Chapter 073. Enteral and Parenteral Nutrition (Part 2)

Decision-making for the implementation of specialized nutrition support (SNS). CVC, central venous catheter; PICC, peripherally inserted central catheter. (Adapted from previous chapter by Lyn Howard, MD.)The first step in deciding to administer SNS is to consider the nutritional implications of the disease process. Is the condition or its treatment likely to impair food intake and absorption for a prolonged period of time? For example, a well-nourished individual can tolerate approximately 7 days of starvation while experiencing a systemic response to inflammation (SRI). The second step is to determine if the patient is already significantly malnourished to the degree that...
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Chapter 073. Enteral and Parenteral Nutrition (Part 2) Chapter 073. Enteral and Parenteral Nutrition (Part 2) Decision-making for the implementation of specialized nutritionsupport (SNS). CVC, central venous catheter; PICC, peripherally inserted centralcatheter. (Adapted from previous chapter by Lyn Howard, MD.) The first step in deciding to administer SNS is to consider the nutritionalimplications of the disease process. Is the condition or its treatment likely toimpair food intake and absorption for a prolonged period of time? For example, awell-nourished individual can tolerate approximately 7 days of starvation whileexperiencing a systemic response to inflammation (SRI). The second step is todetermine if the patient is already significantly malnourished to the degree thatcritical functions such as wound healing, immune function, or ventilatory functionare impaired (Chap. 72). An unintentional weight loss of >10% during theprevious 6 months or a weight/height 20% of usualor the method of delivery should be determined. The optimal route depends on thedegree of gut function and somewhat on the available technical resources. The timing of nutritional support is based on evaluation of the preexistingnutritional status, the presence and extent of SRI, and the anticipated clinicalcourse. SRI is identified by the standard clinical signs of leukocytosis, tachycardia,tachypnea, and/or temperature elevation or depression. Although the degree ofhypoalbuminemia provides an estimate of SRI severity, normal serum albuminlevels will not be restored by adequate nutritional support until the SRI remits,even though nutritional benefits can be achieved by adequate feeding. The SRI can be graded as severe, moderate, or mild. Examples of severeSRI include sepsis or other inflammatory conditions like pancreatitis requiringICU care, multiple trauma with an Injury Severity Score > 20–25 or APACHE II >25, closed head injury with a Glasgow Coma Scale < 8, or major third-degreeburns of >40% of body surface area. Moderate SRI includes less severe infections,injuries, or inflammatory conditions like pneumonia, major surgery, acute hepaticor renal insufficiency, and exacerbations of ulcerative colitis or regional enteritisrequiring hospitalization. PCM should also be defined as severe, moderate, orminimal as assessed by weight/height, percent recent weight loss, and body massindex. The body mass index in relation to nutritional status is listed in Table 73-1.A patient with a severe SRI requires early feeding within the first several days ofcare because the condition is likely to produce inadequate spontaneous intake overthe next 7 days. A moderate SRI, as commonly seen during a postoperative periodwithout oral intake that exceeds 5 days, benefits from adequate feeding by day 5–7if the patient was initially well nourished. If severely malnourished, candidates forelective major surgery benefit from preoperative nutritional repletion for 5–7 days.However, this is not often possible. Thus, early postoperative feeding is indicated.Patients with a moderate SRI and moderate PCM also benefit from earlier feedingwithin the first several days. Table 73-1 Body Mass Index (BMI) and Nutritional Status BMI Nutritional Status >30 kg/m2 Obese >25–30 kg/m2 Overweight 20–25 kg/m2 Normal