***TASK*** the task is to summarize an input biomedical literature in six sentences 
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    Input: Intraoperative infusion of amino acids stimulates oxygen uptake with a result ing increase in heat production , especially during emergence from anesthesia . To determine whether the increased thermogenesis in response to amino acid infusion during and after anesthesia induces any additional stress in surgical patients , plasma catecholamines were measured . Fourteen patients aged 44 + /- 15 yr scheduled for gall bladder surgery during isoflurane anesthesia were studied . Seven patients received an IV amino acid infusion at the rate of 126 mL/h throughout anesthesia , and seven control subjects received equal volumes of nutrient-free saline . At five defined times during and after anesthesia , arterial adrenaline and noradrenaline concentrations were determined . Arterial blood pressure and heart rate were recorded simultaneously . There were considerable variations from baseline in levels of plasma adrenaline and noradrenaline , heart rate , and blood pressure during the study period , but there were no significant differences between the two groups at any time throughout anesthesia and surgery . In conclusion , the augmented thermogenic effect of amino acids during and at emergence from anesthesia is suggested to occur without imposing any additional stress in the surgical patient . Implication s : Amino acid infusion during anesthesia has been demonstrated to markedly increase oxygen consumption and heat production . To determine whether this evokes any stress in the patients , we measured plasma catecholamines during anesthesia . We suggest that temperature preservation during anesthesia by an amino acid infusion occurs without additional sympathoadrenal activity . ( Anesth Analg 1998;87:637 - 40 BACKGROUND Mild perioperative hypothermia , which is common during major surgery , may promote surgical-wound infection by triggering thermoregulatory vasoconstriction , which decreases subcutaneous oxygen tension . Reduced levels of oxygen in tissue impair oxidative killing by neutrophils and decrease the strength of the healing wound by reducing the deposition of collagen . Hypothermia also directly impairs immune function . We tested the hypothesis that hypothermia both increases susceptibility to surgical-wound infection and lengthens hospitalization . METHODS Two hundred patients undergoing colorectal surgery were r and omly assigned to routine intraoperative thermal care ( the hypothermia group ) or additional warming ( the normothermia group ) . The patient 's anesthetic care was st and ardized , and they were all given cefam and ole and metronidazole . In a double-blind protocol , their wounds were evaluated daily until discharge from the hospital and in the clinic after two weeks ; wounds containing culture-positive pus were considered infected . The patients ' surgeons remained unaware of the patients ' group assignments . RESULTS The mean ( + /- SD ) final intraoperative core temperature was 34.7 + /- 0.6 degrees C in the hypothermia group and 36.6 + /- 0.5 degrees C in the normothermia group ( P < 0.001 ) Surgical-wound infections were found in 18 of 96 patients assigned to hypothermia ( 19 percent ) but in only 6 of 104 patients assigned to normothermia ( 6 percent , P = 0.009 ) . The sutures were removed one day later in the patients assigned to hypothermia than in those assigned to normothermia ( P = 0.002 ) , and the duration of hospitalization was prolonged by 2.6 days ( approximately 20 percent ) in hypothermia group ( P = 0.01 ) . CONCLUSIONS Hypothermia itself may delay healing and predispose patients to wound infections . Maintaining normothermia intraoperatively is likely to decrease the incidence of infectious complications in patients undergoing colorectal resection and to shorten their hospitalizations UNLABELLED Amino acid infusion during general anesthesia induces thermogenesis and prevents postoperative hypothermia and shivering . We propose that amino acid prevention of hypothermia during anesthesia shortens the hospital stay . Core temperatures and pulmonary oxygen uptake were measured in 45 patients , receiving an IV amino acid mixture , 126 mL/h , before and /or during isoflurane anesthesia and 30 control patients receiving acetated Ringer 's solution .  