The Relationship Of The Surgical Pleth Index Values With Postoperative Pain Score And Analgesia Consumption
Condition: Acute Pain; Analgesia
MeSH terms: Pain, Postoperative; Acute Pain
Study type: Observational

Summary: 
      Postoperative pain management has an important role in anesthesia practice. In order to
      ensure postoperative patient comfort, postoperative rehabilitation should start early and be
      managed effectively1. It is known that if adequate analgesia is not provided before the
      patient wakes up, the severity of pain and the total opioid consumption increases. This
      increased opioid use causes complications such as nausea, vomiting, constipation, increased
      sleepiness and respiratory depression2. For this reason, the provision of adequate analgesia
      before the patient is awakened from general anesthesia has an important place in the process.
      Measurement of pain has different characteristics in patients under sedation or general
      anesthesia compared to conscious patients. However, since it is not possible for the patient
      to define pain under general anesthesia, different measurement and evaluation methods are
      needed. In order to monitor the intraoperative balance between nociception and
      antinociception, several non-invasive methods with different physiological approaches have
      been researched and made available for use in the last decade. The aim of these methods is
      individualize the intraoperative and postoperative opioid dose3. In this context, it has been
      suggested that the Surgical Pleth Index (SPI) method can be used in the evaluation of the
      analgesic component of anesthesia.
    

Detailed description: 
      After arrival in the operating room, patients were monitored with electrocardiogram (ECG),
      non-invasive arterial pressure measurement, pulse oximetry, neuromuscular monitoring (GE
      Datex, Ohmeda TOF module), entropy (GE Datex, Ohmeda Entropy Module) and SPI. Intravenous
      midazolam (0.03-0.05 mg/kg), fentanyl (1mcg/kg) were used before induction of anaesthesia.
      For anesthetic induction, propofol was administered until the entropy value fell below 60,
      followed by rocuronium was performed intravenous 0.6mg/kg. Patients were intubated with
      endotracheal tube than the mechanical ventilation was initiated with a mixture of O2 and air
      with FiO2 0.5 and adjusted to maintain end-tidal CO2 pressure of 35 and 40 mmHg. Intravenous
      propofol and remifentanil infusion were used for anesthesia maintenance and entropy was
      maintained below 60. Furthermore, SPI was maintained below 50.

      Tenoxicam 20 mg, paracetamol 1 g and 0.5 mg/kg tramadol intravenously were administered 30
      minutes before the end of the surgery to each patient who had no contraindications. After the
      last suture, the anesthetic agents were stopped and was considered the end of the surgery.
      Then SPI data were recorded at one-minute intervals during the last five minutes (6 times in
      total) until the entropy value reached 60. Patients who has cooperation were extubated and
      taken to the recovery room. The first time that the patients cooperated in the recovery room
      was considered as the zeroth minute. During the postoperative observation, the patient's pain
      score was questioned using the Numeric Rating Scale (NRS) every five minutes. If NRS≥4,
      intravenous tramadol 10 mg (100 mg as the maximum dose) was administered to the patient. The
      patient was followed in the recovery room for 30 minutes and until NRS <4. However, if NRS≥4
      was still present at the end of the observation period, an additional 2 mg dose of morphine
      was administered. The maximum dose of morphine was determined as 0.1mg/kg.
    

Intervention name(s): Surgical Pleth Index (SPI)
Intervention type(s): Device
Intervention description(s): SPI data were recorded at one-minute intervals during the last five minutes (6 times in total) until the entropy value reached 60
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Patients aged 18 to 65 years with ASA physical status I-III who received craniotomy and
        intracranial mass excision in the ITF Neurosurgery Clinic were enrolled in the study after
        providing written informed consent
      
Keywords: Surgical pleth index; Craniotomy