Efficacy of individualized mini-fluid challenge test in determining fluid responsiveness in patients undergoing surgery in prone position / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the efficacy of individualized mini-fluid challenge test in determining the fluid responsiveness in the patients undergoing surgery in prone position.Methods:A total of 47 patients of either sex, aged > 18 yr, with boy mass index of 18-30 kg/m 2, of American Society of Anesthesiologists Physical Status classification Ⅰ or Ⅱ, undergoing elective spinal surgery in prone position, were included. The volume-controlled mode was used for mechanical ventilation, and the tidal volume was set at 8 ml/kg. The hemodynamic parameters were monitored by FloTrac/Vigileo system. The patient was changed to prone position at 5 min after endotracheal intubation (T 1), hydroxyethyl starch 130/0.4 sodium chloride injection 2 ml/kg was intravenously given at 5 min of prone position (T 2), and fluid 3 ml/kg was continuously infused at 1 min after 2 ml/kg fluid infusion (T 3), and both infusion rates were 0.5 ml·kg -1·min -1. A mini-fluid challenge test was performed during T 2-T 3 period, the standard volume therapy (total infusion of liquid 5 ml/kg) was carried out from T 2 to 1 min after infusion of liquid 3 ml/kg (T 4). The rate of change in SV at T 3 time point (ΔSVT 3) was calculated relative to T 2 time point, and the rate of change in SV at T 4 time point (ΔSVT 4) was calculated relative to T 2 time point. Positive fluid responsiveness test was defined as an increase in ΔSVT 4≥10%, and patients were divided into volume response group (Rs group) and non-volume response group (NRs group). ΔSVT 3, ΔSVT 4 and stroke volume variation and pulse pressure variation at T 3 and T 4 time points were selected, the receiver operating characteristic curve predicting fluid responsiveness was generated, and the area under the receiver operating characteristic curve (AUC) was calculated. Results:Forty-one patients were finally enrolled, including 18 cases in Rs group and 23 cases in NRs group. The AUC of ΔSVT 3 determining fluid responsiveness was 0.976, with the sensitivity 0.944 and specificity 0.957. The AUC of ΔSVT 4 determining fluid responsiveness was 0.971, with sensitivity 0.889 and specificity 0.95. The AUC of stroke volume variation at T 3 and T 4 in predicting fluid responsiveness was 0.632 and 0.609, respectively. The AUC of pulse pressure variation at T 3 and T 4 predicting fluid responsiveness was 0.470 and 0.380, respectively. Conclusions:Individualized mini-fluid challenge test (2 mg/kg colloidal solution) can accurately determine the fluid responsiveness in the patients undergoing surgery in prone position.