Chronic Refractory Angina

Nursing Guidance for Intrathecal Pump Drug Administration
AlgoMedÙ

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

Introduction

Intrathecal pumps are used in the suppression of pain by the infusion of a prescribed medication such as morphine directly into the intrathecal space. Opioids being very effective in the relief of chronic pain and recommended in-patients with chronic refractory angina. However dose related side effects are common and many patients find this intolerable. Epidural or intrathecal opioid administration enables much smaller doses of opioids to be delivered and thereby allows for a more accurate assessment of dose related side effect.

Within the algorithm of treatments some patients will have effectively been managed by repeated epidurals infusions. Epidural infusions however are only used in the sort term and to assess the effectiveness of opioids in controlling the patients pain. In the long-term the administration of intrathecal opioids via a totally implantable device is safer.

In this section we describe our nursing guidance for intrathecal opioids. The availability of fully implantable systems for the relief of pain, such as neuroaxial opiate infusion(1) offers an opportunity to resolve the problem of refractory anginal pain that has not been successfully treated by less invasive therapies within the clinical guideline algorithm.

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 intrathecal opioid administration 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

Criteria for Intrathecal Pump

We only consider opioid administration by this route if the patient continues to have unacceptable levels of pain and alternative routes of administration are unacceptable.

Safety

Clinicians are naturally concerned about the potential risks of masking myocardial ischaemic pain, which because of the negative feedback of chest pain theoretically may increase the risk of myocardial infarction. However it has been suggested that through the relief of pain myocardial oxygen demand is reduced without altering coronary perfusion pressure(3.4.5). In addition studies have demonstrated that totally implanted programmable device for infusion decreases the risk of infection(6) and as shown by Pasqualucci et al small amounts of intrathecal morphine provides excellent pain relief but without circulatory or respiratory side effects(7).

Definition

For the administration of medication into the intrathecal space.

AlgoMedÙ Infusion System (MEDTRONIC)

The implantation of Algomed infusion system is a surgical procedure requiring complete aseptic technique and prophylactic antibiotics.

There are three main components that make up the system. The catheter, which is small bore and made of radiopaque silicone rubber, allows the administration of the prescribed drug into the spinal canal. The reservoir which is made of silicone rubber; and holds 50mls of fluid which is implanted under the abdominal wall close to the surface, and is connected to the Control pad. The Control pad consists of three functional components: a reservoir fill port, a pumping chamber and an activation valve. A connector is located on each side of the control pad and joins the reservoir tubing and catheter to the control pad.

The filler port allows access to the reservoir that holds the medication. The pump is designed to deliver a controlled amount of medication through the catheter into the intrathecal space the maximum volume being 1ml. Following the bolus injection the chamber takes ninety minutes to refill with drug before the next bolus can be given. The drug dosage per ml will depend on the drug concentration the effect of which will be assessed at each refill.

Refilling the reservoir.

• To prevent improper injection or damage to the catheter access port, always use the appropriate refill kit for the refill procedures.

• If local or systemic infection is suspected, use extreme caution when emptying or refilling the pump reservoir.

• Do not refill until the pump reservoir has been completely emptied.

• The refill volume must not exceed 50.

• Do not inject at a rate that exceeds more than 1ml per 3seconds.

• Do not allow air into the pump's reservoir whilst refilling.

• Always use a filter when injecting into the access port.

Injecting into filler Port

1. Identify control pad site and locate the reservoir fill port, pumping chamber, and activation valve.

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

3. The skin should be visibly clean before any skin preparation is made. 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. The skin disinfection should be repeated.

4. Use sterile procedure to assemble the 22 gauge none coring needle, extension tubing and 10ml syringe. 

5. Insert needle through the skin and into the filler port.

6. Open clamp and remove all residual drug from the reservoir.

7. Close clamp and record volume removed and then discard syringe with aspirate.

8. The amount of residual volume when added to the amount of doses given should equate to the previous refill volume.

1. Confirm total volume to be used does not exceed the maximum requirement of 50mls.

2. Attach 50ml syringe and filter to extension tubing with the 22 gauge needle.

3. Open clamp and inject prescribed drug.

4. Caution must be taken following drug dose alteration, as there will be a residue of the original strength remaining within the catheter this will still continue to be delivered following dosage alteration and this should be taken into account.

