Changes in weight, fluid balance and serum albumin in patients referred for nutritional support

Starvation and injury impair the excretion of an excess sodium and water load, resulting in oedema and hypoalbuminaemia, which may have adverse effects on gastrointestinal physiology. We have retrospectively assessed clinical signs and fluid balance in 44 adult patients referred for nutritional support for >== 10 days.

Clinical evidence of oedema was noted. Oedematous patients were managed with a low sodium (0-50 mmol/day), low volume (2 l/day) feed. Some also received albumin and a diuretic. Body weight was recorded daily and serum albumin three times weekly. The lowest recorded weight during nutritional support and the weight at the time of discharge were correlated with serum albumin concentration.

The 21 patients with oedema had acute surgical conditions and complications such as sepsis while the 23 non-oedematous patients had chronic conditions with gradual nutritional depletion. During nutritional support the mean (SEM) weight in kg of the oedematous patients fell from 79.3 (2.9) to 69.2 (3.2) (P>> 0.00001) and subsequently rose to 70.1 (3.2) (P= 0.005). Corresponding values for the non-oedematous patients were 61.4 (4.0), 60.2 (3.9) (P>> 0.05) and 61.2 (3.7) (P= 0.002) respectively. Weight reduction reflected negative salt and water balance and correlated with a rise in serum albumin (r = -0.61 for oedematous and r = -0.65 for non-oedematous patients) largely reflecting reversal of previous dilution.

These findings have important implications for the salt and water content of perioperative fluid and nutritional prescriptions. They also emphasize the dilutional component of hypoalbuminaemia in these patients.