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Status unknownNCT02701478Updated Nov 18, 2016

ANI and NoL Index Variations After Standard Nociceptive Stimulus at 0, 50, 25 % of Inhaled N2O in the Anesthetic Mixture

A Phase 4 interventional study of N2O exposure in Pain, sponsored by Maisonneuve-Rosemont Hospital. Status unknown at 1 site in Canada. Open to participants aged 18 Years to 70 Years. Per ClinicalTrials.gov, last updated 2016-11-18.

Sponsored by Maisonneuve-Rosemont Hospital · Phase 4, Interventional, and Diagnostic

The sponsor has not verified this record recently (last verified Nov 2016), so the status shown — last known as Recruiting — may be out of date.
Phase
Phase 4
Study type
Interventional
Enrollment
40
Allocation
Not applicable
Ages
18 Years to 70 Years
Sex
All
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Study summary

N2O has been used during general anesthesia (GA) for more than 100 years. It is known to have anesthetic agents sparing effect. But small is know on his real analgesic effect during GA. So far, the only way to monitor pain during GA was based on vital signs that are not specific and not sensitive. Few devices tried to evaluated pain under GA during the last 2 decades. More recently, better devices were proposed such as the Physiodoloris device and the PMD200 device. The first offers an index called ANI based on heart rate variability (HRV) assessment. The second offers the NoL index based on the analysis of 5 parameters. The aim of the present study is to evaluate quantitatively the analgesic index of N2O during GA using the two indices ANI and NoL.

Read the detailed description

Title: Assessment of the intraoperative analgesic effect of 50%/50% Nitrous Oxide / Oxygen inhalation by the pain index ANI following a standardized electrical forearm stimulus in patients undergoing laparotomies under general anesthesia and with an intraoperative active epidural analgesia. Comparison to the new NoL analgesic index.

Objectives: To observe the variations of the intraoperative pain indexes ANI and NoL after a classical and standardized electrical stimulation of the forearm (applied with the commonly used nerve stimulator we use for muscle relaxation monitoring) at different concentrations of inhaled Nitrous Oxide (N2O) (from 0% to 50%, concentrations that are commonly used in daily anesthesia). This will allow a quantification of the analgesic effect of N2O.

Study Design: Prospective, open label, observational and descriptive study Subject Population: Adult patients scheduled to undergo abdominal surgery by laparotomy under general anesthesia with an active intraoperative epidural analgesia Sample Size: 40 patients will be evaluated in this study Study Duration: 1 year Study Center: Maisonneuve-Rosemont Hospital, Montreal, Quebec, Canada Adverse Events: None expected

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Conditions studied

  • Pain

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03

In context

Pain

2,450 studies on the registry are indexed under Pain; 945 are open to participants now.

This study's planned enrollment of 40 is below the median of 70 across 2,101 interventional studies indexed under Pain.

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Lead sponsor

Maisonneuve-Rosemont Hospital is the lead sponsor of 73 studies on the registry; 4 are open to participants now.

Counted across the registry records on this site, refreshed daily.

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Who can participate

Ages eligible
18 Years to 70 Years
Sexes eligible
All
Accepts healthy volunteers
No

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  • ASA status I, II or III
  • Patients aged 18 to 70 years
  • Laparotomy for gynecological or bowel surgery
  • Duration and type of surgery requiring an epidural analgesia via an epidural catheter placed prior the general anesthesia induction and an arterial line placed after induction of general anesthesia

Exclusion criteria

Exclusion Criteria:

  • When 100% O2 ventilation is required during anesthesia (except for the induction phase during which all the patients receive O2 100%).
  • Patients having received intraocular injection of gas (such as SF6, C3F8, C2F6) within 3 months prior to the present surgery.
  • Any condition where internal entrapped air could expand and become dangerous, such as:

    • head injury within 6 months prior to surgery
    • maxillofacial injuries within 6 months prior to surgery
    • pneumothorax within 6 months prior to surgery
    • gas embolism within 6 months prior to surgery
    • decompression sickness within 6 months prior to surgery
    • bubbles of emphysema known for this patient
    • middle ear, inner ear and sinus surgery
    • major abdominal distension/occlusion and emergent surgery for intestinal obstruction
    • if air has been injected into the epidural space to determine the placement of the needle for epidural anesthesia (only saline is used in our center for the loss of resistance technique to place the catheter into the epidural space)

Any contra-indication or patient's refusal for epidural placement

  • Unexpected difficult airway requesting excessive, possibly painful airway manipulations.
  • Unexpected surgical complications requiring strong haemodynamic support (transfusions, volume challenges, vasopressors, inotropic drugs).
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Study design

