P02 Methods used when preparing non-standard glucose concentrations: a survey of UK neonatal units
Authors: Hart Robyn , Rifai Adriece Al , Wignell Andrew 
Published: August 2020

Aims

Administering intravenous (IV) glucose is common practice on the Neonatal Intensive Care Unit (NICU). The varying metabolic demands of patients in this environment coupled with the need for fluid restriction means the limited range of pre-made commercial products is not appropriate in every case. This can necessitate bedside preparation of glucose solutions, usually through addition of concentrated 50% glucose solution to a commercially available bag. Most IV glucose bags available contain an overage, i.e. they are filled to a greater volume than stated on the bag. Overages are quoted as ranges rather than absolute values, and vary according to manufacturer. This may lead to uncertainty as to the exact amount of 50% glucose to add in order to create the intended final concentration.

We aimed to determine the availability of guidelines to facilitate the safe, accurate preparation of non-standard glucose concentrations in NICUs across the UK, and to ascertain the range of methodologies in use.

Methods

NICUs throughout the UK were identified and contacted via telephone. The following questions were asked:

Do you ever prepare non–standard glucose concentrations, for example 12.5%, 15% or 25%?

If yes, do you have a guideline which describes how these infusions should be prepared?

Where non-standard glucose concentrations were used and a guideline available, NICUs were asked to share this guideline for the purposes of analysis. Following receipt of the guidelines, they were categorised according to the broad method of glucose solution manufacture:

Removal of fluid from bag prior to addition of 50% glucose, taking into account published overage.

Removal of fluid from bag prior to addition of 50% glucose, not taking into account published overage.

Addition of 50% glucose, without prior removal of fluid from bag.

Mixing ratios of concentrations in a burette.

‘Piggybacking’ a 50% glucose infusion onto an infusion of 5% glucose, guided by use of an online calculator.

Results

69.2% of the 65 NICUs contacted responded (n=45). 66.7% of respondents (n=30) had guidelines in use: these 30 guidelines were subjected to analysis.

Method a) was used in 6.7% of guidelines seen (n=2); method b) was used in 60% of cases (n=18); method c) was used in 3.3% of cases (n=1); method d) was used in 6.7% of cases (n=2); method e) was used in 10% of cases (n=3). 6.7% of guidelines used a different method according to the glucose concentration required (n=2). 6.7% of guidelines advised preparation of glucose in a syringe rather than an infusion bag (n=2).

Although method b) was the most commonly used, there was wide variation in recommended volumes to be added and/or removed.

Only 6.7% of guidelines reviewed specified the brand of infusion bag to be used (n=2).

Conclusions

Considerable variation was seen in the methods of glucose infusion preparation used throughout the UK, suggesting a range of opinions as to the most accurate method of manufacture. Further work is needed to determine the relative accuracy of the different methods, and the clinical significance of the variation observed.