Muscle chemistry of critically ill surgical patients and the effects of a course of intravenous nutrition.

The water, electrolyte and nitrogen contents of muscle were measured in 15 critically ill surgical patients before and after a course (approximately 2 weeks) of intravenous nutrition and in 8 normal individuals. The muscle from the surgical patients contained a significantly increased ratio of water to fat-free dry weight (P less than 0.01) due to an increase in the proportion of extracellular to intracellular water, and this was not corrected by intravenous nutrition. These changes could be due to an accumulation of extracellular fluid alone or to a loss of cell cytoplasm or a loss of whole muscle fibres. Intracellular chemistry was normal in the ill surgical patients and was not changed by intravenous nutrition.