***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: We hypothesized that lactate levels even within the normal range are prognostic and that low lactate levels predict a beneficial response to vasopressin infusion in septic shock . We conducted a retrospective analysis using the Vasopressin in Septic Shock Trial ( VASST ) as a derivation cohort ( n = 665 ) , then vali date d using another single-center septic shock cohort , St Paul ’s Hospital ( SPH ) cohort ( n = 469 ) . Lactate levels were divided into quartiles . The primary outcome variable was 28-day mortality in both cohorts . We used receiver operating characteristic ( ROC ) curve analysis to compare the prognostic value of lactate concentrations versus Acute Physiology and Chronic Health Evaluation II scores . We then explored whether lactate concentrations might predict beneficial response to vasopressin compared with noradrenaline in VASST . Normal lactate range is less than 2.3 mmol/L. At enrolment , patients in the second quartile ( 1.4 < lactate < 2.3 mmol/L ) had significantly increased mortality and organ dysfunction compared with patients who had lactate ⩽1.4 mmol/L ( quartile 1 ) ( P < 0.0001 ) . Quartile 2 outcomes were as severe as quartile 3 ( 2.3 ⩽ lactate < 4.4 mmol/L ) outcomes . Baseline lactate values ( area under the ROC curve = 0.63 , 0.66 ; VASST , SPH ) were as good as Acute Physiology and Chronic Health Evaluation II scores ( area under the ROC curve = 0.66 , 0.73 ; VASST , SPH ) as prognostic indicators of 28-day mortality . Lactate concentrations of 1.4 mmol/L or less predicted a beneficial response in those r and omized to vasopressin compared with noradrenaline in VASST ( P < 0.05 ) . Lactate concentrations within the “ normal ” range can be a useful prognostic indicator in septic shock . Furthermore , patients whose lactate level is less than or equal to 1.4 mmol/L may benefit from vasopressin infusion . ABBREVIATIONS APACHE — Acute Physiology and Chronic Health Evaluation ATP — adenosine triphosphate COPD — chronic obstructive pulmonary disease ScvO2— central venous oxygen saturation SPH — St Paul ’s Hospital VASST — Vasopressin and Septic Shock ABSTRACT Objective : The objective of this study was to compare vasopressor requirements between African American ( AA ) patients and white patients in septic shock . Methods : This was a retrospective cohort review conducted over a 2-year period measuring total and mean dosage of various vasopressors used between two racial groups during the treatment of patients admitted with septic shock . The study included patients admitted to the intensive care unit with septic shock at an 805-bed tertiary , academic center . All septic shock patients were managed with vasopressors . Vasopressor selection , dosage , and duration were at the discretion of the treating physician . Total , mean , and duration of vasopressor dosing requirements were obtained for study participants . Comorbidities , prehospitalization antihypertensive medication requirements , intravenous fluids given during the septic shock phase , and source of infection were analyzed . Results : One hundred fifty-nine patients with septic shock were analyzed , of which 96 ( 60.4 % ) were AAs ( P < 0.059 ) . African Americans had higher rates of end-stage renal disease and hypertension compared with whites , 85.7 % vs. 14.3 % ( P < 0.011 ; odds ratio [ OR ] , 15.684 ) and 68.3 % vs. 31.7 % ( P < 0.007 ; OR , 3.357 ) , respectively .  Norepinephrine  ( NE ) was administered to 150 patients , 57.2 % of which were AAs ( P < 0.509 ) . Thirteen patients received  dopamine  ( 5 % AAs , P < 0.588 ) , 40 patients received  phenylephrine  ( 15.7 % AAs , P < 0.451 ) , and five patients received  epinephrine  ( 1.9 % AAs , P < 0.660 ) . Comparing vasopressors between races , only NE showed statistical significance via logistic regression modeling for the AA race in terms of total dosage ( AAs 736.8 [ SD , 897.3 ] & mgr;g vs. whites 370 [ SD , 554.2 ] & mgr;g , P < 0.003 ) , duration of vasopressor used ( AAs 38.38 [ SD , 34.75 ] h vs. whites 29.09 [ SD , 27.11 ] h , P < 0.037 ) , and mean dosage ( AAs 21.08 [ SD , 22.23 ] & mgr;g/h vs. whites 12.37 [ SD , 13.86 ] & mgr;g/h , P < 0.01 ) . Mortality between groups was not significant . Logistic regression identified discrepancy of the mean dose NE in AAs compared with whites , with OR of 1.043 ( P = 0.01 ) . Conclusions : African American patients with septic shock were treated with higher doses of NE and required longer duration of NE administration compared with white patients Objective To investigate the effect of norepinephrine ( NE ) on hemodynamics , oxygen metabolism and renal function in patients with severe septic shock . Design Prospect i ve study . Setting Post-operative ICU in a municipal general hospital . Patients The study included 56 patients with extreme low resistance states due to abdominal sepsis , who remained hypotensive ( MAP<60 mmHg ) despite optimal fluid therapy and dopamine>20μg/kg/min and cumulative doses of dopamine and dobutamine>30μg/kg/min , respectively . Interventions After registration of baseline values dopamine was reduced to 2.5μg/kg/min , and norepinephrine was administered starting at a dose of 0.05 μg/kg/min until a mean arterial pressure of more than 60 mmHg could be maintained . Measurements and results During norepinephrine infusion ( dosage ranging between 0.1–2μg/kg/min , mean dose rate : 0.4μg/kg/min ) mean arterial pressure and systemic vascular resistance index increased significantly ( p<0.001 ) . After 8h a significant increase in stroke volume ( p<0.05 ) and decrease