A Phase IV Study Investigating the Effects of Remifentanil Concentrations on Propofol Requirements for Loss of Consciousness, Response to Painful Stimuli, Bispectral Index and Associated Haemodynamic Changes

March 10, 2016 updated by: Hannah Scott, The University of Hong Kong

A Phase IV Study to Investigate the Effects of Varied Remifentanil Concentrations on Propofol Requirements for Loss of Consciousness, Response to Painful Stimuli, Bispectral Index and Associated Haemodynamic Changes

A prospective, randomised, phase IV trial including 150 patients.

To evaluate the effects of varied concentrations of remifentanil on the proposal requirements for the loss of consciousness and response to pain and to evaluate the haemodynamic changes and processed EEG (BIS) during induction of anaesthesia.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

BackGround

The combination of remifentanil and propofol infusions is a widely used method of total intravenous anaesthesia. (1) Target controlled infusion (TCI) is a pharmacokinetic (PK) infusion system using data from a large population of patients to calculate and deliver stable concentrations of a drug based on a three compartment PK model. Both propofol and remifentanil are ideal drugs for delivery in this way because of their quick distribution, metabolism and excretion. (2) Remifentanil is a potent synthetic opioid receptor (MOR) agonist with a short recovery irrespective of the duration of its administration. This is due to it being quickly broken down by non-specific esterases in blood and tissues. (3) Remifentanil like all opioids is not very hypnotic in clinically relevant concentrations. (4)

Remifentanil has been shown to reduce propofol requirements during induction and maintenance of anaesthesia. (5)(6) Also modest doses of remifentanil markedly reduce the amount of propofol required to ablate response to painful stimuli. The relationship between propofol and remifentanil has been reported as synergistic but additive when using propofol concentrations within the clinical range. (7)(8) However in other studies, BIS has shown no interaction between propofol and remifentanil (9)(10) A correlation between BIS, painful stimuli and other opioids has been demonstrated. (11) It has been suggested that BIS values can change with propofol and painful stimuli and this can aid administration of remifentanil in a dose dependent manner. (12) Since propofol and remifentanil are ubiquitously used together, the interaction between these drugs and EEG needs to be defined in more detail.

Trial Objectives To see whether remifentanil affects the dose of proposal required for loss of consciousness and loss of response to painful stimuli and whether this is reflected in changes in brain EEG (bispectral index BIS)

Hypothesis That the effect site concentration of proposal at loss of consciousness will only be moderately affected by concurrently remifentanil infusion but BIS will not change. That the clinical response to painful stimuli will markedly decrease when there is concurrent infusion of remifentanil. With painful stimuli there will be an increase in BIS but this will be blocked by remifentanil.

Methodology From the start date of the study, the first 100 patients eligible will be included. Patients will be allocated into one of two groups, group A or group B by a computer generated randomization table.

For each patient, after receiving written consent, the patient will enter the theatre where they are going to have their elective operation. Standard anaesthetic monitoring will be applied, plus a BIS monitor. External peripheral nerve stimuli electrodes will be placed over the ulner nerve on the dominant arm. IV access will be gained by the anaesthetist. All infusions will run through the same IV cannula using standardized one way valves.

One anaesthetist will look after the air way while the second anesthetist or a research assistant will fill in the data collection sheet and determine point of loss of consciousness and point of loss of response to painful stimuli. The air way anesthetist will know by a sealed envelope whether the patient is on group A or B. For the patients in group A, the remifentanil infusion, using the minto effect site concentration model, will be set at 0ng/ml. For the patients in group B the remifentanil infusion will be set at 3ng/ml. After 5 minutes the propofol infusion will commence, using the Marsh effect site concerntration TCI model, at 1mcg/ml and will be increased by 0.2mcg/ml every one minute. Heart Rate, blood pressure and BIS number will be recorded every minute. Every 30 seconds the anaesthetist will prompt the patient with the vocal stimuli "say your name" in a constant tone and volume. Loss of consciousness will be defined as the point at which the patient fails to respond to the vocal stimuli and light tactite stilulation. At this point BIS, heart rate, blood pressure and propofol effect site concentration will be recorded.

After loss of consciousness, a tetanic stimuli will be applied using the peripheral nerve stimulator and repeated every thirty seconds. The propofol infusion will continue to be increased every one minutes by 0.2mcg/ml. Loss of response to painful stimuli will be defined as the point at which the patient fails to make a withdrawal motion from the tetanic stimulation. Here, heart rate, blood pressure BIS number and propofol effect site concentration will be recorded.

After loss of response to painful stimuli the study is complete, no further date will be collected, the peripheral nerve stimulator will be removed, the anaesthesia will continue and surgery will commence as usual.

Study Type

Interventional

Enrollment (Actual)

100

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Hong Kong
      • Pok Fu Lam, Hong Kong
        • Queen Mary Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

16 years to 63 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

ASA I or II patients (healthy or with mild systemic illness) undergoing planned surgery requiring general anaesthetic

Exclusion Criteria:

  1. Subjects with pre-existing neurological or psychiatric illness.
  2. Subjects on CNS acting medication or analgesics.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: remifentanil effect site concentration 0ng/ml
remifentanil run as an infusion using the minto TCI model, at an effect site concentration of 0 nano grams per millilitre, commenced from start of proposal infusion to point at which patient is anaesthetised and not responding to painful stimuli.
Drug: Remifentanil
short acting opiate
Drug: Propofol
hypnotic drug
Other: Bispectral index
electroencephalograph
Active Comparator: remifentanil effect site concentration 3ng/ml
remifentanil run as an infusion using the minto TCI model, at an effect site concentration of 3 nano grams per millilitre, commenced from start of proposal infusion to point at which patient is anaesthetised and not responding to painful stimuli.
Drug: Remifentanil
short acting opiate
Drug: Propofol
hypnotic drug
Other: Bispectral index
electroencephalograph

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Effect site concentration of propofol at time of loss of consciousness for each of the two groups
Time Frame: every 1 minute up to 40 minutes
every 1 minute up to 40 minutes
Effect site concentration of propofol at loss of response to painful stimuli for each of the three groups
Time Frame: every 1 minute up to 40 minutes
every 1 minute up to 40 minutes

Secondary Outcome Measures

Outcome Measure
Time Frame
Time to loss of consciousness
Time Frame: every 1 minute up to 40 minutes
every 1 minute up to 40 minutes
EEG Bispectral index BIS
Time Frame: every 1 minute up to 40 minutes
every 1 minute up to 40 minutes
heart rate
Time Frame: every 1 minute up to 40 minutes
every 1 minute up to 40 minutes
blood pressure
Time Frame: every 1 minute up to 40 minutes
every 1 minute up to 40 minutes

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

The University of Hong Kong

Investigators

  • Study Chair: Michael Irwin, MbChB, Hong Kong University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

February 1, 2015

Primary Completion (Actual)

August 1, 2015

Study Completion (Actual)

August 1, 2015

Study Registration Dates

First Submitted

October 24, 2014

First Submitted That Met QC Criteria

November 5, 2014

First Posted (Estimate)

November 10, 2014

Study Record Updates

Last Update Posted (Estimate)

March 11, 2016

Last Update Submitted That Met QC Criteria

March 10, 2016

Last Verified

March 1, 2015

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • uhongkong

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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