What is the goal of nutrition in the intensive care unit?

Abstract

It is difficult to give a simple answer to this question for a number of reasons. Firstly, because the major determinants of outcome on the ICU are the severity of the disease, coincident cardiorespiratory pathology, sepsis and organ failure. Nutritional support is therefore likely to have only a modest effect on survival although it may have an important role in accelerating recovery. On the other hand, prolonged periods of starvation are deleterious, as is excessive or inappropriate nutrition. Secondly, as pointed out by Griffiths et al. [1] in their studies on glutamine supplementation, it is important to follow the whole course of the patient’s illness before, during and after the intensive care unit (ICU) episode, through convalescence to full recovery (fig. 1), since the patients pre-ICU condition and treatment during ICU stay may influence subsequent events. Our goals must therefore be longas well as short-term. Thirdly, the ICU population is not only heterogeneous within each institution, but also varies from center to center. In a recent paper by Van Den Berghe et al. [2], 63% of the population studied were patients recovering from cardiac surgery. In our own ICU there are none. Berger et al. [3] have a high proportion of burned patients in their practice. Another unit may contain a high proportion of patients recovering from major abdominal surgery or even, in some American series, of gunshot wounds. The patient ventilated for 24–48 h for status asthmaticus suffers not one jot from being starved during their stay. In contrast, the catabolic patient ventilated for 1–2 weeks intuitively needs feeding to minimize a huge loss of lean mass. The average length of stay in many ICUs may be 3–4 days, but this average conceals a wide range.