Hospital Pharmacist
Vol 11 No 8 p346
September 2004

British Pharmaceutical Nutrition Group / Hospital Pharmacists’ Group

Growth in the market for ready to use parenteral nutrition bags was one of the topics discussed at the British Pharmaceutical Nutrition Group and Hospital Pharmacists’ Group joint study day held in London on 6 July. Ruth Newton and Gil Hardy report

Does one size fit all?

Over 100,000 “ready to use” (RTU) bags were used in total in just over 90 hospitals in 2003, according to Tim Sizer (School of Continuing Education at Leeds University). Mr Sizer made this statement when setting out the findings of an audit carried out by Bruce McElroy (Royal Shrewsbury NHS Trust) on behalf of the British Pharmaceutical Nutrition Group.

The main reason for the growth in the use of RTU bags, according to the survey, is staffing and capacity constraints in hospital aseptic units. There is also a perception that parenteral nutrition compounding is a high risk activity. Cost (ie, not incurring the expenses associated with aseptic production) is also a factor.

Although there are RTU bags to suit most stable patients requiring parenteral nutrition, bags for children, infants and metabolically compromised patients are not yet available, Mr Sizer said. Moreover, none of the commercially-prepared bags are actually “ready to use” in as much as vitamins, trace elements and often electrolytes need to be added, so they still need to be “sprayed in”.

The BPNG audit also indicated that 60 per cent of hospitals have a nutrition support team (NST) but only 40 per cent of parenteral nutrition is prescribed by such teams. This is not necessarily a problem, providing the advice of the NST is sought before prescribing is done, Mr Sizer said. However, the findings of the audit suggest that this is not happening –– the nutritional requirements of 28 per cent of patients who received parenteral nutrition were not assessed in the first place and one third of those patients whose requirements were assessed did not receive the correct amount of vitamins and minerals. Part of the reason for this might be that RTU bags can be seen by non-NST staff as a “one-stop solution”, bypassing the need for tailoring parenteral nutrition to meet the requirements of individual patients, he said.

Mr Sizer concluded that one size does not fit all, but that RTU bags clearly have a place in nutritional therapy, providing that, whenever parenteral nutrition is provided, it must be complete and customised by pharmacists to meet patients’ requirements.

Supplementary prescribing

Having NSTs where pharmacist and nurse members (as well as doctors) prescribe parenteral nutrition regimens can make the day-to-day tailoring of therapy to a patients’ individual requirements easier, according to Peter Rhodes, principal pharmacist for technical services at Southampton University Hospitals NHS Trust. Mr Rhodes is one of three pharmacists at the trust who prescribe parenteral nutrition for appropriate patients, the idea being that he is able to make suitable adjustments to treatments without having to get a doctor “sign off” on the prescription, once a clinical management plan has been agreed. There are procedural issues around obtaining informed consent (many critical care patients are unconscious) and using unlicensed additives, including whether or not their addition to parenteral nutrition bags is covered by the “reformulation for the purposes of administration” exemption, he said, but these are in the process of being sorted out.

... And what about the route of clinical nutrition?

Deciding which route of nutrition to use is relatively easy, if an algorithm is followed, according to Dr Simon Gabe of St Mark’s Hospital, London. The basic rule in the algorithm is that parenteral nutrition is reserved for patients who have intestinal failure. If the gastrointestinal tract is functioning, even to only a small degree, then nutritional support can be given by the enteral route, maximising treatment with special feeds and with drug treatments such as prokinetics. Although this is the basic rule, the decision process must also examine issues such as the duration of intestinal failure, aetiology, comorbidity, prognosis and the availability of venous access, he said.

If enteral nutrition has been tried, and the patient is not progressing, then parenteral nutrition might be an option. However, other changes to treatment, such as supportive therapy with parenteral fluids and electrolytes for the short to medium term, might also be appropriate. The advantage of these, Dr Gabe added, is that fluids (as opposed to nutrition) do not require peripheral or central line insertion but can be administered subcutaneously. Finding suitable veins for peripheral access is a problem in critical care patients, he explained, and there are also infection risks.