RESUMO
Objective To compare the volume kinetics of lactated Ringer' s solution during induction of general and epidural anesthesia in elderly patients.Methods Forty ASA Ⅰ or Ⅱ patients,aged 66-86 yr,weighing 45-86 kg,undergoing elective surgery,were studied.In epidural anesthesia group (n =20),lactated Ringer' s solution was infused intravenously starting from 10 min before epidural anesthesia was performed with local anesthetics.In general anesthesia group (n =20),lactated Ringer' s solution 1000 ml was infused intravenously over 60 min starting from 20 min before induction of anesthesia.Arterial blood samples were obtained every 5 min for measurement of hemoglobin concentrations.The plasma dilution,volume increase,and volume expansion efficacy were calculated.Results The plasma dilution,volume increase and volume expansion were significantly higher at 30-60 min of lactated Ringer' s solution infusion in general anesthesia group than in epidural anesthesia group (P ＜ 0.05 or 0.01).Conclusion The volume expansion of lactated Ringer' s solution is greater in elderly patients during induction of general anesthesia than that during induction of epidural anesthesia.