5. Record the refill date, volume, drugs, and concentration in patient's log book.

6. Using the patientÌs logbook data and the number of days since last refill, estimate when the patient should return for the next refill.

Caution the reservoir should always contain at least 5mls volume at the time of refill.

When changing drug concentration or solution, you must rinse out the reservoir twice with 10mls of 0.9% normal saline to remove the drug remaining in the dead space of the reservoir.

Adverse effects with the use of Intrathecal Opioid Infusion.

• Medication side effects Pruritus

• Nausea and vomiting

• Urinary retention

• Constipation

• Oedema-increase of weight

Medical (surgical) Complications 

1. Bleeding.

2. Infection.

3. Neurological deficits related to tissue damage.

4. Cerebrospinal fluid leaks.

Technical (delivery problems) complications.

1. Catheter fracture

2. Kinking.

3. DisconnectionÌs

4. Tip obstruction

5. Dislodgment

6. Accidental withdrawal

The pharmacological side effects of intrathecal opioids

The pharmacological short term side effects of intrathecal morphine when compared with systemic

administration are similar (8) differing only on the degree of drowsiness which is more acute in the systemic delivery.

Pruritus is a common side effect associated with intrathecal opioid delivery (9) the effect of which may precede pain relief but antihistamine should be prescribed to control the "itch reflex".

Nausea will usually occur within four hours of morphine delivery and can be controlled by an anti emetic and or by reducing drug delivery and gradually increasing it over the next few days.

Urinary retention following the administration of intrathecal opioids is more common than intravenous or intramuscular administration and is not dose related(10) treatment with cholinomimetic drugs or intermittent catheterisation can be useful in its treatment.

Constipation commonly occurs with the use of opioids mild laxatives and stool softeners should be used.

Respiratory depression following intrathecal opioid delivery is more likely to occur in opioid-naŒve patients(11) but is not usually a major problem in those patients who have gone through screening test prior to pump implantation.

Weight gain/oedema in opioid delivery is thought to be related to hormonal changes and cannot be controlled by diet and is not dose dependent but are commonly observed in long term patient(12).

MEDICAL (surgical) Complications

Implantation of a pump for intrathecal opioid delivery must be done with the highest level of care to minimize surgical complications, which may include bleeding, infection, tissue damage, and CSF leaks.

Bleeding excessively post surgery can be minimized by carefully screen the patient pre surgery for coagulopathies and for those patients on NSAIDs check platelet count.

Necrosis, Seromas, Skin perforations, at the pump pocket site may be caused by improper positioning of the pump or reaction to the size/or construction of the pump(13).

Infection may occur along the superficial or deep catheter track, the pump insertion site, or within the epidural or intrathecal space.  Meningitis while rare requires immediate explantation of all foreign body materials and the start of intravenous antibiotics therapy( 15).

Neurological deficits related to tissue damage following implantation of the catheter into the spinal canal can lead to damage of the nerve roots or the spinal cord. Damage to these tissues can lead to radiculitis, myelitis, paralysis, paresis, loss of bowel and bladder control, and or myelopathic pain( 14).

Cerebrospinal fluid (CSF) leaks into the epidural space are inevitable due to the nature of the procedure, due to the Tuohy needle being of a larger size to that of the catheter. This leak usually will stop within several days, but may on occasions persist. Other reasons for CSF leaks are incomplete tissue sealing around the catheter at the site of insertion, multiple subarachniod punctures during insertion of the catheter, dislodgment, disconnection, break, puncture, or migration of the catheter. Leaks of CSF around the incision site will always require re-suturing.

