Clinical trial NCT02701478: ANI and NoL Index Variations After Standard Nociceptive Stimulus at 0, 50, 25 % of Inhaled N2O in the Anesthetic Mixture
Official title: Assessment of the Intraoperative Analgesic Effect of 50%/50% N2O/O2 Inhalation by the Pain Index ANI Following a Standardized Electrical Stimulus in Patients Under Anesthesia. Comparison to the New NoL Analgesic Index.
Study type: INTERVENTIONAL
Overall status: UNKNOWN
Phase: PHASE4
Conditions: Pain
Lead sponsor: Maisonneuve-Rosemont Hospital
Sponsor class: OTHER
First posted: 2016-03-08
Enrollment: 40
Sex: ALL
Minimum age (years): 18
Maximum age (years): 70
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: NA
Intervention model: SINGLE_GROUP
Primary purpose: DIAGNOSTIC

Brief 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.

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

Eligibility criteria: 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:

* 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).

Primary outcomes:
measure: ANI variation after stimulation in patients under GA at End-Tidal N2O 0% and 50%.
timeFrame: 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:
measure: NoL index variation after electrical stimulation in patients under GA atEnd-Tidal N2O 0% and 50%.
timeFrame: 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.
measure: ANI and NoL indices variations after the same standard stimulus when ET-N2O is slowly decreased from 50% to 25%, , then to 0%.
timeFrame: Within the same anesthesia and surgery
Other outcomes:
Locations:
city: Montreal
country: Canada
facility: Hopital Maisonneuve Rosemont
state: Quebec
Study officials:
affiliation: Maisonneuve-Rosemont Hospital
name: Philippe Richebe, MD PhD
role: PRINCIPAL_INVESTIGATOR
References:
citation: 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.