***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: OBJECTIVE To specifically compare the effect of two hydroxyethyl starches ( HES ) on the splanchnic microcirculation and systemic inflammation during abdominal aortic aneurysm ( AAA ) surgery . MATERIAL S AND METHODS A prospect i ve r and omised study was carried out on 62 patients who received HES of molecular-weight 200 kDa ( HES200/0.62 ) , 130 kDa ( HES130/0.4 ) or gelatine for 24h peri-operatively .  Gastric-mucosal pHi ( GpHi ) and anti-endotoxin antibody were used as markers of splanchnic perfusion and endotoxaemia respectively . C-reactive protein ( CRP ) and lung-injury score ( LIS ) were used as markers of systemic inflammation and end-organ dysfunction respectively . Data was collected prospect ively . RESULTS The drop in GpHi was least with HES200/0.62 compared to HES130/0.4 and gelatine at reperfusion ( 7.32 vs 7.28 and 7.28 , p=0.017 and 0.009 respectively ) and compared to gelatine at 2h as well ( 7.43 vs 7.28 , p=0.001 ) . GpHi dropped less with HES130/0.4 compared to gelatine at 2h ( 7.39 vs 7.28 , p=0.002 ) . Endotoxaemia increased only with gelatine . CRP was lower with HES200/0.62 ( 178 mg/mL ) than gelatine ( 221 mg/mL ) and HES130/0.4 ( 223 mg/mL ) at 48 h ( p=0.049 and p=0.009 respectively ) . There was no difference in LIS but ventilation duration was less with HES200/0.62 compared with gelatine ( 4 vs 11h , p=0.012 ) . CONCLUSION During AAA surgery , HES200/0.62 provides the best splanchnic microcirculation protection , also reducing inflammation and duration of ventilation BACKGROUND Gastric intramucosal pH ( pHi ) , a surrogate marker of splanchnic oxygenation , falls following abdominal aortic aneurysm surgery . AIM To investigate the effects of volume expansion with hydroxyethyl starch ( eloHAES ) on splanchnic perfusion compared to another colloid such as gelofusine . PATIENTS AND METHODS Twenty-two consecutive patients undergoing AAA repair were r and omised to receive either eloHAES or gelofusine as plasma exp and ers . Tissue oxygenation was monitored ( 10 gelofusine and 12 eloHAES ) indirectly by measuring pHi using a nasogastric tonometer . RESULTS Compared to the eloHAES group , the fall in pHi was significantly greater in the gelofusine group at clamp release ( 7.29 vs 7.33 , P=0.003 ) and at 4 h following clamp release ( 7.29 vs 7.33 , P=0.03 ) . There was a good inverse correlation between the lowest pHi and the peak serum interleukin-6 ( r(s)= -0.47 , P=0.03 ) . By multivariate analysis , the only factor that influenced the pHi was the type of colloid used ( F=5.54 , P=0.005 ) . The eloHAES treated patients required significantly less colloid on the first postoperative day ( 3175 + /- 175 vs 4065 + /- 269 ml , P=0.01 ) . CONCLUSION In patients undergoing abdominal aortic aneurysm repair , plasma expansion with eloHAES improves microvascular perfusion and splanchnic oxygenation In a prospect i ve r and omized trial of 16 patients undergoing abdominal vascular reconstructive procedures  , changes in plasma volume , serum oncotic pressure ( pis ) , serum albumin and total protein concentration , alveolar to arterial oxygen tension differences ( AaDO2 , FIO2 = 1.0 ) , creatinine clearance , body weight , and fluid and sodium intake were examined . By r and om assignment patients received either an albumin- or a sodium-rich intraoperative fluid regimen .  Pulmonary arteriovenous admixture was significantly less in the albumin group ( n = 7 ) than in the electrolyte group ( n = 9 ) on the first postoperative day . The change in AaDO2 correlated positively with the total sodium intake in the electrolyte group . Despite the larger fluid load and significantly greater gain of body weight , patients in the electrolyte group had a postoperative plasma volume significantly lower than the preoperative value . Postoperative values of albumin concentration , circulating albumin mass and pis were significantly greater in the albumin group in comparison to the electrolyte group . Creatinine clearance values were not different between the two groups . The change in pis correlated significantly with sodium intake and circulating albumin mass . Pulmonary