Monitoring Pupillary Reflex Dilatation for Optimized Postoperative Opioid Delivery Before Extubation.
Condition: Postoperative Pain
MeSH terms: Pain, Postoperative
Study type: Interventional

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

Detailed description: 
      Pupillometric pain measurements helps clinicians determine and administer the optimized
      amount of opioids and so avoids opioid-induced side effects.The study will be designed to
      investigate the effect of pupillometry guided compared to non-PPI-guided postoperative pain
      therapy, conducted before extubation, on total postoperative opioid consumption during the
      first 2 postoperative hours after elective ENT surgery.

      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 pupillometry-guided opioid administration
      immediately postoperative in the OR leads to less opioid requirement during the first 2
      postoperative hours compared to a non-pupillometry-guided treatment.

      Secondary aim is to evaluate postoperative pain intensity during the first 2 postoperative
      hours in patients after pupillometry-guided versus non-pupillometry -guided opioid therapy in
      the OR.

      Hypotheses

      The investigators hypothesis that through a targeted pain therapy based on the measurement of
      immediate postoperative pupillometry scores, 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): Pupillometry-Opioid treatment; Pupillometry -standardized opioid treatment
Intervention type(s): Diagnostic Test; Diagnostic Test
Intervention description(s): At the end of anesthesia, before extubation, pupillometry measurements will be performed on both eyes, using the tetanus mode T30 (30mA tetanic stimulation) and T60 (60mA tetanic stimulation) and the standardized pupillary pain index (PPI) mode at the pupillometer.
Opioid administration will be given by a single dose of piritramid (0.1 mg kg -1) in case of measured PDR values of ≥12 (high analgesic sensitivity as specified by the producer) after T30 and T60 stimulation. The pupillometry measurement will be repeated once on both eyes.; At the end of anesthesia, before extubation, pupillometry measurements will be performed on both eyes, using the tetanus mode T30 (30mA tetanic stimulation) and T60 (60mA tetanic stimulation) and the standardized pupillary pain index (PPI) mode at the pupillometer.
A standardized single dose of piritramid (0,1 mg kg -1) will be given intravenously, regardless of the measured values. The pupillometry measurement will be repeated once on both eyes.
Intervention MeSH terms: Analgesics, Opioid
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Care Provider)
Primary purpose: Treatment
Keywords: Postoperative Pain; Infrared Pupillometry; Postoperative Opioid Consumption