The nurse’s role in caring for patients undergoing LDL-Apheresis

Elaine Jefford

LDL-Apheresis is a new, exciting, highly computerised treatment which is currently being researched. It selectively removes the harmful lipoproteins, in particular Low Density Lipoprotein (LDL) to which is attributed accelerated coronary artery disease 2-3 years after cardiac transplantation. Accepting the rather unique nursing role caring for patients receiving this treatment, the author has found that the research programme has opened up a challenging and very interesting variation in her career using advanced computerised technology. But it has also provided increased opportunity for her to use nursing skills, particularly in the area of communication, to enhance her relationship with the patients and raise the standard of care given.

With the introduction of more sophisticated

computers to monitor and assist the manage- ment of patients’ conditions, nurses’ knowledge

and expertise has had to adapt and expand.

According to Sinclair (1988, p 37):

‘There has perhaps never been a greater need for well-educated nurses, capable of assuming

accountability for analysing the computer’s

sophisticated data and trusting their own clinical impressions, correlating both sets of

data without feeling intimidated by the computer’

The purpose here is to show from experience

that while playing a role in a research study pioneering a new treatment for coronary artery disease in patients following transplantation, the

Elaine Jofford EN, C & C 730, ENB 934, Research Nurse, currently working within the transplant unit at Harefield Hospital, Cambridge, UK

(Requests for offprints to EJ)

Manuscript accepted 10 September 1992

62

extended role of the nurse can be technological

and still leave time for nursing care. In addition

the process of this new treatment is explained.

Coronary artery disease has now reached

epidemic proportions worldwide. In 1990 within

the United Kingdom there were 58 deaths per

100000 of the population per annum under the age of 65 years, and 895 deaths per 100000 of

the population over the age of 65, all attributed

to coronary artery disease (Health of the Nation,

1992). The current treatments available for this disease are listed in Table 1. Although cardiac transplantation is a well established end-stage treatment for coronary artery disease, it is becoming apparent that a major complication occurring significantly 2-3 years after transplant is coronary artery disease. It has been suggested that this is associated with serum cholesterol and triglyceride levels in the blood (Barbir et al, 1991).

In June 1991 a research study using a pro- cedure called LDL-Apheresis was commenced at Harefield Hospital to assess the effectiveness of

INTENSIVE AND CRITICAL CARE NURSING 63

Tabbl TreatmeW mmilabb for coronary artery diwue

Drug therapy nitrates, nitrites, beta-blockers, calcium antagonists Angiopkty an invasive procedure which dilates the artery by means of a balloon catheter, flattening the fatty plaques Coronary Artery Bypass Grafts (CABGI an invasive procedure that grafts arteries on to existing arteries, bypassing the occlusion Cardiac tfansdant8tion only in selective cases

selectively removing lipoproteins associated with

raised cholesterol and triglycerides. The patients

included in this study had to show evidence of

accelerated coronary artery disease on angiogra- phy at a minimum of 3 years after cardiac

transplant. Their serum cholesterol levels had to

be greater than 5.7mmols/l with dietary and

lipid-lowering drug therapy proving unsuccess-

ful. The aim of the treatment is to reduce serum cholesterol levels by 30-40%. At the recruitment

phase of the study the patients were requested to

sign a consent form, following full explanation

of the treatment and study, as requested by the

ethical committee. Patients’ initials only are used

when presenting findings.

Cholesterol is a fatty substance that is trans-

ported within serum as lipoproteins which

synthesises steroids, vitamin D and is a necessary constituent of cellular membranes aiding cell

growth and division (Beisiegel, 1990). Chole-

sterol itself can be broken down into various

subdivisions of lipoproteins, but for relevance to the usage of LDL-Apheresis in cardiac trans-

plantation only High Density Lipoprotein (HDL), Low Density Lipoprotein (LDL), Lipo-

protein (a) Lp(a), will be discussed.

HDL has many roles within the transport of

cholesterol, the most important being in the reverse cholesterol transport. In other words it is believed to absorb cholesterol crystals deposited on arterial walls and can transfer the cholesterol into intermediate density and LDL to be returned to the liver for excretion (Schmitz et al,

1990), therefore helping to protect against the development of athersclerosis (Guyton, 1991).

LP(a) is made up of apolipoproteins(a), which links to apolipoproteins(B) by disulphide bonds,

and seems to have thrombotic and artetioscler-

otic properties. Recent evidence has shown Lp(a)

to be a major risk factor, independent of other lipoproteins, in the development of coronary

artery disease in transplant patients (Barbir et al, 1992).

LDL is one of 4 lipoproteins which is con-

verted from Very Low Density Lipoprotein

(VLDL) particles after the liver and tissue capill-

aries remove various substances (Hunninghake, 1988). In a number of epidemiological studies,

the most well-known being Framingham (Cas-

telli et al, 1986) it has been concluded to be the

most distinctively related lipoprotein to coro-

nary artery disease. LDL-Apheresis is the reduc- tion of selected lipoproteins.

