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Anaesthesia and Pain Management

Regional Anaesthetic Infusion Blocks

  • This pain management guideline was written by the staff of the Children's Pain Management Service for the Royal Children's Hospital, Melbourne.This guideline may NOT be suitable for use in other institutions

    Nurse competencies

    • All Registered Nurses caring for patients receiving regional anaesthetic infusions should be competent in epidural management.
    • The epidural self directed learning and competency can be accessed at: www.rch.org.au/anaes/pain/

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    Indications

    •  Regional anaesthetic blocks/infusions are used to provide local anaesthetic to a discrete area of the body.
    •  Regional anaesthetic block/infusion is used for the management of moderate to severe pain. Commonly employed regional anaesthetic techniques include extrapleural or paravertebral blocks, intrapleural blocks, blockade of the femoral nerve, blockade of the brachial plexus by either an interscalene (proximal), infraclavicular (mid), or axillary (distal) approach, a catheter placed into the wound itself, and the more traditional epidural block (thoracic, lumbar or caudal approach).

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    Extrapleural/paravertebral

    • The catheter is placed next to the vertebral column in the paravertebral space, which exists between T1 and T12. The catheter may be placed percutaneously or under direct vision during surgery.

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    Intrapleural

    • The catheter is placed in the intrapleural space between the parietal and visceral pleurae under direct vision during surgery.
    • Extrapleural/intrapleural infusions are used for unilateral thoraco-abdominal incisions for example thoracotomy, breast, gall bladder or renal surgery, and provide unilateral analgesia on the side the catheter is placed.

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    Femoral

    • The catheter or block is placed into the femoral nerve canal.
    • The femoral nerve is located lateral to the femoral artery just below the inguinal ligament.
    • This technique is used for managing fractured femur, skin graft donation sites and surgical incisions over the cutaneous distribution of the femoral nerve - anterior aspect of thigh and femur periosteum.

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    Brachial plexus/Axillary

    • The catheter or block is placed via the axilla into the perineural sheath next to the axillary artery. The brachial plexus is derived from the cervical roots C5, C6, C7, C8 and the thoracic root T1.

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    Brachial plexus/Interscalene

    • The catheter or block is placed at the site of the interscalene groove level to the cricoid cartilage.
    • This approach was developed to avoid a pneumothorax.The axillary and interscalene catheter/blocks are used for surgical procedures of the shoulder and upper arm

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    Wound catheter

    • A multi-hole catheter is placed under the skin along the wound to deliver local anaesthetic solution. 

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    Caudal and Epidural

    Prescription of regional anaesthetic infusions 

    • Regional anaesthetic infusions are a specialised analgesic technique and are managed by CPMS.
    • ONLY CPMS and Anaesthesia staff may prescribe regional anaesthetic infusions.
    • The regional anaesthetic infusion is prescribed according to the guidelines on the Regional anaesthetic infusion prescription. 
    • The site of insertion of the catheter and catheter position at the skin are recorded on the Regional anaesthetic infusion prescription.
    • The local anaesthetic solution to be used and additives (if any) are prescribed on the Regional anaesthetic infusion prescription, with the infusion rate prescribed in mL/hr.
    • For rapid relief of breakthrough pain, a bolus dose may be prescribed +/- an alteration to the infusion rate. In some situations only CPMS staff may administer the bolus. The reason for this will be documented.
    • Pump settings prescribed.

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    Regional anaesthetic infusion solutions

    • Ropivacaine 0.2% is the usual local anaesthetic solution prescribed. Less commonly, other strengths of other local anaesthetics may be used. More dilute concentrations may be prescribed if less sensorimotor blockade is desired.
    • Flasks of 0.2% ropivacaine (100 mL or 200 mL) are kept in the ward drug cupboard and are available from the RCH pharmacy department.
    • It is important to ensure that sufficient solution is ordered for nights, weekends and public holidays. CPMS should be contacted if there is a problem with availability of regional anaesthetic solutions out of hours.