At awakening , mean core temperature was 36.5 degrees+/-0.1 degrees C in the amino acid group and 35.7 degrees+/-0.1 degrees C ( P < 0.001 ) in the controls . Energy expenditure increased by 54%+/-9 % from baseline in amino acid patients in whom shivering was uncommon , but only by 5%+/-4 % ( P < 0.001 ) in control patients , of whom the majority developed postoperative shivering . The estimated difference in hospital stay between the two groups was 2.7 days ( CI 95 % : 1.3 - 4.0 ) . Multiple regression analysis showed that the variables best predicting hospitalization were duration of surgery , amino acid treatment , and awakening temperatures . Duration of surgery was similar in the two groups and core temperatures at awakening were a result of amino acid infusion , which indicates that amino acid infusion during anesthesia and surgery was the most important factor for the shorter hospitalization . IMPLICATION S Amino acid infusion during general anesthesia induces thermogenesis and prevents postoperative hypothermia and shivering . Multiple regression analysis indicated that this result ed in a shorter hospital stay Objective Hypothermia may occur during general anaesthesia and is associated with postoperative coagulopathy , ischaemic cardiac events , wound infections and increased metabolic expenditure due to shivering . The purpose of the present pilot study was to determine whether the administration of certain amino acids ( Vamin 18 ) during general anaesthesia could prevent postoperative hypothermia Aim : To investigate the effect of intraoperative amino acid infusion on blood glucose in patients under general anesthesia combined with epidural block . Methods : 36 patients were r and omly assigned to receive an intraoperative infusion of 18 compound amino acids ( group AA ) or lactated Ringer solution ( group LR ) at 2 ml·kg–1·h–1 . Nasopharyngeal temperature , and blood glucose , plasma insulin , C-peptide and glucagon concentrations were measured 30 min before induction ( T0 ) , 10 min after induction ( T1 ) , 30 min and 2 h after skin incision ( T2 , T3 ) , and 30 min and 2 h postoperatively ( T4 , T5 ) . Results : Nasopharyngeal temperature values , which decreased during surgery in both groups , were significantly higher in group AA than in group LR from T3 to T5 . Compared with T0 , the blood glucose concentration increased significantly from T2 in group AA and T3 in group LR to T5 . Plasma insulin and C-peptide concentrations did not change significantly in group LR , while both increased significantly in group AA from T1 to T4 . The plasma glucagon concentration did not change significantly in either group . Conclusion : Intraoperative amino acid infusion in patients under general anesthesia combined with epidural block may accelerate the increase of blood glucose concentration and stimulate insulin secretion , and can alleviate hypothermia during the later period of surgery and postoperatively Intraoperative infusion of amino acids has been found to stimulate energy expenditure and thereby prevent anaesthesia-induced hypothermia . Rectal temperature and respiratory gas exchange were measured in 24 female patients before and after isoflurane anaesthesia . Sixteen patients had an amino acid mixture of 240 kJ h-1 , infused over 1 - 2 h before anaesthesia and eight control patients received saline . We compared the results with data from six female volunteers treated with amino acids ; they were not premedicated or anaesthetized . In lorazepam premedicated patients , amino acids increased the pre-anaesthesia temperature by 0.3 degrees C h-1 , twice that observed in the volunteers . At awakening after anaesthesia , energy expenditure increased to 50 - 60 % above baseline in the amino acid treated patients , while in the control patients , receiving saline , no increase occurred , despite vigorous shivering .  Amino acid infusion prevented hypothermia by increasing heat accumulation and causing delayed stimulation of heat production . The heat accumulation response to amino acid infusion was increased after premedication with lorazepam 1 . Intravenous infusion of amino acids stimulates energy expenditure and heat accumulation in normal man . To find out whether such stimulation also occurs during general anaesthesia , thermogenesis was measured in 21 patients before , during and after anaesthesia and surgery . 2 . Ten patients received a mixture of 19 amino acids ( 240 kJ/h ) infused intravenously throughout the anaesthesia . The other 11 patients , serving as controls , received saline . Using catheters previously inserted into the pulmonary and a systemic artery , cardiac output , arteriovenous oxygen difference , pulmonary oxygen uptake and mixed blood temperature were measured . 