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Trial registered on ANZCTR

Registration number
Ethics application status
Not yet submitted
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
Pharmacokinetic-Pharmacodynamic Modelling of Sevoflurane
Scientific title
For patients having general anaesthetic with sevoflurane, how arterial concentrations change with time in relation to end-tidal sevoflurane concentrations and how Bispectral index values change in relation to arterial concentrations of sevoflurane.
Secondary ID [1] 281555 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Pharmacokinetics and pharmacodynamics of sevoflurane 287831 0
Condition category
Condition code
Anaesthesiology 288178 288178 0 0

Study type
Description of intervention(s) / exposure
Patients will be given information and consented.
Patients will have arterial line inserted prior to induction.
BIS monitoring will be applied prior to induction.
Induction of anaesthesia will be done by gaseous induction with sevoflurane as it is a well recognised option for induction. Amount of sevoflurane given to patient will be dictated by the level of anaesthesia required for each patient as it is a normal anaesthetic practice. Normally sevoflurane will be to achieve MAC (Minimal alveolar concentration) of 0.8~1.2.
Analgesia will be provided using remifentanil infusion.

During the process of the induction, maintenance and emergence of anaesthesia, serial arterial blood samples will be taken at varying intervals. one prior to induction, at 2 min, 4 min, 8 min, 16 min, 32 min and every 15~30 min thereafter. The total volume of blood withdrawn would be about 30mL which would be around 1% of blood volume. These samples will be analysed for arterial concentration of sevoflurane. Other data related this study are automatically collected by comupter recording system of anaesthetic machine. This is a normal part of our anaesthetic practice.

Along the anaesthetic process, Bispectral monitoring data will be collected and recorded onto our anaesthetic computer recording system. This will be used to analyse pharmacodynamic aspect of sevoflurane. This is a routine anaesthetic practice.
Intervention code [1] 286071 0
Treatment: Other
Comparator / control treatment
Not applicable
Control group

Primary outcome [1] 288379 0
Arterial concentration of sevoflurane
Timepoint [1] 288379 0
Before the start of general anaesthesia, at 2 minute, 4 minutes, 8 minute, 16 minute, 32 minute then every 15~30 minute. The interval after 32nd minutes of anaesthesia will be determined by the clinical situations and recommendation of attending doctors. If they prefer to monitor arterial pressure reading at the particular moment, we will hold off taking arterial samples as arterial pressure can not be read briefly while arterial sample is being taken. As by 32nd minute the sevoflurane concentration in endtidal and arterial sample should be stablised, taking samples at either 15 minute interval or 30 min interval should not vary too much.
All the outcomes will be measured as long patient is anaesthetised.
Primary outcome [2] 288400 0
End-tidal concentrations of sevoflurane
Timepoint [2] 288400 0
This will be measured continuously using anaesthetic machine
Primary outcome [3] 288401 0
Bispectral monitoring data
Timepoint [3] 288401 0
This will be measured continuously using BIS monitoring
Secondary outcome [1] 300009 0
Blood pressure
Timepoint [1] 300009 0
It will be measured continuously using arterial line until the end of anaesthesia. This is a routine anaesthetic practice.

Key inclusion criteria
- Adults undergoing surgery requiring general anaesthesia and use of a volatile anaesthetic
- Surgery expected to last at least one hour
Minimum age
16 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
- Unable to consent
- Surgery often associated with blood loss mandating blood transfusion, pregnant
- Unable to monitor bispectral index

Study design
Purpose of the study
Educational / counselling / training
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Theatre list will be screened by investigators and their immediate assistants and appropriate patients will be identified. They will be then approached by investigators and their assistants. Potential participants will be given information regarding the study and a choice to either participate or not. If participating, written informed consent will be obtained.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
There is no randomization
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Single group
Other design features
Prospective study.
Not Applicable
Type of endpoint(s)
Pharmacokinetics / pharmacodynamics
Statistical methods / analysis

Recruitment status
Not yet recruiting
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment outside Australia
Country [1] 4684 0
New Zealand
State/province [1] 4684 0

Funding & Sponsors
Funding source category [1] 286338 0
Government body
Name [1] 286338 0
Australian and New Zealand College of Anaesthetists
Address [1] 286338 0
Australian and New Zealand College of Anaesthetists
630 St Kilda Road
Country [1] 286338 0
Primary sponsor type
Auckland City Hospital
Level 8 Anaesthetic department
Auckland City Hospital
2 Park Road,
Auckland 1023
New Zealand
Secondary sponsor category [1] 285130 0
Name [1] 285130 0
Address [1] 285130 0
Country [1] 285130 0
Other collaborator category [1] 277185 0
Name [1] 277185 0
AnQual Laboratories, School of Pharmacy, University of Auckland
Address [1] 277185 0
Private Bag 92019
Auckland 1023
Country [1] 277185 0
New Zealand

Ethics approval
Ethics application status
Not yet submitted
Ethics committee name [1] 288414 0
Ethics committee address [1] 288414 0
Ethics committee country [1] 288414 0
Date submitted for ethics approval [1] 288414 0
Approval date [1] 288414 0
Ethics approval number [1] 288414 0

Brief summary
Although sevoflurane is one of the most commonly used volatile that anaesthetists use world-wide, there has been incomplete study on pharmacokinetics namely the progress of sevoflurane arterial concentration with induction, maintenance and emergence from anaesthesia. We aim to elucidate this aspect of anaesthesia. Furthermore we intend to find out pharmacodynamics of sevoflurane by recording Bispectral data as well.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 34962 0
A/Prof Timothy Short
Address 34962 0
Department of Anaesthesia and Peri-operative Medicine,
Auckland City Hospital
2 Park Road
Auckland 1023
Country 34962 0
New Zealand
Phone 34962 0
+64 274 542464
Fax 34962 0
Email 34962 0
Contact person for public queries
Name 18209 0
Dr Robin Kang
Address 18209 0
Department of Anaesthesia and Peri-operative Medicine,
Auckland City Hospital
2 Park Road
Auckland 1023
Country 18209 0
New Zealand
Phone 18209 0
Fax 18209 0
Email 18209 0
Contact person for scientific queries
Name 9137 0
Dr Robin Kang
Address 9137 0
Department of Anaesthesia and Peri-operative Medicine,
Auckland City Hospital
2 Park Road
Auckland 1023
Country 9137 0
New Zealand
Phone 9137 0
Fax 9137 0
Email 9137 0

No information has been provided regarding IPD availability
Summary results
No Results