The machine used for LDL-Apheresis is a twin column MAO1 system. It is a sterile disposable

closed circuit system, including a Sulflux Plasma

Separator FS05 colume 2 and Liposorbers

LA15 adsorption columns (Kaneka, 1991) (Fig.

1). The system is assembled prior to treatment. Once the tubing is locked a rinse cycle begins

either using 11 of Ringer’s compound normal

saline solution or normal saline. A second rinse

follows once the filters have been manually

connected. For the priming stage the fluid used

as 11 Ringer’s compound normal saline solution with 3000i.u. heparin added, which is replaced

with a continuous infusion of heparin lOOOi.u./

ml set at a rate of 1.5ml/h when the operation

stage of the procedure begins. The Liposorbers

LA-15 filters contain a special selectively per-

meable membrane called Dextran Sulphate Cel-

lulose which is positively charged, enabling it to

bind selectively with the negatively charged LDL, as it washes through the filters. Through-

out the entire procedure a special fluid called

Regeneration Fluid with a concentration of 4.1%

normal saline is used. This fluid is a key factor in

the procedure when it washes through the Liposobers LA- 15. The Regeneration Fluid has far stronger positive charges due to the concen- tration of the normal saline, than the Liposor- bers LA- 15; therefore it is able to negatively- positively bind together with the LDL, thus be collected for disposal. All the other plasma constituents are returned to the patient, so that the possibility of disequilibrium syndrome, a

64 INTENSIVEANDCRITICALCARENURSING

Fig. 1 Kanaka MAO1 LDL-Apheresis system.

possible complication of some other types of exchanges such as haemofiltration, does not occur (Sheppard, 1989). It has been found that certain parameters set on the machine provide significant reductions in total cholesterol (TC), triglycerides (TG) and LDL (see Table 2).

Limited preparation of the patient is required prior to treatment, including assessing the patient’s understanding of the procedure while allowing time for questions to be asked, and checking that all the pre-treatment observations are done and recorded in the appropriate nur- sing records. The nurse also ensures that the patient is comfortable and provides the options of magazines, radio or television for the duration of the procedure (Fig. 2).

Before the venous access of linking the patient to the MAO1 takes place, base-line observation of blood pressure, weight, and heart rate are recorded. Once the doctor has examined the

patient cannulation is done using a 16 and 17 gauge access needle. All routine bloods are taken: full blood count, full lipid profile, creatine kinase, urea and electrolytes, creatine and liver function test. This permits determination of how effective each treatment is in relation to the individual patient. An initial dose of heparin 5000i.u. is given to aid blood flow through the filters and to prevent clotting. After 15min the base-line observations are repeated and if satis- factory the parameters on the machine are increased. The procedure takes 2-2.5h, depending on the volume of plasma to be treated. Once this is completed routine blood specimens are then repeated, to give a com- parison of test results before and after treat- ment. For the return stage the blood warming bag is inverted, the heparin infusion is disconti- nued, and all the blood/plasma held within the extracorporeal circuit (400ml) is returned to the patient. This part of the procedure takes about 15-20 min. Upon completion, the cannulae are removed and a pressure bandage is applied to prevent excess bleeding. This can be removed by the patient 4-6 h later. Base-line observations are repeated.

It has been noted that the doctor’s role involves the cannulation and examination of the patient. Thus the nurse is very much involved with the observation and assessment of the patient, and changing the parameters as needed to meet the aim of treatment. Several compli- cations from the procedure have been identified (Fig.3 ). Thus the nurse should place great importance on accurate assessment and observa- tion of the patient throughout the procedure.

Whilst the patient is undergoing this pro- cedure there is excellent opportunity for the

Table 2 Parameters for treatment

Parameters

Treated plasma volume: 3000ml Blood flow rate: 6Omllmin increasing to lOOml/min after 15min Plasma flow rate: 15mVmin increasing to 30mllmin after 15min Blood return pressure: 120mmlHg with an added alarm value of 50mmlHg

INTENSIVE AND CRITICAL CARE NURSING 65

particular group of patients. In all this research it is easy to forget that the patients have to attend the hospital every 2 weeks for treatment for 1 year, at their own expense, with some patients living 200 miles away. It has provided the author with the oppor- tunity to enter a new field of treatment which, if it proves successful, could revolutionise the man- agement of hypercholesterolemia in patients following cardiac transplantation; it has also

Fii. 2 The patient is made comfortable, with something to do e.g. reading material.

made it possible to establish very good relation- ships with patients, which in turn improves the standard of care given. Experience suggests that

nurse involved to develop a relationship with the patient, which can be utilised to the full. In this Fig. 3 Complications of LDL-Apheresis and treatment. one-to-one relationship situation patients are A doctor should be notified if any of the following

more likely to discuss their anxieties (Fig. 4). Occur. Thus there is time to communicate with the Hypot=sion patient, to give and receive all types of informa- Causes The amount of circulating extracorporeal

tion, to counsel where necessary, to explain volume. Hypovolaemic, anaphylaxis, vaso-vagal, cardiac failure causes.

