Validation Study of Covariates Model (VaSCoM) for Propofol (VaSCoM)

August 11, 2017 updated by: Golden Jubilee National Hospital

Anaesthesia for surgical procedures can be provided using a continuous infusion of intravenous drug. The most commonly used drug for this technique is propofol. Infusion devices programmed with pharmacokinetic models can be used to infuse propofol to achieve a target blood concentration. These pharmacokinetic models predict the rate of distribution of propofol within the body and also the rate at which it is cleared. In practice, the anaesthetist enters patient details such as age, sex and weight as well as a target blood concentration of propofol. The infusion device then infuses propofol at the appropriate rate to achieve this concentration.

White and colleagues recently published the Covariates Model for propofol. It is anticipated that this model will have reduced bias and inaccuracy compared to the models in current clinical use. The VaSCoM study has three objectives:

  1. Prospective validation of the Covariates Model
  2. Modelling of the effect site concentration of propofol
  3. Comparison of propofol concentration in venous and arterial blood samples

To achieve the above objectives, patients over 18 years of age and undergoing elective non-cardiac surgery will be recruited to the study. Anaesthesia will be delivered using a target controlled infusion device programmed with the Covariates Model for propofol. The target blood concentrations will be set according to a pre-determined schedule and all measurements will be made prior to the start of surgery.

Prospective validation of the Covariates Model will be done by comparing blood concentration of propofol predicted by the model to those actually measured. These results will then be compared to the predictions made using the models in current clinical practice.

Modelling of the effect site means predicting the concentration of propofol in the brain for a given blood concentration. This will involve using depth of anaesthesia monitors (such as bispectral index) as surrogate markers of brain concentration and comparing this to the predicted and measured blood concentrations of propofol.

Finally, important information on the distribution and clearance of propofol can be gained through the comparison of venous and arterial blood samples. In this study, simultaneous sampling of venous and arterial blood will facilitate this comparison.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

40

Phase

  • Not Applicable

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

  • United Kingdom
      • Clydebank, United Kingdom, G81 4HX
        • Golden Jubilee National 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

18 years and older (ADULT, OLDER_ADULT)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Aged over 18 years
  • ASA I/II
  • Elective non-cardiac surgery expected to last longer than 30 minutes

Exclusion Criteria:

  • Patient refusal or unable to consent
  • Premedication, sedative or anaesthetic in the previous 12 hours
  • Pre-operative GCS less than 15
  • ASA III/IV
  • Allergy to constituents of propofol
  • Excess alcohol intake
  • Drug abuse
  • Mental retardation
  • Difficult airway
  • BMI over 35

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: OTHER
  • Allocation: RANDOMIZED
  • Interventional Model: PARALLEL
  • Masking: SINGLE

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
EXPERIMENTAL: Low-high-low blood target concentration
Patients in the low-high-low group will receive an infusion of propofol with an initial blood target concentration of 2 mcg/ml. After 15 minutes the target will be increased to 5 mcg/ml and after a further 15 minutes the target will be reduced back to 2 mcg/ml for a further 15 to 30 minutes.
Drug: Propofol
Patients in the low-high-low group will receive an infusion of propofol with an initial blood target concentration of 2 mcg/ml. After 15 minutes the target will be increased to 5 mcg/ml and after a further 15 minutes the target will be reduced back to 2 mcg/ml for a further 15 to 30 minutes.
Drug: Propofol
Patients in the high-low-high group will receive an infusion of propofol with an initial blood target concentration of 5 mcg/ml. After 15 minutes the target will be reduced to 2 mcg/ml and after a further 15 minutes the target will be increased back to 5 mcg/ml for a further 15 to 30 minutes.
EXPERIMENTAL: High-low-high target blood concentration
Patients in the high-low-high group will receive an infusion of propofol with an initial blood target concentration of 5 mcg/ml. After 15 minutes the target will be reduced to 2 mcg/ml and after a further 15 minutes the target will be increased back to 5 mcg/ml for a further 15 to 30 minutes.
Drug: Propofol
Patients in the low-high-low group will receive an infusion of propofol with an initial blood target concentration of 2 mcg/ml. After 15 minutes the target will be increased to 5 mcg/ml and after a further 15 minutes the target will be reduced back to 2 mcg/ml for a further 15 to 30 minutes.
Drug: Propofol
Patients in the high-low-high group will receive an infusion of propofol with an initial blood target concentration of 5 mcg/ml. After 15 minutes the target will be reduced to 2 mcg/ml and after a further 15 minutes the target will be increased back to 5 mcg/ml for a further 15 to 30 minutes.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Performance error of predicted blood propofol concentration (venous blood samples)
Time Frame: 1.5, 5, 16.5, 20, 31.5, 35, 45-60 minutes post infusion start time

Performance error is calculated as:

((Measured blood concentration - Predicted blood concentration)/ Predicted blood concentration) x 100

The median performance error and the absolute performance error can then be calculated as measures of bias and inaccuracy respectively.
1.5, 5, 16.5, 20, 31.5, 35, 45-60 minutes post infusion start time

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Depth of anaesthesia
Time Frame: 0 to 45-60 minutes post infusion start time
Depth of anaesthesia (as measured by bispectral index and index of consciousness) will be used as a surrogate marker of propofol effect site concentration. By using complex statistical analysis to compare depth of anaesthesia to measured and predicted blood concentrations, we aim to determine the Keo. This is the rate constant for elimination of propofol from the effect site compartment and will be incorporated to the Covariates Model to predict brain concentration for a given blood concentration of propofol.
0 to 45-60 minutes post infusion start time
Comparison of performance errors calculated from venous blood samples to performance errors calculated from arterial blood samples
Time Frame: 1.5, 5, 16.5, 20, 31.5, 35, 45-60 minutes post infusion start time

Performance error is calculated as:

((Measured blood concentration - Predicted blood concentration)/ Predicted blood concentration) x 100
1.5, 5, 16.5, 20, 31.5, 35, 45-60 minutes post infusion start time

Collaborators and Investigators

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

Sponsor

Golden Jubilee National Hospital

Investigators

  • Principal Investigator: Stefan Schraag, Golden Jubilee National Hospital

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 (ACTUAL)

January 1, 2011

Primary Completion (ACTUAL)

February 1, 2013

Study Completion (ACTUAL)

February 1, 2013

Study Registration Dates

First Submitted

December 8, 2011

First Submitted That Met QC Criteria

December 13, 2011

First Posted (ESTIMATE)

December 15, 2011

Study Record Updates

Last Update Posted (ACTUAL)

August 14, 2017

Last Update Submitted That Met QC Criteria

August 11, 2017

Last Verified

August 1, 2017

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • VaSCoM005
  • 2009-017900-10 (EUDRACT_NUMBER)

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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