***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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    Input: BACKGROUND The assessment and treatment of trauma patients begins in the prehospital environment . Studies have vali date d the shock index as a correlate for mortality and the identification of shock in trauma patients . We investigated the use of the first shock index obtained in the prehospital environment and the first shock index obtained upon arrival in the trauma center as correlates for other outcomes to evaluate its usefulness as a triage tool . METHODS This is a retrospective review of data from a level I trauma center .  Prehospital and trauma center shock indices for 16,269 patients were evaluated as correlates for duration of hospital stay , duration of stay in the intensive care unit , the number of ventilator days , blood product use , and destination of transfer from the trauma center . RESULTS Pearson correlation coefficients revealed that the relationship of prehospital and trauma center shock indices were correlates for duration of hospital stay , duration of stay in the intensive care unit , the number of ventilator days , and blood product use . A chi-square analysis found that shock indices ≥0.9 indicate a higher likelihood of disposition to the intensive care unit , operating room , or death . CONCLUSION A prehospital shock index for trauma correlates with measures of hospital re source use and mortality . A prospect i ve study is needed to determine the use of this measure as a triage tool BACKGROUND Emergency Medical Services ( EMS ) personnel provide care in the out-of-hospital setting . The EMS report , including blood volume estimates , influences hospital management . Our objective was to assess the accuracy of EMS blood volume estimates . METHODS In this prospect i ve , observational study , EMS providers were asked to view four simulated blood loss scenarios in r and om order . Each scenario used a specific volume of spilled blood corresponding to the loss likely to cause the four classes of hemorrhagic shock . Estimates are reported using median and interquartile ranges . RESULTS Ninety-two EMS providers gave 368 estimates . Only 8 % were within 20 % of the actual volume . Furthermore , only 24 % were within 50 % of actual volume . There was no correlation between accuracy and any demographic variable , level of training , or years of EMS experience . CONCLUSION EMS personnel are unable to estimate " blood " volume accurately irrespective of level of training BACKGROUND Visually estimated amount of blood loss may influence decision making in the prehospital setting . The purpose of this study was to determine the ability and accuracy of paramedics and emergency physicians to visually estimate a volume of external blood loss and the influence of different vital signs . METHODS In a prospect i ve , blinded , observational design , participants were asked to visually estimate the amount of blood in six simulated trauma scenarios . Casualties were provided with a simulated injury , and a certain amount of artificial blood that was poured on the casualties ' clothing and on the floor . In addition , vital signs ( i.e. , blood pressure and heart rate ) were given . Each two moulage patients were provided with the same injury pattern and the same simulated blood loss . Although one patient seemed to be normovolemic , the other seemed to be hypovolemeic by the given vital signs . RESULTS With regard to all given amounts of blood loss , providing vital parameters suggesting instability ( i.e. , low blood pressure , high heart rate ) led to a higher estimation of the lost blood volume in both paramedics and emergency physicians . However , estimations were influenced impressively by the given parameters . For both stable and unstable patients , small actual volumes were overestimated , whereas higher volumes tended to be underestimated . Neither occupational status ( emergency physician or paramedic ) nor gender or level of experience influenced accuracy of estimated blood loss significantly INTRODUCTION AND AIMS The use of intravenous oxygen carriers ( packed red blood cells ( PRBC ) , whole blood and synthetic haemoglobins ( HBOCs ) for selected pre-hospital trauma resuscitation cases has been reported , despite a lack of vali date d clinical indications . The aim of this study was to retrospectively identify a sub-group of adult major trauma patients most likely to benefit from pre-hospital oxygen carrier administration  and determine the predictive relationship between pre-hospital shock index ( SI ) [ pulse rate/systolic blood pressure ] and haemorrhagic shock , blood transfusion and mortality . METHODS A retrospective review of adult major trauma patients recorded in The Alfred Trauma Registry was conducted . Patients were included if they received at least 1L of pre-hospital crystalloid and spent over 30 min in transit .  