofol	Equilibrium Period: During this period propofol will be infused at a constant rate of 100mcg/kg/min

Timeline

• Start date: 2015-07-01
• Primary completion: 2019-12-31
• Completion: 2019-12-31
• First posted: 2015-06-25
• Last updated: 2019-01-10

Locations

1 site across 1 country: United Kingdom