3 . During anaesthesia and surgery , the blood temperature fell by 0.67 + /- 0.09 degrees C/h in the control patients and by 0.38 + /- 0.06 degrees C/h in the amino acid-treated patients . Anaesthesia during 34 + /- 4 min before surgery reduced the pulmonary oxygen uptake by 145 + /- 9 ml/min in the control patients and by 81 + /- 10 ml/min in the amino acid-treated patients , corresponding to reductions in total energy expenditure of 47 W in the control group and 26 W in the amino acid-treated group . The difference , 21 W , illustrates the thermogenic action of the amino acids . This value may be compared with that of 4 W , observed in unanaesthetized individuals subjected to 30 min of identical amino acid infusions . 4 . At awakening after the anaesthesia , the oxygen consumption rose to 71 + /- 21 % above the pre-anaesthesia level in the amino acid-treated patients , who , without shivering , rapidly returned to normothermia , whereas in the control patients the oxygen uptake remained slightly below the pre-anaesthesia level , despite sustained hypothermia and vigorous shivering . ( ABSTRACT TRUNCATED AT 250 WORDS Mild intraoperative hypothermia is common . We therefore studied the effects of mild hypothermia on  propofol pharmacokinetics , hepatic blood flow , and atracurium duration of action in healthy volunteers . Six young volunteers were studied on two r and omly assigned days , at either 34 degrees C or 37 degrees C. Anesthesia was induced with thiopental , 3 mg/kg , and maintained with 70 % N2 O and 0.6 % isoflurane . Core hypothermia was induced by conductive and convective cooling . On the other study day , normothermia was maintained by a Bair Hugger Registered Trademark ( Augustine Medical , Inc. , Eden Prairie , MN ) forced-air warmer . Propofol , 1 mg/kg lean body mass ( LBM ) , then was given , followed by a 4-h infusion at 5 mg centered dot kg-1 centered dot h-1 . After 2 h , atracurium 0.5 mg/kg was administered as an intravenous bolus . Indocyanine green was administered for estimation of hepatic blood flow . Arterial blood was assayed for propofol and indocyanine green concentration . Pharmacokinetic analysis was performed using NONMEM . Results are reported as means + /- SEM .  Propofol blood concentrations averaged approximate equals 28 % more at 34 degrees C than at 37 degrees C ( P < 0.05 ) . Hepatic blood flow decreased 23 % + /- 11 % in normothermic volunteers during the propofol infusion , and 33 % + /- 11 % in hypothermic volunteers ( P = not significant ) . A three-compartment mamillary model fitted the data best . Inclusion of hepatic blood flow change from the prepropofol baseline as a covariate for total body clearance significantly improved the fit . The intercompartmental clearances were decreased in the presence of hypothermia . Core hypothermia prolonged the time to recovery of the first twitch in the train-of-four to 10 % of its control value ( T1 = 10 % ) after atracurium administration by approximate equals 60 % ( P < 0.05 ) , from 44 + /- 4 min to 68 + /- 7 min . In contrast , T1 = 25%-75 % remained unchanged . We conclude that 3 degrees C of core hypothermia increased propofol blood concentrations and prolonged atracurium duration of action . Hepatic blood flow was decreased during propofol administration , and this change was a significant predictor of propofol clearance , indicating that the effect of propofol on hepatic blood flow impairs the clearance of propofol itself . ( Anesth Analg 1995;80:1007 - 14 OBJECTIVE Amino acid administration helps to prevent intraoperative hypothermia but may enhance thermogenesis when combined with glucose infusion . The aim of this study was to examine the effect of intraoperative amino acid administration , with or without glucose infusion , on temperature regulation during laparoscopic colectomy . METHODS Twenty-one patients whose physical status was classified I or II by the American Society of Anesthesiologists , and who were undergoing elective laparoscopic colectomy were enrolled . The exclusion criteria were a 
    Output:
    
Intravenous amino acids may keep participants up to a half-degree C warmer than the control .
This difference was statistically significant at the end of surgery , but not at other time points .
However , the clinical importance of this finding remains unclear .