Individual research recommendation details

Recommendation ID

NG154/4

Question

What overall osmolality (or concentration of calcium and glucose/dextrose) in parenteral nutrition can determine whether to administer centrally or peripherally?

Any explanatory notes
(if applicable)

Why the committee made the recommendations

Venous access (recommendations 1.2.1 and 1.2.2)
There was some evidence that included a comparison of fluid concentrations (as measured by osmolality or osmolarity, which depends on the level of calcium and glucose within the same amount of fluid) for peripheral venous lines. This evidence included delivering peripheral parenteral nutrition at concentrations of up to 1,425 mOsm/l. However, the committee agreed that it was not possible to recommend a specific safe concentration for parenteral nutrition delivered peripherally because of the wide range of concentrations used in the different groups in the study. Furthermore, there was no evidence that compared centrally with peripherally inserted catheters for any given level of concentration of parenteral nutrition. Therefore, the committee made their recommendations using the available evidence, as well as their knowledge and experience.

The committee discussed the risks and benefits associated with centrally and peripherally inserted catheters. The committee acknowledged that there is variation in clinical practice, and some units routinely use peripherally inserted catheters, whereas others prefer centrally inserted catheters and avoid using peripherally inserted catheters.

The committee agreed that centrally inserted catheters should normally be the preferred option for delivering neonatal parenteral nutrition. This is because centrally inserted catheters have a longer lifespan, and the central vein is bigger and has a lower risk of thrombophlebitis. However, they also agreed that peripherally inserted catheters can be used safely (which was supported by the evidence) when use of a peripheral line will be short term, and should be used when parenteral nutrition would otherwise be delayed or interrupted (for example, because there is no one available to insert a central venous catheter, a central venous catheter has stopped working and needs to be removed, or there are concerns about line infection). The committee did not define how long parenteral nutrition can be delayed before peripheral venous access should be considered, because this decision will be based on clinical judgement. Ideally, delays should not exceed the 8 hours specified in recommendation 1.1.6, but healthcare professionals will need to consider the risks and benefits of inserting a peripheral line if it is anticipated that a central venous catheter would be inserted soon.

The benefits and risks of surgically inserted central catheters were also discussed by the committee, and recommendations were made that these should only be used in exceptional circumstances when non-surgical insertion is not possible, or it is expected that parenteral nutrition would be needed for a long time.

Because of the limited evidence, the committee decided to prioritise this topic for further research. This is important because peripheral lines (although not the preferred choice of the committee) are generally easier to insert, and are very commonly used for a number of indications on neonatal units. However, they have a shorter life span and therefore would need to be changed more frequently. Because the infusions run into a smaller peripheral vein, there is a greater risk of the infusion causing direct damage to the vein. This is particularly true if there is a higher concentration (as measured by osmolality or osmolarity, depending on the unit of measurement) of the parenteral nutrition infusion fluid, for example, a formulation with a higher dextrose load.

Protection from light (recommendation 1.2.3)
Photo-degradation and oxidation are processes that do not lend themselves to comparative clinical studies (because of safety risks if the integrity of the solution is compromised) that are commonly used as evidence in NICE guidelines, so the committee made the recommendation based on a formal nominal group consensus method and their knowledge and experience.

The committee discussed photo-degradation and oxidation of parenteral nutrition solutions (including aqueous and lipid components), which can be managed by protecting both the infusion set (tubing) and bag from light. The committee discussed whether to recommend protecting just the bag, or the bag, the tubing and syringe. They recognised that it is simple to cover the bag, and this is already done in current practice. The committee agreed that, although some units would need to use a different type of infusion set, it is best practice to also protect the infusion set and syringe of both aqueous and lipid parenteral nutrition solutions from light, in line with European Medicines Agency and Medicines and Healthcare products Regulatory Agency guidance that states 'for administration to neonates and children below 2 years of age, parenteral nutrition products containing amino acids and/or lipids should be protected from light (containers and administration sets)'.

Filtration
The committee acknowledged that adding a terminal filter to the infusion set makes giving parenteral nutrition significantly more expensive. They discussed that adding filters can remove particulate matter, fungi, bacteria and endotoxins depending on the size of the filter. However, making up parenteral nutrition in aseptic units and using bags instead of syringes reduces the risk of bacterial contamination. Breaking a line to change the filter when running lipid from a bag was thought to pose more of an infection risk than changing the bag and filter frequently (every 48 hours). Given these uncertainties around benefits and harms, as well as additional costs, the committee were not able to make a recommendation related to filtration.

How the recommendations might affect practice
Venous access
The recommendations reinforce current best practice. The recommendations may affect clinical practice by reducing the current delay that some units experience when siting a central line for giving parenteral nutrition, because peripherally inserted catheters may now be used as a short-term alternative.

Protection from light
Any likely changes in practice and costs associated with light-protected bags and light-protected tubing will be outweighed by the benefits associated with preserving the integrity of the parenteral nutrition solution.

Full details of the evidence and the committee's discussion are in evidence review B: venous access and evidence review J: general principles.

Source guidance details

Comes from guidance

Neonatal parenteral nutrition

Number

NG154

Date issued

February 2020

Other details