HOWTO: YaNuCa

YaNuCa is a web-tool to support the calculation of artificial nutrition for intensive care patients.

Current online version (for use directly from the WWW):

YaNuCa is free software. You are welcome to redistribute and/or modify it under the terms of the GNU Affero General Public License.

YaNuCa was originally released by nursix.org.

The YaNuCa "Nutrition Model"

YaNuCa does not provide a model for artificial nutrition of ICU patients, but is simply a calculation tool. Nevertheless, as such, YaNuCa supports a special kind of nutrition models, which we want to describe here in short.

The Supply Roadmap

YaNuCa calculates a nutrition plan on 5 stages - one stage for total parenteral nutrition (TPN) and four stages (1-4) for building up an enteral (tube-)nutrition.

For each step of the supply roadmap YaNuCa shows supply rates for tube food and parenteral nutrition solutions. The particular product for tube feeding can be selected by the user, while the parenteral nutrition is always assembled from a 10% amino acid solution, 40% glucose solution and a 20% lipid emulsion (no special product named or recommended).

Water Balance

In addition to the supply rate for tube food the hourly water quota is shown (tube food only, for parenteral solutions usually the full rate is used for the water balance).

Application of Parenteral Nutrition

For parenteral nutrition we assume that you supply the solutions continously 24 hours per day. Except for stage TPN, the enteral nutrition is included into the calculation of the parenteral supply rates.

Tube feeding

Tube nutrition shall be supplied over a gastric tube in intervals of 4 hours on the given rate, each followed by a pause. The pause is used for tolerance and passage checking. Depending on how many of these 4-hour-cycles are neccessary to supply the calculated daily amount of enteral nutrients within 24 hours, the pause intervals last for 1 or 2 hours (4 cycles/d=2h pause, 5 cycles/d=1h pause). The neccessary number of cycles per day is shown on the nutrition plan.

Maximum Rate of Tube Feeding

YaNuCa allows a maximum enteral supply rate of only 150 ml/h, so that the stomach cannot be overfilled within one 4-hour-cycle (500-700ml). For patients with a resected stomach or a duodenal nutrition tube as well as for other reasons such as special positioning, kinetic therapy etc. you probably should select a lower limit (e.g. 50 ml/h).

Reflow Check and Passage Problems

At the end of each pause interval you should check, if the tube food is tolerated by the patient and has passed the stomach. That means, less than 50% of the prior supplied amount or max. 200ml should reflow through the tube when you open it. If that is the case you may proceed with the next 4-hour-cycle. Important: All reflow up to 200ml should be given back into the stomach (except blood).

If the reflow is too high, you may suspend the next cycle as a first step, meanwhile clearing the cause. Maybe you have to step back to the previous stage (or even to stage "TPN") of the nutrition plan. It is always advisable to position up the upper body 10 to 30 degrees to support the food passage.

Build-up of enteral nutrition

To build up the enteral nutrition you usually start with stage 1 and then step up one stage per day. Even if you had to step back one stage due to high reflow problems you may nevertheless try an increase again on the next day.

In cases that the patient initially does not already suffer from malnutrition and has no higher risk for malnutrition, you may perhaps omit the parenteral supplements within the first 3 to 5 days.

Minimum Enteral Nutrition

If the patient does not even tolerate the enteral supplies of stage 1, you will have to step down to total parenteral nutrition (Stage TPN). YaNuCa tells you to try to supply at least 10 ml/h of tube food with TPN to protect the gastrointestinal tract from atrophy and keep up its blood flow, but since this is not mandatory, this supply is not factored in to the calculation of the parenteral supply rates during TPN.

How to use YaNuCa

The YaNuCa front end is structured into four sections which shall be handled from top to bottom.

The upper (grey) section is used to declare the patient data.

In the middle (red) section you can choose the tube nutrition product and define parameters for oral/enteral nutrition.

The middle (yellow) section shows YaNuCa's "Nutrition Receipe", that means: the calculated requirements and neccessary nutrient and energy supplies. Within this section (on the right) you find several option fields to correct this calculation manually if neccessary.

The bottom (grey and blue) section shows the calculated "Supply Roadmap", with the different build-up stages.

The whole document can simply be printed on one A4 sheet. Just press the "Print"-button of your browser.

Patient Data

These input fields explain themselves very well.

If the initial weight of the patient is unknown or cannot be measured properly, you can leave the "Weight"-field "unkown". In this case YaNuCa will calculate a standard weight based on the other data you provided (the actually used weight will be shown on the "Receipe"). But if you rather choose a particular weight, the "Figure"-field will be ignored instead.

The assignment to a particular patient group results a special "stress factor" for this patient. Together with the given thermal factor this scales the requirements from 70 up to 200% of the estimated basal metabolic rate of the patient.

Stress factors are dynamic - they might vary for the same patient from day to day, therefore you should re-calculate the nutrition plan daily.

Selection of tube food and other nutrition parameters

In the middle (red) section you can choose a particular tube food and set up parameters for enteral and oral nutrition.

The nutrient composition of the selected tube food will be factored in to the calculation of the nutrition roadmap. Which product you should choose depends on the availability of this product as well as on the individual compatibility and needs of the patient. Therefore, the pre-selected product does not represent a recommendation.

The maximum rate for tube food can be choosen individually, but if YaNuCa finds a lower rate limit for the selected tube food in its internal data tables then the program will use the lower limit. Independent of the tube food you select, YaNuCa will never calculate a higher rate than 150 ml/h.

If the patient can eat normally (an amount worth mentioning) then YaNuCa can include this into the calculation. To use this function, you only have to estimate the amount of orally assimilated food (energy) and make the appropriate selection in the "Oral Nutrition"-field.

In this way you may also calculate a supportive (additional) parenteral nutrition, if the patient can eat normally but does not meet his energy requirements with it.

The Receipe

The receipe does not show requirements of the patient, but the neccessary nutrient supplies according to the user settings. These amounts can be corrected manually if neccessary.

The first two lines of the receipe show the actually used patient weight and the estimated total energy needs.

The table below shows the neccessary amounts of the particular nutrients and the total energy supply, detailed as absolute (total daily amount) and relative (daily amount related to the patient weight) values.

On the "Protein"-line of this table you can choose another individual relative protein amount, e.g. in case of renal failure, liver failure, dialysis, large wounds etc.

On the "Carbohydrates"-line you may manually reduce the relative carbohydrate supply, e.g. to support weaning from artificial ventilation, or if the plasma glucose of the patient is out of the targeted range (e.g. 80..120 mg/dl, max. 140 mg/dl) in spite of maximum insulin supply (e.g. 10 IU/h, this value may vary from hospital to hospital).

On the last line you can manually modify the relative energy supply, if the automatic calculation from the stress factors is not appropriate (enough) for your patient.

All those option fields in the "Receipe" are only for manual intervention in special cases. Normally, you can simply leave them on "automatic".