I am a RN working in an intensive care unit and we must calculate the calories required for patients.


I am an RN working in an intensive care unit at a local hospital. For our patients on a ventilator, we must calculate the calories required. To do this we use the Harris-Benedict formula. My question is what is the correct formula. We have been told to use the factor of 655 when calculation for a female. Some of my research has shown that the factor of 65.5 should be used.

Which is correct? If it were correct to use 65.5 would you give me a source that I can show at the hospital?

Thanks in advance for any information.

The correct factor for women is 655 and for men 66, but the Harris-Benedict formula is much more involved than that. This calorie calculation includes weight, height, and age. There are better algorithms to use with hospitalized people.  Talk to your hospital dietitian.

The Harris-Benedict formula can be found in most clinical nutrition textbooks. Also, the Harris-Benedict formula doesn’t include activity calories or stress/fever factors due to illness which can range from 10 to 100% over basal energy expenditure (Harris-Benedict).

So if you want to correctly calculate the required calories for this ventilator patient, I would suggest that if you have a clinical dietitian working in your hospital, that you get her/him involved in this patient’s care even if you need a doctor’s referral. There are some formulas /diets that stress patients on ventilators because of the high carbohydrate content. High carbohydrate intakes increase oxygen consumption and the patient takes a long time getting weaned off the ventilator if his / her diet is wrong. This patient needs nutrition therapy from a Registered Dietitian.

In case you haven’t tried the Healthy Body Calculator®, you can use it to calculate calories and nutrients for your patients. It does not, however, include a stress factor, which you will have to add calories and other nutrients due to disease or metabolic processes. But it does most of the basic calculations for you.