Blood Propofol Concentrations in Children During Spinal Surgery

August 29, 2013 updated by: Great Ormond Street Hospital for Children NHS Foundation Trust

Comparison of Measured Versus Predicted Blood Propofol Concentrations During Total Intravenous Anaesthesia in Children Undergoing Spinal Surgery

During major spinal surgery evoked potential monitoring is performed to detect spinal cord damage. Intra-venous anaesthesia is the preferred anaesthetic technique because volatile anaesthetic agents supress the evoked potentials. Total Intra-Venous Anaesthesia (TIVA) with propofol is commonly administered as a Target Controlled Infusion (TCI). The TCI is an automated drug delivery system which administers propofol to achieve a desired blood concentration, based on an in built pharmaco-kinetic data (TCI model) derived from previous studies. The TCI model also provides a real time predicted blood concentration to facilitate the anaesthetist to adjust the target concentration of propofol.

The TCI algorithm is based on pharmaco-kinetic data derived from previous studies in a relatively small number of patients, by a "best fit" relationship between blood levels, infusion rates and other factors (such as age and weight). Several factors make it possible for a wide discrepancy between the predicted and the true blood concentrations. This difference can be higher in children compared to adults. Also blood loss and administration of large volumes of intravenous fluids can affect the blood concentrations. This study aims to identify the difference between the predicted and true blood concentrations by using Pelorus 1500, a bedside blood propofol measurement device, in children undergoing major spinal surgery under TIVA.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

20

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

  • United Kingdom
      • London, United Kingdom, WC1N 3JH
        • Great Ormond Street Hospital for Children NHS Trust

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

5 years to 18 years (Child, Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Children undergoing major spinal surgery under propofol TCI
  • Surgery expecting to last more than 3 hours.

Exclusion Criteria:

  • Major hepatic or renal disease

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

  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Single arm
The intervention in this study involves taking blood sample from an existing arterial line for measurement of blood propofol levels. The drug in evaluation is Propofol 2% (Diprivan 2%, Astra Zeneca UK) administered as a target controlled infusion using the commercially available paediatric TCI models (Paedfusor and Marsh models). The dose range is usually between a target concentration of 3-8 mcg/ml. However the anaesthetic management is not changed for the study. The blood concentrations of propofol will be measured using Pelorus 1500 (Sphere Medical, UK), a CE marked device. The anaesthetist will be blinded from the measurements, unless the measured value was outside the safe limit ( < 3 mcg/ml or > 10mcg/ml).
Device: Pelorus 1500
a bedside blood propofol measurement device
Other Names:
  • Sphere Medical, UK
Drug: Propofol 2% (Diprivan 2%, Astra Zeneca UK)

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
The absolute difference between the measured and predicted concentrations of propofol in micrograms per ml of blood.
Time Frame: Up to 5 hours during the maintenance phase of anaesthesia, to allow a maximum of 10 samples at 20 to 30 min intervals.
Up to 5 hours during the maintenance phase of anaesthesia, to allow a maximum of 10 samples at 20 to 30 min intervals.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Median Performance Error (MDPE)
Time Frame: Up to 5 hours during the maintenance phase of anaesthesia, to allow a maximum of 10 samples at 20 to 30 min intervals.
The median value of ratio between the measured and predicted concentration of propofol to the predicted concentration (Performance error) in blood. Expressed as a percentage. This is a measure of overall bias of the target controlled infusion.
Up to 5 hours during the maintenance phase of anaesthesia, to allow a maximum of 10 samples at 20 to 30 min intervals.
Median Absolute Performance Error (MDAPE)
Time Frame: Up to 5 hours during the maintenance phase of anaesthesia
The median value of the ratio of the absolute difference (excluding the sign) between the measured and predicted concentrations to the predicted concentration (Absolute performance error) in blood. Expressed as percentage. This is a measure of the accuracy of the target controlled infusion.
Up to 5 hours during the maintenance phase of anaesthesia
Wobble
Time Frame: Up to 5 hours during the maintenance phase of anaesthesia
The median value of the difference between the individual performance errors and the Median Performance Error (MDPE). This is a measure of the distribution of the performance errors around the median.
Up to 5 hours during the maintenance phase of anaesthesia
Divergence
Time Frame: Up to 5 hours during the maintenance phase of anaesthesia
The median of the regression coefficient of the performance error against time. This is a measure of how the target controlled infusion performs with time.
Up to 5 hours during the maintenance phase of anaesthesia

Collaborators and Investigators

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

Sponsor

Great Ormond Street Hospital for Children NHS Foundation Trust

Investigators

  • Study Director: Michael RJ Sury, FRCA PhD, Great Ormond Street Hospital For Children NHS Foundation Trust
  • Principal Investigator: Selvakumar Panchatsharam, MBBS FRCA, Great Ormond Street Hospital For Children NHS Foundation Trust

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

January 1, 2013

Primary Completion (Actual)

July 1, 2013

Study Completion (Actual)

July 1, 2013

Study Registration Dates

First Submitted

August 13, 2013

First Submitted That Met QC Criteria

August 29, 2013

First Posted (Estimate)

August 30, 2013

Study Record Updates

Last Update Posted (Estimate)

August 30, 2013

Last Update Submitted That Met QC Criteria

August 29, 2013

Last Verified

August 1, 2013

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 12AR04

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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