Nutrition Support in the ICU

Chapter 80 Nutrition Support in the ICU



Sharon Del Bono, RD, CNSD, LDN, Julia M. Toto, MD




Cases Considered



1. Nutritional requirements for a 24-year-old male with a cranial gunshot wound

2. Nutrition management of a 73-year-old with cancer cachexia

3. Nutrition support of a 30-year-old female with Crohn’s-related enterocutaneous fistula



Speaking Intelligently


When evaluating the nutritional status of an ICU patient, it is essential to differentiate between preexisting malnutrition and acute physiological processes that have nutritional consequences. The decision to provide nutrition support needs to be viewed in terms of risk versus benefit; once benefit is decided, it must be determined which route of administration is indicated. The goal of nutritional intervention is to meet the energy requirements (measured or calculated) while providing enough protein to balance the protein losses of catabolism.



Clinical Thinking


When I’m asked to see a patient for the question of nutritional support, I ask the following questions:


• Is the patient suffering from preexisting malnutrition?

• Is nutrition support indicated and will it improve outcome?

• What is the most appropriate route: enteral or parenteral support?

• What are the nutritional goals?

• How will we assess if the nutritional goals are met?

• What are the potential complications of nutrition support?


Candidates for Nutrition Support



• Patient is hemodynamically stable/adequately resuscitated

• Critically ill patients not expected to eat for greater than 5 days

• Patients with a disruption in the ability to ingest or absorb food



Case 1


A 24-year-old male sustained a gunshot wound to the head and was taken by the neurosurgical team to the OR, where he underwent bilateral decompressive craniotomies. He was transferred in stable, but critical, condition to the surgical ICU, where he required ventilatory support.



Working Dx


Brain injury–induced catabolism that results in acquired malnutrition. An NG feeding tube was placed for the initiation of enteral feeding. Initial nutritional parameters showed his electrolytes, LFTs, and triglycerides to be within normal limits. Albumin was 2.8 g/dL. Prealbumin was 10.6 mg/dL. His usual body weight was 75 kg and his height was 5 ft 9 in (175 cm).




Medical Knowledge



Initial Nutritional Determinations


The majority of critically ill patients simply require 25 to 30 kcal/kg/day. This is a simple method of estimating requirements that is commonly utilized by nutrition support practitioners when formulating the initial nutrition support regimen.



Protein Requirements


In the ICU setting, protein requirements are elevated over the usual requirement of 0.8 to 1.0 g protein/kg/day. Stressed, critically ill patients may require 1.5 to 2.0 g protein/kg/day. Patients who are severely catabolic may require additional protein.



Nutritional Products


After calorie and protein requirements have been determined, a specific prescription for protein, carbohydrate (CHO), and fat can be formulated. Commercial tube feeding formulae vary considerably in how much of these three substrates they contain; TPN solutions can be specifically formulated to meet nutritional needs. In general, CHO constitutes 60% to 70% of energy needs; fats comprise 20% to 30% and protein the remainder.



Predicting Energy Requirements


Energy needs vary based on age, sex, body mass (height and weight), presence of chronic illness, and severity of illness. Multiple equations have been developed to predict basal energy requirements; the most widely used tool is the Harris-Benedict equation, which depends on sex (males > females), weight, height, and age.



Basal Energy Expenditures (BEE)


Males: 66 + 13.8 (weight in kg) + 5 (height in cm) – 6.8 (age)


Females: 65.5 + 9.6 (weight in kg) + 1.85 (height in cm) – 4.7 (age)


The estimated energy expenditure is obtained by multiplying the BEE by a “stress factor”—approximately 1.5 to 2.0 for most significant disease processes (e.g., acute pancreatitis, sepsis, fistulae). See Sabiston 7; Becker 7, 12.

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Mar 20, 2017 | Posted by in GENERAL SURGERY | Comments Off on Nutrition Support in the ICU

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