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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
Date results information initially provided
Type of registration
Retrospectively registered

Titles & IDs
Public title
A study of the behavior of the lungs in critically ill patients to optimise treatment
Scientific title
A study to model the mechanical behavior of the lung in critically ill patients undergoing mechanical ventilation to determine the impact of different ventilation strategies
Secondary ID [1] 273352 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Acute lung injury (ALI) 279125 0
Acute respiratory distress syndrome (ARDS) 279135 0
Condition category
Condition code
Respiratory 279317 279317 0 0
Other respiratory disorders / diseases

Study type
Patient registry
Target follow-up duration
Target follow-up type
Description of intervention(s) / exposure
Having gained consent, patients will be sedated, or sedated and paralysed using muscle relaxants, to prevent spontaneous respiratory efforts. The patient’s initial ventilator settings- plateau pressure at end expiration (P plat), tidal volume (Vt), and positive end expiratory pressure (PEEP), will be recorded.

All patients will be ventilated using volume controlled, synchronised intermittent mandatory ventilation (SIMV) while the study is being conducted. SIMV sets the tidal volume, with the airway pressure dependent on the patient’s condition. The tidal volume selected by the clinician treating the patient will not be changed for the duration of the measurements. However, if the patient is already on a pressure controlled mode of ventilation, the tidal volume is not directly set by the clinician. If a patient is on pressure controlled ventilation, they will be switched over to SIMV. The measured tidal volume of the pressure controlled mode will be then used to set the mandatory tidal volume of the SIMV mode.

Patients who are spontaneous breathing will be trailed on SIMV and given additional sedation to synchronise their respiratory efforts with the ventilator. If necessary, a muscle relaxant may be added providing the patient is unaware of their surroundings.

All patients in the study, while still mechanically ventilated will undergo a protocolised recruitment maneuver up to twice daily. Airway pressure and volume data from each maneuver will be collected. Heart rate, blood pressure and pulse oximetry will also be recorded to ensure there is no adverse impact on their circulation. During this maneuver, the airway pressure must be high enough to recruit most of the alveoli. However, if the peak airway pressure is too high, then there is a risk of over distending healthy alveoli and further injuring the lung. A target peak pressure of 45 cmH2O will be used.

As the PEEP (Positive End Expiratory Pressure) is increased, the corresponding peak airway pressures also increase. However the increases in peak pressures are not predictable, and vary from patient to patient. To provide a safe trial for the patient, prior to the clinical protocol, a “practice protocol” will be performed to determine the maximum allowable PEEP (PEEPmax) that will produce a peak airway pressure of 45 cmH2O.

Prior to the commencement of the protocol, a sample of blood will be taken to determine the arterial blood gas concentrations. This process is then repeated 30 minutes after the protocol is finished.

The practice protocol will involve the clinician titrating PEEP until PEEPmax is achieved for the patient. Once PEEPmax is determined, then the clinician has an idea of the upper bound that the protocol can be carried out.

1. Pneumotachometer is attached to the ‘Y’ connector of the patient’s ventilation circuit. System is tested
2. Carry out PEEP titrations for practice protocol and determine PEEPmax
3. Apply 5 cm PEEP and carry out 5 PV loops with tidal volume of 500ml (or set to the patient’s previous setting, which ever is the lesser). This data will be captured.
4. This tidal volume will remain constant for the duration of the study.
5. Apply an additional 5 cm PEEP to the last PEEP used and carry out 5 PV loops.
6. Repeat step 5 until PEEPmax is achieved.
7. Trial Time (extra time required) = 11 – 17 minutes (Only PEEP titration), 41-47minutes (inclusion of arterial blood gas information).

The observation will be carry out for 24 months.
Intervention code [1] 283696 0
Not applicable
Comparator / control treatment
Control group

Primary outcome [1] 279925 0
Observation of lung mechanics with the change of mechanical ventilation settings (PEEP change).
Timepoint [1] 279925 0
Continuous recording from the ventilator/ airway pressure and flow during recruitment maneuver.
Secondary outcome [1] 294795 0
Observation of Arterial blood gas information before and after recruitment maneuver.
Timepoint [1] 294795 0
Before recruitment maneuver and 30 minutes after recruitment maneuver.

Key inclusion criteria
All recruited participants have acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). Patients with ALI have a P/F ratio 200-300 mmHg, and those with ARDS have a P/F ratio less than 200 mmHg. The P/F ratio is defined as the partial pressure of oxygen in the arterial blood divided by the fraction of inspired oxygen. The more severe the lung injury the lower this number.
Minimum age
16 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
1. Patients who are improving and likely to be discontinued from mechanical ventilation within 24 hours

2. Patients who are not expected to survive.

3. Patients who are minimally sedated but oriented in either time or place or person. These patients are excluded because they will require additional sedation or relaxants to participate, which may cause additional inconvenience and prolong their length of stay.

