Acute PainNCT07618676
The 50:50 Nitrous Oxide vs 2% Lidocaine Challenge
A study testing Nitrous Oxide-Oxygen and Lidocaine 2% Injectable Solution in people with Acute Pain and Anxiety, run by Institute for Oncology and Radiology of Serbia at 1 site in Serbia.
Trial summary
The main goal of the project is to assess pain levels and patient comfort during the administration of a 50:50 Nitrous Oxide/Oxygen gas mixture, in comparison to the same parameters under the standard method used at our institution, which includes injecting a local anaesthetic at the site of planned puncture for… Read more about this study
- Who is it for?
- Ages 18 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- Acute Pain, Anxiety, Central Venous Catheter
- What is being tested?
- Nitrous Oxide-Oxygen and Lidocaine 2% Injectable Solution
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 62 participants
- Where
- 1 siteSerbia
- Study dates
- 6 Jun 2025to 22 Oct 2026
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Subjects who have not previously received Nitrous Oxide.
- Subjects of both sexes, aged between 18 and 65 inclusive.
- Subjects who have signed informed consent with full disclosure; no study-related procedure may begin until the subject signs the consent form.
Who cannot join
- Infection at the planned puncture site.
- Pregnancy.
- Intracranial hypertension.
- Vitamin B12 deficiency.
- Hemodynamic instability.
- BMI over 35.
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- Glasgow Coma Scale (GCS) score less than 15.
- Presence of chronic pain.
- Neurological disorders.
- Hematologic disorders.
- Systemic or intrathecal methotrexate therapy
- More than two attempts at venous puncture (Subject Withdrawal Criterion).
- Subject experienced an adverse event requiring early discontinuation (Subject Withdrawal Criterion).
- Withdrawal of consent by the subject (Subject Withdrawal Criterion)
Trial locations and contacts
1 site in 1 country.
Serbia1 site
Institute for Oncology and Radiology of Serbia
Belgrade, Savski Venac, 11000
About this study
Official title: The 50:50 Nitrous Oxide Challenge: A Prospective Randomised Trial - Needle, Meet Your Match
The main goal of the project is to assess pain levels and patient comfort during the administration of a 50:50 Nitrous Oxide/Oxygen gas mixture, in comparison to the same parameters under the standard method used at our institution, which includes injecting a local anaesthetic at the site of planned puncture for central venous catheterisation.
- Conditions
- Acute Pain, Anxiety, Central Venous Catheter
- Being tested
- Nitrous Oxide-Oxygen, Lidocaine 2% Injectable Solution
- Medical subject headings
- Acute Pain, Anxiety Disorders
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Nitrous Oxide-OxygenDrug
Also called Experimental Treatment
After placing the patient in the appropriate supination + Trendelenburg position, the operative field (neck and subclavian region) is prepared using antiseptic measures.Five minutes before needle insertion, a mask connected to a 50:50 Nitrous Oxide/Oxygen cylinder with a flow rate of 6 liters per minute is placed on the patient's face and held by the patient. The mask has a valve that opens only when the patient creates negative pressure during inhalation.The patient is instructed to breathe spontaneously; the mask is removed once the catheter is inserted into the target vein or after cessation of painful stimulation.
Lidocaine 2% Injectable SolutionDrug
Also called Control
After placing the patient in the appropriate supination + Trendelenburg position, the operative field (neck and subclavian region) is prepared using antiseptic measures. Then, under ultrasound control, the most favorable central vein for puncture is determined (v. jugularis interna or v. subclavia) and a 25-gauge needle is used to infiltrate the skin and subcutaneous tissue above the selected vein with local anesthetic. Five minutes after infiltration, puncture of the selected vein is performed using the Seldinger technique. Continuous communication with the patient is maintained throughout the procedure.
| Study group | Role | What they receive |
|---|---|---|
| Nitrous Oxide Group | Experimental | This will be the experimental group in which the patients will receive a mixture of gases to assess the efficacy of the treatment compared to the control. Receives: Drug: Nitrous Oxide-Oxygen |
| Lidocaine 2% | Active comparator | The control group receiving the standard of care for this intervention. Receives: Drug: Lidocaine 2% Injectable Solution |
What is being measured
The primary outcome is the main question the study is designed to answer.
Pain Intensity During Needle Insertion
Assessed using a standard Numeric Rating Scale (NRS) ranging from 0 (no pain) to 10 (worst imaginable pain). Higher scores indicate greater pain intensity.
Measured: At the time of needle insertion
Pain Intensity During Catheter Placement
Assessed using a standard Numeric Rating Scale (NRS) ranging from 0 (no pain) to 10 (worst imaginable pain). Higher scores indicate greater pain intensity.
Measured: During catheter placement
Pain Intensity Post-Intervention
Assessed using a standard Numeric Rating Scale (NRS) ranging from 0 (no pain) to 10 (worst imaginable pain). Higher scores indicate greater pain intensity.
Measured: 2 minutes after gas inhalation (Treatment 1) or 2 minutes post-intervention (Treatment 2)
Secondary outcomes (3)
Patient Anxiety Score
Assessed using a standard Numeric Rating Scale (NRS) ranging from 0 (no anxiety) to 10 (worst imaginable anxiety). Higher scores indicate greater anxiety levels.
Measured: Post-intervention (at the conclusion of the central venous catheterization procedure)
Patient Satisfaction Score
Assessed using a Numeric Rating Scale (NRS) where patients rate their overall satisfaction with the anesthetic method. The scale ranges from 0 (completely unsatisfied) to 4 (completely satisfied). Higher scores indicate greater satisfaction.
