Lignocaine Infusion for Complex Pain

Introduction

Lignocaine is a local anaesthetic known to have analgesic and anti-inflammatory properties (Koraskey et al, 2013). Lignocaine is a sodium channel blocker that halts impulse conduction in neural tissues. These drugs have effects on any conducting tissue, including the cardiac and central nervous systems. There is evidence (Tremont-Lukats et al, 2005) for its use in treating chronic neuropathic pain when other pharmacological i.e. Amitriptyline, Gabapentinoids and non-pharmacological i.e. physiotherapy interventions have been unsuccessful. The typical description of neuropathic pain can include the descriptors burning, tingling, shooting, stabbing and electric shock type discomfort.

Indication for use

Systemic administration of lignocaine maybe used as a therapeutic or diagnostic tool for chronic neuropathic pain in patients that have had no improvement or response from other management methods. It can be used to reduce opioid exposure and assist management of central neural sensitisation syndrome. Lignocaine is often administered in conjunction with a multimodal regime.

The decision to commence a lignocaine infusion is made by the Pain Service.

Responsibility

The lignocaine infusion will be prescribed by the Pain Service consultant and commenced by a member of the Complex Pain Service. The patient will be cared for in the post anaesthetic care unit (PACU) during the infusion and will be observed and managed by a member of the pain nurse specialist team.

Contraindications

• No availability of bed space in appropriate monitoring area

• Known or suspected allergy to lignocaine or other amide local anaesthetics

• Significant heart disease or cardiac arrhythmia

• Reduced conscious state or known seizure disorder

• Renal or liver dysfunction

• Cardiovascular instability

• Electrolyte disturbances

• Consult with Pain Service Consultant if patient is on Mexiletine

Lignocaine Dosing

Set up and Management

Prescription

The lignocaine infusion will be prescribed on the patients’ fluid balance chart (CR5713) and patient medication chart by the Pain Service Consultant.

Equipment

• Intravenous cannula

• Alaris infusion pump (sourced from equipment pool if none available in PACU)

• 500 mL Sodium Chloride 0.9% intravenous fluid bag

• Intravenous fluid administration set

• Monitoring equipment

• Lignocaine 2% vials Lidocaine (Lignocaine Hydrochloride 20 mg/mL) 2%

Intravenous Cannula Insertion (IVC)

A member of the Pain Service will insert an IVC when the patient arrives at Starship. This will be done either in Day Surgery Unit or in the anaesthesia waiting room.

Medication preparation

Remove 25 mL from 500 mL Sodium Chloride 0.9% intravenous fluid bag and then add 25 mL of Lignocaine 2% to the bag of Sodium Chloride. This makes a bag concentration of 500 mg/500 mL (1 mg/mL).

A patient label and medication additive label must be attached to the prepared medication bag with the time, date and initials of the two registered nurses completing the check.

Ensure medication and patient checking procedures are completed as per medication administration policy .

Administration

The patient will be cared for during the infusion in PACU with a member of the pain nurse specialist team in attendance. Alternatively, an infusion can be administered in the Paediatric Intensive Care Unit (PICU) under close monitoring by PICU staff.

The infusion can be commenced once the patient has been attached to a cardiac monitor and following a baseline set of vital signs.

The medication should be infused via an Alaris fluid pump over 4 - 6 hours at the continuous rate prescribed.

Observations

The patient will remain on cardiac and oxygen saturation monitoring throughout the duration of the lignocaine infusion.

Baseline vital signs should include a pain score, temperature, heart rate (HR), respiratory rate (RR), oxygen saturation (Sp0₂) and blood pressure (BP).

Patient should have HR, RR, BP and Sp0₂ should be recorded every 5 minutes for the first 15 minutes. Then observations can be done every 30 minutes for 1 hour. Thereafter observations can then be done hourly for the remainder of infusion unless otherwise indicated.

A pain score should be repeated 1 hour post commencement of infusion then hourly until the infusion is completed.

30 minutes post infusion completion a final set of observations should be completed, including temperature and pain score.

Neurological status should be observed throughout the infusion with any significant changes documented within the patient clinical notes.

Therapeutic lignocaine levels will be taken if indicated by the consultant.

Please note lignocaine levels are sent to Christchurch Hospital and have a turnaround time of 8-9 days. Urgent tests can be arranged in advance with the lab but will still take 2-3 days.

Documentation

The lignocaine infusion will be prescribed in the patient medication chart and fluid balance chart (CR 5713).

Observations will be recorded on a post anaesthetic care unit record (CR 8833) chart as detailed above or Patient Early Warning Score PEWS chart.

A fluid balance record should also be completed for the duration of the infusion.

Clinical notes should be updated with details throughout the infusion and at completion.

Potential Side Effects

The symptoms of lignocaine toxicity tend to follow a predictable progression.

Mild to moderate adverse effects are early signs of toxicity:

• Numbness and tingling especially perioral tingling / numbness or tingling tongue

• Metallic taste

• Tinnitus (ringing in the ears)

• Dizziness / light headedness

• Headache

• Nausea / vomiting

• Tremors / muscle twitching

• Vision changes

• Paraesthesia

• Slurred speech

• Impaired concentration

• Sedation / drowsiness

• BP / HR changes (hypotension and bradycardia)

Severe adverse effects involve the cardiac and central nervous system:

• Cardiac

  • Sinus tachycardia

  • Sinus arrest

  • Partial or complete atrio-ventricular dissociation

  • Cardiac arrest

• Central Nervous System

  • Tonic-clonic seizures

  • Unconsciousness

  • Coma

  • Death

Response

• Reduce infusion by 50% and call for medical review – presence of the mild symptoms of tingling tongue, perioral numbness/tingling, metallic taste or tinnitus

• Cease infusion and call for medical review – if any other symptoms present or patient not tolerating infusion

Reversal

Intralipid 20% is used in the management and treatment of local anaesthetic toxicity. Refer to AABGI 2013 guidelines as per resuscitation trolley.

• Cease infusion

• Call code blue (777)

• Maintain airway, give 100% Oxygen (O₂). Monitor DRSABC

• Confirm intravenous access

• Assess cardiovascular system throughout

• Refer to intralipid policy on administration

Discharge

The patient can be discharged from Starship Childrens Health 30 minutes post completion of the infusion if vital signs are stable.

The IVC should be removed prior to discharge.

The patient will be followed up, as arranged, by the Complex Pain service.