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Specialized services CHAPTER 40
infusions. Specialized and very high-risk administration routes, such as intrathecal chemotherapy, are
the subject of specific and detailed guidelines. For
example, in the UK, the NHS Executive published
National Guidance on the Safe Administration of
Intrathecal Chemotherapy (HSC 2003/010) in
2003. Pharmacy has a major role in assuring error-free
drug administration. Infusions must be presented in
the appropriate form and container, and must be
clearly labelled so that nursing staff are provided with
unambiguous information about the route, method
and rate of administration. The involvement of the
oncology clinical pharmacist in the development of
drug administration procedures is crucial.
Provision of chemotherapy at home
The introduction of effective oral chemotherapy for
cancer, such as capecitabine, has enabled increasing
numbers of patients to receive treatment at home. It
is also possible to provide parenteral chemotherapy in
the domiciliary setting, with home chemotherapy
programmes. Patients have more involvement in the
administration of their medicines, are able to spend
more time with their families and avoid the inconvenience of regular hospital treatment. This, in turn,
liberates hospital beds to treat other patients.
Chemotherapy infusions can be administered to
patients at home or at work using small, portable
ambulatory pumps. These range from sophisticated,
programmable electronic devices and battery operated syringe drivers to simple, disposable elastomeric
pumps which have a fixed rate of infusion. For a more
detailed review of ambulatory infusion devices, the
reader is referred to Chapter 38 of this publication
and to The Cytotoxics Handbook (Allwood et al
2002).
The pharmacist responsible for the centralized
cytotoxics service must have a good working knowledge of chemotherapy regimens and the appropriate
infusion devices available for home chemotherapy. In
certain oncology centres, the pharmacist may also
become involved in training patients to manage their
infusion devices, and in the safe handling and disposal
of cytotoxic drugs. This is necessary to ensure the
health and safety of patients and their carers in the
home-care environment.
The implications for a pharmacy department setting up a home chemotherapy service are wide ranging. Many home chemotherapy doses are supplied for
1 or 2 weeks at a time. Staff will need to be trained
and validated in the techniques used for filling the
ambulatory infusion devices required for home chemotherapy. Early home chemotherapy regimens were
relatively simple, for example 5-fluorouracil continuous infusion for colorectal cancer. However, more
complex, multiple agent regimens are now used. In
cases where either the therapeutic response or drug
clearance is influenced by a circadian rhythm, it is
possible to exploit chronotherapy to optimize treatment using electronic infusion pumps programmed to
administer different amounts of chemotherapy over a
24-hour period.
The stability of drug infusions in ambulatory
devices is a key element in the provision of home
chemotherapy services. In addition to prolonged storage under refrigerated conditions, ambulatory infusion devices are worn under the patient’s clothing,
exposing drug infusions to elevated temperatures
C) for extended periods of time. Stability data
(37
on cytotoxic infusions are documented in The Cyto-
toxics Handbook (Allwood et al 2002) and Handbook
on Injectable Drugs (Trissel 2006). In many cases,
stability data appropriate to specific combinations of
drug infusions and devices can only be found in the
scientific literature, or may need to be determined de
novo. In this context, the continuation of research on
drug stability under clinical conditions is a crucial role
for the few hospital pharmacy departments with a
research laboratory.
Centralized intravenous additive service (CIVAS)
The Breckenridge Reportproduced in the UK in 1976
made recommendations that IV infusions should be
prepared, where possible, by hospital pharmacies. Although the preparation of IV cytotoxic medicines was
taken up soon after this report, the wider provision of
an IV additive service did not commence until the
1980s and then only in a limited number of hospitals.
The establishment of the UK national CIVAS
group in 1991 gave more hospital pharmacists the
initiative and support for the provision of a CIVAS.
By 1998 the CIVAS Handbook was produced to provide guidelines for hospital pharmacists setting up
a CIVAS. Currently a large proportion of hospital
pharmacists in the UK and many European countries
provide a CIVAS, and this is augmented by a growing
number of commercial compounding units. Despite
these developments, it is estimated that of all
459
SECTION FOUR Dispensing and related pharmaceutical practice activities
infusions prepared in UK hospitals, less than 40% are
prepared in pharmacy CIVAS units.
Scope of a CIVAS
A CIVAS is set up to provide a range of parenteral
dosage forms suitable for administration to patients.
