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

This study has been completed.
Sponsor:
ClinicalTrials.gov Identifier:
NCT01492712
First Posted: December 15, 2011
Last Update Posted: August 14, 2017
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
Information provided by (Responsible Party):
Golden Jubilee National Hospital
  Purpose

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.


Condition Intervention
Target Controlled Infusion of Propofol Drug: Propofol

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single (Participant)
Primary Purpose: Other
Official Title: Validation Study of Covariates Model (VaSCoM) for Propofol

Resource links provided by NLM:


Further study details as provided by Golden Jubilee National Hospital:

Primary Outcome Measures:
  • 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.



Secondary Outcome Measures:
  • 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.

  • 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



Enrollment: 40
Actual Study Start Date: January 2011
Study Completion Date: February 2013
Primary Completion Date: February 2013 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
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.
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 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.

  Eligibility

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Criteria

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
  Contacts and Locations
Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01492712


Locations
United Kingdom
Golden Jubilee National Hospital
Clydebank, United Kingdom, G81 4HX
Sponsors and Collaborators
Golden Jubilee National Hospital
Investigators
Principal Investigator: Stefan Schraag Golden Jubilee National Hospital
  More Information

Responsible Party: Golden Jubilee National Hospital
ClinicalTrials.gov Identifier: NCT01492712     History of Changes
Other Study ID Numbers: VaSCoM005
2009-017900-10 ( EudraCT Number )
First Submitted: December 8, 2011
First Posted: December 15, 2011
Last Update Posted: August 14, 2017
Last Verified: August 2017

Keywords provided by Golden Jubilee National Hospital:
Propofol
Pharmacokinetics
Pharmacodynamics
Infusion Pumps

Additional relevant MeSH terms:
Propofol
Hypnotics and Sedatives
Central Nervous System Depressants
Physiological Effects of Drugs
Anesthetics, Intravenous
Anesthetics, General
Anesthetics