Total parenteral nutrition and energy expenditure in general surgery, trauma and sepsis

It is widely believed that sepsis and trauma cause increased energy expenditure and consequently it is held that energy intake by TPN must be greatly increased. Resting energy expenditure (REE) was measured by indirect calorimetry in 9 general surgery and trauma patients (19 measurements) and in 11 septic patients (71 measurements). REE was compared with basal energy expenditure (BEE) as defined by the Harris-Benedict formula. Data was classified as hypermetabolic (REE > 125% of predicted) normometabolic (75-125% of predicted) and hypometabolic (<75% of predicted). Fifty four per cent of septic data was normometabolic, 35% hypermetabolic and 11% hypometabolic. Hypometabolic patients had lower cardiac output and impaired contractility in respect of normo and hypermetabolic patients. Harris-Benedict formula can not accurately predict actual energy expenditure in a great number of septic patients and REE direct measurement seems to be of great value for the rational planning of energy intake and prevent complication of these critically ill septic patients.