Medical, nursing and pharmacy staff involved in
patient care in this field will decide the range of dosage forms supplied. A CIVA service can provide the
following:
*
IV antibiotics, antivirals, antifungals and steroids
*
Patient-controlled analgesia, and other opioid
infusions for postoperative analgesia and palliative
care
*
Epidural analgesics infusions
*
Ambulatory infusion devices for various IV
therapies at home
*
Electrolyte infusions (that are not commercially
available)
*
Clinical trial medicines (if licensed).
Often a CIVAS is operated in conjunction with other
aseptic compounding services in the pharmacy (e.g.
cytotoxic reconstitution and compounding of parenteral nutrition solutions). Given that CIVAS are
resourced to provide only a proportion of the IV additive/compounding needs of a hospital, they normally prioritize the services offered according to clinical
risk. Accordingly, CIVAS-produced infusions often
include antibiotics for neonates and paediatric
patients which require extensive dilution to the required doses. Other high-risk infusions such as complex electrolyte mixtures and ambulatory infusions
for home use are often prepared by hospital CIVAS
units or are sourced from commercial suppliers. Economic factors can also influence which infusions are
prepared in CIVAS units. Many IV medicines contain
no preservative and are designed for single use only.
Preparation of infusions from these medicines on the
hospital ward can often result in significant wastage
because only the dose required for immediate use can
be taken. However, subject to validated infusion stability, it is possible for a CIVAS unit to prepare a batch
of infusions for several days’ use, or even longer, so
reducing or eliminating drug wastage. In the UK,
aseptically prepared medicines may only be assigned
a shelf-life of >7 days if supported by validated stability data and providing the unit in which the infusions are prepared holds a ‘Specials Manufacturing
License’ issued by the Medicines and Healthcare
products Regulatory Agency (MHRA).
It is likely that the recent NPSA Alert 20 on injectable medicines will provide the stimulus for more
ward or clinic-prepared infusions to be transferred to
pharmacy CIVAS units to reduce the risk of medication errors.
CIVAS dosage forms
Most hospital pharmacies supply IV additives in the
form of a pre-filled syringe or a minibag. Minibags are
small volume infusion bags containing volumes of 50–
250 mL of common infusion diluents such as 0.9%
sodium chloride infusion, 5% glucose infusion or water for injection. Nursing staff often prefer CIVAS
doses supplied in minibags as they are easier to administer than syringes, although local preference can
vary. Reconstitution procedures are usually required
as IV doses are normally received from the manufacturer as sterile freeze-dried powders in sealed vials.
The freeze-dried presentation enables the manufacturer to assign a realistic shelf life to these medicines,
which are often relatively unstable in aqueous solution. These vials are then reconstituted with the appropriate diluent and drawn up into a syringe. The
syringe is then sealed with a blind hub, or if a minibag
presentation is required, the dose is transferred to an
appropriate minibag ready for administration to the
patient. In some cases it will be necessary to withdraw
a predetermined volume from the minibag to allow
the additive volume to be accommodated. In addition
to pre-filled syringes and minibags, CIVAS also provide pre-filled ambulatory infusion devices for domiciliary treatments.
Provision of a CIVAS
Traditionally, IV doses were prepared on the ward or
clinic by nursing staff or junior doctors who have
limited training in aseptic technique and little experience of calculating appropriate doses and the complex manipulations required for preparing IV
medicines. Ward facilities for preparing IV medicines
are not ideal and increase the risk of the product being
contaminated as it is not prepared under aseptic conditions. A CIVAS operated by trained, competencyassessed pharmacy staff using purpose-built aseptic
dispensing facilities ensures that IV products are
prepared to the highest possible standards. Clear,
comprehensive labelling, full documentation and improved control of ward stocks of IV medicines are also
possible with a pharmacy CIVAS. These attributes
460
Specialized services CHAPTER 40
can significantly improve the risk management of
infusions used in a wide variety of therapeutic areas.
The issues to be considered when setting up a
CIVAS are essentially the same as those discussed
previously for establishing centralized cytotoxic reconstitution services, although the health and safety
and occupational exposure aspects are less important
with CIVAS. A dialogue should be established between representatives from pharmacy, medical staff,
nursing staff and hospital administrators. Information
should be gathered on the number of IV doses being
used, who prepares them and the conditions under
which they are prepared. The proportion of this workload that should be transferred to the proposed pharmacy CIVAS unit can be identified through a risk
assessment, and the resources necessary to provide
this capacity can be determined. It may be helpful
to clearly define the service that wards and clinics
can expect through the development of service level
agreements.
