Enrollment, randomization, and blinding
Patients were randomized allocated on one-to-one basis to either into a standard conventional fluid therapy group (group C) or GDFT group (group G) using a closed envelope system. A research personnel otherwise not involved in the study prepared and sealed the opaque, consecutively numbered envelopes. Patients were blinded to group allocation. Care providers and investigators in the operating room who supported to fluid strategy administration and recorded intraoperative data could not be blinded due to the presence of the cardiac index trending monitor. The postoperative assessors were blinded to the allocation.