***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 
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    ***EXAMPLES*** 
    Input: Rationale : Assessment of fluid responsiveness relies on dynamic echocardiographic parameters that have not yet been compared in large cohorts . Objectives : To determine the diagnostic accuracy of dynamic parameters used to predict fluid responsiveness in ventilated patients with a circulatory failure of any cause . Methods : In this multicenter prospect i ve study , respiratory variations of superior vena cava diameter ( & Dgr;SVC ) measured using transesophageal echocardiography , of inferior vena cava diameter ( & Dgr;IVC ) measured using transthoracic echocardiography , of the maximal Doppler velocity in left ventricular outflow tract ( & Dgr;VmaxAo ) measured using either approach , and pulse pressure variations ( & Dgr;PP ) were recorded with the patient in the semirecumbent position . In each patient , a passive leg raise was performed and an increase of aortic velocity time integral greater than or equal to 10 % defined fluid responsiveness . Measurements and Main Results : Among 540 patients ( 379 men ; age , 65 ± 13 yr ; Simplified Acute Physiological Score II , 59 ± 18 ; Sequential Organ Failure Assessment , 10 ± 3 ) , 229 exhibited fluid responsiveness ( 42 % ) . & Dgr;PP , & Dgr;VmaxAo , & Dgr;SVC , and & Dgr;IVC could be measured in 78.5 % , 78.0 % , 99.6 % , and 78.1 % of cases , respectively . & Dgr;SVC greater than or equal to 21 % , & Dgr;VmaxAo greater than or equal to 10 % , and & Dgr;IVC greater than or equal to 8 % had a sensitivity of 61 % ( 95 % confidence interval , 57‐66 % ) , 79 % ( 75‐83 % ) , and 55 % ( 50‐59 % ) , respectively , and a specificity of 84 % ( 81‐87 % ) , 64 % ( 59‐69 % ) , and 70 % ( 66‐75 % ) , respectively . The area under the receiver operating characteristic curve of & Dgr;SVC was significantly greater than that of & Dgr;IVC ( P = 0.02 ) and & Dgr;PP ( P = 0.01 ) . Conclusions : & Dgr;VmaxAo had the best sensitivity and & Dgr;SVC the best specificity in predicting fluid responsiveness . & Dgr;SVC had a greater diagnostic accuracy than & Dgr;IVC and & Dgr;PP , but its measurement requires transesophageal echocardiography Introduction Acute hemodynamic instability increases morbidity and mortality . We investigated whether early non-invasive cardiac output monitoring enhances hemodynamic stabilization and improves outcome . Methods A multicenter , r and omized controlled trial was conducted in three European university hospital intensive care units in 2006 and 2007 . A total of 388 hemodynamically unstable patients identified during their first six hours in the intensive care unit ( ICU ) were r and omized to receive either non-invasive cardiac output monitoring for 24 hrs ( minimally invasive cardiac output/MICO group ; n = 201 ) or usual care ( control group ; n = 187 ) . The main outcome measure was the proportion of patients achieving hemodynamic stability within six hours of starting the study . Results The number of hemodynamic instability criteria at baseline ( MICO group mean 2.0 ( SD 1.0 ) , control group 1.8 ( 1.0 ) ; P = .06 ) and severity of illness ( SAPS II score ; MICO group 48 ( 18 ) , control group 48 ( 15 ) ; P = .86 ) ) were similar . At 6 hrs , 45 patients ( 22 % ) in the MICO group and 52 patients ( 28 % ) in the control group were hemodynamically stable ( mean difference 5 % ; 95 % confidence interval of the difference -3 to 14 % ; P = .24 ) . Hemodynamic support with fluids and vasoactive drugs , and pulmonary artery catheter use ( MICO group : 19 % , control group : 26 % ; P = .11 ) were similar in the two groups . The median length of ICU stay was 2.0 ( interquartile range 1.2 to 4.6 ) days in the MICO group and 2.5 ( 1.1 to 5.0 ) days in the control group ( P = .38 ) . The hospital mortality was 26 % in the MICO group and 21 % in the control group ( P = .34 ) . Conclusions Minimally-invasive cardiac output monitoring added to usual care does not facilitate early hemodynamic stabilization in the ICU , nor does it alter the hemodynamic support or outcome . Our results emphasize the need to evaluate technologies used to measure stroke volume and cardiac output -- especially their impact on the process of care -- before any large-scale outcome studies are attempted . Trial Registration The study was registered at Clinical Trials.gov ( Clinical Trials identifier NCT00354211 Introduction Several studies have shown that goal -directed hemodynamic and fluid optimization may result in improved outcome . However , the methods used were either invasive or had other limitations . The aim of this study was to perform intraoperative goal -directed therapy with a minimally invasive , easy to use device ( FloTrac/Vigileo ) , and to evaluate possible improvements in patient outcome determined by the duration of hospital stay and the incidence of complications compared to a st and ard management protocol . Methods In this r and omized , controlled trial 60 high-risk patients scheduled for major abdominal surgery were included . Patients were allocated into either an enhanced hemodynamic monitoring group using a cardiac index based intraoperative optimization protocol ( FloTrac/Vigileo device , GDT-group , n = 30 ) or a st and ard management group ( Control-group , n = 30 ) , based on st and ard monitoring data . Results The median duration of hospital stay was significantly reduced in the GDT-group with 15 ( 12 - 17.75 ) days versus 19 ( 14 - 23.5 ) days ( P = 0.006 ) and fewer patients developed complications than in the Control-group [ 6 patients ( 20 % ) versus 15 patients ( 50 % ) , P = 0.03 ] . The total number of complications was reduced in the GDT-group ( 17 versus 49 complications , P = 0.001 ) . Conclusions In high-risk patients undergoing major abdominal surgery , implementation of an intraoperative goal -directed hemodynamic optimization protocol using the FloTrac/Vigileo device was associated with a reduced length of hospital stay and a lower incidence of complications compared to a st and ard management protocol .Trial Registration Clinical trial registration information : Unique identifier : STUDY OBJECTIVE Annually , 38 million people are evaluated for trauma , the leading cause of death in persons younger than 45 years . The primary objective is to assess whether using a protocol inclusive of point-of-care , limited ultrasonography ( PLUS ) , compared to usual care ( control ) , among patients presenting to the emergency department ( ED ) with suspected torso trauma decreased time to operative care . METHODS The study was a r and omized controlled clinical trial conducted during a 6-month period at 2 Level I trauma centers . The intervention was PLUS conducted by verified clinician sonographers . The primary outcome measure was time from ED arrival to transfer to operative care ; secondary outcomes included computed tomography ( CT ) use , length of stay , complications , and charges . Regression models controlled for confounders and analyzed physician-to-physician variability . All analyses were conducted on an intention-to-treat basis . Results are presented as mean , first-quartile , median , and third-quartile , with multiplicative change and 95 % confidence intervals ( CIs ) , or percentage with odds ratio and 95 % CIs . RESULTS Four hundred forty-four patients with suspected torso trauma were eligible ; 136 patients lacked consent , and attending physicians refused enrollment of 46 patients . Two hundred sixty-two patients were enrolled : 135 PLUS patients and 127 controls . There were no important differences between groups . Time to operative care was 64 % ( 48 , 76 ) less for PLUS compared to control patients . PLUS patients underwent fewer CTs ( odds ratio 0.16 ) ( 0.07 , 0.32 ) , spent 27 % ( 1 , 46 ) fewer days in hospital , and had fewer complications ( odds ratio 0.16 ) ( 0.07 , 0.32 ) , and charges were 35 % ( 19 , 48 ) less compared to control . CONCLUSION A PLUS-inclusive protocol significantly decreased time to operative care in patients with suspected torso trauma , with improved re source use and lower charges This pilot trial aims at gaining support for the optimization of acute burn resuscitation through noninvasive continuous real-time hemodynamic monitoring using arterial pulse contour analysis . A group of 21 burned patients meeting preliminary criteria ( age range 18–75 years with second- third- degree burns and TBSA ≥10–75 % ) was r and omized during 2010 . A hemodynamic monitoring through lithium dilution cardiac output was used in 10 r and omized patients ( LiDCO group ) , whereas those without LiDCO monitoring were defined as the control group . The modified Brooke/Parkl and formula as a starting resuscitative formula , balanced crystalloids as the initial solutions , urine output of 0.5 ml/kg/hr