    Special patient groups 

     

    Special patient groups for regional local anaesthetic infusions that may require modified dosing and duration include: 

    • Neonates (<44 weeks corrected PMA) 

    • Infants less than 8 months of age 

    • Children with significantly impaired liver synthetic-metabolic function  


    These patients may have a higher risk of local anaesthetic toxicity. They have immature liver production of the carrier protein [alpha1 acid glycoprotein: AAG] and may have slower metabolism of local anaesthetics. The unbound fraction causes toxicity. Infants have higher unbound plasma concentrations at 20% for ropivacaine and bupivacaine.

    At 8 months of age, infants achieve adult liver handling of local anaesthetics and adult plasma concentrations of AAG at 12 months when the unbound concentration is the same as in adults at 5%. 
     
    RCH Department of Anaesthesia and Pain Management recommends a conservative dosing schedule in these special groups that may be adjusted according to the patient's comorbidities.  
     
    For regional (epidural, caudal) infusion:

    • Usual duration of 48-72 hours is recommended for
      • usual concentration of 0.2% ropivacaine when receiving 0.2mLs/kg/hr

    • Shorter duration may be considered for
      • usual concentration at higher infusion rates e.g. >0.25mls/kg/hr 

    • Longer durations may be administered
      • usual concentration of 0.2% ropivacaine is infused at a lower rate i.e less than 0.2mLs/kg/hr 
      • lower concentrations are used eg 0.1% ropivacaine infused at less than 0.4mLs/kg/hr  
     

    For wound catheter infusions:  

    • The usual concentration of 0.2% is typically infused at low rates of 0.1mLs/kg/h which is acceptable for 48-72 hours or longer 


    Note 
    Low concentration eg. 0.1% ropivacaine may be ordered to enable greater spread of the block. 
    The anaesthetist writing the order for the infusion should specify the planned duration of the infusion in these special patient groups. The planned time of cessation may be extended upon CPMS review if deemed beneficial for the patient (and the initial infusion dosing has been low).



    Regional infusion lines and giving sets

  • The regional anaesthetic infusion solution must be prepared in accordance with RCH medication policy and labelled clearly with a regional label

    • Only REM-EPISETTM is to be used for delivery of regional anaesthetic infusions
    • The REM-EPISETTM tubing has a T-configuration. The clear tubing with the bag spike connects to the flask of anaesthetic solution. The short yellow tubing is connected to the syringe, allowing the syringe to be refilled. The long yellow tubing with the yellow luer lock connects to the filter or the catheter hub. There are two one-way valves in the REM-EPISETTM  tubing to prevent the risk of gravity free-flow.
    • A yellow dedicated Alaris PCAM must be used for all regional anaesthetic infusions. A handset is used for the bolus delivery.
    • The two authorised persons who put up each flask of infusion solution must sign the record of infusion on the Epidural/Regional anaesthetic infusion .
    • The regional anaesthetic infusion lines are to be maintained as a closed system.
    • Changing flasks of infusion solution must be done using aseptic technique.
    • To refill the syringe from the flask the infusion should be paused and the syringe removed from the pump before being refilled from the flask. Use the key at the side of the pump to open the perspex lid.
    • Ensure the spiked end of the flask is pointing downwards to avoid air being drawn into the tubing.

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    Securing the regional anaesthetic catheter

    • A sterile sponge or gauze may be applied at the insertion site to soak up any leaking local anaesthetic solution.
    • An occlusive clear dressing (eg Tegaderm or Opsite) is placed over the catheter and sponge.
      • NB: The extrapleural catheter site is usually covered by the surgical dressing. There is a suture securing this catheter.
      • Wound catheters are under the surgical dressing. There is no suture securing this catheter.
      •  Where possible a 'window' is made around the clear dressing with tape to reinforce the clear dressing and to allow viewing of the insertion site and catheter markings. Hypoallergenic and firmly adhering tape (eg Hyperfix or Mefix) is preferred.
    • The filter (if used) should be securely taped to the patient (in a place where it is comfortable) to avoid dislodgement of the catheter.
    • Any loose catheter tubing should be securely taped to the skin to prevent kinking and/or disconnection.
    • Routine dressing changes are not indicated and are only to be done by a member of CPMS as required.

