The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been endorsed by the ANZCTR. Before participating in a study, talk to your health care provider and refer to this information for consumers
Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Retrospectively registered

Titles & IDs
Public title
Does carbon dioxide insufflation during colonoscopy minimise post colonoscopy pain?: A randomised controlled trial
Scientific title
Does carbon dioxide insufflation for a patient during colonoscopy minimise their post colonoscopy pain compared to air.
Secondary ID [1] 281642 0
nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
post colonoscopy pain 287930 0
Condition category
Condition code
Oral and Gastrointestinal 288309 288309 0 0
Other diseases of the mouth, teeth, oesophagus, digestive system including liver and colon

Study type
Description of intervention(s) / exposure
Carbon dioxide (a medicinal gas) was drawn from a CO2 tank and delivery system to a receptacle and then passed intermitently through the endoscope during the colonoscopy at the control of the endoscopist pressing a button on the hand piece of the endoscope. The intention of gas is to insufflate the colon during colonoscopy.
Intervention code [1] 286182 0
Treatment: Drugs
Comparator / control treatment
` standard treatment` was insufflation of room air drawn from a receptacle (called the air/water bottle), to the endoscope and passed intermitently through the endoscope at the control of the endoscopist pressing a button on the hand piece of the endoscope. The purpose of this gas is to insufflate the colon during colonoscopy.
Control group

Primary outcome [1] 288506 0
A comparison of reported abdominal pain using a self reported 0-10 point numeric rating scale(NRS)
Timepoint [1] 288506 0
Intra procedure (0) and post procedure at 10, 30 and 60 minutes
Secondary outcome [1] 300344 0
Timepoint [1] 300344 0

Key inclusion criteria
Patients on the waiting list for elective colonoscopy. These will be new patients with symptoms and also patients for surveillance colonoscopy (for reasons of past history of; colon cancer, adenomas, strong family history of bowel cancer and inflammatory bowel disease)
Minimum age
16 Years
Maximum age
90 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Age under 16 and over 90
Inability to understand participant information
Patients with severe chronic obstructive pulmonary disease (COPD)
Refusal to participate

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
The receptionist send trial invitations to patients within the age criteria off the waiting list. On presenting for their colonoscopy the participatns consent and suitability for inclusion was assessed by a nurse.
allocation concealment by sealed randomisation envelopes: Envelopes (120) numbered for men and 12 for women. Inside the envelope it was stated on a slip of paper either the experimental `CO2 or `usual` ( the control air group)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
simple randomisation using an excel computer programme used to allocate numbers to envelopes
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
SPSS 17.0 software. Differences in mean numeric rating scale scores analysed using independent samples t-tests. Chi-squared test for independence was used to assess the differences between the proportions of those reporting 0 pain at four time intervals. The p value was set at < 0.05.

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 outside Australia
Country [1] 4749 0
New Zealand
State/province [1] 4749 0
Palmerson North

Funding & Sponsors
Funding source category [1] 286461 0
Name [1] 286461 0
MidCentral Health District Health Board
Address [1] 286461 0
PO box 2056
Palmerston North,4410
New Zealand
Country [1] 286461 0
New Zealand
Primary sponsor type
MidCentral District Health Board
PO box 2056
Palmerston North, 4410
New Zealand
New Zealand
Secondary sponsor category [1] 285250 0
Name [1] 285250 0
Address [1] 285250 0
Country [1] 285250 0

Ethics approval
Ethics application status
Ethics committee name [1] 288538 0
Health and Disability Ethics Committee (Central Regional Ethics Committee
Ethics committee address [1] 288538 0
Ministry of Health
PO Box 5013
Wellington, 6145
Ethics committee country [1] 288538 0
New Zealand
Date submitted for ethics approval [1] 288538 0
Approval date [1] 288538 0
Ethics approval number [1] 288538 0

Brief summary
The aim of the study is to determine that carbon dioxide (CO2) , instead of air insufflated during colonoscopy reduces pain experienced by patients post colonoscopy.
the Hypothesis: Those receiving carbon dioxide (CO2) insufflation during colonscopy will experience less post colonoscopy pain than those receiving air insufflation.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 36494 0
Mrs Anne Cleland
Address 36494 0
Gastroenterology Department
MidCentral Health
PO box 2056
Palmerson North, 4410
Country 36494 0
New Zealand
Phone 36494 0
+64 6 3508865
Fax 36494 0
+64 6 3508807
Email 36494 0
Contact person for public queries
Name 36495 0
Mrs Anne Cleland
Address 36495 0
Gastroenterology Department
MidCentral Health
PO box 2056
Palmerston North, 4410
Country 36495 0
New Zealand
Phone 36495 0
+64 6 3508865
Fax 36495 0
+64 6 3508807
Email 36495 0
Contact person for scientific queries
Name 36496 0
Mrs Anne cleland
Address 36496 0
Gastroenterology Department
MidCentral Health
PO box 2056
Palmerston North, 4410
Country 36496 0
New Zealand
Phone 36496 0
+64 6 3508665
Fax 36496 0
+64 6 3508807
Email 36496 0

No information has been provided regarding IPD availability
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