***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: OBJECTIVE Determine whether prehospital advanced life support ( ALS ) improves the survival of major trauma patients and whether it is associated with longer on-scene times . METHODS A 36-month retrospective study of all major trauma patients who received either prehospital bag-valve-mask ( BVM ) or endotracheal intubation ( ETI ) and were transported by paramedics to our Level I trauma center . Logistic regression analysis determined the association of prehospital ALS with patient survival . RESULTS Of 9,451 major trauma patients , 496 ( 5.3 % ) had either BVM or ETI . Eighty-one percent received BVM , with a mean Injury Severity Score of 29 and a mortality rate of 67 % ; 93 patients ( 19 % ) underwent successful ETI , with a mean Injury Severity Score of 35 and a mortality rate of 93 % . Adjusted survival for patients who had BVM was 5.3 times more likely than for patients who had ETI ( 95 % confidence interval , 2.3 - 14.2 , p = 0.00 ) . Survival among patients who received intravenous fluids was 3.9 times more likely than those who did not ( p = not significant ) . Average on-scene times for patients who had ETI or intravenous fluids were not significantly longer than those who had BVM or no intravenous fluids . CONCLUSION ALS procedures can be performed by paramedics on major trauma patients without prolonging on-scene time , but they do not seem to improve survival Objective To evaluate whether the type of on-site care a trauma patient receives affects outcome . Summary Background Data The controversy regarding the prehospital care of trauma patients between Advanced Life Support ( ALS ) and Basic Life Support ( BLS )  is ongoing . Due to this unresolved controversy , as well as historical , cultural , and political factors , there are significant variations with respect to the type of prehospital care available for trauma patients . Methods This prospect i ve cohort study compared three types of prehospital trauma care systems : Montreal , where physicians provide ALS ( MD-ALS ) ; Toronto , where paramedics provide ALS ( PMD-ALS ) ; and Quebec City , where emergency medical technicians provide BLS only ( EMT-BLS ) . The study took advantage of this variation to evaluate the association between the type of on-site care and mortality in patients with major life-threatening injuries . All patients were treated at highly specialized tertiary ( level I ) trauma hospitals . The main outcome measure was death as a result of injury . Follow-up was to hospital discharge . Results The overall mortality rates by type of on-site personnel were physicians 35 % , paramedics 24 % , and EMTs 18 % . For patients with major but survivable trauma , the overall mortality rates were physicians 32 % , paramedics 28 % , and EMTs 26 % . The overall mortality rate of patients receiving only BLS at the scene was 18 % compared to 29 % for patients receiving ALS . For the subgroup of patients with major but survivable injuries , the mortality rates were 30 % for ALS and 26 % for BLS . The adjusted increased risk for mortality in patients receiving ALS at the scene was 21 % . Conclusions In urban centers with highly specialized level I trauma centers , there is no benefit in having on-site ALS for the prehospital management of trauma patients Objectives : The benefits of prehospital trauma management remain controversial . This study aim ed to compare the processes of care and outcomes of trauma patients treated by paramedics , who are trained in advanced prehospital trauma care  , with those treated by ambulance technicians . Methods : A six year prospect i ve study was conducted of adult trauma patients attended to by the Scottish Ambulance Service and subsequently admitted to hospital .  Prehospital times , interventions , triage , and outcomes were compared between patients treated by paramedics and those treated by technicians . Results : Paramedics attended more severely injured patients ( 16.5 % versus 13.9 % , p<0.001 ) ; they attended a higher proportion of patients with penetrating trauma ( 6.6 % versus 5.7 % , p = 0.014 ) and had longer prehospital times . Patients managed by paramedics were more likely to be taken to the intensive care unit , operating theatre or mortuary , ( 11.2 % versus 7.8 % , p<0.001 ) and had higher crude mortality rates ( 5.3 % versus 4.5 % , p = 0.07 ) . However , no difference in mortality between the two groups was noted when corrected for age , Glasgow coma score and injury severity score . Conclusions : This large scale national study shows that paramedics show good triage skills and clinical judgement when managing trauma patients . However , the value of the individual interventions they perform could not be ascertained . Further controlled trials are necessary to determine the true benefits of advanced prehospital trauma life support A sample of 360 severely injured patients was selected from a cohort of 8007 trauma victims followed prospect ively from the time of injury to death or discharge . A case referent study was used to test the association between on-site care , total prehospital time , and level of care at the receiving hospital with short-term survival . Multiple logistic regression analyses showed that use of Advanced Life Support ( ALS ) at the scene was not associated with survival , whereas treatment at a level I compatible hospital was associated with a 38 % reduction in the odds of dying , which approached statistical significance . Total prehospital time over 60 minutes was associated with a statistically significant adjusted relative odds of dying ( OR = 3.0 ) . The results of this study support the need for regionalization of trauma care and fail to show a benefit associated with ALS Background : To date , the benefit of prehospital advanced life-support programs on  trauma-related mortality and morbidity has not been established Methods : The Ontario Prehospital Advanced Life Support ( OPALS ) Major Trauma Study was a before – after systemwide controlled clinical trial conducted in 17 cities . We enrolled adult patients who had experienced major trauma in a basic life-support phase and a subsequent advanced life-support phase ( during which paramedics were able to perform endotracheal intubation and administer fluids and drugs intravenously ) . The primary outcome was survival to hospital discharge . Results : Among the 2867 patients enrolled in the basic life-support ( n = 1373 ) and advanced life-support ( n = 1494 ) phases , characteristics were similar , including mean age ( 44.8 v. 47.5 years ) , frequency of blunt injury ( 92.0 % v. 91.4 % ) , median injury severity score ( 24 v. 22 ) and percentage of patients with Glasgow Coma Scale score less than 9 ( 27.2 % v. 22.1 % ) . Survival did not differ overall ( 81.1 % among patients in the advanced life-support phase v. 81.8 % among those in the basic life-support phase ; p = 0.65 ) . Among patients with Glasgow Coma Scale score less than 9 , survival was lower among those in the advanced life-support phase ( 50.9 % v. 60.0 % ; p = 0.02 ) . The adjusted odds of death for the advanced life-support v. basic life-support phases were nonsignificant ( 1.2 , 95 % confidence interval 0.9–1.7 ; p = 0.16 ) . Interpretation : The OPALS Major Trauma Study showed that systemwide implementation of full advanced life-support programs did not decrease mortality or morbidity for major trauma patients . We also found that during the advanced life-support phase , mortality was greater among patients with Glasgow Coma Scale scores less than 9 . We believe that emergency medical services should carefully re-evaluate the indications for and application of prehospital advanced life-support measures for patients who have experienced major trauma 
    Output:
    
In the uncontrolled before- and -after study , ' a priori ' sub-group analysis showed an increase in mortality among patients who had a Glasgow Coma Scale score of less than nine and received care from ALS trained ambulance crews .
Additionally , when the pre-hospital trauma score was taken into account in logistic regression analysis , mortality in the patients receiving care from ALS trained crews increased significantly .
At this time , the evidence indicates that there is no benefit of advanced life support training for ambulance crews on patient outcomes