Chapter 8: Nutrition and fluid balance
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Source: Adapted from NCCAC ([108]) with permission of NICE.
Post‐procedural considerations
Ongoing care
Administration sets should always be changed every 24 hours (Loveday et al. [91], NICE [119], O'Grady et al. [132]). Existing injection sites on the administration set should never be used to give additional medications as parenteral nutrition is incompatible with numerous medications. Drugs may bind to the nutrients or the parenteral nutrition bag, reducing their availability. If any additional medications, blood products or central venous pressure (CVP) readings are required then they should be given or taken via a separate lumen or via an alternative device (NCEPOD [110]).
A volumetric infusion pump must be used to ensure accurate delivery of parenteral nutrition. No bag should be used for longer than 24 hours (BNF [23]).
If the infusion must be discontinued, the catheter should be flushed to maintain patency. The risk of infection increases if the infusion is disconnected from the central venous device; therefore, it is not advisable to disconnect parenteral nutrition until the whole daily requirement has been administered (NCEPOD [110]).
During intravenous feeding, monitoring is necessary to detect and minimize complications. Once feeding is established and the patient is biochemically stable then the frequency of monitoring may be reduced if the clinical condition of the patient permits (Table 8.19).
Table 8.19 Monitoring in nutrition support
| Parameter | Frequency of monitoring | Rationale | Interpretation |
|---|---|---|---|
| Catheter entry site | Daily | Signs of infection or inflammation | Interpret with knowledge of infection control |
| Skin over insertion site and tip of cannula or midline catheter | Daily | Signs of thrombophlebitis | |
| General condition | Daily | To check tolerance of feed and that feed and route continue to be appropriate | |
| Temperature/blood pressure | Daily, then as needed | Sign of infection, fluid balance | |
| Sodium, potassium, urea, creatinine | Baseline, then daily until stable, then one or two times a week | Assessment of renal function, fluid status | Interpret with knowledge of fluid balance and medication; urinary sodium may be helpful in complex cases with gastrointestinal fluid loss |
| Glucose | Baseline, then one or two times daily until stable (more if needed), then weekly | Glucose intolerance is common | Good glycaemic control is necessary |
| Magnesium, phosphate | Baseline, then daily if risk of refeeding syndrome, then three times a week until stable, then weekly | Depletion is common and under‐recognized | Low concentrations indicate poor status |
| Liver function tests | Baseline, then twice weekly until stable, then weekly | Abnormalities common during PN | Complex; may be due to sepsis, other disease or nutritional intake |
| Calcium, albumin | Baseline, then weekly | Low or high levels may occur | Correct measured serum calcium concentration for albumin; hypocalcaemia may be secondary to magnesium deficiency; low albumin reflects disease, not protein status |
| C‐reactive protein | Baseline, then two or three times a week until stable | Assists interpretation of protein, trace element and vitamin results | To assess the presence of an acute‐phase reaction; the trend of results is important |
| Zinc, copper | Baseline, then every 2–4 weeks depending on results | Deficiency is common, especially with increased losses | Patients are most at risk when anabolic zinc decreases and copper increases in acute‐phase reaction |
| Selenium | Baseline if risk of depletion, further testing depending on this | Deficiency is likely in severe illness and sepsis, and in long‐term nutrition support | Decreases in acute‐phase reaction; long‐term status better assessed by glutathione peroxidase |
| Full blood count | Baseline, then one or two times a week until stable, then weekly | Anaemia due to iron or folate deficiency is common | Effects of sepsis may be important |
| Iron, ferritin | Baseline, then every 3–6 months | Iron deficiency is common in long‐term PN | Iron status is difficult to assess in acute‐phase reaction; iron decreases while ferritin increases |
| Folate, vitamin B12 | Baseline then every 2–4 weeks | Iron deficiency is common | Serum folate/B12 sufficient with full blood count |
| Manganese | Every 3–6 months if on home PN | Excess provision to be avoided, more likely in liver disease | Red blood cell or whole blood better measure of excess than plasma |
| Vitamin D | Six‐monthly if on long‐term PN | Low levels if housebound | Requires normal kidney function for effect |
| Bone densitometry | On starting home PN, then every 2 years | Diagnosis of metabolic bone disease | Together with lab tests for metabolic bone disease |
| PN, parenteral nutrition. |
Home parenteral nutrition
There are a few indications for home parenteral nutrition. It may be necessary in patients who have complete intestinal failure or insufficient bowel function to maintain an adequate nutritional status via the enteral route, for example short bowel syndrome due to Crohn's disease or a high‐output fistula. It may also be required if it is not possible to access the gastrointestinal tract, although all possible enteral routes should be explored.
This is a complicated and specialist treatment, requiring 24‐hour access to advice and support, and should be co‐ordinated through a specialist intestinal failure centre.
No patient should be considered for home parenteral nutrition without a multidisciplinary discussion with the patient and the formulation of a clear management plan. If continuation of hospital‐initiated parenteral nutrition is considered essential, the implications must be discussed with the multiprofessional team, including the medical consultant, dietetics, pharmacy, intravenous therapy team, complex discharge co‐ordinator and patient (BAPEN [12]).
Patients require an extensive period of specialized training to manage parenteral nutrition in the home environment. This should only be undertaken by specialist intestinal failure units or home parenteral nutrition (HPN) designated units with a multidisciplinary nutrition support team with the appropriate expertise (BAPEN [12]).
It is important that all members of the multidisciplinary team, including the dietician, nurse, doctor, pharmacist and community services, are involved in the patient's nutritional care to ensure a thorough and co‐ordinated approach to nutritional management.
Termination of parenteral nutrition
Parenteral nutrition should not be terminated until oral or enteral tube feeding is well established (NICE [123]). Parenteral nutrition may require weaning at a reduced rate if there is concern about rebound hypoglycaemia or management of concurrent insulin, as well as to ensure adequate nutritional intake via an alternative route. It is important that all members of the multidisciplinary team are involved in the decision to terminate parenteral nutrition and that enteral intake is monitored sufficiently.
