A number of assessment tools serve as proxies for BCM.
However, because they rely on assumptions that do not hold
true during metabolic stress, they are of limited use in the
critically ill burn patient. In fact, most nutritional assessment
tools available in a clinical setting are confounded by the
physiological elements of the inflammatory response. Even
the simplest measures of total body weight or weight change,
which are usually reasonable markers of fat and lean tissue
status, are obscured by the expansion of extracellular water
following acute burn injury [7]. Visceral proteins are better
prognostic indicators than parameters of protein status in
burn patients during the acute phase response [8,9]. Overestimates
of nitrogen intake and underestimates of nitrogen
output often invalidate nitrogen balance studies, leading to
falsely positive results. In burn injury, the magnitude of error
is even further compounded by exudative wound losses and
increased ammonia (versus urea) nitrogen excretion that is
typical in critical illness