THE PROFESSIONAL NURSE IN THE CELL SUPPORT UNIT LUCILLE WOOD SRN , CRM , Chief Professional Nurse

These may be of different types but the one used at Groote Schuur Hos­ pital (figure 1) is the NCI-IBM 2997 model which uses disposable pre­ sterilised plastic tubing and a sepa­ ration band (figure 2) which is as­ sembled, inserted into the machine and all air flushed out with physio­ logical saline. The machine func­ tion, integrity of the tubing, and the alarm systems are tested before the subject is started on the procedure. Each cell separator is operated by one full-time professional nurse who never leaves her station at any stage during the procedure. The machine can be used for different purposes including white cell collec­ tion, known as leucopheresis, plate­ let harvesting, known as plateletpheresis, plasma exchange or plas­ mapheresis, and red cell exchange. The different techniques are collec­ tively known as apheresis. The Cell Support Unit is ideally an integral part of the Department of Haematology, where it fulfils the function of providing white cells and platelets for the leukaemia and transplantation programme, collec­ tions of haematopoietic stem cells for bone marrow grafting, and a wide range of emergency pro­ cedures not only for haematology patients but for those in the remain­ der of the hospital. OPSOMMING ’n Goed-opgeleide verpleegkundige is die sentrale flguur in ’n Selondersteuningseenheid. So ’n eenheid bestaan uit gesofistikeerde bloedsel-afskeiers waarvan elk voltyds deur ’h verpleegkundige beman word. Die apparaat kan gebruik word om witbloedselle (leukopherese), of plaatjies (plaatjiepherese) te versamel. om plasma af te skei (plasmapherese) of vir rooibloedseluitruiling. Gesamentlik staan die verskillende tegnieke bekend as apherese. Die rol van die verpleegkundige tydens apherese val in twee kategorieë. Eerstens moet sy die masjien bedien en enige newe-effekte of komplikasies by die pasiënt onmiddellik herken en dienooreenkomstig optree. Tweedens het sy ’n be­ langrike rol by die werwing van skenkers. Meeste skenkers word deur andere saamgebring maar dit impliseer dat daar ’n gelukkige atmosfeer in die eenheid moet heers en dat die personeel bekwaam moet wees. Die eise wat in hierdie eenheid vir die veiligheid van skenkers en pasiënte gestel word beklemtoon die rol van die verpleegkundige as ’n gelyke vennoot van die geneesheer in die lewering van moderne gesondheidsorg.

These may be of different types but the one used at G roote Schuur Hos pital (figure 1) is the NCI-IBM 2997 model which uses disposable pre sterilised plastic tubing and a sepa ration band (figure 2) which is as sembled, inserted into the machine and all air flushed out with physio logical saline.The machine func tion, integrity of the tubing, and the alarm systems are tested before the subject is started on the procedure.
Each cell separator is operated by one full-time professional nurse who never leaves her station at any stage during the procedure.The machine can be used for different purposes including white cell collec tion, known as leucopheresis, plate let harvesting, known as plateletpheresis, plasma exchange or plas mapheresis, and red cell exchange.The different techniques are collec tively known as apheresis.
The Cell Support Unit is ideally an integral part of the D epartm ent of Haematology, where it fulfils the function of providing white cells and platelets for the leukaemia and transplantation program m e, collec tions of haematopoietic stem cells for bone marrow grafting, and a wide range of emergency pro cedures not only for haematology patients but for those in the rem ain der of the hospital.

THE NURSE -A CENTRAL FIGURE
The well-trained nurse is the central figure in the efficient operation of the Cell Support Unit.This indi vidual is responsible for the safety of those undergoing the proce dures, whether they be volunteer donors or patients and has as a pre requisite thorough training and competence in intensive nursing care.
To this basic requirement must be added a minimum of three months in an accredited training centre to become familiar with the operation of the cell separator in order that malfunction of the instru ment and complications arising in donor or patient may be recognised immediately and appropriate cor rective steps taken.This new breed of professional nurse reflects in part the introduction of sophisticated technology and in part the increas ing role played by nurses at the forefront of health care.

THE UNIT
The Cell Support Unit consists of expensive sophisticated machines called blood fraction separators.After the introduction and de velopment of separators in univer sity departments, they are being slowly introduced into blood trans fusion services for more efficient collection of platelets; here as well, the professional nurse should be in control of the procedure.