shunting and expansion of the extracellular fluid volume may be minimized without adverse effects on renal function by administration of fluids rich in albumin in preference to sodium AIM The present study was design ed to assess whether prophylactic use of bicarbonated Ringer 's solution ameliorates metabolic acidosis in patients undergoing aortic surgery . METHODS Twenty patients undergoing elective infrarenal aortic aneurysm repair were r and omly assigned to receive either bicarbonated Ringer 's solution or acetated Ringer 's solution . The pH , PaCO(2 ) , and base excess ( BE ) were measured before surgical incision ( T0 ) , 5 min before reperfusion ( T1 ) , 5 min after reperfusion ( T2 ) , and 30 min after reperfusion ( T3 ) . Data were compared between the two groups . RESULTS Both pH and BE initially showed a slight decrease in both groups during clamping . After unclamping of the aorta , an additional decrease in pH was observed in both groups ( T0 to T2 , and T3 ) . There were no significant differences in pH between the groups throughout the study period . CONCLUSIONS Aortic cross-clamping leads to the development of metabolic acidosis , with a decrease in pH and BE . The effect of administration of bicarbonated infusion fluid during elective abdominal aortic surgery had not significant compared with that of acetated Ringer 's solution with respect to acid-base homeostasis PURPOSE The net benefit of routine intraoperative autotransfusion ( IAT ) in patients undergoing elective infrarenal aortic surgery was studied . METHODS One hundred patients undergoing abdominal aortic aneurysm ( AAA ) repair ( n = 50 ) or aortofemoral bypass ( AFB ) for occlusive disease ( n = 50 ) were r and omized to IAT and control groups .  This experience accounted for 58 % of patients undergoing aortic surgery during the 16-month study period . RESULTS IAT and control groups were balanced for preoperative demographics , disease ( 50:50 split of AFB : AAA in each group ) , and risk factors . There were no significant differences between patients r and omized to IAT and control patients in estimated blood loss ( EBL ) , allogeneic blood transfusion ( units administered intraoperatively , postoperatively , and total ) , proportion of patients not receiving allogeneic blood ( 34 % of patients r and omized to IAT and 28 % of control patients ) , postoperative hemoglobin/hematocrit levels , and complications .  IAT did not reduce allogeneic blood transfusion among all patients undergoing aortic surgery nor in any subgroups that might be more likely to benefit , such as those undergoing AAA repair , those with 1000 mL or more EBL , and those receiving larger volumes of IAT-processed blood . CONCLUSION We could find no net benefit of IAT in patients undergoing elective , infrarenal aortic surgery Metabolic acidosis and changes in serum osmolarity are consequences of 0.9 % normal saline ( NS ) solution administration . We sought to determine if these physiologic changes influence patient outcome . Patients undergoing aortic reconstructive surgery were enrolled and were r and omly assigned to receive lactated Ringer ’s ( LR ) solution ( n = 33 ) or NS ( n = 33 ) in a double-blinded fashion . Anesthetic and fluid management were st and ardized . Multiple measures of outcome were monitored . The NS patients developed a hyperchloremic acidosis and received more bicarbonate therapy ( 30 ± 62 mL in the NS group versus 4 ± 16 mL in the LR group ; mean ± sd ) , which was given if the base deficit was greater than −5 mEq/L. The NS patients also received a larger volume of platelet transfusion ( 478 ± 302 mL in the NS group versus 223 ± 24 mL in the LR group ; mean ± sd ) . When all blood products were summed , the NS group received significantly more blood products ( P = 0.02 ) . There were no differences in duration of mechanical ventilation , intensive care unit stay , hospital stay , and incidence of complications . When NS was used as the primary intraoperative solution , significantly more acidosis was seen on completion of surgery . This acidosis result ed in no apparent change in outcome but required larger amounts of bicarbonate to achieve predetermined measurements