Treatment Outcome of Crystalloids Versus Colloids for Optimization After Induction of General Anesthesia

OBJECTIVE To evaluate the therapeutic effects for volume optimization between Ringer's lactate and hydroxyethyl starch 130/0.4 after induction of general anesthesia.METHODS It was a prospective double-blinded study. Between July 2011 and March 2013, 81 patients with American Society of Anesthesiologist physical status Ⅰ-Ⅱ scheduled for gastrointestinal cancer surgery were divided into 2 groups:Group Ⅰ (Bolus with hydroxyethyl starch 130/0.4, n=56) and Group Ⅱ (Bolus with Ringer's lactate, n=25). Three boluses of fluid infusion was with 3 mL·kg^-1 either hydroxyethyl starch 130/0.4 or Ringer's lactate over 7 min for each bolus. Mean arterial blood pressure (MAP), stroke volume index (SVI), blood volume expansion efficiency, and oxygen delivery (DO₂) were recorded pre-and-post induction of anesthesia, 5 min after each bolus infusion.RESULTS Induction of anesthesia decreased the SVI and MAP, which was comparable between the two groups. Responsiveness to three fluid boluses was 64% vs 20% (P<0.001), 43% vs 13% (P<0.001) and 23% vs 14% (P=0.101) respectively for patients in GroupⅠ and Ⅱ. At the same time, the cumulative percent of volume optimized post 1st or 2nd bolus in Group Ⅰ was lower than in Group Ⅱ (25% vs 74%, P<0.001 and 46% vs 81%, P<0.001), while post 3rd bolus it was similar between the two groups (88% vs 89%, P=0.825). Compared with the patients in Group Ⅱ (68% of baseline), SVI rose bigger in Group I (86% of baseline) (P<0.001) after three boluses, but the changes of MAP were comparable. Blood volume expansion efficiency in response to starch (Group I) exceeded to Ringer's solution (Group Ⅱ) after the 2nd or 3rd bolus, while after the 1st it was the same. DO₂ decreased both in response to the induction of general anesthesia and following the fluid induced plasma dilution, there was no difference between the two groups.CONCLUSION Colloid has an advantage over crystalloids for treatment of volume optimization, which suggests that colloid be used for volume optimization.