Fluid resuscitation is important in shock therapy, but the choice of fluids, especially the choice of crystalloid is under debate. It is said that normal saline is related to hyperchloremia， which might lead to acute kidney injury. Thus the hypothesis of the study is to explicit whether balanced salt solution could reduce the incidence of acute kidney injury when compared with normal saline.

Inclusion Criteria:

• Shock patients

Exclusion Criteria:

• History of chronic renal failure