Table 2.

Components of nutrition assessment for patients with intestinal failure.

Component	Description
Dietary history and fluid balance	Detailed information about previously tried diets including route, amount, and type of nutrition/formula with reasons for lack of success, and measurement of current fluid balance is required for designing a new individualized feeding regimen.
Anatomy of intestine	It is important to document the anatomy and function of the intestine or remaining intestine. Most nutrients are absorbed in the first part of the jejunum. In case of jejunum resection, the residual ileum is able to adapt and to partly take over the role of the jejunum in nutrient absorption. However, when the terminal ileum is resected, the reabsorption of vitamin B12 and bile salts cannot be replaced by jejunal cells. Resection of the ileocecal valve decreases intestinal transit time and supposedly predisposes to reflux of colonic content (including higher bacterial counts) back into the small intestine. Dysmotility and/or dilated loops cause intestinal stasis leading to SIBO, which negatively impacts the digestion and absorption of nutrients. [14]. High-output stomas may cause water, sodium, and magnesium depletion [15].
Energy requirements, anthropometrics, sex and age	Energy requirements are preferably measured by indirect calorimetry. If this is not possible, these requirements should be calculated based on body weight, height, sex, and age, and adjusted accordingly by patient response (i.e., when not gaining weight as expected). To measure the effect of a nutritional intervention, anthropometrics should be monitored with growth charts in pediatric patients. Next to weight and height, it is also recommended to assess and monitor body composition (with for example air-displacement plethysmography) and muscle function (with for example handgrip strength). In a recent study in pediatric IF patients receiving long-term PN, Neelis et al. reported that these children had higher fat mass and lower fat-free mass (i.e., muscle, water, bone, and internal organs), compared with healthy peers [16]. In another study, involving adult IF patients, it was shown that 73% had sarcopenia (i.e., loss of muscle mass and function) [17].
Biochemistry: electrolytes and micronutrients	Micronutrient deficiencies are common in IF patients [18,19]. Electrolytes such as sodium and magnesium may be low due to excessive gastrointestinal losses, whereas calcium, phosphate and potassium can be elevated as a consequence of dehydration [20]. Screening of electrolytes, vitamins, and trace elements should be performed at baseline and monitored thereafter. Electrolytes should be monitored every 1–3 months or more frequently when indicated (e.g., in the case of recent PN composition change or increased gastro-intestinal losses); vitamins and trace elements should be monitored every 6–12 months [21,22].
Medication	Some medication may increase intestinal losses (e.g., non-steroidal anti-inflammatory drugs, proton pump inhibitors, antibiotics) [23]. Proton pump inhibitors are frequently used to reduce gastric PH and gastric fluid production which is most markedly increased in the hypersecretory acute phase of IF [24]. Also, because of the decreased enteral absorption of nutrients and fluids by the small intestine, medication dosages may have to be adjusted or converted to intravenous supplementation. If it is uncertain whether the medication will be enterally absorbed, the intravenous route is the preferred one [25].

IF: intestinal failure, PN: parenteral nutrition, SIBO: small intestinal bacterial overgrowth.