Phase
Phase 4
Primary purpose
Diagnostic
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrollment
40 participants (estimated)

Study arms

  • Other
    N2O exposure

    There is only one arm in this study. All patients under General Anesthesia are exposed to 4 different doses or concentrations of inhaled N2O that is combined with the anesthetic desflurane. Each patient will be submitted to the standard nociceptive stimulus when inhaled N2O is at 0, 50, 25, and finally back to 0%. ANI and NoL Indices variations between "before stimulus" and "after stimulus" at each N2O concentration will be assessed and compared. This will allow to demonstrate an analgesic effect (less variations of ANI and NoL) when inhaled N2O is high (50%) testifying for the analgesic effect of this gas N2O.

    Drug: N2O exposure

Interventions

  • The aim of this study is to evaluate the nociceptive response to a standardized forearm electrical stimulus applied to patients under GA, during surgery, at different End-Tidal concentrations of N2O (ET-N2O: 0%-50%-25%-0%), and to see if ANI and NoL indices show less pain when inhaled N2O is higher.

    Also known as: N2O

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What researchers measure

Primary outcomes

  1. ANI variation after stimulation in patients under GA at End-Tidal N2O 0% and 50%.

    The same patient is anesthetized without N2O in the gas mixture first. The first standard stimulus is applied on the forearm of the patient when the N2O concentration in the anesthesia mixture is at 0%. ANI response to the stimulus is recorded. Then N2O is slowly increased to reached et-N2O 50% in the anesthesia mixture. Then, at ET-N2O 50%, the same standard stimulus is applied and ANI variations registered.

    Time frame: First stimulus is applied when the patient breaths 0% N2O in his anesthesia mixture. Second stimulus is applied at 50% End-Tidal N2O in the anesthesia mixture during the surgery.

Secondary outcomes

  1. NoL index variation after electrical stimulation in patients under GA atEnd-Tidal N2O 0% and 50%.

    The same patient is anesthetized without N2O in the gas mixture first. The first standard stimulus is applied on the forearm of the patient when the N2O concentration in the anesthesia mixture is at 0%. NoL response to the stimulus is recorded. Then N2O is slowly increased to reached et-N2O 50% in the anesthesia mixture. Then, at ET-N2O 50%, the same standard stimulus is applied and NoL variations registered.

    Time frame: First stimulus is applied when the patient breaths 0% N2O in his anesthesia mixture. Second stimulus is applied at 50% End-Tidal N2O in the anesthesia mixture during the surgery.

  2. ANI and NoL indices variations after the same standard stimulus when ET-N2O is slowly decreased from 50% to 25%, , then to 0%.

    During the surgery, for primary and secondary objectives, N2O will be at 0, then 50%. For these secondary objectives, N2O inhaled concentration in teh anesthetic mixture will be set at 25% and then again at 0% and the same standard stimulus will be applied and ANI and NoL responses recorded and compared to the ones gotten at 50% .

    Time frame: Within the same anesthesia and surgery

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Study locations

1 of 1 sites recruiting
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References and documents

Publications

  • Coulombe MA, Decary E, Maximos S, Brulotte V, Drolet P, Tanoubi I, Issa R, Zaphiratos V, Verdonck O, Fortier LP, Godin N, Idrissi M, Raft J, Richebe P. Assessing the antinociceptive effect of nitrous oxide to tetanic stimulation in anaesthetised patients with new intra-operative nociception monitors: An observational study. Eur J Anaesthesiol. 2021 May 1;38(5):512-523. doi: 10.1097/EJA.0000000000001431. PubMed 33399383 ↗

Individual participant data

Plan to share: No

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Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Nov 18, 2016, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
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Registry details

Key details

Study ID
NCT02701478
Lead sponsor
Maisonneuve-Rosemont Hospital
Responsible party
Philippe Richebé (Full Professor of Anesthesiology and Pain medicine, Maisonneuve-Rosemont Hospital) — Principal investigator
First posted
Mar 8, 2016
Start date
Jan 2016
Primary completion
Dec 2016 (estimated)
Completion
Dec 2016 (estimated)
Last update
Nov 18, 2016

Study contacts

Philippe Richebe, MD PhD
Contact
philipperichebe@live.com
+1-514-743-6558
Nadia Godin, RN
Contact
ngodin.hmr@ssss.gouv.qc.ca
514-252-3400 ext. 3193
Philippe Richebe, MD PhD
principal investigator · Maisonneuve-Rosemont Hospital

Oversight

Data monitoring committee
No
View the source record on ClinicalTrials.gov ↗

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Studies of the drug tested here: Nitrous Oxide

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