Correlation Between NOL Index After Stimulus and Post-operative Opioid, Pain, Pre-operative Phenotype

Correlation Between NoL Index Response to Standardized Stimulus Under General Anesthesia and: Post-operative Opioid Consumption and Pain, Pre-operative Phenotype and Pain Biomarkers

This study evaluates the correlation between NoL index response to standardized stimulus under general anesthesia and the post-operative pain, assessed by opioid consumption and numerical pain scores after video-assisted thoracoscopy (VATS).

The NoL index, a nociception monitor using a multiparametric approach, has shown an excellent sensitivity and specificity in detecting noxious stimuli under general anesthesia. This monitor is better than any other parameter in grading nociception under general anesthesia. More recently, it has recently been shown a strong correlation between NoL index response to nociceptive stimulus and the level of opioid analgesia during surgery. No study has evaluated that NoL could predict post-operative pain so far. It has not yet been proven that NoL was correlated with post-operative opioid consumption or with post-operative pain scores.

Some phenotypic factors were previously shown to correlate with post-operative pain and opioid consumption, such as psychological factors and tests, or also assessment of some pre-operative nociceptive thresholds (NT). Pain catastrophizing was proven in several studies to correlate with acute post-operative pain.

So far, no study compared each of these preoperative psychological factors or nociceptif thresholds to the NoL index response to intraoperative standardized pain stimulus in terms of correlation with post-operative opioid requirements and pain scores.

Moreover, there is no study evaluating the pro-inflammatory protein profiles that might likely be correlated to inter-individual differences in NoL response after this standardized nociceptive stimulus under general anesthesia.

This study will assess the level of correlation between NoL index response to standardized stimulus under general anesthesia and the post-operative pain, assessed by opioid consumption and numerical pain scores after video-assisted thoracoscopy (VATS). It also evaluates the correlation between NoL index response to standardized stimulus under general anesthesia and pre-operative phenotype and post-operative pain biomarkers.

Inclusion Criteria:

• Adult patient (Age 18 or older)
• ASA status I, II or III
• elective video assisted thoracoscopy under general anesthesia

Exclusion Criteria:

• history of coronary artery disease
• serious cardiac arrhythmia (including atrial fibrillation),
• history of substance abuse,
• chronic use of psychotropic and/or opioid drugs,
• use of drugs that act on the autonomic nervous system (including β-blockers),
• history of psychiatric diseases,
• allergy to any drug used in the study protocol,
• refusal of the patient
• unexpected difficult airway requesting excessive, possibly painful airway manipulations
• unexpected intraoperative complications requiring strong hemodynamic support (transfusions, vasopressors, inotropes)
• conversion to thoracotomy