anything that the patient wishes to know, or to Treatment Reduce blood flow rate, lie patient flat and

offer a contact oerson who can helo. For raise the foot of the bed. 1 1

example, patient X presented with a particular Air embolism

social problem which, after a long discussion, the Symptoms Cough, dyspnoea, tachycardia, low blood oressure.

author found she was unable to deal with. But ‘Treatment Stoo the procedure. Place patient in an

she was able to refer the patient to the relevant orthopnoeic position. Give oxygen according to the

person who provided help, ending in a satisfac- doctor’s instructions.

tory outcome. In a different situation the anxiety Bleeding

suffered by patient Y was identified by the Cause Over anticoagulation. Treatment Stop the heparin infusion and the

author, who was able to offer some relief within procedure. Apply pressure to the cannulation site.

her capacity as a nurse by discussing relevant Give protamine sulphate (ll-13mg) intravenously.

problems, planning new goals and giving tnfection Of cannuta site

information. In both cases the problems would Symptoms Red, hot, swollen, inflamed site. Treatment Stop the procedure, remove the cannula,

communication skills of questioning and

listening, but most importantly, if she had not

had the opportunity to establish a therapeutic

relationship.

not have been identified if the author lacked

Cannula in the tissues Symptoms Painful to touch, hard, swollen. Treatment Stop the procedure. Remove the cannula. Apply pressure.

apply pressure.

Raised return pressure Cause A blockage in the return system. Treatment Try to reposition the return access needle. Stop the procedure. Remove the needle, apply pressure.

Knowledge of effectiveness of LDL-Apheresis on blood lipids and cardiac transplant patients is

yet to be gleaned from the current research. A

highly specialised piece of equipment is required, with each treatment costing in the

region of several hundred pounds, and at

Raised tmnsmembrans pmssum Cause A blockage in the Sulflux filter Symptoms TMP readings increase.

present few people are trained or qualified to use Treatment Try to flush the Sulflux filter through with

it. It is hoped that LDL-Apheresis will be more Ringers Solution Normal Saline. If it continues to

cost-effective than re-transplantation, but in any increase stop the procedure. Remove the access needles. Apply pressure.

66 INTENSIVE AND CRITICAL CARE NURSING

References

Barbir M et al 199 1 Relationship of immunosuppression and serum lipids to the development of coronary arterial disease in the transplanted heart. International lournal of CardioloEv 32: 51-56

Barbir M et al 1592 Lipoprotein (a) %d accelerated coronary arterial disease in cardiac transplant recipients. Lancet (in press)

Beisiegel U 1989 Regulation of cellular cholesterol concentration. Treatment of severe Hypercholesterolemia in the prevention of coronary heart disease, 12-19. 2nd International Symposium, Munich, Karger

Fig. 4 During the technical procedure there is time to develop the nurse-patient relationship.

the continuity of seeing the same nurse at each

treatment enhances this relationship with patients, providing an insight into their prob-

lems and feelings and facilitates the exchange of

information throughout the research pro-

gramme.

Acknowledgements

In order to learn this procedure the author and the Senior Nurse of the Practice Development Intensive Care Unit, Maria Wilson spent some time at Kaneka’s main Euro- pean headquarters in Germany. Unfortunately, due to the pioneering nature of this procedure the support network in England is extremely limited, but the author’s thanks go to Dr Barbir, Senior Registrar, Senior Research Fellow, under the guidance of Professor Sir Magdi Yacoub, and Maria Wilson for their help and advice. Also to Sue West, Nurse Teacher at Harefield Hospital, for her unlimited time and help with this article.

Castelli W P 1986 Incidence of coronary heart disease and lipoprotein cholesterol levels. The Framingham Study JAMA, 256: p 2835-2838

Guyton M D I99 1 Textbook of Medical Physiology. 8th ed. Philadelphia, W B Saunders

Hunninghake D 1988 Unit 2 Lioprotein metabolism and regulation. Clinical Perspectives on Blood Lipids. Current Medical Literature

Kaneka 1991 MA-01 Apheresis unit. Kaneka Deutschland GmbH

Kaneka 1991 Sulflux plasma seperator FS-05. Kaneka Deutschland GmbH

Kaneka 1991 Liposorber LA-15. Kaneka Deutschland GmbH

Schmitz G et al 1989 The role of HDL in the reverse cholesterol transport and its disturbance in Tangier disease and HDL deficiency with xanthomas. Treatment of Severe Hypercholesterolemia in the Prevention of Coronary Artery Disease, 20-30. 2nd International symposium, Munich, Karker

Sheppard A 1989 Continuous high volume haemofihration -a nursing perspective. Care of the Criticallv Ill. 3 (4)

Sinclair V’1988 I-&h technology in critical care. Focus on Critical Care I5 (4): 36-4 1

HMSO 1992 The Health of The Nation. A Strategy for Health in England. Presented to Parliament bv Secretary of &ate for Health, by command of’Her Majesty. Her Majesty’s Stationery Office (HMSO)