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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
Double-blind randomised controlled trial of low pressure vs standard pressure in keyhole surgery for the gallbladder: a study to reduce pain following surgery
Scientific title
Laparoscopic Intra-abdominal Pressure Study comparing pain scores following low and standard pressure in elective laparoscopic cholecystectomy patients: A double blinded randomised controlled trial
Secondary ID [1] 297338 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Gallstones 311464 0
Post-operative Pain 311500 0
Condition category
Condition code
Surgery 310105 310105 0 0
Surgical techniques
Anaesthesiology 310135 310135 0 0
Pain management
Oral and Gastrointestinal 310141 310141 0 0
Other diseases of the mouth, teeth, oesophagus, digestive system including liver and colon

Study type
Description of intervention(s) / exposure
This study aims to answer the question whether it is beneficial to perform laparoscopy at low intra-abdominal pressure in a laparoscopic cholecystectomy operation (keyhole surgery to remove the gallbladder). The two primary objectives of the study are to establish the level of post-operative pain experienced by the patient through both a Likert post-operative pain score and totalling the quantity of opiate analgesia used, and to ensure that there is no compromise to the safety under which the operation is performed.

This will be a double blinded randomised controlled trial with both surgeon and patient blinded to the intra-abdominal pressure used. The intra-abdominal pressures will be randomised to either 8mmHg or 12mmHg. Intra-operative data will be collected in real time (through direct observation by a study investigator including monitoring fidelity to the intervention), and protocols have been designed to protect patient safety in the event that surgeons feel the intra-abdominal view is compromised, which include the ability of the surgeon to increase intra-abdominal pressure to improve the view if required and a limit on pressure increases before the pressure becomes unblinded to all clinicians.
Intervention code [1] 313594 0
Treatment: Surgery
Comparator / control treatment
This will be a double blinded randomised controlled trial with both surgeon and patient blinded to the intra-abdominal pressure used during laparoscopic cholecystectomy. The intra-abdominal pressures will be randomised to either 8mmHg (low pressure) or 12mmHg (standard pressure - the control group). Protocols exist to allow surgeons to increase pressure to allow safe surgery if required.
Control group

Primary outcome [1] 318999 0
The primary outcome is a completed pain score following laparoscopic cholecystectomy. This will be done through a 10 point verbal rating scale.
Timepoint [1] 318999 0
The primary timepoint is 24 hours post-operatively
Secondary outcome [1] 366694 0
The secondary outcome is the number of times the surgeon requests an increase in pressure. This will be measured in real time by a study investigator who is observing the operation.
Timepoint [1] 366694 0
The secondary outcome is at the time of operation.
Secondary outcome [2] 366695 0
The additional secondary outcome is morbidity following operation.
Timepoint [2] 366695 0
Patients will be followed for a minimum of 30 days post-operatively to document any complications. Complications will be assessed by a review of the patient record including discharge summary and the standard 4 week post-operative clinic review.

Key inclusion criteria
All patients at Northern Health undergoing elective laparoscopic cholecystectomy
Minimum age
18 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
• Any patient undergoing emergency laparoscopic cholecystectomy
• Any patient in whom a second operation is performed
• Any patient under 18 years of age
• Any patient who has a chronic pain syndrome/taking regular opiate medication for non-biliary pain prior to the operation
• Any patient allergic to opiate medication
• Any patient who cannot communicate in English

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation is concealed. Randomisation done via computer random number generator and transcribed into sealed envelopes by an investigator not involved in data collection or patient recruitment.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation using a randomisation table created by computer software (i.e. computerised sequence generation)
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes
Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
A continuous endpoint, two independent sample study power calculation was performed. Assuming that pain scores are 10% higher with standard intra-abdominal pressure laparoscopic cholecystectomy with a standard deviation of 15% of the measures, and assuming a type I error of 0.05 and a type II error of 0.2, power calculations reveal that 86 participants (43 in each group) will give a significant result. Allowing for randomisation and for participant dropout for latter post-operative pain questionnaires, the study is aiming for 100 randomised participants.

Statistical analysis will be performed using Chi-Square for categorical data, and T-test and ANOVA for continuous data. Subset analysis will be performed with groups determined by age, gender, and ASA grade. Decreased post-operative pain will be determined by lower post-operative pain scores between both groups, with secondary measures of analgesia requirement and length of stay used to confirm these findings. Safety of the procedure will be established by a non-significant difference in morbidity and mortality, with secondary measures of length of operation, surgeon satisfaction, and anaesthetic measures used to confirm these findings.

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] 13079 0
The Northern Hospital - Epping
Recruitment postcode(s) [1] 25588 0
3076 - Epping

Funding & Sponsors
Funding source category [1] 301901 0
Name [1] 301901 0
Northern Health
Address [1] 301901 0
185 Cooper St
Epping VIC 3076
Country [1] 301901 0
Primary sponsor type
Northern Health
185 Cooper St
Epping VIC 3076
Secondary sponsor category [1] 301665 0
Name [1] 301665 0
Address [1] 301665 0
Country [1] 301665 0

Ethics approval
Ethics application status
Ethics committee name [1] 302591 0
Austin Health HREC
Ethics committee address [1] 302591 0
Austin Health
Studley Rd
Heidelberg VIC 3084
Ethics committee country [1] 302591 0
Date submitted for ethics approval [1] 302591 0
Approval date [1] 302591 0
Ethics approval number [1] 302591 0

Brief summary
Recent literature has suggested that laparoscopy with higher intra-abdominal pressures may increase post-operative pain, theorised to be because of increased tension of the peritoneum, the highly sensitive inner lining of the abdominal wall. This studyis a randomised controlled study and aims to answer the question whether it is beneficial to perform laparoscopy at low intra-abdominal pressure (8mmHg) compared to normal pressure (12mmHg) in a laparoscopic cholecystectomy operation (keyhole surgery to remove the gallbladder).

Our hypothesis is that laparoscopic surgery can be performed safely at lower intra-abdominal pressures, and that this leads to lower post-operative pain.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 90746 0
Mr Russell Hodgson
Address 90746 0
Division of Surgery
Northern Health
185 Cooper St
Epping VIC 3076
Country 90746 0
Phone 90746 0
+61 3 84058000
Fax 90746 0
Email 90746 0
Contact person for public queries
Name 90747 0
Mr Russell Hodgson
Address 90747 0
Division of Surgery
Northern Health
185 Cooper St
Epping VIC 3076
Country 90747 0
Phone 90747 0
+61 3 84058000
Fax 90747 0
Email 90747 0
Contact person for scientific queries
Name 90748 0
Mr Russell Hodgson
Address 90748 0
Division of Surgery
Northern Health
185 Cooper St
Epping VIC 3076
Country 90748 0
Phone 90748 0
+61 3 84058000
Fax 90748 0
Email 90748 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?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary