Chronic Refractory Angina

Nursing Guidance for High Thoracic Epidural Infusion

These Guidance recommendations have been produced in accordance with the NHS Executive publication "Clinical Guidelines" (May 1996) and incorporate those standards produce by the King's Fund for evidence based clinical practice.

Produced for the National Refractory Angina Centre
Introduction (see clinical section)

High thoracic epidural analgesia has been reported as being effective in the relief of refractory angina. Blomberg (1,2) demonstrated that this technique was useful in both short and long-term treatment of patients with unstable angina by giving a bolus injection and then infusion. Toft and Jorgenson (3) used continuos thoracic epidural bupivacaine to relieve the pain of myocardial infarction. Gramling and Babb and co-workers 4 published data on ten patients who all had improvement in their symptoms. There was one non-epidural related death and no patients had either myocardial infarction or significant arrhythmia.

Definition

The administration of local anaesthetic into the epidural space to block the thoracic sympathetic ganglion. It is considered if stellate ganglion and Paravertebral block fails to adequately ameliorate symptoms

It is essential that at all stages of treatment a clear treatment contract is developed with attainable goals set by the patient and careers. Thoracic Epidural cannot cure the problem. The actual aim of the treatment, being to ameliorate the effect of angina so that the patient and their family can enjoy a better quality of life. The treatment program and expectations of the patient and their carers are dealt with at all stages of the treatment by the angina management team. This helps to ensure that the patient and carers expectations on pain relief are not unrealistic and thereby unachievable. Generally HTEA is a short term treatment that can provide a pain holiday. It is not a suitable long term treatment.

Patients on Anticoagulant Therapy

There are different indications for anticoagulation in cardiac patients, which can be stratified into low-risk e.g. atrial fibrillation with no previous embolic history; and high-risk groups e.g. metal valve replacement, when considering the temporary interruption of their warfarin.

In the low risk group, anticoagulants can be stopped when the INR is <1.4. This usually takes three days. In the high-risk group the "therapeutic window" must be tightly controlled to minimise the embolic risks to the patient without exposing them to the risk of haematoma. The medical team looking after the patient must closely monitor the control of the anticoagulant.

Pre-procedure

The patients skin should be clean before any skin preparation is applied. The patient should shower/bathe within a skin disinfectant on the morning of the procedure. Shaving is not recommended, if hair removal is necessary clippers should be used.

Equipment

1. Venflon for venous access.

2. Chlorhexidine or equivalent skin cleansing agent.

3. Local anaesthetic Lignocaine 2%.

4. Normal Saline 20mls.

5. Anaesthetic 6mls of 0.5% plain Bupivacaine.

6. Selection of needles, Blue 24g and green 21g.

7. 10ml and 20ml syringe

8. Sterile dressing pack.

9. 18G Tuohy needle.

10. Epidural catheter pack with filter. , which includes - 18g Tuohy needle, obturator, low friction syringe, filter, and extension lead.

11. Occlusive dressing.

12. Infusion pump

13. Sterile gowns.

14. Gloves.

15. Towels.

Anaesthesia Bupivacaine (usually) for infusion rate to be decided by the doctor.

Analgesia Fentanyl 250mg over 24hours via infusion pump.

Preparation

Epidural catheterization should be carried out in a theatre or a clinical room that has been documented as complying with HTM2025 guidelines.

An aseptic technique must be adhered to and sterile gloves; surgical mask and gown should be worn.

The skin should be visibly clean before any skin preparation. An antiseptic skin preparation of either alcoholic chlorhexidine or alcoholic povidone Ò iodine solution should be applied to the insertion site and surrounding area vigorously, using gauze swabs rather than cotton wool. The skin must be allowed to dry before proceeding in order to ensure decontamination of the skin is effective. The skin disinfection should be repeated.

Observation of the patient pre procedure.

Base line observation of the blood pressure, pulse, temperature and respiratory rate will be taken.

1. The procedure will be explained to the patient. To ensure that the patient understands the procedure and gives written consent.

2. An electrocardiograph is performed pre and Initially as routine base line and then post if problems develop post procedure To observe for any ECG changes (e.g. ischaemia, infarction).

3. The patientÌs back is prepared with cleaning solution. To reduce risk of infection.

4. Patient to sit on a hard surface with arms resting on a table or pillow. To allow identification of the spinous process and prevent sudden movement.

5. Give the patient support and encouragement. Reassurance is very important.

Doctor/Nurse action

1. The skin and subcutaneous spaces are infiltrated with local anaesthetic. To reduce discomfort felt by the patient on insertion of Tuohy needle.

2. The Tuohy is introduced between 5cmlateral to the midline at the level of T3-T4. The needle is advanced until the costotransverse ligament is felt and the needle 'gives' as it enters the epidural space. A negative aspiration must be obtained before injection of 15mls 0.5%.Bupivacaine. Constantly reassure and explain procedure.

3. Following insertion the catheter is connected to the extension line, filter and infusion pump.The rate of infusion to be decided by medical team.

Complications

It is estimated that minor complications occur in less than 5% of cases(5) and tend to occur during injection or shortly afterwards. In a large series of patients having mainly perioperative blocks, the main complications were hypotension in 4.6%, vascular puncture in 3.8%, pleural puncture in 1.1% and pneumothorax in 0.5% (6).

Accidental extradural or intrathecal injection is rare and due to taking too medial an approach. Total spinal anaesthesia has been reported, with no long-term sequelae (7)

Assist the doctor as required during the insertion and removal of epidural catheter.

Observe effectiveness of pain relief following the procedure.

Wound Management post procedure

The epidural site must be covered with a sterile dressing e.g. Tegarderm or IV3000 for their increased moisture vapour transmission capability. A secondary dressing may be required to anchor the line and minimise the risk of catheter movement. The epidural dressing should be observed regularly to ensure it remains intact and secure. If there is slight leakage of blood/serious fluid it may be aspirated using a syringe and blunt needle. The puncture site should be resealed with a smaller occlusive dressing. If the dressing is no longer intact or is no longer adhering to the skin it should be changed. The skin should be observed for trauma and allergic reaction to the dressing.

Before all dressing changes or handling of the line hands should be decontaminated in accordance with hospital policy.

Wound Site inspection must be carried out on a daily basis for signs and symptoms of infection.

The obvious signs and symptoms include:

Erythema, tenderness, swelling or purulent discharge and its appearance documented

A spreading erythema accompanied by tenderness or swelling.

Back pain, neurological deficits (paralysis, weakness) or meningitis may indicate the presence of a spinal abscess.

If a problem is suspected then the managing clinical team must be informed immediately.

Post-operative wound dressing must be performed using an aseptic technique. During dressing replacement, great care must be taken not to dislodge the epidural catheter. The replacement of the epidural administration line, filter and syringe must also take place under strict aseptic technique.

Line and filter contamination.

If the line or filter are suspected of being contaminated the incident must be documented, the team managing care informed and the epidural removed, a swab will be taken for culture and sensitivity (C+S) from the wound site and the catheter tip taken for also for C+S.( 8)

Catheter removal

The removal must be under taken under strict aseptic technique, the site must continue to be inspected daily for signs and symptoms of infection. The catheter tip must be sent for virology analysis.

Observation for potential side effects post procedure.

Refractory angina patients will be on drug therapies that may cause hypotension and bradycardia in their mode of action. It is therefore important to record the patients blood pressure pulse and respiratory rate prior to the procedure to evaluate base line observations.

Hypotension - check blood pressure every 15 minutes for the first hour and then 1/2 hourly for

the next two hours post procedure.

Bradycardia- check pulse every 15 minutes for the first hour and then 1/2 hourly for

the next two hours post procedure

Respiratory depression - record respiratory rate, depth and pattern of breathing

every 15 minutes for the first hour and then 1/2 hourly for

the next two hours post procedure

Inadvertent Epidural anaesthesia - loss of power to the lower torso. Place patient into supine

position and call for medical assistance.

Total spinal anaesthesia - rapid loss of consciousness with cardiovascular collapse and apnoea

medical emergency - call crash team, institute Cardiopulmonary Resuscitation.

Local anaesthetic toxicity - caused by systemic adsorption of local anaesthetic resulting in

high blood levels occurring 20-30 minutes after the block. It is characterised by tingling of the lips and tongue, confusion, light headedness, unconsciousness, convulsions and coma. Lie the patient flat and get medical assistance urgently.

Observe infiltration site for haematoma - recent anticoagulant therapy can predispose to haemorrhage into the epidural space.

Nausea or vomiting - side effect of local anaesthetic and hypotension.

Headache - may be caused by accidental puncture of the dura.

Urinary retention - due to parasympathetic block of the sacral level of the spinal cord.

Discharge from hospital

Inform district nurses prior to discharge and instruct on aim of treatment and care of the epidural catheter.

References

1. Blomberg SG Long-term home self-treatment with a high thoracic epidural analgesia in patients with severe coronary artery disease. Anesth Analg 1994;79:413-21

2. Blomberg SG, Curelau I, Emanuelsson H, Herlitz J, Ponten J, Ricksten SE. Thoracic epidural Anaesthesia in patients with unstable angina pectoris. Eur Heart J 1989;10:437-44.

3. Toft P, Jorgenson A, Continuos thoracic epidural analgesia for the control of pain in myocardial infarction. Intens Care Med 1987;13:388-9.

4. Gramling-Babb P, Miller MJ, Reeves ST, Roy RC, Zile MR. Treatment of medically and surgically refractory angina pectoris with high thoracic analgesia. Initial clinical experience Am Heart J 1997;134:648-55.

5. Richardson J, Sabanathan S. Thoracic paravertebral analgesia. A review. Acta Anaethesiologica Scandinavica 1995;39:1005-15.

6. Lñnnqvist PA, Mackenzie J, Soni AK, Conacher ID. Paravertebral blockade: failure rate and complications. Anaesthesia 1995;50:813-5.

7. Gay GR, Evans JA. Total spinal anaesthesia following lumbar paravertebral block: a potentially lethal complication. Anesthesia and analgesia 1971;50:344-8.

8. Hardy PAJ, Williams NE. Plasma concentrations of bupivacaine after stellate ganglion block using two volumes of 0.25% bupivacaine plain solution. British Journal of Anaesthesia 1990;65:243-4.

9. Crul B. Delhaas E. Technical complications during long-term sudarachnoid or epidural administration of in terminally ill cancer patients. Regional Anesthesia 1991:16;209-13

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