***TASK*** the task is to summarize an input biomedical literature in six sentences 
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    Input: BACKGROUND Traditional fluid resuscitation strategy in the actively hemorrhaging trauma patient emphasizes maintenance of a normal systolic blood pressure ( SBP ) . One human trial has demonstrated improved survival when fluid resuscitation is restricted , whereas numerous laboratory studies have reported improved survival when resuscitation is directed to a lower than normal pressure . We hypothesized that fluid resuscitation titrated to a lower than normal SBP during the period of active hemorrhage would improve survival in trauma patients presenting to the hospital in hemorrhagic shock . METHODS Patients presenting in hemorrhagic shock were r and omized to one of two fluid resuscitation protocol s : target SBP > 100 mm Hg ( conventional ) or target SBP of 70 mm Hg ( low ) . Fluid therapy was titrated to this endpoint until definitive hemostasis was achieved . In-hospital mortality , injury severity , and probability of survival were determined for each patient . RESULTS One hundred ten patients were enrolled over 20 months , 55 in each group . The study cohort had a mean age of 31 years , and consisted of 79 % male patients and 51 % penetrating trauma victims . There was a significant difference in SBP observed during the study period ( 114 mm Hg vs. 100 mm Hg , p < 0.001 ) . Injury Severity Score ( 19.65 + /- 11.8 vs. 23.64 + /- 13.8 , p = 0.11 ) and the duration of active hemorrhage ( 2.97 + /- 1.75 hours vs. 2.57 + /- 1.46 hours , p = 0.20 ) were not different between groups . Overall survival was 92.7 % , with four deaths in each group . CONCLUSION Titration of initial fluid therapy to a lower than normal SBP during active hemorrhage did not affect mortality in this study . Reasons for the decreased overall mortality and the lack of differentiation between groups likely include improvements in diagnostic and therapeutic technology , the heterogeneous nature of human traumatic injuries , and the imprecision of SBP as a marker for tissue oxygen delivery Although intravenous ( IV ) fluid therapy is routinely prescribed for hypotensive injury victims , there are concerns that elevating the blood pressure before hemorrhage is controlled may be detrimental . This is a preliminary report of an ongoing r and omized study design ed to evaluate the effect fluid resuscitation , delayed until surgical intervention , has on the outcome for hypotensive victims of penetrating truncal injury . In the first year , 300 consecutive patients with gunshot or stab wounds to the trunk who had a systolic blood pressure of 90 mm Hg or less were entered into the study . Patients were excluded from the outcome analysis because of death at the scene or minor injury not requiring surgical intervention . The remaining study patients were r and omized into ( 1 ) an immediate resuscitation group ( n = 96 ) for whom IV fluid resuscitation was initiated in the ambulance and in the emergency center before surgical intervention , or ( 2 ) a delayed resuscitation group ( n = 81 ) for whom IV fluid resuscitation was delayed until the time of surgical intervention . The two study groups were found to be well balanced with respect to anatomic injury severity , pretreatment vital signs , survival probability , and preoperative treatment times . There were no significant differences in the rate of survival to hospital discharge ( immediate resuscitation group , 56 % ; delayed resuscitation group , 69 % ) . There were no significant differences in the rate of postoperative complications . Further study is necessary to determine if it is advantageous to delay fluid resuscitation until surgical intervention Background and objective To examine the kinetics of volume loading with crystalloid and colloid infusions in critically ill patients after major surgery , using the pulse contour cardiac output ( PiCCO ) monitoring technique . Methods This prospect i ve , r and omized , multicentre study of 11 ICUs involved 200 mixed postoperative hypovolaemic patients ( 50 patients per group ) in Hungary . Patients received 10 ml kg−1 of lactated Ringer 's solution , succinylated gelatin 4 % w/v , 130/0.4 hydroxyethyl starch 6 % w/v ( HES ) or human albumin 5 % w/v over 30 min . A complete haemodynamic profile was obtained at 30 , 45 , 60 , 90 and 120 min after baseline . The peak haemodynamic effects , the 120 min changes compared with baseline , the area under the curve ( AUC ) for the haemodynamic parameters over 120 min and the haemodilution effect of the solutions were analysed . The primary outcome was to compare the AUCs and the secondary outcome was to evaluate the haemodynamic changes at 120 min . Results There were significant differences in the AUCs of the haemodynamic parameters  between colloids and lactated Ringer 's solution in the cardiac index and global end-diastolic volume index ( GEDVI ) ; human albumin vs. lactated Ringer 's solution  in stroke volume variation ( SVV ) ; and succinylated gelatin , HES vs. lactated Ringer 's solution in the oxygen delivery index ( DO2I ) . Colloid infusions ( mainly HES and human albumin ) at 120 min caused significant changes in central venous pressure , cardiac index , GEDVI , SVV , DO2I and central venous oxygen saturation compared with baseline . The haemodilution effect was significantly greater in colloids vs. lactated Ringer 's solution . Conclusion In postoperative hypovolaemic patients , lactated Ringer 's solution can significantly improve haemodynamics at the end of volume loading , but this effect completely disappears at 120 min . Ten millilitres per kilogram of colloid bolus ( especially HES ) improved the haemodynamics at 120 min ; however , this was by only 5–25 % compared with baseline . The colloids caused significantly larger AUCs than lactated Ringer 's solution , but only in the cardiac index , GEDVI and DO2I , plus human albumin in the SVV The rapid infusion system ( RIS ) , which can deliver fluids/blood products rapidly at precise rates and normothermic conditions , was compared with conventional fluid administration ( CFA ) in a r and omized study of 36 hypovolemic trauma patients . Admission stratification criteria of the groups were similar relative to age , Glasgow Coma Score ( GCS ) , Injury Severity Score ( ISS ) and plasma lactate . Despite the lack of difference in blood loss between the 24-h survivors of the two groups , the CFA group required greater total fluids ( 23.6/20.21 ) , red blood cells ( 5.5/4.61 ) , fresh frozen plasma ( FFP ) ( 2.8/1.91 ) , platelets ( 523/204 ml ) , and crystalloids ( 12.9/10.61 ) . Lactate levels were lower in the RIS group at virtually all times from hours 1 to 24 ( 4.3/5.3 mM/l , t-value = 3.3 , DF = 279 , P = 0.001 ) . Post-admission hypothermia was greater in the CFA group at all times during the first 24 h ( 35.2/36.4 degrees C , t-value = 5.6 , DF = 250 , P = 0.001 ) . The mean partial thromboplastin time was significantly higher in the CFA group ( 47.3/35.1 s , t-value = 3.1 , DF = 279 , P = 0.002 ) . The PTT and PT were related to the degree of lactic acidosis ( P = 0.0001 ) and hypothermia ( P = 0.001 ) but not to the amount of FFP given ( P = 0.14 ) . The hospital costs , days in the ICU , and days on the ventilator were greater for the CFA group , as was the incidence of pneumonia ( 0/11 vs. 6/17 ; P = 0.03 ) . Hypovolemic trauma patients resuscitated with the RIS needed fewer fluid/blood products and had less coagulopathy ; more rapid resolution of hypoperfusion acidosis ; better temperature preservation ; and fewer hospital complications than those resuscitated with conventional methods of fluid/blood product administration The effect of citrated stored blood on coagulation was studied initially in a pilot study where 25 patients with acute severe gastrointestinal haemorrhage had their whole blood coagulation measured using the Biobridge  Impedance Clotting Time ( ICT ) . This demonstrated that there is a hypercoagulable response to haemorrhage which was partially reversed by blood transfusion . Similar changes were noted in Kaolin Cephalin Clotting Times ( KCCT ) . A further 50 patients were then r and omized to receive , during the 24h after admission , either at least 2 units of blood or no blood transfusion unless the haemoglobin fell below 8 g/dl or they were shocked . In the transfused group nine patients re‐bled compared with only one in the non‐transfused group ( P < 0·01 , χ2 with Yates ' correction ) . Early blood transfusion appears to reverse the hypercoagulable response to haemorrhage thereby encouraging rebleeding and hence the need for an operation The ‘ optimal ’ hematocrit to which patients should be resuscitated