Scalp Block Versus Scalp Infiltration With Dexmedetomidine and Local Anesthetic for Post Craniotomy Pain
Condition: Headache
MeSH terms: Headache
Study type: Interventional
Phase: Phase 2

Summary: 
      This study has been designed to assess the efficacy of dexmedetomidine as an adjuvant to
      local anaesthetic agent bupivacaine in scalp nerve block and scalp infiltration to control
      post craniotomy pain.A third group where patients were administered bupivacaine only
      infiltration has also been created.
    

Detailed description: 
      Patients were randomly allocated into three equal groups by computer generated random
      numbers. For randomization, the simple random allocation rule was followed, wherein the total
      sample size (n = 150) was randomly divided into three equal groups. In the event of any case
      has to be excluded because of requirement of postoperative ventilation, altered sensorium or
      high grade fever in the post-operative period, the same random number code was allocated to
      the next patient in order to ensure an equal sample size without any modification to the
      original random number table. The random numbers were then kept in opaque sealed envelopes,
      numbered sequentially which were opened just before shifting patient inside operation
      theatre.

      The anaesthesiologist who prepared and administered the study drug were not involved in
      collection of data. The anaesthesiologist who collected the data from the patient in the
      postoperative period, the operating surgeon and the patient were blinded to the group
      assigned to the patient.

      Pre-operative Assessment:

      Pre-operative anaesthetic evaluation was done on the day prior to the surgery. This included
      a detailed history regarding physical health, any co-morbid illness, current medications,
      drug allergy and previous anaesthetic experience. The patient was made familiar about the NRS
      (0-10, with 0 = no pain, 10 = worst pain ever). A written and informed consent was taken.
      Patients were fasted and premedicated according to the departmental protocol.

      Duration of study period-

      Study period started after closure of skin incision of the scalp and continued till 48 hours
      in the postoperative period

      Study groups-

      Patients were randomly divided into three groups:

      Group BI - Bupivacaine infiltration around surgical incision.

      Group BDI - Bupivacaine and dexmedetomidine infiltration around surgical incision

      Group BDNB- Bupivacaine and dexmedetomidine used in scalp nerve block.

      Anaesthesia Technique-

      A standard anaesthesia technique according to the departmental protocol was followed in all
      the patients. Pre-induction monitoring (Datex- Ohmeda S/5 Avance, Madison, WI, USA) consisted
      of 5-lead electrocardiography, heart rate, automated non-invasive blood pressure, and pulse
      oximetry. The patients were then be induced with propofol (1-2 mg/kg) or thiopentone
      (4-6mg/kg) and trachea were intubated with vecuronium 0.1 mg/kg. Anaesthesia was maintained
      with intravenous (propofol) or inhalational (isoflurane/sevoflurane/desflurane) anaesthetic
      agent along with nitrous oxide-oxygen mixture (60:40) and intermittent doses of intravenous
      vecuronium (0.02 mg/kg). Ventilation was maintained at ETCO2 30 to 35mm Hg. Total fresh gas
      flow rate was kept at 1-2 L/min. A radial artery catheter was inserted for continuous blood
      pressure monitoring and blood sampling if indicated. Intraoperative analgesia was maintained
      with intravenous morphine 0.1mg/kg and morphine repeated at a dose of 0.05 mg/kg if duration
      of surgery was more than 3 hours. Patients were reversed with neostigmine (0.05mg/kg) and
      glycopyrolate (0.01mg/kg) after administration of study drugs and were extubated once patient
      started responding to verbal commands and able to generate adequate tidal volume under
      spontaneous respiration.

      Methods of postoperative analgesia- In all the patients, analgesic procedure was done
      ensuring proper aseptic precaution at the end of the surgery, after closure of skin incision
      and before putting the dressings over the incision. Patients were reversed from anaesthesia
      after the administration of study drugs.

      Group BI: The incision site was infiltrated with 15-20 ml of bupivacaine (0.25%). {1/3rd in
      the muscle and 2/3rd in the subcutaneous tissue}. Maximum dose of bupivacaine kept less than
      2 mg /kg.

      Group BDI: The incision site was infiltrated with 15-20 ml bupivacaine (0.25%) and
      dexmedetomedine (1 µg/kg). {1/3rd in the muscle and 2/3rd in the subcutaneous tissue}.
      Maximum dose of bupivacaine kept less than 2 mg /kg.

      Group BDNB: Scalp nerve blocks were given with15-20 ml of combination of Bupivacaine (0.25%)
      and Dexmedetomedine (1 µg/kg). Maximum dose of bupivacaine kept less than 2 mg /kg.

