Chronic Refractory Angina

Nursing Guidance for Stellate Ganglion Block

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.
E-Mail Dave.Trenbath@ccl-tr.nwest.nhs.uk

SGB procedure

This is an outpatientÌs minor procedure involving the administration of local anaesthetic around the cervical sympathetic ganglion in the neck to relieve the pain of refractory angina (1).

Treatment contract

It is essential that from the very beginning there is complete agreement made about the aims of treatment, between the patient their carers and the treatment team. The actual aim being to improve the patient and carers quality of life by reducing the effect of angina but it should be emphasised that as with all treatments for chronic refractory angina pectoris Stellate Ganglion block cannot cure the problem. At all stages of the treatment, expectations must be discussed to ensure that the patient and carers expectations on pain relief are not unrealistic and unachievable.

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 until 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.

Recommendation for infection control.

The procedure should be carried out in a clean area/room, using aseptic technique.

Skin preparation

The skin should be visibly clean before any skin preparation. An antiseptic skin preparation of either alcoholic chlorhexidine or alcoholic povidone Û 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.

1. Chlorhexidine or equivalent skin cleansing agent.

2. Local anaesthetic 0.5% Bupivacaine 20mls

3. Green needle 21g

4. 20ml syringe.

5. Electrocath extension tubing (for use with needle and syringe).

6. Sterile dressing pack.

7. Adhesive dressing.

8. Venflon for venous access. (Must be inserted before procedure)

9. Phenylephedrine or Methoxamine should be available for emergency requirement.

Observation of the patient pre procedure.

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

Procedure

1. Explain the procedure to the patient and ensure that the patient understands and has given proper written consent.

2. An electrocardiograph is performed.

3. Many patients with advanced coronary artery disease have impaired left ventricular function and find lying flat uncomfortable.The patient is placed in a reclined position at 20É -30É with a pillow behind their head in the central "sniff the morning air" position. 

4. Give the patient support and encouragement.

5. The patientÌs neck is prepared with cleaning solution.

Complications following procedure

The stellate ganglion is often very close to the vertebral artery and so care must be taken when positioning the needle as injection of local anaesthetic into the vascular system can precipitate convulsions. Spread of injectate into the epidural space can result in hypotension and bradycardia and there is also a risk of subarachnoid injection and total spinal block. Pneumothorax is uncommon but there is an increased chance when performing a C7 block. Associated brachial plexus block is seen in up to 10% of patients. As with all local anaesthetic patients can develop an allergic reaction, which may be serious: however this is very rare particularly when using amide local anaesthetics.

Death is extremely rare and the few complications that do occur are nearly always fully reversable within 24 hours ^2,3.

Observation of the patient post procedure.

Acute complications

1. Any major central nervous system complications will generally occur during injection of the local anaesthetic or shortly afterwards. The patient is therefore observed in a fully equipped resuscitation room for at least 15 minutes post procedure.

2. Observe heart rate - Stellate Ganglion Block (SGB.) may affect electrical conduction of the heart and thereby influence the Sinus nodal rate, Atrio-Ventricular rate and Ventricular fibrillation threshold.

• Vascular injection of local anaesthetic - resuscitate - rare.

• Pneumothorax - rare

• Grand-mal seizure - rare.

• Vasovagal - rare.

Note: Different blocks in the same patient can produce varying amounts of spread.(3)

Horners syndrome - Following infiltration of the left stellate ganglion with 10-18mls of local anaesthetic solution Bupivicaine 0.5%, Horners syndrome may occur. This is usually accepted as being an indicator of effective infiltration of the stellate ganglion⁴. This may manifest itself ipsilaterally but there have been reported cases of bilateral effect, these effects include the following:-

a. Myosis - constricted pupil - normal.

b. Ptosis - drooping of the upper lid - normal.

c. Enoph/thalmos - eye appears sunken - common.

d. Reddening of the conjunctiva - common.

These indicators are apparent 2-20 minutes after stellate ganglion infiltration and may last for 8-12 hours post procedure.

Patients often complain of a feeling of grit in the eye Û mild discomfort only.

Gutmans The recurrent laryngeal nerve lies medially to the sympathetic chain and slightly anterior to it. As local anaesthetic spreads, this may also be blocked resulting in a hoarse voice and a unilateral vocal cord paresisthesia(4).

• Loss of voice - uncommon.

• Hoarse voice - common.

Other effects

Increase in skin temperature in the arm, face, neck or chest on the injection side.

Observation for potential side effects post procedure.

Phenylephrine or Methoxamine should be available.

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

Hypotension - check blood pressure every 15 minutes for one hour post procedure, and then hourly for two hours.

Bradycardia - record pulse every 15 minutes for one hour post procedure, and then hourly for two hours.

Respiratory rate - 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

Haematoma - at the site of infiltration.

Laryngeal Nerve Block

In approximately 5% of patients there is a paralysis of the vocal cord resulting in a hoarse voice. This occurs because of the position of the recurrent laryngeal nerve, which lies medially to the sympathetic chain and slightly anterior to it.

This increases the likelihood of aspiration of food and drink. The patient is allowed sips of water only for 30 minutes post procedure. If tracheal irritation does not occur the patient may eat and drink normally. If irritation does occur the patient may only have sips of water until voice returns to normal.

Brachial Nerve Palsy

There may be weakness or numbness of the arm on the side of injection due to local anaesthetic spreading posteriorly to the cervical nerve roots.

Oesophageal effects

Occasionally there is oesophageal irritation causing swallowing restriction which can last for some hours, but which should resolve.

Local Anaesthetic Toxicity

Caused by systemic absorption of local anaesthetic resulting in high blood levels peaking 20-30 minutes after the block⁶. Toxicity to local anaesthetic is characterised by tingling of the lips, and tongue, mild confusion and light-headedness. Severe toxicity can lead to unconsciousness convulsions and coma but is not expected at the dosage recommended.

Discharge

Patients are allowed home later the same day after they have eaten. Driving is discouraged but should they wish to drive themselves home, they must wait at least four hours post procedure and have no visual impairment that could be attributed to HornerÌs syndrome.

The patient records their quality of life on a linear scale and re-evaluates the aims of treatment. If the stellate ganglion block fails to achieve a satisfactory improvement in quality of life then Paravertabral block can be considered.

Clinical section

References

1. Hammond C, Leach AA, Chester MR. Temporary sympathectomy in refractory angina. Heart 1999; 81(suppl):56.

2. Hammond C, Leach A, Chester M.R. Stellate Ganglion Block for the treatment of Refractory

Angina. Pain in Press.

3. Wulf H. Complications of Stellate ganglion blockade: resulta of survey Anaesthetist

1992,41.146-51.

4. Hardy PAJ, Wells JCD. Extent of sympathetic blockade after stellate ganglion block with bupivacaine. Pain 1989;36:193-6.

5. Malmqvist EL, Bengtsson M, SorensenJ. Efficacy of stellate ganglion block: a clinical study with bupivacaine. Regional Anesthesia 1992;17:340-7.

6. 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.

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