Blood Propofol Measurement During Anaesthesia Using Propofol Target Controlled Infusion

Study Overview
=================
Brief Summary
-----------------
Propofol is a commonly used agent for sedation and anaesthesia in the intensive care unit and the operating room. The pharmacokinetics of propofol are difficult to predict in patients not conforming to the norms in which the original pharmacokinetic research was based. Such patients, including the critically ill, and morbidly obese, are increasingly being encountered. The investigators group have been involved in the development of a device which can measure blood propofol concentrations, and hope for this to be available to use in the operating room in a clinically useful timeframe in the future. Data will be collected on patients undergoing propofol based general anaesthesia. The Marsh target controlled algorithm in effect site mode (commonly used by anaesthetists) will be assessed for accuracy using the propofol monitor. A new proportional correction method will be developed using this data, designed to enable recalibration of the TCI algorithm in near real time in order to achieve a more accurate estimated propofol concentration in these identified patient groups. The research will investigate the effectiveness of a correction of estimated propofol levels based on a one off measurement early on in the anaesthetic, and will take subsequent samples to measure propofol levels without modifying the TCI algorithm. Additionally, data on anaesthetist choice of TCI model, and method of administration in this relatively unselected group of patients will be analysed.

Official Title
-----------------
Use of a Novel Point of Care Device to Measure Blood Propofol Levels During Propofol Based General Anesthesia by Target Controlled Infusion Using the Marsh Model in Effect Site Mode

Conditions
-----------------
General Anaesthesia, Propofol, Target Controlled Infusion, Pharmacokinetics

Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Only patients undergoing major surgery where blood sampling through arterial or central venous catheters is part of their routine clinical care will be recruited. Only patients undergoing total intravenous anaesthesia using propofol will be recruited. Exclusion Criteria: Anaemic patients will not be recruited into the study. Patients unable to consent will not be recruited into the study.

Ages Eligible for Study
-----------------
Minimum Age: 16 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| General Anaesthesia<br>Patients undergoing general anaesthesia using Marsh model target controlled infusion in effect site mode. | |

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Median percentage prediction error of estimated propofol concentration compared to measured concentrations (Bias) |  | duration of anaesthesia (up to 24 hours) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Median absolute percentage prediction error of estimated propofol concentration compared to measured concentrations (inaccuracy) |  | duration of anaesthesia (up to 24 hours) | 
| Change in median percentage prediction error(bias)for propofol levels measured beyond thirty minutes following proportional correction at thirty minutes |  | thirty minutes | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Propofol, Target controlled infusion, General anaesthesia