Nociception-directed Erector Muscle Spinae Plane Block in Open Heart Surgery
Condition: Regional Anesthesia; Heart Surgery
Study type: Interventional
Phase: Phase 4

Summary: 
      With the advent of ultrasound (US) guidance, use of regional anaesthesia (RA) is poised to
      grow and evolve. Recently, cardiac surgery has benefited from newer US guided interfascial
      techniques as they promise to fulfil all the prerequisites of an enhanced recovery after
      surgery (ERAS) strategy(1,2).

      The erector spinae plane (ESP) block represents such an alternative(3). Speed and ease of
      performance are paramount to encourage spread of its use. Hence, the scope of this trial is
      to investigate the effects on perioperative opioid consumption and several other secondary
      outcomes of a minimalist approach encompassing a bilateral single shot ESP block when applied
      as an adjunct to general anaesthesia.
    

Detailed description: 
      DETAILED DESCRIPTION OF STUDY

      A. Ethics

      Local Ethics Committee approval and Informed Consent from patient or next-of-kin are obtained
      prior to study enrolment.

      B. Study enrolment

      Eighty adult patients scheduled for elective open cardiac surgery under general anaesthesia
      (GA) are randomly allocated to receive either GA plus ESP block (ESP group, n = 40) or GA
      alone (control group, n = 40).

      C. Methods - Preinduction

        1. Premedication with intramuscular morphine 0.1mg/kg 30 minutes before induction.

        2. 16-G peripheral intravenous cannula and radial artery catheter.

        3. Five-lead ECG, pulse oximetry, non-invasive and invasive blood pressure monitoring.

        4. Analgesia monitor - the NoL index (PMD200TM, Medasense) finger probe will be connected
           to the index finger of the non-cannulated hand.

        5. Surgical antibiotic prophylaxis (Cefuroxime 1.5g)

        6. Stress ulcer prophylaxis (omeprazole 40 mg)

      D. Methods - ESP block (intervention group only)

      Before induction, patients in the intervention group are placed in sitting position under the
      close supervision of the attending nurse anaesthetist. After skin asepsis with chlorhexidine
      2%, a high-frequency linear ultrasound probe is positioned parasagittally, 2-3 cm from
      midline, bilaterally, at the level of the T5 transverse process. A 25-G echogenic block
      needle is inserted at 20⁰-30⁰ in a caudal-to-cephalad direction until the tip of the needle
      reaches the interfascial plane between the erector spinae muscle and the inter-transverse
      ligaments. Correct hydrodissection at T5 level is first certified using normal saline.
      Subsequently, ropivacaine 0.5% with dexamethasone 8mg/20ml is used and maximum spread is
      attained by slowly advancing the needle as the interfascial plane splits up ahead. A maximum
      dose of 3mg/kg ropivacaine is used, corresponding to 1.5 mg/kg per side (e.g., 20 ml
      ropivacaine 0.5% / side for a 70kg adult). Supine position is resumed after completion of
      block.

      E. Methods - General anaesthesia

        1. End tidal CO2 (ETCO2).

        2. Bispectral index (BIS) monitoring of hypnotic depth (target 40-60).

        3. The nociception monitor (PMD200TM, Medasense) is started after induction of general
           anaesthesia; a calibration period of 1-2 minutes is usually required.

        4. CVP insertion into the right internal jugular vein under ultrasound guidance. Any other
           hemodynamic monitor deemed useful is left at the discretion of the treating
           anaesthetist.

        5. Urinary catheter, rectal temperature probe placement.

        6. Intubating conditions

           6.1. Propofol 1-1.5 mg/kg or Etomidate 0.2-0.3 mg/kg.

           6.2. Fentanyl 5 mcg/kg.

           6.3. Atracurium 0.5 mg/kg.

        7. Maintenance of anaesthesia

      7.1. Sevoflurane in O2 during periods of preserved pulmonary blood flow and mechanical
      ventilation according to BIS (see target above).

      7.2. Propofol infusion according to BIS (see target above) during periods of extracorporeal
      support.

      7.3. Atracurium 0.2-0.3 mg/kg/h for adequate neuromuscular blockade.

      7.4. Management of analgesia divides in:

      7.4.1. Analgesia support

      7.4.1.1. ESP block in the intervention group only:

      • Theoretical duration of ESP block with surgical intensity is 4-6 hours.