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    Catheters used for regional anaesthetic block infusions

    A range of catheters may be used. 

    The kits used at RCH

    PortexTM 18G and PortexTM 19G

    Braun Perifx® Paed series 18G and 20G

    Wound catheters

    • Wound catheters have multiple holes (fenestrated) between the tip and the first depth mark. These catheters are only used for wound infiltration.
    • The catheter must not be cut prior to insertion, as there is a fine wire inside the tubing.
    • A double mark is located at 10cms from the most proximal fenestration, a triple mark at 15cm and four lines at 20cm. The tip of the catheter has a black mark, ensure the catheter is intact on removal. 
    • Document on the LDA


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    Regional anaesthetic infusion delivery via ON-Q PainBuster®

    • The ON-Q PainBuster® used at RCH is pressurized to deliver LA at a specified rate that cannot be adjusted.
    • The rate may be 2ml/h or 5 ml/h depending on the pump specification.
    • The time that the pump empties will depend on the volume of the ON-Q PainBuster® attached to the soaker catheter. For example, a 100ml ON-Q PainBuster® delivering at 2 ml/h will be empty 50 hours after the clamp is unclamped. A 270ml  ON-Q PainBuster® delivering at 5 ml/h will be empty 54 hours after the clamp is unclamped.   

  • The usual infusion rate range is 0.1mL/kg/hr - 0.3mL/kg/hr.

  • The regional anaesthetic infusion is commenced in recovery.

  • https://www.rch.org.au/rchcpg/hospital_clinical_guideline_index/Wound_catheter_management/

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    • Changing the infusion rate 

    • Only if delivery is via Alaris PCAM
    • The rate is not to be changed except following an order by CPMS or an anaesthetist.
    • Changes in infusion rate must be prescribed and documented on the Regional anaesthetic infusion . The reason for the change should also be documented. The pump settings must be prescribed 


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    Observations

    • Patients require routine post operative clinical observations 
    • Pain score: 1 hourly (using developmentally appropriate scale eg Wong-Baker Faces scale, Numeric scale, FLACC scale or PAT score for neonates).
    • check pain buster catheter exit site at the skin and the operative wound dressing for excessive leak.
    • Pulse oximetry if indicated.
    • See PainBuster® Wound Catheter CPG                               

     The effectiveness of the analgesia should be recorded in the Nursing Progress notes.


    Observations following infusion rate increase: (See epidural CPG)

    • Heart rate, respiratory rate & blood pressure 1 hourly for 4 hours.
    • If the observations remain unchanged return to routine epidural observations.
    • Unilateral Horner's sign may be associated with a high paravertebral block.
    • CPMS should be called if pain relief is inadequate 30 minutes after a bolus is given.
    • Any observations outside reportable limits or outside normal values for age should be reported to CPMS +/- the primary treating team.

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    Assessing sensory and motor block

    Contact CPMS if:

    • No evidence of block
    • Block insufficient to relieve pain

    Motor Block:

    • Motor nerves (as well as sensory nerves) may be affected by local anaesthetics.
    • It is important to assess motor block:
      •  to prevent pressure areas
      •  to ensure the patient is safe to ambulate
      •  to detect the onset of complications
    • With extrapleural/paravertebral, axillary and interscalene blocks, upper limb motor function should be assessed by testing bilateral hand and finger extension and flexion.
    • Motor block assessment should be done 4 hourly and at the following times:
      • In the recovery room on waking from anaesthetic
      • On return to the ward/unit from the operating suite
      • Prior to ambulation
      • 1 hour after a bolus or increase in infusion rate
    • Contact CPMS if:
      • major changes in motor function (particularly any sudden change)
      • reduced hand or finger motor function with axillary, interscalene or paravertebral block

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    Catheter position and insertion site

    • At least once each nursing shift the catheter insertion site should be checked if visable, for redness, tenderness, leaking and dressing integrity.
    • The catheter markings at the point of skin insertion should be checked against those documented on the regional anaesthetic infusion prescriptiont if applicable.
    • Any change or abnormality must be reported to CPMS urgently.

