***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: Background Intraoperative haemorrhage is a known predictor for perioperative outcome of patients undergoing hepatic resection . While anaesthesiological lowering of central venous pressure ( CVP ) by fluid restriction is known to reduce bleeding during transection of the hepatic parenchyma its potential side effects remain poorly investigated . In theory it may have negative effects on kidney function and tissue perfusion and bears the risk to result in severe haemodynamic instability in case of profound intraoperative blood loss . The present r and omised controlled trial evaluates efficacy and safety of infrahepatic inferior vena cava ( IVC ) clamping as an alternative surgical technique to reduce CVP during hepatic resection . Methods / Design The proposed IVC CLAMP trial is a single-centre r and omised controlled trial with a two-group parallel design . Patients and outcome -assessors are blinded for the treatment intervention . Patients undergoing elective hepatic resection due to any reason are enrolled in IVC CLAMP .  All patients admitted to the Department of General- , Visceral- , and Transplant Surgery , University of Heidelberg for elective hepatic resection are consecutively screened for eligibility and written informed consent is obtained on the day before surgery . The primary objective of this trial is to assess and compare the amount of blood loss during hepatic resection in patients receiving surgical CVP reduction by clamping of the IVC  as compared to anaesthesiological CVP without infrahepatic IVC clamping reduction . In addition to blood loss a set of general as well as surgical variables are analysed . Discussion This is a r and omised controlled patient and observer blinded two-group parallel trial design ed to assess efficacy and safety of infrahepatic IVC clamping during elective hepatectomy . Trial registration Clinical Trials AIM To investigate the effect of low central venous pressure ( LCVP ) on blood loss during hepatectomy for hepatocellular carcinoma ( HCC ) . METHODS By the method of sealed envelope , 50 HCC patients were r and omized into LCVP group ( n=25 ) and control group ( n=25 ) . In LCVP group , CVP was maintained at 2 - 4 mmHg and systolic blood pressure ( SBP ) above 90 mmHg by manipulation of the patient 's posture and administration of drugs during hepatectomy , while in control group hepatectomy was performed routinely without lowering CVP . The patients ' preoperative conditions , volume of blood loss during hepatectomy , volume of blood transfusion , length of hospital stay , changes in hepatic and renal functions were compared between the two groups . RESULTS There were no significant differences in patients ' preoperative conditions , maximal tumor dimension , pattern of hepatectomy , duration of vascular occlusion , operation time , weight of resected liver tissues , incidence of post-operative complications , hepatic and renal functions between the two groups . LCVP group had a markedly lower volume of total intraoperative blood loss and blood loss during hepatectomy than the control group , being 903.9+/-180.8 mL vs 2 329.4+/-2 538.4 ( W=495.5 , P<0.01 ) and 672.4+/-429.9 mL vs 1 662.6+/-1 932.1 ( W=543.5 , P<0.01 ) . There were no remarkable differences in the pre-resection and post-resection blood losses between the two groups . The length of hospital stay was significantly shortened in LCVP group as compared with the control group , being 16.3+/-6.8 d vs 21.5+/-8.6 d ( W=532.5 , P<0.05 ) . CONCLUSION LCVP is easily achievable in technique . Maintenance of CVP < or= 4 mmHg can help reduce blood loss during hepatectomy , shorten the length of hospital stay , and has no detrimental effects on hepatic or renal function Background : Hepatic resection is the most effective treatment for many malignant and benign conditions affecting the liver and biliary tree . Despite improvements , major partial hepatectomy can be associated with considerable blood loss and transfusion requirements . Transfusion of allogeneic blood products , although potentially life-saving , is associated with many potential complications . The primary aim of this study was to determine if acute normovolemic hemodilution ( ANH ) , an established blood conservation technique , reduces the requirement for allogeneic red cell transfusions in patients undergoing major hepatic resection . Methods : One hundred thirty patients undergoing major hepatic resection ( ≥3 segments ) were prospect ively r and omized to undergo either ANH or st and ard anesthetic management ( STD ) . In the ANH group , intraoperative blood collection was performed to a target hemoglobin of 8.0 g/dL. Low central venous pressure anesthetic technique was used intraoperatively for both groups . A st and ardized