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The 50:50 Nitrous Oxide vs 2% Lidocaine Challenge

The 50:50 Nitrous Oxide Challenge: A Prospective Randomised Trial - Needle, Meet Your Match

Status
Active, not recruiting
Phases
Unknown
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT07618676
Enrollment
62
Registered
2026-06-01
Start date
2025-06-06
Completion date
2026-10-01
Last updated
2026-09-03

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Acute Pain, Anxiety, Central Venous Catheter

Brief 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 central venous catheterisation.

Interventions

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.

DRUGLidocaine 2% Injectable Solution

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.

Sponsors

Institute for Oncology and Radiology of Serbia
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Outcomes Assessor)

Eligibility

Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
Yes

Inclusion criteria

* 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.

Exclusion criteria

* Infection at the planned puncture site. * Pregnancy. * Intracranial hypertension. * Vitamin B12 deficiency. * Hemodynamic instability. * BMI over 35. * 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)

Design outcomes

Primary

MeasureTime frameDescription
Pain Intensity During Needle InsertionAt the time of needle insertionAssessed 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 PlacementDuring catheter placementAssessed 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-Intervention2 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.

Secondary

MeasureTime frameDescription
Incidence of Treatment-Related Adverse EventsFrom the start of the intervention through 30 minutes post-procedurePercentage of participants experiencing specific adverse events, including nausea/vomiting, unpleasant dreams, paresthesias, dizziness, and euphoria, as recorded by subjective patient reports.
Patient Anxiety ScorePost-intervention (at the conclusion of the central venous catheterization procedure)Assessed using a standard Numeric Rating Scale (NRS) ranging from 0 (no anxiety) to 10 (worst imaginable anxiety). Higher scores indicate greater anxiety levels.
Patient Satisfaction ScorePost-intervention (at the conclusion of the central venous catheterization procedure)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.

Countries

Serbia

Contacts

PRINCIPAL_INVESTIGATORAna Cvetković, MD, PhD

Institute for Oncology and Radiology of Serbia

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Sep 4, 2026