Notes from the Video

What are you going to learn in this video?

Lets take a look at a few questions...

How do you write orders for total parenteral nutrition?

How do you evaluate your patients nutritional status both in the elective setting and in the critically ill?

How do you provide the right perioperative nutrition?

After this video you're going to be comfortable assessing your patient's nutritional status and you will be well on your way to thinking about the indications for parenteral nutrition.

Why do we need to understand nutrition?

Nutrition is a critical topic in surgery because we know that operating on patients with poor nutritional status can lead to increased preoperative morbidity and mortality.

We know that some of our preoperative nutritional markers like albumin have consequences if they're low like increased mortality increased risk of SSI, increased hospital length of stay and so if you have patients that have weight loss, low BMI and a low albumin preoperatively and you can change that by optimizing the patient you can really improve their outcomes.

If you don't understand nutrition, you can't help and you may be putting your patients at risk!

How go you do a nutritional assessment in surgical patients?

We have anthropometric data, we have preoperative labs, we have a history of weight loss, we have a history of inability to eat..

Which of these are most important?

This most important thing is to begin with a thorough and complete history and physical exam.

Does the patient have a history of weight loss?

Does the patient have a history of cancer?

What is the patient's diet?  Are they at risk of vitamin deficiencies?

Is the patient an alcoholic?

Is there liver disease?

What is the patient's BMI?

These are just a few questions to stimulate your thinking on how to approach the history in a patient and evaluate nutritional status.

There are a lot of nutrition scores out there but I want to keep it real simple today with two references that I want to drive you toward: and I want you to

1. ESPEN guidelines published in 2012
2. The Hitchhiker's Guide TPN

One point that I want to drive home again and again...

Undernutrition has incredible risk and is associated with increased infectious complications, increased mortality, an increased hospital length of stay!

We know that in patients who have severe malnutrition or are at severe nutritional risk benefit greatly from seven to ten days of preoperative nutrition to increase and optimize their nutritional status.

What about labs?

One of the traps that we fall into is looking specifically at lab tests for an indicator of nutrition.

Let me say one thing and let me say it loudly! 

Labs are NOT a adequate measure of nutritional status!

While they are helpful we should not be looking at them in isolation.

We do know that hypoalbuminemia, less than 3-3.5g/dl is an indicator of increased infectious complications and mortality, but it's not necessarily a gauge of your nutritional status.

One of my favorite papers to talk about with respect to hypoalbuminemia and other risk factors is a paper by Dr. Leah Neumayer and colleagues on risk of Surgical Site Infection. 

In this paper she looks at multiple variables that lead to an increased risk of an SSI (surgical site infection) and albumin is one of them.  The point of this is that yes your SSI rate does go higher if your albumin is less than 3.5 g/dl but there are also a lot of other factors that contribute to increase SSI risk.

If you do have a patient that has a low albumin, that patient may benefit from oral nutritional supplements to increase that albumin level for seven to ten days before an elective operation.

Severe nutritional risk, what does that mean?

Severe nutritional risk means that a patient has one of these features:

1.). Weight loss of greater than ten to fifteen percent in the last six months

2.). BMI of less than 18.5

3.). Pre-op serum albumin less than 3g/dl

4.). SGA grade C

If you identify your patient has one of these features and they're at severe nutritional risk they have a much higher risk of infectious complications, mortality, length of stay in the hospital and you would definitely want to optimize with preoperative nutrition.

If we want to look at the evidence it suggests that preoperative nutrition, preoperative optimization really only shows a statistical benefit for those patients that are at a severe nutritional risk so additional preoperative nutrition will most likely provide benefit in patients who are not at risk.

What are some other labs we see in a workup of nutritional status?

Here are some half lives of common nutritional labs...

• Albumin is the longest at 18 days
• Retinol binding protein = 12 days
• Transferrin = 8 days
• Prealbumin is the shortest at 3 days

What are the reasons that prealbumin is not the best measure of nutritional status in the perioperative setting?  Specifically critical care critical illness, burns, and trauma?

The reason is that prealbumin is a negative acute phase reactant, which means that in trauma or in critical illness, prealbumin will be artificially low because the liver is busy making acute phase proteins during that inflammatory response.

In the first few videos on the metabolic response to injury we discussed the inflammatory response and specifically when TNF alpha, il-1, il-6 are released and promote the acute phase protein production in the liver.  That means that all these other proteins like CRP are being produced while prealbumin is not and so you get an artificially low level of prealbumin in these patients.

So you look and say "oh my gosh" the prealbumin is 9! 

It doesn't mean that the patient is in horrible nutritional status, what it means is they have a crazy inflammatory response happening!

Remember, nutritional assessment is more than just the lab value!

References:

1.). ESPEN Guidelines

2.). Hitchhikers Guide to TPN

3.). Neumayer - Surgical Site Infection