of base deficit and was associated with the use of larger amounts of blood products . These changes should be considered when choosing fluids for surgical procedures involving extensive blood loss and requiring extensive fluid administration Preoperative normovolemic hemodilution ( PNH ) has been proposed for patients scheduled to undergo aortic surgery . Coronary artery disease is frequent in these patients . The aim of the study was to assess the effect of PNH on hemodynamics and segmental wall motion ( SWM ) evaluated by transesophageal echocardiography in such patients . Twenty patients with coronary artery disease were allocated r and omly to either PNH or no PNH ; PNH was performed after anesthetic induction using dextran 60,000 .  Patients were operated on under general anesthesia and monitored intraoperatively with electrocardiographic lead CM5 , radial and pulmonary artery catheters , and transesophageal echocardiography positioned to obtain a short-axis view .  Hemodynamic and transesophageal echocardiographic data were collected after anesthetic induction and after PNH , before and 5 min after aortic clamping , after unclamping , and at the end of surgery . Aortic clamping induced a significant increase in systemic vascular resistance and arteriovenous difference in oxygen and a decrease in cardiac index ( P < 0.05 ) , but the effect of aortic clamping was inversely related to hemodilution . The SWM score ( grade d from 1 = normal to 5 = dyskinesia ) was significantly increased after aortic clamping , mainly in the anterior segment ( P < 0.05 ) . Four patients in the control ( no PNH ) group and one in the PNH group developed new SWM abnormalities indicative of myocardial ischemia during surgery ( P = NS ) . This study suggests that PNH may improve hemodynamic tolerance to aortic clamping in patients with coronary artery disease . The observed changes in SWM indicate that PNH may not worsen myocardial ischemia in patients scheduled to undergo aortic surgery Objective To determine if gastric intramucosal pH (pHi)-guided therapy reduces the number of complications and length of stay in the intensive care unit ( ICU ) or the hospital after elective repair of infrarenal abdominal aortic aneurysms . Design Prospect i ve , r and omized study . Setting Surgical intensive care unit ( SICU ) of a University Hospital . Patients Fifty-five consecutive patients r and omized to group 1 ( pHi-guided therapy ) or to group 2 ( control ) . Interventions Patients of group 1 with a pHi of lower than 7.32 were treated by means of a prospect i ve protocol in order to increase their pHi to 7.32 or more . Measurements and results pHi was determined in both groups on admission to the SICU and thereafter at 6-h intervals . In group 2 , the treating physicians were blinded for the pHi values . Complications , APACHE II scores , duration of endotracheal intubation , fluid and vasoactive drug treatment , treatment with vasoactive drugs , length of stay in the SICU and in the hospital and hospital mortality were recorded . There were no differences between groups in terms of the incidence of complications . We found no differences in APACHE II scores on admission , the duration of intubation , SICU or hospital stay , or hospital mortality . In the two groups the incidence of pHi values lower than 7.32 on admission to the SICU was comparable ( 41 % and 42 % in groups 1 and 2 , respectively ) . Patients with pHi lower than 7.32 had more major complications during SICU stay ( p<0.05 ) , and periods more than 10 h of persistently low pHi values ( < 7.32 ) were associated with a higher incidence of SICU complications ( p<0.01 ) . Conclusions Low pHi values ( < 7.32 ) and their persistence are predictors of major complications . Treatment to elevate low pHi values does not improve postoperative outcome . Based on these data , we can not recommend the routine use of gastric tonometers for pHi-guided therapy in these patients 
    Output:
    
This review demonstrated that no single fluid affects any outcome measure significantly more than another fluid across a range of outcomes .
There are no studies examining the effects of combination fluid therapy .