Any consideration of the resources required to set
up a CIVAS must consider the capital costs for the
aseptic unit and associated equipment (laminar flow
hoods, labelling systems), maintenance costs for facilities and equipment, staff costs for both the CIVAS
and the associated QA systems, staff training costs
and consumable costs. It should also be possible to
estimate the proportion of these costs that can be
offset by savings from reduced drug wastage. There
may also be the possibility of generating income by
providing CIVAS to neighbouring hospitals and private clinics, providing there is adequate capacity.
The main goals of providing a CIVAS should include:
*
Improved patient safety
*
Improved use of hospital resources
*
Improved services to patients, particularly with
home infusions
*
Improved pharmacy control and reduced risk of
medication errors.
Although there are compelling reasons for the provision of pharmacy CIVAS in all major hospitals, it is
important in presenting a balanced argument to be
aware of potential disadvantages to the hospital and
healthcare system:
*
Increased pharmacy expenditure, including capital
expenditure, diverts funds from other healthcare
services.
*
Pharmacy CIVAS, once established, should be
available 24 hours a day, including weekends and
public holidays. This will require a major
commitment from pharmacy staff and will also
need to be fully funded.
*
There is a potential risk of de-skilling ward staff in
the preparation of drug infusions. This need not be
a problem if the CIVAS is reliable and always
available.
*
Some wards and departments may be difficult to
service, e.g. accident and emergency and intensive
care, because doses of some drugs may be required
urgently, particularly in an emergency situation.
*
Expectations of the CIVAS by medical and nursing
staff may not always be realistic. For example,
prescribers may not feel the need to furnish
prescriptions for infusions in a timely manner,
which then places great pressure on the CIVAS
unit and causes frustration to nursing staff waiting
to administer infusions.
*
The capacity of the CIVAS is not infinite but there
will always be pressures to add new drugs to the
service as soon as these enter clinical use.
Many of these problems can be overcome through
good communication, both within the pharmacy
department and with medical and nursing staff. A
service level agreement (SLA) is a useful device for
ensuring that all stakeholders know their responsibilities and that the service operates within the confines
of the available resources.
Techniques used in CIVAS
The techniques, procedures, documentation systems
and validation requirements of CIVAS are essentially
the same as those described previously for chemotherapy services. The main difference is that CIVAS
medicines tend to be less hazardous so there is a much
lower emphasis on occupational exposure control.
This means that instead of isolators and Class II
cabinets, CIVAS units tend to use conventional
horizontal and vertical laminar flow cabinets. However, it should be recognized that some antibiotics
(e.g. penicillins) are sensitizing agents, and some
hospitals prefer to use isolator technology for both
their cytotoxic and CIVA services.
The reduced hazards associated with CIVAS
medicines enable the use of pressurized systems in
the reconstitution of freeze-dried drugs and in fluid
transfer systems. For example, if minibags are used, a
reconstitution device can be used to transfer the
diluent into the vial, then, after vigorous shaking, back
into the bag again. Throughout this procedure the vial
and minibag remain attached via the reconstitution
461
SECTION FOUR Dispensing and related pharmaceutical practice activities
undertaken. This will include the use of settle plates
(normally at every work session), finger-dab plates
by each operator at the end of each session, and
active microbial sampling, air particulate sampling
and measurement of air flows from filters at least
monthly. Clean room over-pressures should be
recorded at least daily, and HEPA filter integrity
checks should be carried out at least on an annual
basis or in the event of any deviation from defined
operating conditions.
Records will be kept for all IV medicines prepared
and will include the batch numbers of products used
during reconstitution procedures. This ensures that in
the event of a product recall or any problems with an
IV medicine, a full audit trail documenting all aspects
of the process can be reviewed. Records of any errors
or complaints should also be maintained, together
with the action taken. This information should also
be used to inform staff training.
Figure 40.5*Reconstitution device used for CIVAS doses.
(Courtesy of Baxter Healthcare Ltd.)
Validation of procedures
device which has a double-ended needle. One end of
the needle is placed through the rubber bung of the
vial and the other end is connected into the rubber
septum of the minibag (Fig. 40.5).
