Crystalloid and colloid preload for maintaining cardiac output in elderly patients undergoing total hip replacement under spinal anesthesia

The aim of the present study was to compare the effects of colloid and crystalloid preload on cardiac output (CO) and incidence of hypotension in elderly patients under spinal anesthesia (SA). A randomized, double-blinded study was conducted including 47 elderly patients undergoing scheduled total hip replacement (THR), who were randomized to three groups: the control group (C group, n = 15), crystalloid (RS group, n =16) and colloid group (HES group, n = 16). An intravenous preload of 8 mL/kg of either lactated Ringer's solution in the RS group or 6% hydroxyethyl starch in the HES group was infused within 20 min before SA induction, while no intravenous preload was given in the C group. There was a trend of decrease in CO and systolic blood pressure after SA with time in the C group. In the RS and HES groups, CO increased significantly after fluid preloading as compared with baseline (P < 0.01). Thereafter, CO remained higher than baseline until 30 min after SA in the HES group. The change of systolic blood pressure was similar to CO, but no significant difference from baseline was observed in each group. Hypotension occurred in 3 patients in the C group and one each in the RS and HES group, respectively (P = 0.362). Intravascular volume preload with colloid is more effective than crystalloid solution in maintaining CO, which may be improved the hemodynamic stability in elderly patients during SA.