A 30% glucose solution was infused for 4 h at a rate of 1.53 ml·kg−1·h−1, corresponding to 10 g·kg−1·24 h−1in 8 critically ill patients requiring parenteral nutrition. The osmotic load resulted in an expanded blood volume due to hemodilution. Stroke volume (SV) increased, while peripheral vascular resistance (PVR) and pulmonary capillary wedge pressure (WP) decreased. Otherwise, no major effects on the circulation were observed. Thus, during these experimental conditions, the heart seems to cope very well with the increased osmotic load.