Prior to removal from the laminar airflow cabinet
or the isolator cabinet, all prepared syringes are sealed
with a blind hub and minibags are sealed with an
additive plug or tamper-evident closure. This ensures
that no further additions are made to the syringe or
minibag outside the pharmacy. All products are
labelled and sealed into an outer bag before being
transported to the ward.
Quality assurance
All procedures used during preparation of CIVAS
doses must be fully validated and documented. Procedures must also be audited and be subject to inprocess monitoring. Staff preparing IV products
should complete appropriate batch documents and
adhere to authorized SOPs and published guidelines.
As with the chemotherapy preparation service described previously, batch documents, finished product, used components and records for environmental
monitoring and operator validation are all considered
as part of the decision-making process for the release
of CIVAS medicines for administration to patients.
As with any procedure carried out under aseptic conditions, routine environmental monitoring must be
Validation of aseptic processes and operator technique will include the use of broth transfer simulations and observation by experienced practitioners.
The level of activity and number of staff working in
the unit should be taken into account as staff movements are a potential cause of microbiological contamination (see Ch. 29). Validation of processes and
operator technique for CIVAS is almost identical to
the validations necessary for chemotherapy preparation (see above), with the exception that fluorescent
dye simulations are arguably less critical. However,
the use of fluorescent dye simulations can still
play a valuable role in the validation of cleaning
procedures.
Infusion stability and shelf life assignment
The assignment of a shelf life or expiry date to any
aseptically prepared medicine is a rigorous, evidencebased process which requires expert interpretation of
physical and chemical stability data and a clear understanding of the level of protection afforded to prevent
microbiological contamination during the aseptic
preparation process.
In the UK, aseptic medicines prepared under
Section 10 of the 1968 Medicines Act, which requires
pharmacist supervision of the process, are restricted
462
Specialized services CHAPTER 40
to a maximum shelf life of 7 days, and then only if
there is evidence to support this. Even if there is
evidence to support a longer shelf life, an expiration
of >7 days cannot be assigned to any CIVAS medicines prepared under this system. On the other hand,
aseptic medicines made under a manufacturer’s
‘specials’ license issued by the MHRA can be assigned
any reasonable shelf life providing this is supported
by rigorous evidence on the physical and chemical
stability of the infusion, and evidence that the microbiological quality of the product is maintained during
both preparation and subsequent storage.
Stability data for CIVAS infusions, including
cytotoxic drugs, can be sourced from a number of
textbooks including Handbook on Injectable Drugs
(Trissel 2006), The Cytotoxics Handbook (Allwood
et al 2002) and the CIVAS Handbook (Needle 2007).
In many cases, it will be necessary to search the scientific and professional literature for original stability
study reports and, on some occasions, the drug manufacturer may be willing to share extended stability
data. Whatever the source of information, stability
data should always be subjected to critical appraisal
before they are used in the assignment of infusion
shelf lives.
It is critical that stability studies are carried out
under pharmaceutically and clinically relevant conditions. The drug concentration, choice of diluent, container and storage conditions must reflect those used
in clinical practice. The method used to assay the drug
must be stability indicating, meaning that it will be
responsive to any drug degradation and that drug degradation products will not interfere with the accurate
determination of the drug itself. This cannot be assumed even for sophisticated and selective analytical
methods such as high-pressure liquid chromatography
(HPLC). It is vital that validation data support the
stability-indicating ability of the assay. In addition to
the drug assay, physical stability is assessed by determination of sub-visual particulate matter, visual appearance, pH and the absence of any material or
chemicals leaching from the container into the infusion. For more complex biological molecules such as
monoclonal antibodies, assessment of stability using
simple chemical and physical testing is not adequate.
These large molecules are held in secondary and tertiary structures by weak intramolecular hydrogen
bonds, and these complex conformations are essential
to maintain biological activity. It is important, therefore, to assess the stability of such molecules on the
basis of biological activity. In all cases, realistic acceptance limits must be defined for drug degradation.
Typically either 5% or 10% degradation is permitted,
depending on the clinical use of the product and the
expected toxicity of the degradation product(s).
Normally, aseptically prepared medicines are
stored under refrigerated conditions (2–8
C) to inhibit the proliferation of any microbial contaminants.