The association of shock index and transfusion was determined . Patients were further sub-grouped by mode of transport to determine the population of trauma patients who could be included into prospect i ve studies of intravenous oxygen carriers . RESULTS There were 1149 patients included of whom 311 ( 21.9 % ) received an acute blood transfusion .  The SI correlated well with transfusion practice . A SI ≥ 1.0 , calculated after at least 1L of crystalloid transfusion , identified patients with a high specificity ( 93.5 % ; 95 % CI : 91.8 - 94.8 ) for receiving a blood transfusion within 4h of hospital arrival . While patients transported by helicopter had higher injury severity and blood transfusion requirement , there were no difference in physiological variables and outcomes when compared to patients transported by road car . CONCLUSIONS A shock index ≥ 1.0 is an easily calculated variable that may identify patients for inclusion into trials for pre-hospital oxygen carriers . Shocked patients have high mortality rates whether transported by road car or by helicopter . The efficacy of pre-hospital intravenous oxygen carriers should be trialled using a shock index ≥ 1.0 despite fluid resuscitation as the clinical trigger for administration BACKGROUND It remains unclear whether the American College of Surgeons Committee on Trauma ( ACSCOT ) " step 1 " field physiologic criteria could be further restricted without substantially sacrificing sensitivity . We assessed whether more restrictive physiologic criteria would improve the specificity of this triage step without missing high-risk patients . METHODS We analyzed an out-of-hospital , consecutive patient , prospect i ve cohort of injured adults > or=15 years collected from December 1 , 2005 , to February 28 , 2007 , by 237 emergency medical service agencies transporting to 207 acute care hospitals in 11 sites across the United States and Canada . Patients were included based on ACSCOT field decision scheme physiologic criteria systolic blood pressure < or=90 , respiratory rate < 10 or > 29 breaths/min , Glasgow Coma Scale score < or=12 , or field intubation .  Seven field physiologic variables and four additional demographic and mechanism variables were included in the analysis . The composite outcome was mortality ( field or in-hospital ) or hospital length of stay > 2 days . RESULTS Of 7,127 injured persons , 6,259 had complete outcome information and were included in the analysis . There were 3,631 ( 58.0 % ) persons with death or LOS > 2 days . Using only physiologic measures , the derived rule included advanced airway intervention , shock index > 1.4 , Glasgow Coma Scale < 11 , and pulse oximetry < 93 % . Rule validation demonstrated sensitivity 72 % ( 95 % confidence interval : 70%-74 % ) and specificity 69 % ( 95 % confidence interval : 67%-72 % ) . Inclusion of demographic and mechanism variables did not significantly improve performance measures . CONCLUSIONS We were unable to omit or further restrict any ACSCOT step 1 physiologic measures in a decision rule practical for field use without missing high-risk trauma patients OBJECTIVES There are many patient assessment challenges in the prehospital setting , especially the estimation of external blood loss . Previous studies of experienced paramedics have demonstrated that external blood loss estimation is highly inaccurate . The objective of this study was to determine if undergraduate paramedic students could accurately estimate external blood loss on four surfaces commonly found in the prehospital environment . METHODS This prospect i ve , observational , blinded study used a convenience sample of undergraduate students study ing at Monash University during 2006 . Students were provided with four clinical vignettes using four different surfaces and varying simulated blood amounts . RESULTS Accurate estimation occurred with the vinyl simulation ( 100 ml ) , with a mean value of the estimations of 98 ml ( 95 % Confidence Interval ( CI ) 84 - 113 ml ) . Carpet and concrete surfaces were both associated with large under-estimations . The carpet simulation ( 1,000 ml ) had a mean value for the estimations of 347 ml ( 95 % CI 320 - 429 ml ) . The concrete simulation ( 1,500 ml ) had a mean value for the estimations of 885ml ( 95 % CI 771 - 999 ml ) . Conversely , the clothing simulation ( 500 ml ) emphasized over-estimation , with a mean value for the estimations of 1,253 ml ( 95 % CI 1,093 - 1,414 ml ) . There was no relationship between increased accuracy and clinical experience , exposure , educational