PPI-guided Postoperative Pain Therapy in the OR
Condition: Postoperative Pain
MeSH terms: Pain, Postoperative
Study type: Interventional

Summary: 
      The study will be designed to investigate the effect of pupillary pain index (PPI)-guided
      compared to non-PPI-guided postoperative pain therapy, conducted immediately at the end of
      surgery, on total postoperative opioid consumption during the first 2 postoperative hours
      after elective ENT surgery.
    

Detailed description: 
      Abstract

      The study will be designed to investigate the effect of pupillary pain index (PPI)-guided
      compared to non-PPI-guided postoperative pain therapy, conducted immediately at the end of
      surgery, on total postoperative opioid consumption during the first 2 postoperative hours
      after elective ENT surgery. Pupillometric pain measurements helps clinicians determine and
      administer the optimized amount of opioids and so avoids opioid-induced side effects.

      Background

      The evaluation of pain intensity during the immediate postoperative period in the operating
      room (OR) is a key factor for post interventional pain treatment. However, this evaluation
      may be difficult when patients are still intubated, restricted in consciousness or are
      showing verbal impairment due to ENT surgery. Verbally impaired patients are at increased
      risk of under treatment for pain.

      With rising opioid consumption, the risk of postoperative side effects like nausea and
      vomiting, sedation with a longer recovery time or respiratory depression increases.
      Especially in the cohort of ENT surgery patients, where a difficult airway is regularly
      presented, such side effects should be avoided. A means of predicting immediate postoperative
      pain after surgery and the response to opiate analgesics would therefore be highly desirable.

      The pupillary dilatation reflex (PDR), measured by pupillometry, has been successfully used
      to assess intraoperative analgesic component of anesthetic regimes and correlates with pain
      intensity measured on a numeric rating scale (NRS).

      Aims

      Primary aim of this study is to investigate if a PPI-guided opioid administration immediately
      postoperative in the OR leads to less opioid requirement during the first 2 postoperative
      hours compared to a non-PPI guided treatment.

      Secondary aim is to evaluate postoperative pain during the first 2 postoperative hours in
      patients after PPI-guided versus non-PPI guided opioid therapy in the OR.

      Hypotheses

      The investigators hypothesis that through a targeted pain therapy based on the measurement of
      immediate postoperative PPI score, opioid consumption and pain intensity can be reduced
      during the first 2 postoperative hours.

      Methods

      The study will be done by observing postoperative pain intensity using pupillometry in
      patients scheduled for elective ENT surgery, carrying out pain intervention (opioid therapy)
      and re-observing to verify the effectiveness of the targeted postoperative opioid
      administration in the OR. Pain on an 11-point verbal Likert response score and total opioid
      consumption will be recorded by a blinded investigator at 30-minute intervals for the initial
      2 postoperative hours.
    

Intervention name(s): PPI measurement
Intervention type(s): Diagnostic Test
Intervention description(s): The pupillary dilatation reflex (PDR), induced by a standardized noxious stimulus will be measured as Pupillary Pain Index(PPI,11-point numeric scale, 0= no pain, 10= worst pain) determined with a portable pupillometer. Patients experiencing mild or more severe pain (PPI> 3) will receive intravenous opioid titration (piritramid, 3 mg bolus steps) and PPI measurement performed before and after intravenous opioid titration.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Investigator)
Primary purpose: Diagnostic
Keywords: Pupillary Pain Index; Postoperative Pain; Infrared Pupillometry; Postoperative Opioid Consumption