However, the limited physical stability of some infusions under refrigerated conditions requires that room
temperature storage is used instead. In some cases,
freezing the infusion at 20
C can extend the shelf
life of CIVAS prepared infusions. Infusions of the
cephalosporin antibiotic ceftazidime are an example
in which infusion stability can be increased from 8
days at 2–8
C to 84 days at 20C. Such infusions
must be fully thawed and equilibrated to room temperature before issue to the clinical area.
Assessment of infusion stability is a key responsibility of any pharmacist managing a CIVAS. In the
case of infusions which are outsourced from commercial compounding units, it is essential that clear and
robust evidence is available to support the assigned
shelf life. Care must be exercised when attempting to
extrapolate published stability data to infusions with
variations in the concentration, diluents or container
used. Expert review and a written justification are
required to validate a shelf life where there is any
variation to the conditions under which the stability
data were obtained.
Consideration must also be given to the transportation and storage of aseptically prepared medicines,
particularly where infusions are transported over long
distances to other hospitals or to patients receiving
home infusion treatments. Cold chain transport systems or refrigerated vans must be fully validated to
ensure that the stability of infusions is not compromised, and the temperature of refrigerators used for
storage of infusions should be monitored at least daily,
but preferably by continuous monitoring and data
logging (see Ch. 43).
Provision of IV doses for home
patients
The potential benefits described previously for home
chemotherapy are also applicable to the treatment of
other, non-malignant diseases. The range of clinical
applications for home infusion therapy is continually
expanding; for example pain control (postoperative
and terminal care), thalassaemia, infections of the
bone, joints and skin, cystic fibrosis (prophylaxis and
acute infection flare-up), Parkinson’s disease, and
463
SECTION FOUR Dispensing and related pharmaceutical practice activities
non-malignant conditions such as rheumatoid arthritis
are treated with cytotoxic drugs. The ambulatory infusion devices used for non-malignant diseases are
similar to those described for cancer chemotherapy,
with the exception that larger infusion volumes tend
to be used and with some drugs, for example antibiotics, the accuracy of the infusion rate is less critical. A
number of different options are available for patients
receiving home IV therapy (see Ch. 38).
Single-dose bolus injections
These are provided as a pre-filled syringe for bolus
administration by either the patient or an outreach
nurse. Pre-filled syringes of ceftriaxone, administered
once daily for the home treatment of cellulitis, are an
example of this type of presentation.
Single-dose infusions
Medicines that need to be given as an infusion at a
frequency of one to four times daily are often administered using single-use, disposable elastomeric
devices, such as the Baxter Intermate. The drug infusion is filled via a luer lock valve into an elastomeric
reservoir which, when expanded, drives the infusion
through a flow-restrictor device which may also incorporate a hydrophobic filter to eliminate any air
bubbles. These devices require no battery and are
available with a wide range of flow rates and infusion
volumes. Elastomeric infusors can be used for selfadministration by patients who can connect the device to a peripheral or central venous catheter. Examples of home infusions using elastomeric devices
include ceftazidime and tobramycin infusions for cystic fibrosis, and desferrioxamine infusion for the treatment of thalassaemia.
Continuous infusions
Prolonged, continuous infusions are required for control of severe pain, where powerful opioid analgesics
are infused, often by the subcutaneous route. Continuous infusions, running for 12 hours or more, are also
used for other drugs such as the dopamine agonist
apomorphine, which is used in the treatment of Parkinson’s disease. This type of infusion can be administered with small, portable syringe drivers. These
battery-operated infusion devices use a syringe as
the infusion reservoir and are ideal for the adminis-
tration of small infusion volumes (<20 mL over
24 hours). More sophisticated electronic infusers
work by a peristaltic mechanism and use polyvinyl
chloride infusion reservoirs of 50–500 mL volume.
These devices are often programmable and are
designed to prevent alteration of settings by the patient. However, they are expensive and tend to suffer
from a relatively short battery life.
The hospital pharmacy CIVAS has a clear role in
providing pre-filled syringes and reservoirs for home
infusion patients. Some centres also provide the
actual infusion devices and other consumables required by home infusion patients (e.g. sharps bins
for disposal of waste, alcohol wipes and sterile gloves).
Close liaison between pharmacy, nursing and medical
staff is required to ensure home infusions are prescribed and prepared when needed, that the infusion
device selected is appropriate to the patient’s needs,
and that the CIVAS unit can respond to any changes
of dose or therapy.
