***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: 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 OBJECTIVES To determine if cell-salvaged autologous blood can serve as an alternative to homologous blood , and to examine the incidence of infected complications and length of postoperative stay . DESIGN A prospect i ve r and omised study comprising autologous and homologous blood transfusions in patients undergoing elective infrarenal abdominal aortic surgery . METHODS Fifty patients undergoing AAA surgery were prospect ively r and omised to homologous blood ( n = 27 ) , or autologous blood transfusion ( n = 23 ) , using a cell salvage autotransfusion device . RESULTS The haemoglobin at the time of hospital discharge was similar for both groups ( 11.0 vs. 10.8 g/dl ) with no difference in perioperative mortality . The length of stay was reduced in those patients who received autologous blood ( 9 days vs. 12 days , p < 0.05 Mann-Whitney U test ) . There were four infected cases in the autologous group and 12 in the homologous group ( p = n.s . , Fisher 's exact probability test ) . However , patients who received 3 - 4 units of homologous blood had an increased risk of infection compared to those who received a similar amount of autologous blood ( 50 % vs. 0 % ) . CONCLUSIONS Cell salvage autologous blood can safely replace , or at least decrease , exposure to homologous blood transfusion , with a reduction in the mean hospital stay In a r and omised prospect i ve study the efficacy of autotransfusion was investigated in two groups of 25 patients , a study group in which autologous blood was collected from the mediastinal tubes and retransfused  , and a second , control group , in which only stored blood was used .  In the study group , a reduction of 50 % in the amount of stored blood required was observed . However , in two out of 25 patients the transfusion system could not be used due to clot formation in one of its components . From the total bloodloss per patient about 25 % became available for autotransfusion . No significant differences between the two groups were found for hemoglobine , hematocrite , white blood count , platelets and fibrinogen level . Coagulation studies of the drain blood indicate that an active process of mediastinal clotting , followed by fibrinolysis occurs during the losing and collecting . The blood available for retransfusion contained a considerable amount of small-sized debris . It is concluded that autotransfusion of drain blood is not to be recommended for routine use In order to evaluate the clinical and haematological implication s of salvage autotransfusion using the Haemolite device ( Haemonetics , Leeds , UK ) , 67 aortic reconstructions were studied .  Bank blood transfused during the operation fell from a median of four units in the control group to zero using the cell saver ( P less than 0.0001 ) , and wound drainage decreased from 250 to 200 ml ( P = 0.12 ) . Evidence of fibrinolytic and platelet activation was found during salvage , but no bleeding diathesis was encountered . There was no morbidity or mortality related to the technique , and median hospital stay was reduced in autotransfused patients . The Haemolite is a safe effective device for autotransfusion in elective aortic surgery , and can substantially reduce exposure of both patients and staff to the dangers of homologous blood PURPOSE The purpose of this study was to attempt to identify a group of patients undergoing infrarenal aortic bypass in whom blood loss is consistently less than 2 units , making the routine use of autotransfusion devices unnecessary . METHODS Four groups of patients were prospect ively studied as follows : abdominal aortic aneurysm ( AAA ) repair with tube graft ( n = 21 ) , AAA repair with bifemoral or biiliac bypass ( n = 19 ) , and aortobifemoral bypass ( AFB ) or biiliac bypass for occlusive disease either with Cell Saver Autotransfusion Device ( Haemonetics Corp. , Braintree , Mass. ) ( n = 18 ) or without Cell Saver ( n = 18 ) . The latter two groups were r and omized on an alternating basis . RESULTS The following parameters were obtained on all patients : preoperative hemoglobin values , estimated blood loss , Cell Saver return volumes , intraoperative and postoperative homologous blood transfused , postoperative hemoglobin values on the day of surgery and on postoperative days 1 and 4 , complications , and length of hospital stay . In comparing the groups undergoing AFB with Cell Saver and AFB without Cell Saver by the above parameters , we found no statistically significant differences , except for a higher hemoglobin level on postoperative day 1 in the group undergoing AFB with Cell Saver ( mean 11.86 vs 10.74 , p = 0.02 ) . The estimated blood loss and Cell Saver return volumes were less for those patients undergoing AFB for occlusive disease compared with those undergoing AFB for aneurysmal disease . Interestingly , estimated blood loss and Cell Saver return volumes for patients with AAA with tube graft and patients undergoing AFB with Cell Saver were similar . CONCLUSIONS We conclude that routine setup and use of rapid autotransfusion devices may not be necessary in every patient undergoing routine aortofemoral bypass for occlusive disease . Furthermore , the possibility that some patients may undergo AAA repair with tube grafts without use of the Cell Saver may be deserving of further investigation The Haemocell S‐350 device has recently been introduced for intraoperative autotransfusion . The system uses a novel membrane filter to process shed blood . In the first part of this study a 0.2‐μm pore size filter was used in a r and omized trial comparing the use of autotransfusion ( n = 8) with bank blood controls ( n = 9 ) during aortic reconstruction . This part of the trial was ab and oned because of unexpected non‐surgical bleeding . Bank blood requirements fell from a median of 3.0 ( range 0.0‐9.0 ) units to 1.5 ( range 0.0–7.0 ) units when autotransfusion was used , but these patients had a greater perioperative blood loss ( 1791 ( range 932–3104 ) versus 1140 ( range 440–3840 ) ml ) . There was evidence of postoperative heparin excess with an activated partial thromboplastin time ratio of 1.3 ( range 0.9–3.0 ) versus 1.0 ( range 1.0–1.2 ) in controls and an activated clotting time of 206 ( range 143–280 ) versus 137 ( range 107–142 ) s. This was confirmed by raised plasma heparin levels and a prolonged thrombin time normalized by protamine . To improve performance a 0.6‐μm pore size filter was studied in ten patients . Filtration efficiency doubled from 19 to 38 per cent . Electron micrographs demonstrated better filter clearance , but 44 per cent of the original concentration of heparin remained in the reinfusate . The S‐350 device may be an attractive alternative to centrifugation for intraoperative autotransfusion but , until efficiency is improved , it should only be used for cardiovascular surgery when excess heparin can be reversed with protamine 
    Output:
    
Conclusion Cell salvage , a commonly used technique to recover red cells from the operative field , has been the subject of several studies in vascular surgery .
There is insufficient evidence to recommend the routine use of cell salvage in elective abdominal aortic aneurysm and aorto-femoral bypass surgeries .
Conclusion La récupération de sang , couramment utilisé pour conserver les globules rouges provenant du champ opératoire , a fait l’objet de quelques études en chirurgie vasculaire .