Postural puncture headaches can occur as a result of CSF leakage in the majority of patient this will disappears within a few days. However in a few patients this can last for months (15).

Catheter complications can include dislodgment, kinks, breakage, occlusion, and migration that may result in drug under infusion leading to lose of analgesia, inconsistent analgesia, or drug withdrawal symptoms.

Treatment of patients who are anticoagulated

Although epidural haematoma is a rare complication following instrumentation of the epidural space, the possible devastating consequences of this requires serious consideration. Full anticoagulation has long been considered a contraindication to epidural catheter placement. However if this rule were to be applied rigidly, many cardiac patients would be denied SCS, which may represent their most promising therapeutic option. Consultation with haematological colleagues is advised. 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 and the stimulator implanted 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 epidural haematoma. The patient should be admitted five days prior to the procedure, warfarin stopped and an intravenous infusion of unfractionated heparin is commenced. Regular APTT estimation is mandatory. On the day of implantation, heparin is discontinued three hours prior to the start of the procedure and APTT is checked once more to ensure there is no coagulopathy. Following implantation, the heparin infusion should be recommenced after 3 hours. Warfarin can be restarted that same evening at the usual loading dose and both drugs should run concomitantly until full anticoagulation is achieved

Post procedure observation of the patient.

1. Hypotension Û check blood pressure regularly for one hour post procedure.

2. Bradycardia Û record pulse for one hour post procedure.

3. Respiratory depression - record respiratory rate depth and pattern of breathing.

4. Nausea or vomiting.

5. Observe infiltration site for haematoma - Recent anticoagulant therapy can predispose to

6. haemorrhage into the epidural space.

7. Headache - May be caused by accidental puncture of the dura.

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

9. Observe effective of pain relief following the procedure.

Nursing Guidelines

Admission assessment procedure

1. Review history Clinical Assessment e.g. Physiological - psychological - social history.

2. Commence Pain assessment chart.

3. Introduction of the patients named nurse.

4. Referral to physiotherapist for explanation of postoperative exercises.

Baseline observations.

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.

Investigations to be requested by the doctor

Electrocardiogram (ECG), Chest X-ray, (CXR), Full blood count (FBC), Urea and electrolytes (U+E's), International Normalised Ratio (INR) if required.

Anticoagulation therapy:

Pre Intrathecal Pump Implant

1. Discuss - goals, benefits, and risks. 

2. It is important to warn the patient that the wound will be too painful to enable the device to be used effectively for up to 10-14 days in some cases.

3. Document patient's response to intrathecal implant pre surgery.

4. Assess their level of pain using an analogue chart.

5. Discuss what functional changes may be required of the patient during the initially few weeks following the operation e.g. Excessive body movement can dislodge the catheter and or accidentally pull it out

6. Information re intrathecal implant.

7. Develop realistic expectations about pain relief with patient.

8. Explain procedure

9. Review medical history and ensure completion of prescription sheet and signed consent for surgery obtained.

10. Reinforce explanation of procedures.

11. Commence pain analogue assessment chart.

12. Identify patients or careers anxieties and address them.

13. Commence discharge planning.

14. Orientate patient to the ward and if possible give approximate time for surgery along with date.

Day of operation

1. Stop heparin three hours prior to surgery and check final APPT to ensure there is no coagulopathy.

2. Nil by mouth for six hours pre surgery.

3. Prepare for theatre - shave and clean skin if required.

4. Check that skin has been marked by the operator and confirm that the position takes account of bra straps etc

5. Give pre-op medication

6. Check patientÌs valuables are safe.

7. Check consent form signed.

8. Check patientÌs observations prior to theatre.

Post operative wound care management and assessment

1. In the operating theatre, following wound closure, an occlusive dressing should be applied, such as a vapor permeable film dressing e.g. Tegaderm or IV3000 or a transperant dressing with an integral pad eg. Steripad. If the exudate is high an occlusive absorbent dressing should be used.

2. The dressing should be inspected regularly, if it is not intact or there is excessive leakage it should be changed using an aseptic technique.