      In this group following nerves were blocked-

        1. Supra-orbital nerve

        2. Supra-trochlear nerve

        3. Zygomatico-temporal nerve

        4. Auriculo-temporal nerve

        5. Posterior auricular branches of the greater auricular Nerve

        6. The greater, lesser, and third occipital nerves

      Post-operative assessment:

      After extubation patients were shifted to the Post anaesthesia care unit (PACU) and assessed
      for haemodynamic parameters, sedation and any complication at 15 minutes interval till 2hrs
      and then at 4, 8, 12, 16, 20, 24, 36 and 48 hours. Assessed for cognitive function at 30 min
      and 60 min.

      Patients were followed after discharge for 6 months by telephonic communication at 1, and 3
      month interval for presence of chronic pain.

      COLLECTION OF DATA-

      Preoperative- Age, sex, weight, ASA status, diagnosis, surgery

      Intraoperative-

        1. Site of incision

        2. Duration of surgery

        3. Intra-operative analgesia- morphine in mg/kg

      Postoperative-

        1. Haemodynamic parameters- Heart rate, systolic and diastolic blood pressure, oxygen
           saturation was recorded at arrival to PACU and every 15 min interval for 2 hours. Then
           heart rate and systolic and diastolic blood pressure at 4, 8, 12, 16, 20, 24, 36 and 48
           hours after surgery.

        2. Respiration rate-was recorded at arrival to PACU and every 15 min interval for 2 hours
           and then at 4, 8, 12, 16, 20, 24, 36 and 48 hours after surgery.

        3. Cognitive function- Patients were evaluated for cognitive function 30 minutes after
           shifting to PACU using a modified self-devised questionnaire of short orientation memory
           concentration test.

           Whenever the subjects were able to recall and count with minimal mistakes (1 to 3), were
           regarded as good, with more than 3 mistakes as fair, and if not be able to recall at
           all, it was regarded as poor. If the cognitive function outcome was poor then same test
           was repeated at 1 hour after shifting to PACU. If outcome was again poor, then that
           patient was excluded from the study.

        4. Assessment of pain- Postoperative pain was assessed by Numerical rating scale (NRS)
           where in 0 shows 'no pain' and 10 shows 'worst imaginable excruciating pain'. It was
           assessed at arrival to PACU and at 0, 0.5, 1, 1.5, 2, 4, 8, 12, 16, 20, 24, 36 and 48
           hours after surgery.

        5. Pain free period- Time of first rescue analgesic administration from the time of test
           drug administration was recorded.

        6. Postoperatively rescue analgesic- When NRS score was ≥ 4, rescue analgesic paracetamol
           1gm was administered intravenously and total rescue analgesic requirement in 24 and 48
           hrs were noted.

        7. Rescue drugs to maintain haemodynamic stability- Any adverse events like bradycardia
           (Heart rate ≤ 40), hypotension (SBP < 90 mm of Hg) were recorded and treated by rescue
           drugs: atropine-15µg/Kg and mephenteramine-3mg/dose respectively. Total amount of rescue
           drug requirement in 24 and 48 hours were noted.

        8. Postoperative sedation- Level of sedation was assessed using Modified Ramsay Sedation
           Scale.

        9. Adverse events-

             1. Respiratory depressions (Respiration rate < 8 breaths/min) was recorded and managed
                accordingly.

             2. Postoperative nausea and vomiting (PONV) was assessed on a 4-point scale. and was
                treated with ondansetron 0.15 mg/kg intravenously if score was >2.
    

Intervention name(s): scalp block; infiltration; Dexmedetomidine; Bupivacaine
Intervention type(s): Procedure; Procedure; Drug; Drug
Intervention description(s): In this group following nerves were blocked-
Supra-orbital nerve
Supra-trochlear nerve
Zygomatico-temporal nerve
Auriculo-temporal nerve
Posterior auricular branches of the greater auricular Nerve
The greater, lesser, and third occipital nerves; The incision site was infiltrated with drug. {1/3rd in the muscle and 2/3rd in the subcutaneous tissue}.; Dexmedetomidine was administered as a dose of 1 µg/kg in 20 ml 0.25% bupivacaine for scalp block or infiltration.; 20 ml of Bupivacaine 0.25% was administered to the patients either in the form of scalp block or infiltration
Other intervention name(s): Precedex; Dexdor; Marcaine; Sensorcaine; Marcain
Intervention MeSH terms: Dexmedetomidine; Bupivacaine
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Care Provider, Outcomes Assessor)
Primary purpose: Prevention
Keywords: dexmedetomidine; nerve block; anesthesia infiltration