transfusion protocol was applied to all patients intraoperatively and throughout the hospital stay . Results : From April 2004 to March 2007 , 63 patients were r and omized to ANH and 67 to STD . Demographics , diagnoses , liver function , extent of resection , intraoperative blood loss , operative time , incidence and grade of complications , and length of hospital stay were similar between the 2 groups . ANH reduced the overall allogeneic red cell transfusion rate by 50 % compared with STD [ 12.7 % ( n = 8) vs. 25.4 % ( n = 17 ) , respectively ; P = 0.067 . ANH patients were less often transfused intraoperatively ( n = 1 , 1.6 % ) compared with the STD group ( n = 7 , 10.4 % ) ( P = 0.036 ) , had higher postoperative hemoglobin levels ( P = 0.01 ) , and tended to require fewer red cell units overall ( 28 vs. 47 units ) . In patients with intraoperative blood loss ≥800 mL , ANH reduced not only the allogeneic red cell transfusion rate ( 18.2 % vs. 42.4 % , P = 0.045 ) but also the proportion of patients requiring fresh frozen plasma ( 21.1 % vs. 48.3 % , P = 0.025 ) . Conclusion : For patients undergoing major liver resection , ANH is safe , effectively reduces the need for allogeneic transfusions , and should be considered for routine use . Given the modest transfusion rate in the STD arm , future efforts should attempt to target ANH use to patients most likely to benefit Objective This prospect i ve r and omized study determined the influence of closed-suction drainage on the incidence of postoperative complications after elective hepatic resection . Summary Background Data Routine drainage is no longer advocated after several intra-abdominal surgical procedures . Methods A series of 81 patients who underwent elective hepatic resection were r and omly allocated to either a nondrainage group ( n = 39 ) and a drainage group with closed-suction drainage ( n = 42 ) . Indications for resection were 42 benign lesions and 39 malignant tumors , including 19 with cirrhosis . Major hepatic resection was performed in 25 patients and minor resection , in 56 . All patients underwent ultrasonography with puncture for bacteriologic cultures of all fluid collection s within the first 5 postoperative days . Results One patient died in each group . Ultrasonography found a significantly higher rate of subphrenic collection s in the drainage group compared with the nondrainage group ( respectively , 36 % vs. 15 % , p < 0.05 ) . These collection s were more frequently infected in the drainage group ( n = 6 ) than in the nondrainage group ( n = 2 ) . After major liver resection , the rate of intra-abdominal postoperative complications ( i.e. , subphrenic fluid collection s , hematomas , and bilomas ) was similar between the two groups . Conclusion Minor liver resection is safer without drainage . Major liver resection can be performed with or without abdominal drainage Background : Dye-enhanced laser ablation ( DLA ) using a low-power diode laser for indocyanine green (ICG)-stained tissue has proven its effectiveness in dye-enhanced laser photocoagulation of retinal vessels or endoscopic surgical mucosectomy . We have applied DLA in hepatectomy and described its histological distinction in comparison with the cavitron ultrasonic surgical aspirator ( CUSA ) . Methods : A diode laser ( UDL-60 Laser unit , Olympus , Tokyo , Japan ) with 810 ± 20 nm wavelength was employed for this study . The ICG dye ( Diagnogreen ® , Daiichi Pharmaceutical , Tokyo , Japan ) with a peak absorption wavelength at 800–810 nm was injected topically into the resection plane of the liver . The liver tissue was divided by touching the tip of the diode laser . Three different concentrations of ICG solution such as 2.0 , 1.0 and 0.5 mg/ml were tested in the preliminary animal experiment . The use of a low-power diode laser at 10 W with an ICG concentration of 0.5 mg/ml was the appropriate combination for liver resection . In the clinical series , 27 hepatectomies were performed by DLA , and 10 with CUSA . Results : DLA  demonstrated smooth cutting and good hemostasis in liver resection . Among the hepatectomy cases given DLA , no postoperative hemorrhage or bile leakage was noted . The postoperative hospital stay was significantly shorter in the DLA than the CUSA group . The cut surface of the liver was sealed microscopically with a layer of protein coagulum . Conclusions : A layer of protein sealant on the cut surface of the liver contributes to the short postoperative hospital stay when using DLA Purpose This r and omized , controlled , single-blinded multicenter study evaluated the efficacy of latest-generation fibrin sealant containing synthetic aprotinin as fibrinolysis inhibitor as supportive treatment for hemostasis after elective partial hepatectomy . Methods Adult subjects undergoing resection of at least one liver segment were assigned to treatment with fibrin sealant or manual compression with a surgical gauze swab if persistent oozing necessitated additional hemostatic measures after primary control of arterial and venous bleeding . The primary outcome measure was the proportion of subjects with intraoperative hemostasis at 4 min after start of r and omized treatment application . Secondary efficacy outcome measures included intraoperative hemostasis at 6 , 8 , and 10 min , intra- and postoperative rebleedings , transfusion requirements , and drainage volume . Results Seventy subjects were r and omized .  