Dynamics of vascular volume and hemodilution of lactated Ringer's solution in patients during induction of general and epidural anesthesia / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the dynamics of vascular volume and the plasma dilution of lactated Ringer's solution in patients during the induction of general and epidural anesthesia.</p><p><b>METHODS</b>The hemodilution of i.v. infusion of 1000 ml of lactated Ringer's solution over 60 min was studied in patients undergoing general (n=31) and epidural (n=22) anesthesia. Heart rate, arterial blood pressure and hemoglobin (Hb) concentration were measured every 5 min during the study. Surgery was not started until the study period had been completed.</p><p><b>RESULTS</b>General anesthesia caused the greater decrease of mean arterial blood pressure (MAP) (mean 15% versus 9%; P<0.01) and thereby followed by a more pronounced plasma dilution, blood volume expansion (VE) and blood volume expansion efficiency (VEE). A strong linear correlation between hemodilution and the reduction in MAP (r=-0.50; P<0.01) was found. At the end of infusion, patients undergoing general anesthesia retained 47% (SD 19%) of the infused fluid in the circulation, while epidural anesthesia retained 29% (SD 13%) (P<0.001). Correspondingly, a fewer urine output (mean 89 ml versus 156 ml; P<0.05) and extravascular expansion (454 ml versus 551 ml; P<0.05) were found during general anesthesia.</p><p><b>CONCLUSION</b>We concluded that the induction of general anesthesia caused more hemodilution, volume expansion and volume expansion efficiency than epidural anesthesia, which was triggered only by the lower MAP.</p>