Effects of norepinephrine on oxygen metabolism and postoperative outcomes in elderly patients undergoing fluid-restricted abdominal surgery / 中华麻醉学杂志

ABSTRACT

ObjectiveTo investigate the effects of norepinephrine on oxygen metabolism and postoperative outcomes in the elderly patients undergoing fluid-restored abdominal surgery.MethodsAfter hospital ethics committee approval,and written informed consent was obtained from all patients,40 elderly patients,aged ＞ 64 yr,with a body mass index of 18-24 kg/m2,undergoing elective colorectal surgery,were randomly divided into 2 groups (n =20 each)routine fluid administration group (group A) and restricted fluid administration group (group B).In group A,lactated Ringer's solution was given routinely.Lactated Ringer's solution was given at a rate of 5 ml· kg- 1 · h- 1 and small dose of norepinephrine was infused intravenously at 0.01-0.03 μg· kg- 1 · h - 1 simultaneously during the surgery,and MAP was maintained ≥65 mm Hg in group B.Intraoperative blood loss was replaced with the equal volume of 6％ hydroxyethyl starch 130/0.4.Before the surgery ( baseline),1 and 2 h after beginning of the surgery,and while leaving postanesthesia care unit,mean arterial pressure (MAP),heart rate (HR),cardiac index (CI) and central venous pressure (CVP) were recorded,and arterial and central venous blood samples were drawn for blood gas analysis.Oxygen delivery index (DO2 I ),oxygen consumption index (YO2I) and oxygen extraction ratio (ERO2) were calculated.The gastric mucosal pH was determined before the surgery and 1 h after beginning of the surgery.Blood samples were taken form the peripheral vein to determine the concentration of Hb,serum albumin,blood urea nitrogen (BUN) and creatinine (Cr) concentrations before the surgery and 1 day after the surgery.The extubation time,duration of stay in hospital,the time when the patients passed the flatus,pulmonary complications,gastrointestinal complications,and wound infections were recorded.ResultsCompared with group A,CI,Hb,ScvO2 and DO2I were significantly increased,CVP and ERO2 were decreased during the surgery,the concentrations of Hb and serum albumin were significantly increased,1 day after the surgery,and the incidence of pulmonary complications and wound infections was significantly decreased after the surgery in group B (P ＜ 0.05 ).There were no significant differences in gastric muscosal pH,the indexes of renal function,extubatiotn time,the time when the patients passed the flatus,duration of stay in hospital and the incidence of gastrointestinal complications between the two groups ( P ＞ 0.05).ConclusionWhen small dose of norepinephrine is used to treat perioperative hypotension induced by fluid restriction,it can increase oxygen delivery,and reduce the incidence of postoperative complications,and has no adverse effects on gastrointestinal microcirculation and oxygen consumption in the elderly patients undergoing colorectal surgery.