Hemostasis at 4 min was achieved in 29/35 ( 82.9 % ) fibrin sealant subjects compared with 13/35 ( 37.1 % ) control subjects ( p < 0.001 ) . Significantly more fibrin sealant subjects achieved hemostasis at 6 ( p < 0.001 ) , 8 ( p = 0.028 ) , and 10 min ( p = 0.017 ) . The number of rebleedings was low in both study arms . Transfusion requirements and 48-h drainage volumes were similar between the study arms . No adverse events related to study treatment were reported . Conclusions Fibrin sealant was shown to be safe and superior to manual compression in the control of parenchymal bleeding after hepatic resection . The use of synthetic aprotinin as fibrinolysis inhibitor further improves the safety margin of fibrin sealant by eliminating the risk of transmission of bovine spongiform encephalopathy and other bovine pathogens Background Despite improvements in liver surgery over the past decades , hemostasis during hepatic resections remains challenging . This multicenter r and omized study compares the hemostatic effect of a collagen hemostat vs. a carrier-bound fibrin sealant after hepatic resection . Methods Patients scheduled for elective liver resection were r and omized intraoperatively to receive either the collagen hemostat ( COLL ) or the carrier-bound fibrin sealant ( CBFS ) for secondary hemostasis . The primary endpoint was the proportion of patients with hemostasis after 3 min . Secondary parameters were the proportions of patients with hemostasis after 5 and 10 min , the total time to hemostasis , and the complication rates during a 3 months follow-up period . Results A total of 128 patients were included . In the COLL group , 53 out of 61 patients ( 86.9 % ) achieved complete hemostasis within 3 min after application of the hemostat compared to 52 out of 65 patients ( 80.0 % ) in the CBFS group . The 95 % confidence interval for this difference [ −6.0 % , 19.8 % ] does not include the lower noninferiority margin ( −10 % ) . Thus , the COLL treatment can be regarded as noninferior to the comparator . The proportions of patients with hemostasis after 3 , 5 , and 10 min were not significantly different between the two study arms . Postoperative mortality and morbidity were similar in both treatment groups . Conclusion The collagen hemostat is as effective as the carrier-bound fibrin sealant in obtaining secondary hemostasis during liver resection with a comparable complication rate Background Hepatic resection is still associated with significant morbidity . Although the period of parenchymal transection presents a crucial step during the operation , uncertainty persists regarding the optimal technique of transection . It was the aim of 
    Output:
    
There was no evidence of differences in most of the comparisons , and where there was , these differences were in single trials , mostly of small sample size .
When direct and indirect comparisons were available , network meta- analysis provided additional effect estimates for comparisons where there were no direct comparisons .
Low- quality evidence suggests that liver resection using a radiofrequency dissecting sealer may be associated with more adverse events than with the clamp-crush method .
Low- quality evidence also suggests that the proportion of people requiring a blood transfusion is higher with low central venous pressure than with acute normovolemic haemodilution plus low central venous pressure ; very low- quality evidence suggests that blood transfusion quantity ( red blood cells ) was lower with fibrin sealant than control ;  blood transfusion quantity ( fresh frozen plasma ) was higher with oxidised cellulose than with fibrin sealant ; and blood loss , total hospital stay , and operating time were lower with low central venous pressure than with control .
There is no evidence to suggest that using special equipment for liver resection is of any benefit in decreasing the mortality , morbidity , or blood transfusion requirements ( very low- quality evidence ) .
In addition , it should be noted that the sample size was small and the credible intervals were wide , and we can not rule out considerable benefit or harm with a specific method of liver resection