A systematic review including 6 studies with a total of 532 subjects was abstracted in DARE. There was little relationship between fluid status or fluid therapy and the experience of thirst (3 studies). Neither of the two studies that examined the possible specific relationship between serum sodium and thirst was able to find one. One study reported no correlation between the use of IV fluids and the level of consciousness, but it did suggest that poorer states of consciousness were associated with higher serum sodium, serum osmolalities, and urine osmolalities. One study concluded that respiratory tract secretions were not significantly related to fluid status.