Chapter 2: Nutritional Assessment of the Critically ill Child

MALNUTRITION IN THE CRITICALLY ILL CHILD

Critical illness greatly influences one's nutritional status; therefore, assessment of nutritional status should be an integral part of patient care. During a child's intensive care stay, however, attention is mostly focused on the primary medical problem, e.g., hemodynamic instability, serious infection, congenital anomaly, and nutritional status is often neglected.

Critically ill children are at high risk of developing nutritional deficiencies and altered nutritional status. Much more than adults, critically ill children are at high risk of clinical depletions because they have limited body reserves of fat and protein, higher energy expenditure, and increased energy requirements for growth and development.

Studies performed in the 1980s revealed that about 20% of the children admitted to a pediatric intensive care unit (PICU) were in poor nutritional state. Despite improvements in intensive care technology, feeding possibilities, and increased awareness of the significance of adequate nutritional support, the prevalence of malnutrition over the last 30 years still remains high—up to 45%.^1,2 The fact that the incidence has not decreased may be explained by certain developments in the care for critically ill children in recent years. As a result of these developments, more and more children with chronic disease or major congenital anomalies survive to an older age, and these children are more likely to be in poor nutritional state on admission to the PICU than are previously healthy children. One has also to take into account the high prevalence of underlying growth-affecting disease in those with acute malnutrition.¹

The acute effects of malnutrition include poor wound healing, higher risk of infections due to poor immune defense, reduced gut function, longer dependency on mechanical ventilation, and longer hospital stays.³ Considering that malnutrition might also jeopardize future growth and development,⁴ it seems all important to identify on admission to the PICU those children with preexisting poor nutritional status and those at risk for developing malnutrition, with a view to tailoring their nutritional care.

With this specific aim in mind, we need to identify nutritional assessment tools that can easily be used in the intensive care setting, are patient friendly, are portable, and that have enough sensitivity/specificity to distinguish children with poor nutritional status from children with normal nutritional status.

CHALLENGES AND STRATEGIES TO DEFINING MALNUTRITION

Although both under- and overnutrition are forms of malnutrition, the term malnutrition used in the context of the PICU commonly refers to undernutrition. (Please see chapter 21 for details on care of the obese child in the PICU.) Malnutrition has been defined as a disorder of body composition characterized by macro- and/or micronutrient deficiencies and resulting from reduced nutrient intake or impaired metabolism. It describes a broad spectrum of clinical conditions ranging in severity from mild to very severe, which may result in reduced organ function, reduced body mass (muscle wasting and ...