Study design
Defined population
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 outside Australia
Country [1] 3943 0
New Zealand
State/province [1] 3943 0

Funding & Sponsors
Funding source category [1] 284177 0
Name [1] 284177 0
University of Canterbury
Address [1] 284177 0
Private Bag 4800
Christchurch 8140
Country [1] 284177 0
New Zealand
Funding source category [2] 284178 0
Name [2] 284178 0
Christchurch Hospital
Address [2] 284178 0
Riccarton Avenue
Private Bag 4710
Christchurch 8140
Country [2] 284178 0
New Zealand
Primary sponsor type
University of Canterbury
Private Bag 4800
Christchurch 8140
New Zealand
Secondary sponsor category [1] 269135 0
Name [1] 269135 0
Christchurch Hospital
Address [1] 269135 0
Riccarton Avenue
Private Bag 4710
Christchurch 8140
Country [1] 269135 0
New Zealand

Ethics approval
Ethics application status
Ethics committee name [1] 286136 0
Upper South A Regional Ethics Committee
Ethics committee address [1] 286136 0
Ministry of Health
4th Floor, 250 Oxford Tce
PO Box 3877
Christchurch 8140
Ethics committee country [1] 286136 0
New Zealand
Date submitted for ethics approval [1] 286136 0
Approval date [1] 286136 0
Ethics approval number [1] 286136 0

Brief summary
This study will test current mathematical models of the lung mechanics (the way injured or damaged lungs move during ventilation) so the best possible ventilation strategy can be applied to each patient. The model estimates the lung condition. The final outcome is that the validated model can provide a fast diagnostic tool in the ICU that can be used to optimise treatment for individual patients.
Trial website
Trial related presentations / publications
Chiew YS, Chase JG, Shaw GM, Desaive T: Respiratory system elastance monitoring during PEEP titration. Critical Care 2012, 16:P103.

Chiew YS, Chase JG, Shaw G, Sundaresan A, Desaive T: Model-based PEEP Optimisation in Mechanical Ventilation. BioMedical Engineering OnLine 2011, 10:111.

Sundaresan A, Shaw GM, Chiew YS, Chase JG: PEEP in mechanically ventilated patients a clinical proof of concept. In Australia-New Zealand Intensive Care Society (ANZICS) ASM; March 31 - April 1; Taupo, New Zealand. 2011: 1-page.

Sundaresan A, Chase J, Shaw G, Chiew YS, Desaive T: Model-based optimal PEEP in mechanically ventilated ARDS patients in the Intensive Care Unit. BioMedical Engineering OnLine 2011, 10:64.
Public notes

Principal investigator
Name 33367 0
Dr Geoffrey M Shaw
Address 33367 0
Christchurch Hospital Riccarton Avenue Private Bag 4710 Christchurch 8140
Country 33367 0
New Zealand
Phone 33367 0
Fax 33367 0
Email 33367 0
Contact person for public queries
Name 16614 0
Dr Dr. Geoffrey M Shaw
Address 16614 0
Christchurch Hospital
Riccarton Avenue
Private Bag 4710
Christchurch 8140
Country 16614 0
New Zealand
Phone 16614 0
Fax 16614 0
Email 16614 0
Contact person for scientific queries
Name 7542 0
Prof Prof J. Geoffrey Chase
Address 7542 0
University of Canterbury
Department of Mechanical Engineering
Private Bag 4800
Christchurch 8140
Country 7542 0
New Zealand
Phone 7542 0
Fax 7542 0
Email 7542 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No/undecided IPD sharing reason/comment
What supporting documents are/will be available?
No other documents available
Summary results
Have study results been published in a peer-reviewed journal?
Journal publication details
Publication date and citation/details [1] 12487 0
Chiew, Y.S., Pretty, C.G., Shaw, G.M. et al. Feasibility of titrating PEEP to minimum elastance for mechanically ventilated patients. Pilot Feasibility Stud 1, 9 (2015).
Attachments [1] 12487 0
Publication date and citation/details [2] 12488 0
Sundaresan, A., Chase, J.G., Shaw, G.M. et al. Model-based optimal PEEP in mechanically ventilated ARDS patients in the Intensive Care Unit. BioMed Eng OnLine 10, 64 (2011).
Attachments [2] 12488 0
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary