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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Type of registration
Retrospectively registered

Titles & IDs
Public title
Effect of a lung recruitment strategy lung gas function during general anaesthesia
Scientific title
Effect of a lung recruitment strategy on ventilation-perfusion scatter and lung gas exchange during general anaesthesia
Secondary ID [1] 297160 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
intraoperative lung atelectasis 311193 0
Condition category
Condition code
Anaesthesiology 309812 309812 0 0
Respiratory 309813 309813 0 0
Other respiratory disorders / diseases

Study type
Description of intervention(s) / exposure
Intraoperative stepped lung recruitment manoeuvre (stepped increases in PEEP [Positive End expiratory Pressure] of 5cmH2O from 0 up to 20cmH2O) using the Maquet Flow-i anaesthesia machine, applied by the anaesthetist after commencement of laparoscopic gas insufflation, with identification of optimal PEEP using monitoring of dynamic lung compliance, with continued ventilation at 6-8 mL/kg tidal volume and optimal PEEP + 2 cmH2O at a rate to mantain EtCO2 at 35-40 mmHg. Data will be logged automatically by the Flow-i and downloaded at the end of the case.
Intervention code [1] 313420 0
Treatment: Devices
Comparator / control treatment
Standard intraoperative ventilation management using the Maquet Flow-i anaesthesia machine: 6-8 mL/kg tidal volume and PEEP 5 cmH2O at a rate to mantain EtCO2 at 35-40 mmHg
Control group

Primary outcome [1] 318771 0
Cumulative sevoflurane consumption, measured internally by the Flow-i anaesthesia machine

Timepoint [1] 318771 0
At end of surgery
Secondary outcome [1] 365984 0
Measured A-a gradient for PCO2 meaured from end-tidal gas monitoring and arterial blood gas sampling

Timepoint [1] 365984 0
60 Minutes post commencement of laparoscopic gas insufflation
Secondary outcome [2] 365985 0
FIO2/PaO2 ratio meaured from inspired gas monitoring and arterial blood gas sampling
Timepoint [2] 365985 0
60 Minutes post commencement of laparoscopic gas insufflation
Secondary outcome [3] 365986 0
Alveolar deadspace fraction calculated using the modified Bohr-Enghoff equation from end-tidal and arterial PCO2 measurements
Timepoint [3] 365986 0
60 Minutes post commencement of laparoscopic gas insufflation
Secondary outcome [4] 365988 0
Measured A/a ratio for sevoflurane, measured from monitored end-tidal waveform concentrations and in aretrial blood from sampling of 10 ML blood and headspace equilibration method.
Timepoint [4] 365988 0
60 Minutes post commencement of laparoscopic gas insufflation
Secondary outcome [5] 365989 0
Time to eye opening to command repeated every 30 seconds after cessation of fresh gas sevoflurane delivery, observed and recorded by the anaaesthetist
Timepoint [5] 365989 0
At end of surgery

Key inclusion criteria
Patients undergoing elective laparoscopic bowel surgery under relaxant general anaesthesia planned to take at least 1 hour where placement of an arterial blood pressure monitoring line is considered appropriate for cardiovascular monitoring (systemic arterial blood pressure and/or cardiac output monitoring) for clinical purposes.
Minimum age
18 Years
Maximum age
85 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Patients unable to provide informed consent
Women who are pregnant
Patients with cognitive impairment
Patients with poor command of English.
Body mass index (BMI) > 35.
Impaired lung function: Patients with severely impaired respiratory function on history and examination (FEV1 TLCO or FVC < 30% predicted),

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Sealed envelopes
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s

Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment hospital [1] 12971 0
Austin Health - Austin Hospital - Heidelberg
Recruitment postcode(s) [1] 25449 0
3084 - Heidelberg

Funding & Sponsors
Funding source category [1] 301713 0
Commercial sector/Industry
Name [1] 301713 0
Maquet Critical Care AB
Address [1] 301713 0
Rontgenvagen 2
S-17155 Solna
Country [1] 301713 0
Primary sponsor type
Austin Health
Studley Rd
VIC 3084
Secondary sponsor category [1] 301450 0
Name [1] 301450 0
Address [1] 301450 0
Country [1] 301450 0

Ethics approval
Ethics application status
Ethics committee name [1] 302433 0
Austin Health Research Ethics Committee
Ethics committee address [1] 302433 0
Studley Rd
VIC 3084
Ethics committee country [1] 302433 0
Date submitted for ethics approval [1] 302433 0
Approval date [1] 302433 0
Ethics approval number [1] 302433 0

Brief summary
A major contributor to postoperative pulmonary complications after major surgery is collapse (atelectasis) in poorly ventilated lung segments during and after general anaesthesia (GA). Atelectasis arises from the reduced muscle tone caused by nearly all anaesthetics,and the non-physiological pattern of distribution of ventilation that characterizes controlled mechanical positive pressure ventilation (CMV), and occurs early in the course of anaesthesia.
Strategies to reduce lung atelectasis and postoperative pulmonary complications include the use of positive end-expiratory pressure (PEEP) and lung recruitment manoeuvres.

Recently, Maquet Critical Care AB (Sweden) have released a new functionality on their Flow-i anaesthesia machine which allows targeted lung recruitment using a stepped increase in PEEP and lung inflation pressures. The system simultaneously monitors airway pressures and dynamic lung compliance, The latter is used to identify the optimal level of PEEP to minimize lung atelectasis, where measured dynamic lung compliance (Cdyn) is maximal.

We wish to measure the effectiveness of this new technology on improving lung function and gas exchange in patients under GA for elective surgery.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 90226 0
Prof Philip Peyton
Address 90226 0
Dept of Anaesthesia
Austin Health
Studley Rd
VIC 3084
Country 90226 0
Phone 90226 0
+61 3 94965000
Fax 90226 0
Email 90226 0
Contact person for public queries
Name 90227 0
Prof Philip Peyton
Address 90227 0
Dept of Anaesthesia
Austin Health
Studley Rd
VIC 3084
Country 90227 0
Phone 90227 0
+61 3 94965000
Fax 90227 0
Email 90227 0
Contact person for scientific queries
Name 90228 0
Prof Philip Peyton
Address 90228 0
Dept of Anaesthesia
Austin Health
Studley Rd
VIC 3084
Country 90228 0
Phone 90228 0
+61 3 94965000
Fax 90228 0
Email 90228 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
What data in particular will be shared?
Individual participant data underlying published results
When will data be available (start and end dates)?
Beginning 6 months and ending 5 years following main results publication
Available to whom?
Researchers who provide a methodologically sound proposal, at the discretion of the Chief Investigator
Available for what types of analyses?
To achieve the aims in the approved proposal
How or where can data be obtained?
Access subject to approvals by Principal Investigator, with requirement to sign data access agreement
What supporting documents are/will be available?
Study protocol
Statistical analysis plan
Informed consent form
Clinical study report
Ethical approval
Summary results
No Results