      7.4.1.2. Fentanyl (both study groups):

        -  Analgesia monitoring (see below) provides feedback to its administration.

        -  Administration follows a combination of continuous infusion and bolus dosing according
           to our local protocol:

             -  Fentanyl 1.5 mg/50ml (30 mcg/ml).

             -  Bolus dose (ml): Weight/20, which is equivalent to 1.5 mcg/kg.

             -  Infusion rate (ml/hour): Weight/10, which is equivalent to 3 mcg/kg/h.

             -  Last infusion rate before large vessel cannulation is maintained throughout the
                bypass period.

      7.4.1.3. Paracetamol (both study groups):

      • Administration of 2 grams following induction of general anaesthesia.

      7.4.2. Analgesia monitoring

      7.4.2.1. NoL index provides a multiderivative assessment of nociception before large vessel
      cannulation; depending on the spontaneous cardiac rhythm, it may be expected to continue
      reflecting nociception even after completion of extracorporeal circulation.

        -  Optimal analgesia is defined as a NoL index of 10-25.

        -  Allow periods of fluctuation of less than 1 minute.

        -  After sternotomy, allow a maximum fluctuation interval of 3 minutes before vital data
           are gathered.

        -  In the ESP group, if NOL target is attained, stop fentanyl administration.

      7.4.2.2. Ancillaries such as mean arterial blood pressure (MAP) and heart rate (HR) provide
      complementary decision loops: targets are within ± 20% of preoperative baseline.

        -  During CBP they provide the only feedback on adequacy of analgesia, although highly
           unspecific.

        -  May be used at any time to complement the NoL index.

      F. Methods - Postoperatively

        1. Criteria to be met before extubation:

           1.1. Normothermia (T◦ ≥ 36◦C).

           1.2. No clinical bleeding.

           1.3. Wakefulness and RASS [-1;1].

           1.4. Hemodynamic stability with minimal vasoactive support (dobutamine < 5 µg/kg/min and
           norepinephrine < 100 ng/kg/min):

           1.4.1. MAP ≥ 60 mmHg

           1.4.2. Lactate ≤ 2 mmol/L

           1.4.3. Preserved flow (CI ≥ 2.2L/min/m2) assessed by:

           1.4.3.1. TTE any time after ICU admission

           1.4.3.2. TOE only before extubation, regardless of patient location

           1.5. Respiratory:

           1.5.1. Adequate gas exchange:

           1.5.1.1. Normocarbia.

           1.5.1.2. PaO2/FiO2 ≥ 250.

           1.5.2. Adequate effort:

           1.5.2.1. Tidal volume ≥ 5 ml/kg.

           1.5.2.2. Negative inspiratory force ≤ -20 cmH2O.

           1.5.3. Adequate airway reflex to handle secretions.

        2. Management of analgesia divides in:

      2.1. Analgesia support:

      2.1.1. Paracetamol 1g iv 6 hourly is standard in both groups.

      2.1.2. Morphine bolus doses of 0.03 mg/kg in combination with continuous iv morphine 0.03
      mg/kg/h as elicited by nociception monitoring (see below).

      2.2. Analgesia monitoring

      2.2.1. The visual analogue scale (VAS) is used to provide feedback on adequacy of analgesia.

      2.2.2. If VAS > 3, then provision of a combination of paracetamol and morphine is warranted
      (see above).
    

Intervention name(s): General anesthetic; Ropivacaine 0.5% Injectable Solution
Intervention type(s): Drug; Drug
Intervention description(s): Fentanyl is administered at induction - standard dose 5 mcg/kg. Further dosing is based on a multiderivative assessment of nociception (NOL index) and ancillaries such as heart rate and mean arterial blood pressure.; Bilateral single shot erector spinae plane block is performed before induction of general anaesthesia.
Ropivacaine 0.5% total dose 3mg/kg with Dexamethasone 8mg/20 ml Ropivacaine 0.5%.
Other intervention name(s): Fentanyl based general anaesthesia; Erector Spinae Plane Block
Intervention MeSH terms: Fentanyl; Ropivacaine; Anesthetics; Anesthetics, General
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: erector spinae plane block; fast-track; rehabilitation; opioid