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    Pressure area care

    • It is important that pressure area care is meticulous for all patients receiving regional anaesthetic infusions.
    • The decreased sensation produced by analgesia removes the usual warning signs that prompt patients to move.
    • Significant motor block may limit patient movement. Both of these factors may contribute to the development of pressure areas.
    • Patients with femoral nerve catheters must be turned 2-3 hourly, have extra pressure control devices (such as an air mattress), and their skin should be regularly checked for signs of pressure.
    • Particular pressure care should be given to the region or limb affected by the regional anaesthetic blockade.

    Nerve compression

    • It is vital that during regular pressure area care, special attention is made to avoid nerve compression.
    • Superficial nerves (eg: common peroneal nerve) are vulnerable to damage from unrecognised pressure due to decreased sensation.

    Intravenous access

    • All patients with a regional anaesthetic (epidural) infusion must have intravenous access at all times with a minimum hourly infusion rate.
    • After the regional anaesthetic (epidural)  infusion is ceased, the IV cannula must remain in situ until the catheter is removed.

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    Concurrent drugs

    Opioids

    • Regional anaesthetic infusions (without an opioid added) may be supplemented by IV or oral opioids to improve analgesia.

    Anti-coagulant medication

    • If a patient is prescribed anti-coagulant medication and will be having a regional anaesthetic block, the first dose must not be administered until after the catheter is inserted.
    • If a patient is on subcutaneous anti-coagulant medication the regional anaesthetic catheter must not be removed until 12 hours after the last subcutaneous dose is administered or as discussed with CPMS.
    • IF ANY PATIENT WITH AN INDWELLING LOCAL ANAESTHETIC CATHETER (ESPECIALLY AN EPIDURAL OR CAUDAL CATHETER) IS TO BE COMMENCED ON ANY FORM OF ANTICAOGULATION, THIS MUST BE DISCUSSED WITH CPMS PRIOR TO COMMENCING THE ANTICOAGULATION

    Sedatives

    • It is uncommon for additives to be included in regional infusions.

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    Patient review

    • CPMS review patients twice daily on week days and once daily on weekends and public holidays.
    •  If a patient is experiencing pain or undesirable side effects CPMS must be called to review the patient.
    • CPMS can be contacted at all times on pager 5773.

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    Minor problems and management

    Inadequate analgesia

    • If the patient complains of pain or appears to be in pain:
    • Assess extent of block.
    • Check catheter at insertion site for leaking/dislodgement.
    • Check at connection of catheter and filter for disconnection/leaking.
    • Assess severity and location of pain.
    • Consider surgical review if risk of surgical complications, e.g. compartment syndrome, infection or haemorrhage.
    • Call CPMS as a bolus may be required.

    Leaking regional anaesthetic catheter

    • If the patient is comfortable (suggesting the regional anaesthetic block is providing adequate analgesia), the dressing should be reinforced and the leakage observed.
    • The rate may be decreased if delivery via Alaris PCAM
    •  Sometimes leaking from an extrapleural/paravertebral catheter is excessive. In these cases CPMS should be contacted, as the catheter may need to be reinforced, adjusted or may need to be removed.
    •  If the patient is in pain or the catheter dressing needs changing, CPMS should be contacted.

    Occlusion

    • Paediatric regional anaesthetic catheters are very fine. They can occlude easily and the infusion may need to be run at a higher pressure than is usual for IV infusions. If the Alaris PCAM infusion pump occludes or is not delivering the programmed rate:
      • Check the infusion line is not occluded or kinked.
      • Check that taping has not resulted in any kinks in the catheter.
      • Check the infusion pump pressure.
      • If the cause for occlusion is not found call CPMS urgently.

