POSTOPERATIVE OPIOID-SPARING EFFECT OF INTRAOPERATIVE PAIN MONITORING USING THE ANALGESIA NOCICEPTIVE INDEX (ANI) DURING IDIOPATHIC SCOLIOSIS CORRECTION IN CHILDREN.
POSTOPERATIVE OPIOID-SPARING EFFECT OF INTRAOPERATIVE PAIN MONITORING USING THE ANALGESIA NOCICEPTIVE INDEX (ANI) DURING IDIOPATHIC SCOLIOSIS CORRECTION IN CHILDREN.
Anaesthesia is often performed using a balanced technique by administering both opioids and
 anaesthetics agents. Intraoperative opioid administration is still relying on simple
 parameters such as heart rate and blood pressure variations. However, many studies in both
 adults and children have shown the poor accuracy of those parameters in predicting pain
 because of their sensibility to other intraoperative events such as depth of anaesthesia and
 volaemic variations. Consequently, intraoperative analgesia is still inadequately managed
 with periods of under dosage or over dosage of opioid agents. This has been hypothesized to
 cause postoperative hyperalgesia related to both intraoperative pain (in case of under
 dosage) or to opioid agents (in case of over dosage). The main resulting effect is an
 increase of postoperative opioid consumption and the inadequate postoperative rehabilitation
 because of adverse effects of opioids.

 During the last decade, many pain-monitors have been investigated. Most of these devices are
 relying on the determination of the sympathetic-to the parasympathetic systems balance. Among
 those monitors, the Analgesia Nociceptive Index (ANI) quantifies the parasympathetic system.
 The ANI device can produce two parameters the instantaneous ANI (ANIi), derived from 60
 seconds analysis and the mean ANI (ANIm) derived from 4 minutes analysis. Studies have shown
 the accuracy of ANIi to detect both experimental and clinical pain in various populations.
 Moreover, a recent randomized controlled trial during spine surgery in adults has found ANIi
 to decrease the intraoperative and postoperative opioid consumption when used
 intraoperatively for guiding the administration of opioid agents
Anaesthesia is often performed using a balanced technique by administering both opioids and
 anaesthetics agents. Intraoperative opioid administration is still relying on simple
 parameters such as heart rate and blood pressure variations. However, many studies in both
 adults and children have shown the poor accuracy of those parameters in predicting pain
 because of their sensibility to other intraoperative events such as depth of anaesthesia and
 volaemic variations. Consequently, intraoperative analgesia is still inadequately managed
 with periods of under dosage or over dosage of opioid agents. This has been hypothesized to
 cause postoperative hyperalgesia related to both intraoperative pain (in case of under
 dosage) or to opioid agents (in case of over dosage). The main resulting effect is an
 increase of postoperative opioid consumption and the inadequate postoperative rehabilitation
 because of adverse effects of opioids.

 During the last decade, many pain-monitors have been investigated. Most of these devices are
 relying on the determination of the sympathetic-to the parasympathetic systems balance. Among
 those monitors, the Analgesia Nociceptive Index (ANI) quantifies the parasympathetic system.
 The ANI device can produce two parameters the instantaneous ANI (ANIi), derived from 60
 seconds analysis and the mean ANI (ANIm) derived from 4 minutes analysis. Studies have shown
 the accuracy of ANIi to detect both experimental and clinical pain in various populations.
 Moreover, a recent randomized controlled trial during spine surgery in adults has found ANIi
 to decrease the intraoperative and postoperative opioid consumption when used
 intraoperatively for guiding the administration of opioid agents
Inclusion Criteria:

 -  Age < 18 years at time of surgery;

 -  Surgical correction of idiopathic scoliosis with or without thoracoplasty;

 -  Weight ≥ 30 kg : in order to allow using target plasma concentration administration of
 the opioid (remifentanil) and anaesthetic (propofol) agents; (pharmacokinetics models
 are not validated under this weight) during the intraoperative period;

 -  ASA (American Society of Anesthesiologist) status I to III

 -  Affiliation to the French national health insurance

 Exclusion Criteria:

 -  Second time of a scoliosis correction in the preceding year (apart the use of
 halo-gravity traction or non-painful procedures such as digestive endoscopy);

 -  Chronic treatment (> 3 months) with: opioid agents, anti-epileptic agents or
 anti-depressant agents;

 -  Bad French language understanding;

 -  Expected difficulties in self-managing pain using the patient-controlled analgesia
 devices;

 -  ASA (American Society of Anesthesiologist) status IV or V;

 -  Any contraindication to one of the compound of the study: propofol, remifentanil,
 atracurium, paracetamol, Non-steroidal anti-inflammatory agents.

 -  Patients with a heart pace-maker device

 -  Patient under anti-arrythmic treatment