KEY POINTS
*
Cancer chemotherapy can include treatment with
cytotoxic drugs and biological ‘targeted’ therapies
*
Cytotoxic drugs can be classified as alkylating
agents, antimetabolites, anti-tumour antibiotics
and miscellaneous drugs
*
Cytotoxic agents may be given orally (tablets,
capsules or suspensions) or parenterally (slow
bolus or IV infusion)
*
There are significant occupational exposure risks
to healthcare workers who handle cytotoxic drugs
*
Compliance with safe handling guidelines,
combined with use of protective equipment,
containment facilities and validated technique can
minimize cytotoxic exposure to healthcare staff
and patient’s carers
*
Use of strict aseptic conditions minimizes the risk
of microbiological contamination during
preparation
*
Detailed standard operating procedures for
preparation and administration of chemotherapy
must be prepared and implemented
*
All personnel involved in provision of a centralized
cytotoxic reconstitutions service must be trained
and validated in all relevant procedures and
techniques
*
Transfer of solutions between cytotoxic drug
vials and syringes must be carried out using a
hydrophobic venting pin or a purpose designed
transfer device to avoid the generation of
aerosols
*
The pharmacy chemotherapy unit has a key role in
the provision of home chemotherapy services
464
Specialized services CHAPTER 40
*
Drug stability is a key issue in assigning infusion
shelf lives, particularly those used for home
infusion
*
Increased use of chemotherapy outpatient or
day-case clinics can place significant pressures
on the workload of the pharmacy chemotherapy
unit
*
New strategies such as ‘dose-banding’ are useful
to manage chemotherapy workload
*
A CIVAS can provide a wide range of aseptically
prepared medicines for hospital and domiciliary
use
*
Potential benefits of CIVAS include reduced risk of
medication errors, improved use of resources,
better services to patients and pharmacy control
*
Potential difficulties in operating a CIVAS, such as
staffing, out-of-hours and emergency provision
and unrealistic expectations can be resolved with
good communication skills
*
Most doses are provided from CIVAS as either prefilled syringes or minibags
*
Home IV therapy may use pre-filled syringes,
single-dose infusers, electronic infusers or syringe
drivers to administer drug infusions
465
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Chapter Forty-One
Parenteral nutrition and dialysis
Lindsay Harper and Liz Lamerton
41
STUDY POINTS
*
Provision of nutritional support for patients
*
Indications for total parenteral nutrition (TPN)
*
Components and compounding of a TPN/home
parenteral nutrition (HPN) formulation
*
Addition of medicines to a TPN or HPN bag
*
HPN training and potential problems
*
Administration of a TPN/HPN formulation
*
British Parenteral Nutrition Group and British
Association of Parentral and Enteral Nutrition
*
Introduction to home care for patients on dialysis
*
Haemodialysis (HD), peritoneal dialysis (PD),
including continuous ambulatory peritoneal
dialysis (CAPD), intermittent peritoneal dialysis
(IPD) and automated peritoneal dialysis (APD)
*
Dialysis solutions
*
Provision of services from a hospital renal unit,
including home dialysis
Introduction
Today an increasing number of patients are requesting
and being provided with healthcare services at home.
Such services include provision of home parenteral
nutrition and home dialysis. This chapter will explore
the provision of parenteral nutrition and dialysis for
patients in hospital and will explain how these services
can be transferred to the home-care setting.
Provision of nutritional support
Studies have shown that up to 50% of medical
and surgical patients can suffer from nutritional
deficiencies. If nutritional support is indicated, enteral feeding is considered as the first option. Patients
can receive nutrients orally or via a tube feed, e.g. by
nasogastric feeding. This is only possible if the gastrointestinal tract is functional. If this is not the case,
parenteral nutrition may be considered. Short-term
(e.g. postoperative) intravenous (IV) administration
of fluids such as 5% dextrose or saline may be sufficient. This could provide the patient with around
500 calories per day but does not provide any protein,
vitamins, minerals or trace elements.
For patients requiring longer-term nutrition, total
parenteral nutrition (TPN) may be required. TPN is a
method of administering adequate nutrients via the
parenteral route. The components of a TPN formulation are added to a sterile infusion bag and administered to the patient via a catheter. Administration can
be via a peripheral venflon, a peripherally inserted
central catheter (PICC) or a central line. However,
TPN fluids are normally highly concentrated mixtures which on a long-term basis could cause damage
to peripheral veins. For this reason, peripheral veins
are only used for TPN administration lasting up to 4
weeks.