after shock and trauma is controversial . To test the hypothesis that sufficient oxygen delivery can be provided at a lower hematocrit without impairing oxygen consumption or hemodynamic function , 25 patients were prospect ively RESULTS In total 1309 patients were entered in the study : 699 ( 53.4 % ) were treated by paramedics operating protocol A and 610 ( 46.6 % ) were treated by paramedics operating protocol B. The r and omisation worked well and there were no significant differences between treatment groups in incident characteristics , ambulance performance times , or patient or injury characteristics , apart from slightly more moderate or severe head injuries in the protocol A group ( 25.3 % versus 20.3 % ) . Protocol compliance was poor , with only 31 % of protocol A patients receiving prehospital fluids and only 80 % of protocol B patients not given fluids . The estimated odds ratio for being given prehospital fluids when treated by protocol A compared to protocol B was 2.09 ( 95 % confidence interval ( CI ) , 1.53 to 2.81 ) . MORTALITY There were 73 deaths within 6 months in the 699 patients in the protocol A group ( 10.4 % ) , and 60/610 ( 9.8 % ) in the protocol B group . Thus the crude odds ratio for deaths when managed by protocol A was 1.07 ( 95 % CI , 0.73 to 1.54 ) . Excluding 26 patients whose cause of death may not have been trauma related , the odds ratio was 1.04 ( 95 % CI , 0.69 to 1.55 ) . Excluding 17 patients who may have been dead on arrival of the ambulance at the scene the odds ratio was 1.04 ( 95 % CI , 0.70 to 1.53 ) . Adjustment for age , injury severity and whether the patient was unconscious at the scene did not significantly alter these odds ratios . COMPLICATIONS A total of 106 patients were identified from hospital notes as having at least one of eight major complications ( adult respiratory distress syndrome , sepsis , acute renal failure , coagulopathy , wound infection , pneumonia , fat embolism or pulmonary embolism ) . The proportions with recorded complications were similar in the two groups : 60/699 ( 8.5 % ) in the protocol A group versus 46/610 ( 7.5 % ) in the protocol B group . HEALTH STATUS : A total of 878 question naires were sent to patients , and 559 ( 64 % ) usable replies were received . The response rate was similar in the two groups ( 62.9 % versus 64.6 % ) . In all eight dimensions of the SF-36 health status measure patients who had been managed by paramedics operating protocol A reported better average health than did patients in the protocol B group . However , none of the differences were at a level considered clinical ly important and only for one of the eight dimensions was the difference statistically significant . COMPOSITE OUTCOMES : No significant differences in outcome were found between the two protocol groups in terms of patients who either died or had serious complications , nor for patients who either died or had known poor health . SUBGROUPS : Subgroups of patients were defined on eight characteristics ( ambulance service area , whether a doctor was on scene , paramedic-patient contact time , injury severity , whether taken to theatre for emergency surgery , type of injuries , type of area , and whether the patient was treated before or after protocol cross-over ) . There was no evidence of any difference in mortality rates or composite outcomes between any subgroups , or between protocol s within any subgroup . Time to A&E department The analysis suggests that patients given fluids spent 12 - 13 minutes longer at the accident scene than did patients not given fluids . However , because only one-quarter of patients were given fluids , and the specific protocol used made little difference to this , average on-scene times were largely unaffected by protocol s. COSTS In the prehospital and immediate-care phase ( including A&E treatment ) , the mean costs of the protocol A and protocol B groups were ¿ 419 and ¿ 416 , respectively . This small difference reflects two small and off setting effects of protocol B : reduced on-scene time ( p = 0.08 ) and increased use of blood in the A&E department ( p = 0.03 ) . There were no other statistically significant differences in 
    Output:
    
AUTHORS ' CONCLUSIONS We found no evidence from r and omised controlled trials for or against early or larger volume of intravenous fluid administration in uncontrolled haemorrhage .