APHERESIS TECHNIQUES
The technique is relatively simple.Intravenous cannulae are intro duced into the brachial vein in the forearm.Blood enters the specially designed band in the machine where it is separated into compo nents based on differences in their specific gravities by means of cir cumferential centrifugation.Any of the components can then be select ively removed by means of roller

Leucopheresis
Leucopheresis is the collection of white cells and with appropriate ad justment in technique this may be largely lymphocytes or, more usually, predominantly granulo cytes.
Lymphocyte depletion may be used as a form of immunosuppres sive therapy and is being investi gated in the treatm ent of autoim mune and immunologically-mediated diseases.Granulocyte transfu sion plays a vital role in patients with neutropenia, as seen in severe acute aplastic anaemia, following bone marrow transplantation, and after cytotoxic chemotherapy in leukaemic patients.
In each of these situations the peripheral blood granulocyte count should be less than 0,5 x 109/€, the patient to have a sustained fever greater than 38,5°C, and having failed to respond to adequate courses of appropriate intravenous antibiotic therapy for 48 hours.Once granulocyte transfusions are commenced, they are continued until the count is greater than 0,5 x 109/€, the infection controlled, and the tem perature normal for 48 hours.
The procedure time for white cell collection is approximately two hours and depends upon the donor's white cell count.It is useful to administer 48 mg of methylprednisolone six to eight hours before commencing the collection to raise the white cell count.Under these circumstances, a 250 ml volume will contain between 2 and 4 x 1010 gra nulocytes which are morphologi cally and functionally normal.
During the procedure a concen trated citrate solution is infused as an anticoagulant in the ratio of 13:1 to the whole blood to ensure that clotting does not occur once blood is in the machine.A sedimenting agent in the form of 500 ml of hydroxyethyl starch is also added to the blood in the separator to im prove granulocyte separation.The donors are always ABO and Rh group compatible with the recipi ents.

Plateletpheresis
Plateletpheresis is undertaken for bleeding when the platelet count is below 20 x 109/€, particularly fol lowing chemotherapy for cancer.It is important that donors do not take any tablets containing aspirin or other antiplatelet drugs prior to do nation since, although the numbers may be normal, their function may be suboptimal.
A similar situation is found in patients with myeloproliferative syndrome and when such individu als require surgery additional plate lets may be needed despite normal numbers.
The procedure time is ninety mi nutes to collect 250 ml of plasma containing between 3 and 5 x 1011 platelets.It is useful, following plate let infusion, to monitor the rise in platelet count which should be ap proximately 50 x 1010/€ /n r for a single such pack and indications for further infusions can be gauged by documenting platelet survival.The latter m easurement is simply car ried out by twice daily platelet counts.

Plasmapheresis
Plasmapheresis refers to the separa tion and removal of plasma and its replacement with an appropriate fluid which may be either fresh, frozen plasma, fractionated serum, or plasmalyte B and albumin.A practical exchange is approximately four litres but will vary with the in dividual's plasma volume.
Flow rates between 30 and 50 ml/ minute are achieved using acid ci trate dextrose as an anticoagulant at a ratio of approximately 1:11 with the blood.Specimens are collected before and after the procedure to monitor the white cell count differ ential, platelet count, biochemical profile, and changes in clotting factor.Serum samples are stored to measure the level of the product re moved, such as cholesterol, antibo dies or immunoglobulin.
A wide variety of indications exist for plasma exchange.Firstly, the hyperviscosity syndromes, as in W aldenstrom's macroglobulinaemia, in multiple myeloma, and in cryoglobulinaemis where abnormal CURATIONIS proteins are precipitated in the cold.
Secondly are antibody-related diseases where the procedure is car ried out in conjunction with immu nosuppressive therapy using predni sone, cyclophosphamide, or azathioprine and aimed at removing the antibody giving rise to the disease.Examples would include Goodpas ture syndrome where renal failure and haemoptysis characterise the clinical syndrome, myasthenia gravis where weakness and paralysis are prominent clinical findings, and less frequently in haemophilia associ ated with antibodies to factor VIII, in diabetes with anti-insulin anti bodies, in rhesus sensitisation where anti-D causes haemolytic disease of the newborn, and in both immune thrombocytopenia and haemolytic anaemia.
Sim ilarly, im m une com plexes formed between foreign antigen and antibody may produce lifethreatening symptoms in systemic lupus erythematosus and fulminat ing glomerulonephritis.
Thirdly there is a group of miscel laneous conditions where plasma exchange may be used to remove poisons or drugs taken in overdose, removal of biologically active sub stances in hypercholesterolaem ia, in liver disease, porphyria, thyro toxic crisis, and even to remove blood group antibodies where in compatibility exists between donor and recipient prior to bone marrow transplantation.

Other indications
Continuous-flow red cell exchange is an efficient and practical way of removing abnormal haemoglobin (HbS) in patients with sickle cell anaemia and replacing this with normal adult haemoglobin (H bA).This may be done prophylactically where patients require surgery or therapeutically when patients pre sent with sickle cell crises.
In addition, therapeutic leuco pheresis may be done where very high white cell counts may interfere with blood flow, as in acute and chronic leukaemia, while platelets may be removed by means of thera peutic plateletpheresis in individu als at risk from throm botic episodes due to thrombocythaemia.

