Parenteral nutrition in the intensive care unit

Abstract

Patients in the intensive care unit (ICU) are unable to nourish themselves orally. In addition, critical illness increases nutrient requirements as well as alters metabolism. Typically, ICU patients rapidly become malnourished unless they are provided with involuntary feeding either through a tube inserted into the GI tract, called enteral nutrition (EN), or directly into the bloodstream, called parenteral nutrition (PN). Between the 1960s and the 1980s, PN was the modality of choice and the premise was that if some is good, more is better, which led to overfeeding regimens called hyperalimentation. Later, the dangers of overfeeding, hyperglycemia, fatty liver, and increased sepsis associated with PN became recognized. In contrast, EN was not associated with these risks and it gradually became the modality of choice in the ICU. However, ICU patients in whom the gastrointestinal tract was nonfunctional (i.e., gut failure) required PN to avoid malnutrition. In addition, EN was shown, on average, to not meet nutrient requirements, and underfeeding was recognized to increase complications because of malnutrition. Hence, the balanced perspective has been reached of using EN when possible but avoiding underfeeding by supplementing with PN when required. This new role for PN is currently being debated and studied. In addition, the relative merits and needs for protein, carbohydrates, lipids, and micronutrients are areas of study.

Effects of dietary omega-3 fatty acids on bones of healthy mice

“…However, PN is associated with significant complications such as intestinal failure-associated liver disease (IFALD), sepsis, and metabolic bone disease (MBD) [1–3]. Several factors have been implicated in the pathogenesis of MBD in the setting of long-term PN administration.…”

Experiences of health professionals with nutritional support of critically ill patients in tertiary hospitals in Malawi

“…In addition, few participants from KCH reported the rare access to parenteral nutrition including amino acid infusions, which was not reported at QECH. Although some patients with gut failure may benefit from parenteral nutrition, the predominance of enteral nutrition observed in this study is desirable and in line with international trends 6 . Parenteral nutrition is not locally available in Malawi, and the few participants who had had some experience with it used donated supplies; we therefore will not further discuss parenteral nutrition.…”

“…Waitzberg et al reported that about half of patients in hospitals in Brazil were malnourished and that physician awareness of malnutrition was low, resulting in under-prescription of nutritional therapy 5 . Enteral nutrition has emerged as the preferred method of nutritional support in critically ill patients as long as the intestines maintain their digestive and absorptive capacity 6 . If the gut cannot be used for some reason, nutritional therapy may be delivered directly into the venous blood (parenteral nutrition) 6,7 .…”

“…Enteral nutrition has emerged as the preferred method of nutritional support in critically ill patients as long as the intestines maintain their digestive and absorptive capacity 6 . If the gut cannot be used for some reason, nutritional therapy may be delivered directly into the venous blood (parenteral nutrition) 6,7 . Whereas parenteral nutrition plays a major role in patients with gastrointestinal failure, enteral nutrition is associated with fewer and less serious complications and is indicated when the gastrointestinal tract is functional.…”

Impact and Outcomes of Nutritional Support Team Intervention in Patients with Gastrointestinal Disease in the Intensive Care Unit

“…sufficiently disabled so that volitional oral feeding is either impossible or unlikely to successfully meet nutrient requirements. [17] Additionally, critically ill patients often have more risks for malnutrition, with high mortality and morbidity rates [8] due to increased metabolic needs and the tendency for underfeeding. [18] These factors can predispose to a systemic inflammatory response, which increases muscle protein catabolism and moderately increases energy expenditure.…”