    Disconnection

    • If the regional anaesthetic catheter becomes disconnected, call CPMS immediately.
    • DO NOT reconnect.
      •  Wrap the two ends in a sterile towel or gauze.
      • Turn off the infusion pump if applicable

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    Complications

    IF RESPIRATORY DEPRESSION OR OVERSEDATION IS SUSPECTED:

    • CEASE the anaesthetic infusion
    • CEASE all other infusions that could be contributing to sedation
    • Attempt to rouse the patient
    • Call 22 22 [MET team] if appropriate
    • If apnoeic: administer bag and mask ventilation with 100% oxygen
    • If breathing: maintain airway, monitor oxygen saturations and administer oxygen via  face mask at 8L/min
    • Check circulation. If pulseless: commence chest compressions
    • Administer naloxone per instructions on the attachment chart if opioid toxicity is suspected

    Call CPMS URGENTLY if any of the following occur:

    • high block >T3
    • fever >38.5o C
    • dense motor block
    • sedation score ﾳ 3 / respiratory depression
    • hypotension
    • signs of local anaesthetic toxicity

    Fever

    • If the patient has a temperature >38.5 C, or is suspected of having sepsis with potential for bacteraemia, the catheter may need to be removed.

    Dense motor block (see epidural CPG)

    • Moderate motor block is common immediately following surgery due to the higher doses of local anaesthetic used during surgery.
    • Mild motor block is common following this initial period. However, because of the serious consequences of perineural abscess and perineural haematoma, all persistent motor block after perineural catheter insertion must be reported and thoroughly assessed (see epidural)

    Sedation / Respiratory depression

    • (see epidural)

    Local anaesthetic toxicity

    • Signs of local anaesthetic toxicity include: dizziness, blurred vision, decreased hearing, restlessness, tremor, hypotension, bradycardia, arrythmias, numbness of tongue, seizures, sudden loss of consciousness.

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    Ceasing the regional anaesthetic infusion

    • Ceasing the regional anaesthetic infusion therapy should only be done in consultation with CPMS or an anaesthetist.
    •  When it is decided that regional anaesthetic analgesia is no longer required, the infusion is ceased and alternative analgesia administered.
    •  It is important to warn the patient and parents about the possibility of experiencing some discomfort as the local anaesthetic wears off and normal sensation returns (usually within 2-4 hours).
    • If significant pain occurs after ceasing the regional anaesthetic infusion despite alternative analgesia, CPMS should be contacted
    • Wound catheters may continue until discharge.

    Removing the catheter

    An accredited Registered Nurse can remove the regional anaesthetic catheter after instruction by CPMS or an anaesthetist.

    • NB If the patient is receiving anti-coagulant medication, refer to concurrent drug section before removing the catheter.
    • If there is any difficulty encountered removing the regional anaesthetic catheter or if any abnormality is detected, CPMS must be called immediately.

    To remove the catheter:

    • Place the patient in a comfortable position.
    • Remove the tape and dressing.
    • Use non-sterile gloves.
    • Cut suture if present (common with extrapleural and femoral catheters).
    • Withdraw the catheter slowly and steadily.
    • If any resistance to catheter withdrawal is felt, STOP and call CPMS urgently. DO NOT forcefully withdraw the catheter.
    • Check the catheter tip is intact and examine the site for redness, pus or any abnormality.
    • Consider placing a bandaid over the insertion site. This can be removed the following day.
    • Complete details about regional anaesthetic catheter removal and sign on the Regional anaesthetic infusion and LDA.
    • If clinically indicated or requested by CPMS, the catheter tip should be sent to pathology along with a skin swab, full-blood examination (FBE) and blood cultures.
    • CPMS must be contacted if this is done.

    Guideline review date:
    First version 2006, Updated July 2023