***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 Some observational studies suggest that the use of pulmonary-artery catheters to guide therapy is associated with increased mortality . METHODS We performed a r and omized trial comparing goal -directed therapy guided by a pulmonary-artery catheter with st and ard care without the use of a pulmonary-artery catheter . The subjects were high-risk patients 60 years of age or older , with American Society of Anesthesiologists ( ASA ) class III or IV risk , who were scheduled for urgent or elective major surgery , followed by a stay in an intensive care unit . Outcomes were adjudicated by observers who were unaware of the treatment-group assignments . The primary outcome was in-hospital mortality from any cause . RESULTS Of 3803 eligible patients , 1994 ( 52.4 percent ) underwent r and omization . The base-line characteristics of the two treatment groups were similar . A total of 77 of 997 patients who underwent surgery without the use of a  pulmonary-artery catheter ( 7.7 percent ) died in the hospital , as compared with 78 of 997 patients in whom a pulmonary-artery catheter was used ( 7.8 percent)--a difference of 0.1 percentage point ( 95 percent confidence interval , -2.3 to 2.5 ) . There was a higher rate of pulmonary embolism in the catheter group than in the st and ard-care group ( 8 events vs. 0 events , P=0.004 ) . The survival rates at 6 months among patients in the st and ard-care and catheter groups were 88.1 and 87.4 percent , respectively ( difference , -0.7 percentage point [ 95 percent confidence interval , -3.6 to 2.2 ] ; negative survival differences favor st and ard care ) ; at 12 months , the rates were 83.9 and 83.0 percent , respectively ( difference , -0.9 percentage point [ 95 percent confidence interval , -4.3 to 2.4 ] ) . The median hospital stay was 10 days in each group . CONCLUSIONS We found no benefit to therapy directed by pulmonary-artery catheter over st and ard care in elderly , high-risk surgical patients requiring intensive care A system has been constructed to evaluate the design , implementation , and analysis of  r and omized control trials ( RCT ) . The degree of quadruple blinding ( the r and omization process , the physicians and patients as to therapy , and the physicians as to ongoing results ) is considered to be the most important aspect of any trial . The analytic techniques are scored with the same emphasis as is placed on the control of bias in the planning and implementation of the studies . Description of the patient and treatment material s and the measurement of various controls of quality have less weight . An index of quality of a RCT is proposed with its pros and cons . If published papers were to approximate these principles , there would be a marked improvement in the quality of r and omized control trials . Finally , a reasonable st and ard design and conduct of trials will facilitate the interpretation of those with conflicting results and help in making valid combinations of undersized trials Introduction Little is known about mortality rates following  general surgical procedures  in the United Kingdom . Deaths are most common in the ' high-risk ' surgical population consisting mainly of older patients , with coexisting medical disease , who undergo major surgery . Only limited data are presently available to describe this population . The aim of the present study was to estimate the size of the high-risk general surgical population and to describe the outcome and intensive care unit ( ICU ) re source use . Methods Data on inpatient general surgical procedures and ICU admissions in 94 National Health Service hospitals between January 1999 and October 2004 were extracted from the Intensive Care National Audit & Research Centre data base and the CHKS data base . High-risk surgical procedures were defined prospect ively as those for which the mortality rate was 5 % or greater . Results There were 4,117,727 surgical procedures ; 2,893,432 were elective ( 12,704 deaths ; 0.44 % ) and 1,224,295 were emergencies ( 65,674 deaths ; 5.4 % ) . A high-risk population of 513,924 patients was identified ( 63,340 deaths ; 12.3 % ) , which accounted for 83.8 % of deaths but for only 12.5 % of procedures . This population had a prolonged hospital stay ( median , 16 days ; interquartile range , 9–29 days ) . There were 59,424 ICU admissions ( 11,398 deaths ; 19 % ) . Among admissions directly to the ICU following surgery , there were 31,633 elective admissions with 3,199 deaths ( 10.1 % ) and 24,764 emergency admissions with 7,084 deaths ( 28.6 % ) . The ICU stays were short ( median , 1.6 days ; interquartile range , 0.8–3.7 days ) but hospital admissions for those admitted to the ICU were prolonged ( median , 16 days ; interquartile range , 10–30 days ) . Among the ICU population , 40.8 % of deaths occurred after the initial discharge from the ICU . The highest mortality rate ( 39 % ) occurred in the population admitted to the ICU following initial postoperative care on a st and ard ward . Conclusion A large high-risk surgical population accounts for 12.5 % of surgical procedures but for more than 80 % of deaths . Despite high mortality rates , fewer than 15 % of these patients are admitted to the ICU BACKGROUND A prospect i ve , r and omized controlled trial comparing conventional intraoperative fluid management with two differing methods of invasive haemodynamic monitoring to optimize intraoperative fluid therapy , in patients undergoing proximal femoral fracture repair under general anaesthesia . METHODS Ninety patients r and omized to three groups ; conventional intraoperative fluid management ( Gp CON  , n=29 ) , and two groups receiving additional repeated colloid fluid challenges guided by central venous pressure ( Gp CVP , n=31 ) or oesophageal Doppler ultrasonography ( Gp DOP , n=30 ) . Primary outcome measures were time to medical fitness to discharge , hospital stay and postoperative morbidity . RESULTS The fluid challenge result ed in significantly greater perioperative changes in central venous pressure between Gp CVP and Gp CON ( mean 5 ( 95 % confidence interval 3 - 7 ) mm Hg ) ( P<0.0001 ) . Important perioperative changes were also shown in Gp DOP with increases of 49.4 ms ( 19.7 - 79.1 ms ) in the corrected flow time , 13.5 ml ( 7.4 - 19.6 ml ) in stroke volume , and 0.9 ( 0.49 - 1.39 ) litre min(-1 ) in cardiac output . As a result , fewer patients in Gp CVP and Gp DOP experienced severe intraoperative hypotension ( Gp CON 28 % ( 8/29 ) , Gp CVP 9 % ( 3/31 ) , Gp DOP 7 % ( 2/30 ) , P=0.048 ( chi-squared , 2 degrees of freedom ( df ) . No differences were seen between the three groups when major morbidity and mortality were combined , P=0.24 ( chi-squared , 2 df ) . Postoperative recovery for survivors , as defined by time to be deemed medically fit for discharge , was significantly faster , in comparison with Gp CON , in both the Gp CVP ( 10 vs 14 ( 95 % confidence interval 8 - 12 vs 12 - 17 ) days , P=0.008 ( t-test ) ) , and Gp DOP ( 8 vs 14 ( 95 % confidence interval 6 - 12 vs 12 - 17 ) days , P=0.023 ( t-test ) . There were no significant differences between groups , for survivors , with respect to acute orthopaedic hospital and total hospital stay . CONCLUSIONS Invasive intraoperative haemodynamic monitoring with fluid challenges during repair of femoral fracture under general anaesthetic shortens time to being medically fit for discharge Organ dysfunction and multiple organ failure are the main causes of prolonged hospital stay after cardiac surgery , which increases re source use and health care costs . Increased levels of oxygen delivery and consumption are associated with improved outcome in different groups of postoperative patients . Cardiac surgical patients are at risk of inadequate perioperative oxygen delivery caused by extracorporeal circulation and limited cardiovascular reserves . The purpose of our study was to test whether increasing oxygen delivery immediately after cardiac surgery would shorten hospital and intensive care unit ( ICU ) stay . Four hundred three elective cardiac surgical patients were enrolled in the study and r and omly assigned to either the control or the protocol group . Goals of the protocol group were to maintain Svo2 > 70 % and lactate concentration ≤2.0 mmol/L from admission to the ICU and up to 8 h thereafter . Hemodynamics , oxygen transport data , and organ dysfunctions were recorded . The median hos-pital stay was shorter in the protocol group ( 6 vs 7 days , P < 0.05 ) , and patients were discharged faster from the hospital than those in the control group ( P < 0.05 ) . Discharge from the ICU was similar between groups ( P = 0.8 ) . Morbidity was less frequent at the time of hospital discharge in the protocol group ( 1.1 % vs 6.1 % , P < 0.01 ) . Increasing oxygen delivery to achieve normal Svo2 values and lactate concentration during the immediate postoperative period after cardiac surgery can shorten the length of hospital stay . Implication s Health care economics has challenged clinicians to reduce costs and improve re source use in cardiac surgery and anesthesia in a patient population increasing in age and in severity of disease . Optimizing cardiovascular function to maintain adequate oxygen delivery during the immediate postoperative period after cardiac surgery can decrease morbidity and reduce length of hospital stay Objective To evaluate the effects of maximizing the oxygen delivery on morbidity and mortality in patients > 60 yrs of age and /or with chronic diseases of vital organs who underwent major elective surgery . Design Prospect i ve , r and omized , controlled trial . Setting A 24-bed general intensive care unit of a teaching hospital . Patients Thirty-seven high-risk patients who underwent major surgery . Interventions The hemodynamic and oxygen transport variables and outcomes in 18 patients ( control group ) treated to maintain normal values of oxygen delivery were compared with 19 patients ( protocol group ) treated to maintain “ supranormal ” values . Therapy in both groups consisted of volume expansion and , when necessary , dobutamine to reach target values , during the surgery and 24 hrs postoperatively . Measurements and Main Results We interrupted the study because of a significant difference in the 60-day mortality rate . The mortality rate in the control group was significantly higher when compared with the protocol group ( 9/18 [ 50 % ] vs. 3/19 [ 15.7 % ] , p < .05 ) . The prevalence of clinical and infectious complications was higher in the control group than in the protocol group ( 67 % and 31 % respectively ; relative risk , 0.47 ; 95 % confidence interval , 0.226–0.991;p < .05 ) and there was a trend toward more severe organ dysfunction in nonachievers patients ( 17/24 [ 71 % ] vs. 6/13 [ 46 % ] , relative risk , 0.65 ; 95 % confidence interval , 0.343–1.237 ; NS ) . Conclusion Older patients with existing cardiorespiratory illness undergoing major surgery have a reduced morbidity and mortality when dobutamine is used to maximize oxygen transport Background Intraoperative hypovolemia is common and is a potential cause of organ dysfunction , increased postoperative morbidity , length of hospital stay , and death . The objective of this prospect i ve , r and omized study was to assess the effect of goal -directed intraoperative fluid administration on length of postoperative hospital stay . Methods One hundred patients who were to undergo major elective surgery with an anticipated blood loss greater than 500 ml were r and omly assigned to a control group ( n = 50 ) that received st and ard intraoperative care or to a protocol group ( n = 50 ) that , in addition , received intraoperative plasma volume expansion guided by the esophageal Doppler monitor to maintain maximal stroke volume . Length of postoperative hospital stay and postoperative surgical morbidity were assessed . Results Groups were similar with respect to demographics , surgical procedures , and baseline hemodynamic variables . The protocol group had a significantly higher stroke volume and cardiac output at the end of surgery compared with the control group . Patients in the protocol group had a shorter duration of hospital stay compared with the control group : 5 ± 3 versus 7 ± 3 days ( mean ± SD ) , with a median of 6 versus 7 days , respectively ( P = 0.03 ) . These patients also tolerated oral intake of solid food earlier than the control group : 3 ± 0.5 versus 4.7 ± 0.5 days ( mean ± SD ) , with a median of 3 versus 5 days , respectively ( P = 0.01 ) . Conclusions Goal -directed intraoperative fluid administration results in earlier return to bowel function , lower incidence of postoperative nausea and vomiting , and decrease in length of postoperative hospital stay Objective To test the hypothesis that dopexamine reduces postoperative mortality and morbidity in high-risk , major abdominal surgery patients , when given to fluid 
    Output:
    
: In high-risk surgical patients , the use of a hemodynamic protocol to maintain tissue perfusion decreased mortality and postoperative organ failure .
Monitoring cardiac output calculating oxygen transport and consumption helped to guide therapy .