Effect of low-dose norepinephrine on efficacy of FloTrac/Vigileo system in guiding goal-directed fluid therapy in neurosurgical procedures

Objective To evaluate the effect of low-dose norepinephrine on the efficacy of FloTrac/Vigileo system in guiding goal-directed fluid therapy(GDT)in neurosurgical procedures. Methods Ninety American Society of Anesthesiologists physical status Ⅰ or Ⅱ patients of both sexes, aged 18-64 yr, with body mass index of 18-24 kg/m2, of New York Heart Association class Ⅰ or Ⅱ, with left ventricular ejection fraction>50%, were divided into 3 groups(n=30 each)using a random number table: control group(group C), group GDT and low-dose norepinephrine plus GDT group(group NE+ GDT). The total volume of fluid infused was calculated according to the 4-2-1 rule, and routine fluid therapy was performed in group C. Fluid therapy was performed according to stroke volume variation(SVV)under the guidance of FloTrac/Vigileo system in group GDT.In group NE+ GDT, fluid therapy was performed according to SVV under FloTrac/Vigileo system guidance, and norepinephrine 0.01-0.03 μg·kg-1·min-1 was intravenously infused at the same time.The total volume of fluid infused, amount of crystalloid solution and colloid solution infused, blood loss, urine volume and requirement for ephedrine were recorded during operation.The pH value, base excess, blood lactate and hemoglobin(Hb)were recorded immediately before skin incision and at the end of operation. Results Compared with group C, the amount of crystalloid solution infused and urine volume were significantly reduced, the amount of colloid solution infused was increased, the requirement for ephedrine was reduced, the concentration of blood lactate was decreased at the end of operation, and the concentration of Hb was increased in group GDT(P 0.05). Conclusion Application of low-dose norepinephrine(0.01-0.03 μg· kg-1·min-1)in neurosurgical procedures does not affect the efficacy of FloTrac/Vigileo system in guiding GDT. Key words: Norepinephrine; Fluid therapy; Neurosurgical procedures