ROLE OF THE NURSE
In all of these sophisticated and relatively complex techniques, the role played by the professional nurse cannot be overstated and falls into two broad groups.Firstly, the thorough competence with all as pects of machine operation includ ing the recognition of hazards and complications associated with the procedures.Secondly, the impor tant role of donor recruitment.

Machine operation and patient observation
Hazards may be associated with the machine.Thus, air embolism may result from incorrect priming, extracorporeal clotting may reflect in sufficient anticoagulant, while hae molysis may be due to a failure to recognise abnormal pressure changes occurring in the circuit.
Anticoagulants, particularly the acid citrate dextrose solution used in the procedures, may lead to side effects including citrate toxicity in which reduction of ionized calcium, due to binding, produces symp toms.The latter may be slight with numbness and tingling in the lips and around the mouth or the extre mities, while priapism may be em barrassing.Failure to immediately recoginse and correct citrate over dosage may lead to more severe side effects such as nausea and vo miting, substernal chest pain with changes in the electrocardiograph, and even cardiac arrest.While cor rection is easy and involves reduc tion in flow rate, failure to obtain immediate reversal may require the intravenous administration of 10 ml of 10 % calcium gluconate over the course of 10 minutes.
The sedimenting agent, hydroxyethyl starch, may result in urticaria, skin irritation with no visible changes which may last for many days, or headache due to plasma ex pansion.The replacement fluid, particularly when this is fresh, frozen plasma, may cause allergic reactions, fever, chills, urticaria, and hypotension.
Finally, the individual under going the procedure may present difficulties because of poor venous access, or anxiety, usually during the first procedure.This can be overcome by a confident operator, reassurance to the patient, and careful step-by-step explanation.
Syncopy or fainting may occur.Haem atoma may occur at the site of intravenous cannulation, particu larly in the hands of inexperienced or poor operators and, similarly, blood may infiltrate the return site.
In each of these situations it is im perative that the professional nurse be able to recognise and separate anxiety from changes in plasma cal cium level due to citrate intoxica tion or dilutional effects.Only ex perience will help the nurse to re cognise more severe reactions that may occur during the course of these procedures and which may c o rre la te w ith the u n derlying disease.
It is completely unacceptable to have a sister nominally present or in charge of such a unit.The only ar rangement appropriate for an aca demic institution is to have a senior member of the nursing faculty posi tively and directly in charge of all aspects of the procedure and re sponsible for the supervision and inservice training of her more junior staff.

Donor recruitment
Neither should the question of d o n o r re c ru itm e n t, which lies within the ambit of the professional nurse, be underestimated.While in many situations families of patients come forward as volunteer donors, the demands of a busy unit require considerable support from the com munity and this can be elicited most efficiently by word of mouth in which one donor brings friends.To be efficient, such a system implies a happy unit competently staffed and with which the donor panel clearly identifies.Additional sources of donor recruitment are the media in cluding the press, radio, television, and illustrated short talks to large firms and factories.Donor selection itself is impor tant since each individual estab lishes a personal relationship with the nursing staff of the Cell Support Unit.It is the moral responsibility of the staff to fully explain the pro cedure to all donors, including the use of drugs, and then to obtain fully informed consent.
Initial screening includes blood and rhesus grouping, screening for hepatitis, malaria, and venereal disease, and excluding underlying serious illness.Donor age is not critical, lying anywhere between 18 and 55 years.A suitably large panel, meticulous control of rota tion and a philosophy never to store products but to collect components only as the specific need arises will mean that donors are used about once every four months for white cell collections but monthly for platelet donation.Following bone marrow grafting, the donor may undergo apheresis daily for five days to collect haematopoietic stem cells.

CONCLUSION
It is concluded that the professional nurse plays a vital role in the Cell Support Unit.The services range from collection of white cells and platelets through continuous-flow red cell, white cell, and platelet ex change to plasmapheresis.In each of the procedures sophisticated equipment with numerous fail-safe devices is used.
Nevertheless, it remains the car dinal principle that safety rests solely on the shoulders of the pro fessional nurse in charge of the pro cedure.Only thorough familiarity with every aspect of the instrument and the procedure is compatible with patient safety and there is no excuse for leaving an instrument unattended at any stage of its oper ation.These prerequisites for donor and patient safety emphasise the everexpanding role of the profess ional nurse as an equal partner with the doctor in delivery of modern health care services.

Fig. 1
Fig. 1 Blood fraction separator.These include replacement of ab normal red cells in patients with sickle cell disease during crisis, plasma exchange for life-threatening a n tib o d y -m e d ia te d d iseases such as myasthenia gravis and Goodpasture syndrome, or removal of immune complexes in rapidly progressive glomerulonephritis.