qualifications , or age of students . CONCLUSIONS External blood loss estimation by undergraduate paramedic students generally is too inaccurate to be of any clinical benefit . Particularly , absorbent and impermeable surfaces precipitated inaccuracies by undergraduate paramedic students OBJECTIVE The aim of this study was to determine the hemodynamic response and calculated shock index ( SI = heart rate [HR]/systolic blood pressure [ SBP ] ) in early acute blood loss . METHODS This was a prospect i ve observational study that enrolled healthy blood donors . Patients were excluded if not eligible for blood donation . Baseline vital signs were obtained , 450 mL of blood was removed over 20 minutes , and vital signs were repeated immediately postdonation while lying and after 1 and 5 minutes of st and ing . Difference was tested using a paired t test with P<.01 set for significance . RESULTS Forty-six patients were enrolled ; means for each time interval are shown below with 95 % confidence intervals . CONCLUSIONS A significant elevation in mean SI was observed in healthy volunteers after st and ing for 1 and 5 minutes . Although significant changes in HR and SBP were observed , these indices were still within " normal " limits . The SI may be more useful in early hemorrhage than either the HR or SBP alone OBJECT This study sought to define hemorrhagic shock from blood pressure and heart rate and then to provide a treatment policy based on response to initial fluid therapy . MATERIAL S This was a prospect i ve clinical observational study conducted in eight hospitals . Subjects were consecutive patients with trauma who met any of the field triage conditions proposed by the Committee on Trauma of the American College of Surgeons .  Initial fluid therapy was performed in patients with suspected hemorrhagic shock . Patients who required blood transfusion ≥ 4 U within 24 hours or interventions for active bleeding within 24 hours were classified into a " bleeding group " ( B ) . A " nonbleeding group " ( non-B ) comprised patients who did not require blood transfusion ≥ 4 U or other interventions within 24 hours . Our committee maintained the data base of survey items . Four of the hospitals were selected at r and om to provide training data and that was used in a recursive partitioning analysis to predict the B group . Data on patients in the other four facilities were used for validation . RESULTS There were a total of 400 patients studied . The training set consisted of 261 patients , 50 of whom were classified into the B group . A total of 94 % patients with  hemorrhagic shock suspected clinical ly , shock index at admission ( first SI ) ≥ 0.8 , and SI at 1 L of fluid resuscitation ( second SI ) ≥ 1.0 were assigned to the B group . The non-B group ( 92 % ) were patients those whose first SI was < 0.8 and base deficits at admission ≥ -1.0 . Validation data consisted of 139 patients .  The sensitivity , specificity , and accuracy of these data to predict the B group were 71 % , 93 % , and 89 % , respectively . CONCLUSIONS Patients whose first SI was ≥ 0.8 and second SI ≥ 1.0 would be diagnosed as " nonresponders " by American College of Surgeons . Patients with first SI < 0.8 and base deficits ≥ -1.0 will not be c and i date s for the B group Background The epidemiology of traumatic deaths was periodically described during the development of the American trauma system between 1977 and 1995 . Recognizing the impact of aging population s and the potential changes in injury mechanisms , the purpose of this work was to provide a comprehensive , prospect i ve , population -based study of Australian trauma-related deaths and compare the results with those of l and mark studies . Methods All prehospitalization and in-hospital trauma deaths occurring in an inclusive trauma system at a single Level 1 trauma center [ 400 patients with an injury severity score ( ISS ) > 15/year ] underwent autopsy and were prospect ively evaluated during 2005 .  High-energy ( HE ) and low-energy ( LE ) deaths were categorized based on the mechanism of the injury , time frame ( prehospitalization , < 48 hours , 2–7 days , > 7 days ) , and cause [ which was determined by an expert panel and included central nervous system-related ( CNS ) , exsanguination , CNS + exsanguination , airway , multiple organ failure ( MOF ) ] . Data are presented as a percent or the mean ± SEM . Results There were 175 deaths during the 12-month period . For the 103 HE fatalities ( age 43 ± 2 years , ISS 49 ± 2 , male 63 % ) , the predominant mechanisms were motor vehicle related ( 72 % ) , falls ( 4 % ) , gunshots ( 8 % ) , stabs ( 
    Output:
    
The SI is a readily available tool and may be useful in predicting CB on arrival to hospital .