Effect Of Intraoperative Infusion Of Amino Acids On Oxygen Consumption

OBJECTIVE The aim of this study is to investigate the effect of general plus epidural anesthesia on oxygen consumption of intraoperative patients with intravenous administration of amino acids.METHODS thirty patients,ASA physical status Ⅰ-Ⅱ,27 to 65 years old,BMI 18 to 25, undergoing abdominal surgery, were randomized to either amino acid infusion group(A group,n=15) or control group(C group,n=15) by SPSS 22.0. For each patient,an epidural catheter was inserted at either thoracic level between T8 and T9 or T9 and T10 and another catheter into the right internal jugular vein together with a third catheter into the left radial artery after the patient’s entry into the operation room(OR). After connecting the monitor, arterial and venous blood samples were harvested for blood gas analysis, and the circulation and blood gas analysis parameters were recorded under basal conditions(To).All patients were induced under the condition of 3 u g/kg bolus of fentanyl and continous infusion of 0.2 μg/kg/min of remifentanil together with continous infusion of propofol with plasma target control infusion model (Cp) (Marsh mode) of 4 u g/ml.Tracheal intubation was then facilitated with 0.6mg/kg bolus of rocuronium, and the patient was ventilated by Drager Primus anesthesia machine with CMV model, and the nasopharyngeal temperature(Tc) was monitored.Anesthesia was maintained with sevoflurane, intravenous propofol, remifentanil together with fentanyl.The Cp of propofol was adjusted to maintain BIS values between 30 and 60,and supplemental doses of rocuronium were applied in needed for complete surgical muscle relaxation.Total 8ml of 0.375% epidural bupivacaine was administered for loading dose before skin incision,and intermittently supplemental bolus dose of 4 ml of 0.375% bupivacaine was given every hour.In group A,an infusion of 11.4% amino acid compounds solution was started at a rate of 4kJ/kg/h simultaneously and continued for 2 hours or until the end of surgery(if the surgery was less than 2 hours),while in group C the amino acid compounds was replaced by saline. MAP, HR,Tc,and Blood gas analysis result [including arterial and venous oxygen tension (PaO2 and PcvO2), arterial and central venous oxygen saturation (SaO2 and ScvO2), arterial blood lactate concentration (Lac),Arteriovenous carbon dioxide tension difference (PvaCO2) and The difference between arterial and venous blood PH(PHav)] were recorded at 10 min afer tracheal intubation(Ti) and at 30(T2),60(T3),120(T4) min after skin incision and before leaving the PACU(T5). After extubation, the patient was transported to the PACU, where oxygen support and monitoring of vital signs was regularly given to the patient. At last, the occurrence of postoperative shivering was recorded. The requirement of anesthetic agents (such as propofol, fentanyl, remifentanil and rocuronium) and vasopressor drugs (phenylephrine and ephedrine) were recorded, respectively.RESULTS There are no significant difference between the two groups on arteriovenous oxygen content difference(P>0.05); In T4 moment, ERO2 of Group A higher than that of Group C(P<0.05);at the same time, ScvO2 of Group A lower than that of Group C.From T4 to Ts,compared with the control group,the experimental group increased lactate levels (P<0.05); and in the T5 moment, PHav of Group A lower than that of Group C(P<0.01).Group A had one case of grade 1 shivering; Group C appears three cases of grade 1 shivering, three cases of grade 2, and one case of grade 3 shivering.The difference between the two groups is significant (P<0.05).CONCLUSION Intraoperative infusion of amino acids had no effect on the body’s oxygen consumption, but it can prevent the occurrence of postoperative shivering.