as a crucial value of adequate intravascular filling were used in both groups . Additionally , the volume and vasopressor/inotropic support were based on dynamic preload parameters in the LiDCO group in the case of circulatory instability and oligouria . Statistical analysis was done using t-tests . Within the first 24 hours postburn , a significantly lower consumption of crystalloids was registered in LiDCO group ( P = .04 ) . The fluid balance under LiDCO control in combination with hourly diuresis contributed to reducing the cumulative fluid balance approximately by 10 % compared with fluid management based on st and ard monitoring parameters . The amount of applied solutions in the LiDCO group got closer to Brooke formula whereas the urine output was at the same level in both groups ( 0.8 ml/kg/hr ) . The new finding in this study is that when a fluid resuscitation is based on the arterial waveform analysis , the initial fluid volume provided was significantly lower than that delivered on the basis of physician-directed fluid resuscitation ( by urine output and mean arterial pressure ) . ( J Burn Care Res 2013;34:537–542 Pulse pressure variation can predict fluid responsiveness in strict applicability conditions . The purpose of this study was to describe the clinical applicability of pulse pressure variation during episodes of patient hemodynamic instability in the intensive care unit . We conducted a five-day , seven-center prospect i ve study that included patients presenting with an unstable hemodynamic event . The six predefined inclusion criteria for pulse pressure variation applicability were as follows : mechanical ventilation , tidal volume > 7 mL/kg , sinus rhythm , no spontaneous breath , heart rate/respiratory rate ratio > 3.6 , absence of right ventricular dysfunction , or severe valvulopathy . Seventy-three patients presented at least one unstable hemodynamic event , with a total of 163 unstable hemodynamic events . The six predefined criteria for the applicability of pulse pressure variation were completely present in only 7 % of these . This data indicates that PPV should only be used alongside a strong underst and ing of the relevant physiology and applicability criteria . Although these exclusion criteria appear to be profound , they likely represent an absolute contraindication of use for only a minority of critical care patients Background Fluid challenges ( FCs ) are one of the most commonly used therapies in critically ill patients and represent the cornerstone of hemodynamic management in intensive care units . There are clear benefits and harms from fluid therapy . Limited data on the indication , type , amount and rate of an FC in critically ill patients exist in the literature . The primary aim was to evaluate how physicians conduct FCs in terms of type , volume , and rate of given fluid ; the secondary aim was to evaluate variables used to trigger an FC and to compare the proportion of patients receiving further fluid administration based on the response to the FC . Methods This was an observational study conducted in ICUs around the world . Each participating unit entered a maximum of 20 patients with one FC .  Results 2213 patients were enrolled and analyzed in the study . The median [ interquartile range ] amount of fluid given during an FC was 500 ml ( 500–1000 ) . The median time was 24 min ( 40–60 min ) , and the median rate of FC was 1000 [ 500–1333 ] ml/h . The main indication for FC was hypotension in 1211 ( 59 % , CI 57–61 % ) . In 43 % ( CI 41–45 % ) of the cases no hemodynamic variable was used . Static markers of preload were used in 785 of 2213 cases ( 36 % , CI 34–37 % ) . Dynamic indices of preload responsiveness were used in 483 of 2213 cases ( 22 % , CI 20–24 % ) . No safety variable for the  FC was used in 72 % ( CI 70–74 % ) of the cases . There was no statistically significant difference in the proportion of patients who received further fluids after the FC between those with a positive , with an uncertain or with a negatively judged response . Conclusions The current practice and evaluation of FC in critically ill patients are highly variable . Prediction of fluid responsiveness is not used routinely , safety limits are rarely used , and information from previous failed FCs is not always 
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There was no mortality advantage of either modality versus st and ard care .