If parenteral nutrition is supplied to patients at
home, it is known as home parenteral nutrition
(HPN). Patients on HPN administer their nutrition
via a central line into a central vein. Commercial pharmaceutical home-care companies most commonly
provide the TPN for HPN patients, although some
patients may receive the TPN from their local hospital
TPN compounding unit.
Parenteral nutrition formulations are prepared
under strict aseptic conditions (see Ch. 29) following
guidelines published by the Medicines and Healthcare
SECTION FOUR Dispensing and related pharmaceutical practice activities
products Regulatory Agency (MHRA) in Rules and
Guidance for Pharmaceutical Manufacturers (2002)
and by the Department of Health in Aseptic Dispensing for NHS Patients (Farwell 1995).
HPN is becoming increasingly prevalent, particularly for patients who require long-term parenteral
nutrition. Guidelines have been published by the
British Association of Parenteral and Enteral Nutrition (BAPEN) and the National Institute for Health
and Clinical Excellence (NICE) to ensure that adequate provision is made for patients receiving HPN
(Wood 1995). Patients who are suitable candidates
for HPN will be initially stabilized on TPN bags while
in hospital. They can then undergo appropriate training to enable them to administer their TPN bags at
home. If the patient is unable to care for their line,
then a carer or nurse would be trained to administer
the TPN at home. However, HPN patients will still
require to return to the hospital for regular check-ups.
This means that pharmacists involved in the care of
HPN patients will require a working knowledge of
the procedures adopted to provide care for patients
in hospital and at home. They may also have to
liaise with the patient’s GP, the community nurse,
primary care trust and other healthcare workers in
this field.
This chapter concentrates on the provision of
adult TPN in hospital and at home, although neonatal
TPN is available.
Indications for TPN
TPN can be required for finite periods of time or can
be required for life. Some of the main indications for
TPN are:
*
Gastrointestinal disease including Crohn’s disease,
ulcerative colitis, pancreatitis and malabsorption
syndrome (e.g. scleroderma patients)
*
Major trauma including severe burns, severe
septicaemia, intensive care patients and acute
renal failure
*
Major abdominal surgery; severely malnourished
patients may benefit from early peri- and
postoperative parenteral nutrition if surgery has
resulted in a non-functioning gastrointestinal
tract
*
Malignancy of the small bowel
*
Radiation enteritis when TPN is considered if
enteritis is severe after treatment of a primary
malignancy
*
High-dose chemotherapy, radiotherapy and bone
marrow transplantation. Patients are often ill for a
limited time (3–6 weeks) and are unable to eat.
TPN can be administered during this period to
ensure that the patient’s nutritional requirements
are adequately met.
Several other conditions may require the nutritional
support of TPN, e.g. patients in a prolonged coma or
AIDS patients.
Assessment of the patient in hospital
TPN aims to provide patients with all their nutritional requirements in one formulation which can
then be infused directly into t he body via the veins,
either central or peripheral. In order to determine
exactly what the patient’s nutritional requirements
are, clinical and biochemical assessments must take
place. A clinical patient history is recorded followed
by a physical examination to give a clearer picture of
the patient’s current medical status. The Malnutrition Universal Screening Tool (MUST) is used to
identify patients who may benefit from TPN.
Patients’ body we ight, height and body mass index
(BMI) can be recorded and comparison made with
their ideal body weight which would be available
from standard charts. In most hospitals a dietician
would review the patient and calculate t heir nutritional requirements.
Biochemical assessment will be undertaken initially by performing a number of routine tests which
can then be repeated as necessary during TPN therapy. Factors investigated will include urea and electrolytes, full blood counts, liver function tests,
triglycerides, blood glucose and fluid balance. Trace
elements are only required if the patient receives TPN
for longer than 28 days. The NICE guidelines for
nutrition support contain a section on the monitoring
required for TPN patients.
Each hospital has its own particular way of designing a TPN regimen. Most hospitals use a range of
standard formulations which are routinely used
to treat TPN patients. Standard bags can be altered
if the need arises, e.g. intensive care patients may
require extra nitrogen in the formulation, renal
patients may need an electrolyte-free formulation.
In general, additions to the finished TPN bags outside
of the pharmacy aseptic unit is not recommended in
order to minimize microbial contamination.
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