3. Post op observation as normally carried out post surgery.

4. Check wound sites for bleeding. Do not remove dressings if clean.

5. Check regularly the patientÌs level of pain.

6. Ensure analgesia is given for wound pain post procedure.

7. If the patient was on a Heparin infusion it can be recommence three hours post surgery.

8. Continue observations as required.

9. Encourage early mobility but for the first 24-48 hours avoid sudden movement.

District nurse

1. To call on the patient 24 to 48 hours post discharge.

2. To check on wound healing process on the back, abdomen and side of chest.

3. Removal of all sutures by the 10^th day.

4. Seromas and discomfort may occur around IPG pocket as scar tissue forms and will disappear in time. Treatment with cold therapy will help (ice packs)

5. Managing pain through effective programming.

6. Level of musculo-skeletal pain and adequate analgesia.

7. Advice from the doctor on medication reduction as appropriate inline with the effectiveness of the pump

References

1. Polliti CE. Cohen AM. Todd DP. Ojemann RG. Sweet WH. Zervas NT: Cancer pain relieved by long term epidural morphine with permanent indwelling systems for self administration. Journal of Neurosurgery 55:581-584 1984.

2. Rosenbaum SH. Barash PG. Is anaesthesia therapeutic? Anaesthetic Analgesia 1989, 69:555-557.

3. Bloomberg S. Emanuelsson H. Ricksten SE. Thoracic epidural anaesthesia and central hemodynamics In patients with unstable angina pectoris. Anaesthetic Analgesia 1989, 69:558-562.

4. Klassen GA. Bramwell RS. Bromage PR. Zborowska-Sluis DT. Effect of acute sympathectomy by epiduralanaesthesia on the canine coronarycirculation. Anaesthesiology. 52:8-15 1980

5. Liem TH. Booij LH. Hasenbos MA. Gielen M. Coronary Artery Bypass Grafting , using two different anaesthetics techniques. Part 1: Haemodynamic results. Journal of Cardiothoracic Vascular Anaesthesia. 1992;6(2):148-155.

6. Wikelmuler M, Winkmuler W. Long term effects of continuous intrathecal opiod treatment in chronic pain of nonmalignant etiology. J Nuerosurg 1196; 85:458-467.

7. Pasqualucci V. Muricca G. Solinas P. Intrathecal morphine for the control of the pain of myocardial infarction. Anaesthesia 36:68-69, 1981.

8. Mueller-Schweffe G. criteria for measuring outcomes of intrathecal therapy. Presented at the 4^th International congress of the International Neuromodulation Society; Sep 20^th 1998 Lucerne Switzerland

9. Paice JA. Penn RD. Shott S. Intraspinal morphine for chronic pain: a retrospective, multicenter study. Journal Pain Symptom Management 1996: 11: 71-80.

10. Martin R. Salbaing J. Blaise G. Tetrault JP. Tetrault L. Epidural morphine for postoperative pain relief: a dose response curve. Anaesthesiology. 1982;56:423-426.

11. Waldman SD.Leak DW. Kennedy LD. Patt RB. Intraspinal opioid therapy. Cancer Pain Philadelphia: J B Lippincott Company 1993: 285-328.

12. Koulousakis A, Imdahl M, Weber M, Continuous intrathecal application of morphine in cancer pain. Procedings of the 8^th World Congress 1998.

13. Krames ES, Intrathecal infusional therapies for intractable pain: patient management guidelines. Journ of Pain Symptom Management. 1993;8:36-46.

14. Naumann C Erdine S, Koulousakis A, Van Buyten P, Schuchard M. Drug adverse events and system complications of intrathecal opioid delivery for pain: Origins, detection, manifestations, and management. Neuromodulation: Journ of the International Neuromodulation society.Vol 2,No2, April 1999. 92-107.

15. Choi A, Laurito CE, Cunningham FE. Pharmacological management of postural puncture headache. Ann Pharmacotherapy 1996; 30:831-839.

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