Parenteral nutrition in the critically ill patient

Abstract

A 67-year-old woman with type 2 diabetes mellitus undergoes extensive resection of the small bowel and right colon with a jejunostomy and colostomy because of mesenteric ischemia. In the surgical intensive care unit, severe systemic inflammatory response syndrome with possible sepsis develops. The patient is treated with volume resuscitation, vasopressor support, mechanical ventilation, broad-spectrum antibiotics, and intravenous insulin infusion.

Low-dose tube feedings are initiated postoperatively through a nasogastric tube. However, these feedings are discontinued after the development of escalating vasopressor requirements, worsening abdominal distention, and increased gastric residual volume, along with an episode of emesis. The hospital nutritional-support service is consulted for feeding recommendations. A discussion with the patient's family reveals that during the previous 6 months, she lost approximately 15% of her usual body weight and decreased her food intake because of abdominal pain associated with eating. Her preoperative body weight was 51 kg (112 lb), or 90% of her ideal body weight. The physical examination reveals mild wasting of skeletal muscle and fat. Blood tests show hypomagnesemia, hypophosphatemia, and normal hepatic and renal function. Central venous parenteral nutrition is recommended.

Figure 1. Potential Metabolic and Clinical Consequences of Overfeeding and the Refeeding Syndrome during Administration of Central Venous Parenteral Nutrition in Patients with Critical Illness

Hypertriglyceridemia can occur with excess administration of carbohydrates or fat emulsion; excess administration of specific electrolytes in a variety of clinical conditions (e.g., acute kidney injury) can lead to elevated blood levels, whereas inadequate administration, especially during refeeding, can lead to decreased blood levels. Inadequate energy provision in relation to the dose of amino acids can contribute to azotemia.