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Trial registered on ANZCTR


Registration number
ACTRN12617000953336
Ethics application status
Approved
Date submitted
26/06/2017
Date registered
4/07/2017
Date last updated
8/06/2018
Type of registration
Prospectively registered

Titles & IDs
Public title
Modelling and measuring anaesthetic gas uptake by the lung
Scientific title
Measurement of the partial pressure cascade for anaesthetic agents during inhalational anaesthesia for cardiac surgery
Secondary ID [1] 292291 0
None
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Lung uptake of anaesthetic gases 303811 0
Inhalational anaesthesia 303812 0
Condition category
Condition code
Anaesthesiology 303178 303178 0 0
Anaesthetics

Intervention/exposure
Study type
Observational
Patient registry
False
Target follow-up duration
Target follow-up type
Description of intervention(s) / exposure
The partial pressure cascade for sevoflurane and desflurane will be measured in patients undergoing inhalational general anaesthesia for cardiac surgery. Measurements of inspired, end-tidal, arterial and mixed venous partial pressure of anaesthetic agent and oxygen and CO2 will be made at one time point during the pre-cardiopulmonary bypass phase. Calculation of pulmonary deadspace and shunt will be done as indices of ventilation perfusion scatter in all patients. In a further group of 10 patients ventilation perfusion scatter will be formally quantified uisng the mIGET.
Intervention code [1] 298465 0
Not applicable
Comparator / control treatment
Patients act as their own controls
Control group
Uncontrolled

Outcomes
Primary outcome [1] 302566 0
The Alveolar deadspace fraction for the anaesthetic agents will be measured from the alveolar-arterial gradient via the Bohr-Enghoff equation, and compared to that calculated in the traditional way using simultaneous PCO2 measurements.
Timepoint [1] 302566 0
60 minutes post induction of anaesthesia or the nearest point where stability of cardiovascular and measured variables is maintained for at least 5 minutes.
Secondary outcome [1] 336377 0
Relationship of A-a differences and pulmonary deadspace to V/Q scatter measured using the MIGET
Timepoint [1] 336377 0
60 minutes post induction of anaesthesia or the nearest point where stability of cardiovascular and measured variables is maintained for at least 5 minutes.

Eligibility
Key inclusion criteria
Patients undergoing coronary artery bypass surgery
Minimum age
18 Years
Maximum age
85 Years
Gender
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Patients unable to provide informed consent
Women who are pregnant
Patients with cognitive impairment
Patients with moderately or severely impaired respiratory function on history and examination (FEV1 or FVC < 50% predicted)
Patients with morbid obesity (Body mass index (BMI) > 40 kg/m2)

Study design
Purpose
Natural history
Duration
Cross-sectional
Selection
Defined population
Timing
Both
Statistical methods / analysis
Mean alveolar deadspace for CO2 will be compared with that for volatile agent.

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
VIC
Recruitment hospital [1] 8453 0
Austin Health - Austin Hospital - Heidelberg
Recruitment postcode(s) [1] 16528 0
3084 - Heidelberg

Funding & Sponsors
Funding source category [1] 296835 0
Charities/Societies/Foundations
Name [1] 296835 0
ANZCA Research Foundataion
Address [1] 296835 0
ANZCA
Ulimaroa
630 St Kilda Rd
Melbourne 3004
Country [1] 296835 0
Australia
Primary sponsor type
Hospital
Name
Austin Health
Address
Studley Rd
Heidelberg
VIC 3084
Country
Australia
Secondary sponsor category [1] 295829 0
None
Name [1] 295829 0
Address [1] 295829 0
Country [1] 295829 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 298067 0
Austin Health
Ethics committee address [1] 298067 0
StudleyRd
Heidelberg 3084
Ethics committee country [1] 298067 0
Australia
Date submitted for ethics approval [1] 298067 0
28/07/2016
Approval date [1] 298067 0
21/10/2016
Ethics approval number [1] 298067 0
DT 16/419

Summary
Brief summary
We will collect observational data on patients undergoing cardiac surgery under general anaesthesia with volatile agent maintenance (sevoflurane or desflurane).

We will collect simultaneous samples of end-tidal gas concentrations, and arterial and mixed venous blood samples for partial pressure measurement for O2 and CO2, and anaesthetic gases, as we done in several previous studies), along with measurements of alveolar ventilation, and of pulmonary blood flow using bolus thermodilution. We will study 10 patients with sevoflurane and 10 patients with desflurane. Samples will be collected once in the pre-cardiopulmonary bypass period and once post-cardiopulmonary bypass.
In a further group of 10 patients we will also perform the Multiple Inert Gas Elimination Technique (MIGET). This is the gold standard method for measuring precise distributions of V/Q ratios in patients. We have developed and validated an adaptation of the MIGET for use in ventilated patients under general anaesthesia. The V/Q distributions generated will be used for application within the model, to obtain precise measurements of shunt fraction and alveolar deadspace. These models will allow us the plot the precise pattern of distribution of anaesthetic gas uptake across the lungs in these patients.
An index of severity of V/Q scatter will be obtained by calculations of shunt fraction and alveolar deadspace using the traditional 3-compartment Riley model, from the Shunt equation and the Bohr-Enghoff equation. Parallel calculations of shunt fraction and alveolar deadspace will be made using measurements of volatile agent for comparison.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 75882 0
A/Prof Philip Peyton
Address 75882 0
Dept of Anaesthesia
Austin Health
Studley Rd
Heidelberg 3084
Country 75882 0
Australia
Phone 75882 0
+61 3 94965000
Fax 75882 0
Email 75882 0
phil.peyton@austin.org.au
Contact person for public queries
Name 75883 0
A/Prof Philip Peyton
Address 75883 0
Dept of Anaesthesia
Austin Health
Studley Rd
Heidelberg 3084
Country 75883 0
Australia
Phone 75883 0
+61 3 94965000
Fax 75883 0
Email 75883 0
phil.peyton@austin.org.au
Contact person for scientific queries
Name 75884 0
A/Prof Philip Peyton
Address 75884 0
Dept of Anaesthesia
Austin Health
Studley Rd
Heidelberg 3084
Country 75884 0
Australia
Phone 75884 0
+61 3 94965000
Fax 75884 0
Email 75884 0
phil.peyton@austin.org.au

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