Can we reduce the environmental impact of nitrous oxide anaesthesia without affecting patient care?
| ISRCTN | ISRCTN66370377 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN66370377 |
| ClinicalTrials.gov (NCT) | Nil known |
| Clinical Trials Information System (CTIS) | Nil known |
| Integrated Research Application System (IRAS) | 347203 |
| Protocol serial number | RG_24-084 |
| Sponsor | University of Birmingham |
| Funder | National Institute for Health and Care Research |
- Submission date
- 24/10/2024
- Registration date
- 27/02/2025
- Last edited
- 17/02/2026
- Recruitment status
- Recruiting
- Overall study status
- Ongoing
- Condition category
- Surgery
Plain English summary of protocol
Background and study aims
Nitrous oxide is a gas used in anaesthesia. The way it is currently used leads to waste and may have an environmental impact too. The way nitrous oxide is delivered is changing in operating theatres. Currently, most hospitals use piped nitrous oxide, whereas in future nitrous oxide may come from a portable cylinder instead. The aim of this study is to check whether nitrous oxide from portable cylinders is as safe for patients and less wasteful than piped nitrous oxide.
Who can participate?
All patients undergoing surgery under general anaesthetic
What does the study involve?
Patients requiring nitrous oxide anaesthesia during their operation will be randomly allocated to receive it either via cylinder or pipeline. No trial-specific data will be collected from the patient, the collection of outcome data will be via hospital record review.
What are the possible benefits and risks of participating?
There will be no direct benefits to individual patients. The intervention (nitrous oxide delivered via cylinder) is in common clinical practice in the UK, therefore there are no specific risks relating to participation in the trial, however, the purpose of the study is to assess whether there is any difference in the safety profile of nitrous oxide delivered via cylinder or via pipeline.
Where is the study run from?
The University of Birmingham (UK)
When is the study starting and how long is it expected to run for?
February 2024 to March 2027
Who is funding the study?
The National Institute for Health and Care Research (UK)
Who is the main contact?
Prof. Rupert Pearse, NOBLE@trials.bham.ac.uk
Contact information
Principal investigator
Adult Critical Care Unit
Royal London Hospital
Whitechapel
London
E1 1FR
United Kingdom
| Phone | +44 (0)20 3594 0351 |
|---|---|
| r.pearse@qmul.ac.uk |
Public
Birmingham Clinical Trials Unit
Public Health Building
University of Birmingham
Birmingham
B15 2TT
United Kingdom
| Phone | +44 (0)7514800721 |
|---|---|
| noble@trials.bham.ac.uk |
Scientific
Birmingham Clinical Trials Unit
Public Health Building
University of Birmingham
Birmingham
B15 2TT
United Kingdom
| Phone | +44 (0)7514800721 |
|---|---|
| noble@trials.bham.ac.uk |
Study information
| Primary study design | Interventional |
|---|---|
| Study design | Pragmatic multi-centre non-inferiority cluster randomized cross-over trial |
| Secondary study design | Randomised cross over trial |
| Scientific title | A multi-centre non-inferiority cluster trial comparing outcomes related to nitrous oxide delivery by portable cylinder and pipeline in all patients undergoing surgery under general anaesthesia: Nitrous Oxide management to Balance heaLthcare and Environmental needs (NOBLE) |
| Study acronym | NOBLE |
| Study objectives | Nitrous oxide delivered via portable cylinder is as safe in terms of patient outcomes as nitrous oxide delivered via pipeline manifold. |
| Ethics approval(s) |
Approved 20/02/2025, East of England - Cambridge Central Research Ethics Committee (2 Redman Place, London, E20 1JQ, United Kingdom; +44 (0)207 104 8089; cambridgecentral.rec@hra.nhs.uk), ref: 24/EE/0268 |
| Health condition(s) or problem(s) studied | Method of nitrous oxide delivery in patients requiring surgery under general anaesthetic. |
| Intervention | The NOBLE trial will have two distinct phases each lasting 5 weeks. Hospitals will be randomised 1:1 either to a control phase (pipeline nitrous oxide supply) followed by an intervention phase (cylinder nitrous oxide supply), or to an intervention phase followed by a control phase. The total trial intervention period will last 10 weeks, with a further 30 days to complete the follow-up of the last included patient to undergo surgery. Hospitals will be allocated in randomised blocks of random length (4 or 6). The allocation list will be prepared by an independent statistician at BCTU, and uploaded to the randomisation module of the REDCap electronic data capture tools hosted at Birmingham University, to ensure allocation concealment when each hospital is randomised. Prior to randomisation, local investigators will ensure all necessary equipment has been procured and is ready for use and will plan the delivery of education and training to anaesthetists and relevant theatre staff. |
| Intervention type | Other |
| Primary outcome measure(s) |
Days Alive and At Home Within 30 Days after surgery (DAH30). The day of surgery is defined as day zero. Patients who die within 30 days after surgery will be given a value of zero. DAH30 data will be collected from routine data in patient health records by local investigators who are members of the direct care team. |
| Key secondary outcome measure(s) |
1. Use of nitrous oxide anaesthesia during surgery (Y/N) |
| Completion date | 31/03/2027 |
Eligibility
| Participant type(s) | Patient |
|---|---|
| Age group | All |
| Sex | All |
| Target sample size at registration | 14400 |
| Key inclusion criteria | All patients (adults and children) undergoing surgery under general anaesthesia in participating hospitals (regardless of exposure to nitrous oxide anaesthesia) |
| Key exclusion criteria | Patients who have opted out of anonymous data sharing Patients undergoing repeat surgery within 30 days after a procedure recorded in the NOBLE trial |
| Date of first enrolment | 01/04/2025 |
| Date of final enrolment | 31/12/2026 |
Locations
Countries of recruitment
- United Kingdom
- England
- Scotland
- Wales
Study participating centres
80 Newark Street
London
E1 2ES
England
Pond Street
London
NW3 2QG
England
Derriford Road
Derriford
Plymouth
PL6 8DH
England
Basildon
SS16 5NL
England
Hollyhurst Road
Darlington
DL3 6HX
England
Barnet
EN5 3DJ
England
Treliske
Truro
TR1 3LJ
England
Marton Road
Middlesbrough
TS4 3BW
England
27 Union Walk
Hereford
HR1 2ER
England
Watford Road
Harrow
HA1 3UJ
England
Kayll Road
Sunderland
SR4 7TP
England
Uttoxeter Road
Derby
DE22 3NE
England
Belvedere Road
Burton-on-trent
DE13 0RB
England
Queen Victoria Road
Newcastle upon Tyne
NE1 4LP
England
Results and Publications
| Individual participant data (IPD) Intention to share | Yes |
|---|---|
| IPD sharing plan summary | Available on request |
| IPD sharing plan | The datasets generated during and/or analysed during the current study will be available upon request from Rachel Lillywhite (NOBLE@trials.bham.ac.uk) |
Editorial Notes
17/02/2026: The following changes were made to the study record:
1. The date of final enrolment was changed from 01/10/2026 to 31/12/2026.
2. The completion date was changed from 31/10/2026 to 31/03/2027.
3. The study participating centres were updated.
14/10/2025: The following changes were made to the trial record:
1. The date of final enrolment was changed from 01/10/2025 to 01/10/2026.
2. The completion date was changed from 31/10/2025 to 31/10/2026.
3. The plain English summary was updated to reflect these changes.
21/02/2025: Study's existence confirmed by the HRA.
