Enteral Nutrition Practice Problems Sample Tube Feeding Calculations

Goal of the tube feed cheat sheet

Probably the most important aspects of nutritional care in the ICU are (1) early initiation of enteral nutrition and (2) providing adequate protein.  A barrier to these goals is the ability to design a tube feed regimen.  If this is difficult,  then it will end up on some resident's to-do list, possibly to be completed 4-6 hours after rounds.  Worse yet, the team might wait for a nutrition consultation, delaying nutrition by a day.

The goal of the tube feed cheat sheet is to make it insanely easy to create an adequate tube feed regimen.  The cheat sheet allows this to be done in seconds, for example during rounds without missing a beat.  No calculations are needed.

What you should know before using the cheat sheet

1. What tube feeds are available in your ICU?  For nearly all patients, it doesn't really matter which one you use.  Go with something cheap that is commonly used in your ICU.
2. What is the form of supplemental protein used in your ICU?  All hospitals have this, either packets of dry protein powder or protein paste.  At Genius General Hospital, supplemental protein is provided in the form of 15-gram packets of Prosource paste.

1.  How to use the cheat sheet for a patient who is average weight or overweight (most patients):

In most cases, you can feed the patient based on their ideal body weight, with a target goal of 25 kCal/kg and 1.5 grams/kg protein for full nutritional support.  This can be done as shown below.

• On the left, find your patient's gender and height.
• On the right, select the tube feed that you are using and your nutritional target (50% or 100% calories)
• The intersection yields your tube feed rate and the number of grams of protein that needed to be supplemented.

2.  How to use the cheat sheet for someone underweight

For a patient who is significantly underweight, you want to feed them based on theiractual dry weight (not their ideal body weight).   To do this,ignore the first two columns on the left.  Instead, start with the third column and find the row corresponding to your patient'sactual weight.

For example, if we were determining a regimen for an underweight patient with an actual weight of 58 kg, it could be done like this:

3.  How to use the cheat sheet for someone morbidly obese (BMI >30)

Recent guidelines recommend that morbidly obese patients should receive mildly hypo-caloric feeding with increased levels of protein.  In order to achieve this, a second high-protein cheat sheet  must be used which has been modified to provide more protein (2.25 g/kg ideal body weight; see below).

4.  Adjusting the tube feed rate for propofol (after patient stabilized)

Basics

• Propofol contains 1.1 kCal per ml.  For an average-size (70kg) patient, 40 mcg/kg/min propofol will provide 16.8 ml/hr propofol, which equals 443 kCal/day.
• Low-dose propofol infusions (e.g. up to ~30 mcg/kg/min) won't make a big difference, but at higher doses failure to account for propofol calories could cause overfeeding.
• It's probably not a great idea to run propofol at rates >40 mcg/kg/min for long periods of time anyway (this will tend to cause hypertriglyceridemia).  Therefore, the ideal approach here might be to add another agent (e.g.  atypical antipsychotic) in order to wean down the propofol dose.

When to adjust for propofol calories:  Only if ALL of the following criteria are met (1):

• Patient is on a continuous propofol infusion at a rate >10-20 ml/hour
• Propofol infusion is expected to continue for at least a day.
• Patient feeds are currently running at or close to the goal rate.

How to adjust for propofol calories:

• Reduce the tube feed rate
  • If using a 1 kCal/ml formula:  reduce rate by 1 x (propofol infusion rate in ml/hr)
  • If using a 1.5 kCal/ml formula:  reduce rate by 0.7 x (propofol infusion rate in ml/hr)
  • If using a 2 kCal/ml formula:  reduce rate by 0.5 x (propofol infusion rate in ml/hr)
• Add back additional protein to achieve your protein target
  • Supplement with an additional amount of protein equal to 1 gram/day x (propofol infusion rate in ml/hr)

That's all!   Clean copies of the two different cheat sheets:

Going further:

• Related
  • Nutritional support & hypocaloric tube feeding
• General
  • PulmCrit table of contents

Notes

1. Loosely based on a protocol from criticalcarenutrition.

sutherlandfoliver.blogspot.com

Source: https://emcrit.org/squirt/food/

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