Measured: Post-intervention (at the conclusion of the central venous catheterization procedure)
Incidence of Treatment-Related Adverse Events
Percentage of participants experiencing specific adverse events, including nausea/vomiting, unpleasant dreams, paresthesias, dizziness, and euphoria, as recorded by subjective patient reports.
Measured: From the start of the intervention through 30 minutes post-procedure
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 Jun 2026
- Study start6 Jun 2025
- Primary completion22 Oct 2026
- Study completion22 Oct 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Acute PainStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 62 participants (actual)
Sponsor and investigators
- Lead sponsor
- Institute for Oncology and Radiology of Serbia
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Ana Cvetković, Institute for Oncology and Radiology of Serbia
- Investigators
- Ana Cvetković, MD, PhD, Principal investigator, Institute for Oncology and Radiology of Serbia
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07618676
- Sponsor's protocol ID
- 01-1/2025/1264
- Status last verified
- May 2026
- First submitted
- 25 May 2026
- Last updated
- 23 Oct 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: There is no current plan to share individual participant data to external registries.
Study at a glance
From the registry record, last updated by the sponsor on 23 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The 50:50 Nitrous Oxide Challenge: A Prospective Randomised Trial - Needle, Meet Your Match
- ClinicalTrials.gov ID
- NCT07618676
- Acronym / sponsor ID
- 01-1/2025/1264
- Conditions
- Acute Pain, Anxiety, Central Venous Catheter
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 62 participants (actual)
- Lead sponsor
- Institute for Oncology and Radiology of SerbiaUniversity, hospital or other
- Study start
- 6 Jun 2025 (actual)
- Primary completion
- 22 Oct 2026 (actual)
- Study completion
- 22 Oct 2026 (actual)
- First posted
- 1 Jun 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The main goal of the project is to assess pain levels and patient comfort during the administration of a 50:50 Nitrous Oxide/Oxygen gas mixture, in comparison to the same parameters under the standard method used at our institution, which includes injecting a local anaesthetic at the site of planned puncture for central venous catheterisation.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Nitrous Oxide Group | Experimental | Drug: Nitrous Oxide-OxygenThis will be the experimental group in which the patients will receive a mixture of gases to assess the efficacy of the treatment compared to the control. |
| Lidocaine 2% | Active comparator | Drug: Lidocaine 2% Injectable SolutionThe control group receiving the standard of care for this intervention. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Subjects who have not previously received Nitrous Oxide.
- Subjects of both sexes, aged between 18 and 65 inclusive.
- Subjects who have signed informed consent with full disclosure; no study-related procedure may begin until the subject signs the consent form.
Key exclusion criteria (14 listed)
- Infection at the planned puncture site.
- Pregnancy.
- Intracranial hypertension.
- Vitamin B12 deficiency.
- Hemodynamic instability.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Nitrous Oxide-OxygenAlso: Experimental TreatmentAfter placing the patient in the appropriate supination + Trendelenburg position, the operative field (neck and subclavian region) is prepared using antiseptic measures.Five minutes before needle insertion, a mask connected to a 50:50 Nitrous Oxide/Oxygen cylinder with a flow rate of 6 liters per minute is placed on the patient's face and held by the patient. The mask has a valve that opens only when the patient creates negative pressure during inhalation.The patient is instructed to breathe spontaneously; the mask is removed once the catheter is inserted into the target vein or after cessation of painful stimulation. | Drug | Nitrous Oxide Group |
| Lidocaine 2% Injectable SolutionAlso: ControlAfter placing the patient in the appropriate supination + Trendelenburg position, the operative field (neck and subclavian region) is prepared using antiseptic measures. Then, under ultrasound control, the most favorable central vein for puncture is determined (v. jugularis interna or v. subclavia) and a 25-gauge needle is used to infiltrate the skin and subcutaneous tissue above the selected vein with local anesthetic. Five minutes after infiltration, puncture of the selected vein is performed using the Seldinger technique. Continuous communication with the patient is maintained throughout the procedure. | Drug | Lidocaine 2% |
Primary outcome
Pain Intensity During Needle Insertion
Time frame: At the time of needle insertion
Assessed using a standard Numeric Rating Scale (NRS) ranging from 0 (no pain) to 10 (worst imaginable pain). Higher scores indicate greater pain intensity.
Pain Intensity During Catheter Placement
Time frame: During catheter placement
Assessed using a standard Numeric Rating Scale (NRS) ranging from 0 (no pain) to 10 (worst imaginable pain). Higher scores indicate greater pain intensity.
Pain Intensity Post-Intervention
Time frame: 2 minutes after gas inhalation (Treatment 1) or 2 minutes post-intervention (Treatment 2)
Assessed using a standard Numeric Rating Scale (NRS) ranging from 0 (no pain) to 10 (worst imaginable pain). Higher scores indicate greater pain intensity.
3 secondary outcomes
Patient Anxiety Score
Time frame: Post-intervention (at the conclusion of the central venous catheterization procedure)
Patient Satisfaction Score
Time frame: Post-intervention (at the conclusion of the central venous catheterization procedure)
Incidence of Treatment-Related Adverse Events
Time frame: From the start of the intervention through 30 minutes post-procedure
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 23 Oct 2026.
- Individual participant dataSharing planned: No. There is no current plan to share individual participant data to external registries.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Ana Cvetković, MD, PhD principal investigator
Institute for Oncology and Radiology of Serbia
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Nitrous Oxide-Oxygen and Lidocaine 2% Injectable Solution in people with Acute Pain and Anxiety, run by Institute for Oncology and Radiology of Serbia at 1 site in Serbia.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 14 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 23 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Serbia. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Pain Intensity During Needle Insertion (time frame: At the time of needle insertion). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 23 Oct 2026.