in heart rate ( P<0.05 ) could be observed . There was no significant change in cardiac index ( CI ) , oxygen delivery ( O2AVI ) and oxygen consumption ( VO2I ) . Creatinine clearance increased significantly ( p<0.005 ) from a control value of 75±37 ml/min to 102±43 ml/min after 48 h NE-trearment . Conclusion Our results suggest that norepinephrine can be used safely in the treatment of severe septic shock states . Mean arterial pressure and glomerular filtration rate improved markedly without deleterious effects on CI , O2AVI and VO2I Objective : To assess the effects of low-dose dopamine on splanchnic blood flow and splanchnic oxygen uptake in patients with septic shock . Design : Prospect i ve , controlled trial . Setting : University hospital intensive care unit Patients : 11 patients with septic shock , diagnosed according the criteria of the 1992 American College of Chest Physicians/Society of Critical Care Medicine consensus conference , who required treatment with norepinephrine .  Measurements and main results : Systemic and splanchnic hemodynamics and oxygen transport were measured before and during addition of low-dose dopamine ( 3 μg/kg per min ) . Low-dose dopamine had a marked effect on total body hemodynamics and oxygen transport . The fractional splanchnic flow at baseline ranged from 0.15 to 0.57 . In 7 patients with a fractional splanchnic flow less than 0.30 , low-dose dopamine  increased splanchnic flow and splanchnic oxygen delivery and oxygen consumption . In 4 patients with a fractional splanchnic flow above 0.30 , low-dose dopamine did not appear to change splanchnic blood flow . Conclusion : Low-dose dopamine has a potential beneficial effect on splanchnic blood flow and oxygen consumption in patients with septic shock , provided the fractional splanchnic flow is not already high before treatment Objective To characterize the acute actions and physiologic dose profile of epinephrine , as a single inotrope , in patients with septic shock . Design Prospect i ve clinical study . The relationship between epinephrine dose and cardiovascular variables was analyzed using repeated- measures analysis of variance . Setting ICU in a university teaching hospital . Patients Eighteen patients with septic shock , mean age 64 ± 8 ( SD ) yrs , and with a mean admission Acute Physiology and Chronic Health Evaluation ( APACHE II ) score of 23 ( range 14 to 35 ) . Interventions Initial volume loading and the measurement of a baseline hemodynamic profile were followed by the administration of an epinephrine infusion at 3 μg/min with subsequent increments of 3 μg/min and the determination of a hemodynamic profile after each dose increment . Therapy was titrated to clinical goals of perfusion and restoration of premorbid systolic arterial BP . Measurements and Main Results After volume loading , mean hemodynamic indices were as follows : mean arterial pressure ( MAP ) 62 ± 7 mm Hg ; cardiac index 3.8 ± 1.1 L/min/m2 ; left ventricular stroke work index 25 ± 11 g.m/m2 ; oxygen delivery ( Do2 ) index 460 ± 168 mL/min/m2 ; and oxygen consumption ( Vo2 ) index 165 ± 64 mL/ min/m2 . In the dose range of 3 to 18 μg/min , epinephrine produced linear increases in average heart rate , MAP , cardiac index , left ventricular stroke work index , stroke volume index , Vo2 , and Do2 . No effect was noted on pulmonary artery occlusion pressure ( PAOP ) , mean pulmonary arterial pressure , or systemic vascular resistance index . Conclusions Epinephrine increases Do2 in septic shock by increasing cardiac index without an effect on systemic vascular resistance index or PAOP . ( Crit Care Med 1993 ; 21:70–77 Arterial hypotension often signifies inadequate systemic perfusion . We hypothesize that in a heterogeneous emergency department ( ED ) population with clinical ly suspected circulatory shock , the severity of hypotension on presentation predicts in-hospital outcome . We performed a secondary analysis of patients with nontraumatic shock enrolled in a noninterventional , r and omized , controlled trial . The setting was an urban , tertiary ED , census > 100,000 visits per year . Patients included nontrauma ED patients , aged > 17 years , with initial ED vital signs consistent with shock ( systolic blood pressure < 100 mmHg or shock index > 1.0 ) , and agreement of two independent observers for at least one sign and symptom of inadequate tissue perfusion . Measurements included interobserver agreement for signs and symptoms of shock , relationship between the depth and duration of ED hypotension and adverse hospital outcome ( in-hospital mortality , need for intensive care unit services , and acute organ failure ) and logistic regression analysis for independent predictors of adverse hospital outcome . Of 202 patients who qualified , 190 patients were included ;  the in-hospital mortality rate was 15 % . The sign or symptom of shock with the highest interobserver agreement was “ unresponsive ” ( κ = 0.74 ) . The adverse hospital outcomes increased with each decile decrease in the lowest ED systolic blood pressure ( SBP ) from 17 % if SBP > 89 mmHg versus 50 % if SBP < 80 mmHg . Forty percent of patients with an adverse hospital outcome had sustained hypotension ( all ED SBP < 100 mmHg for ≥60 min ) . Sustained hypotension was the strongest independent predictor of an adverse hospital outcome ( odds ratio 3.1 ; 95 % CI 1.5–7.1 ) . Mortality among patients who present to the ED with undifferentiated shock is high . The depth and duration of systolic blood pressure appears to have a dose – response relationship to adverse hospital outcome Background The current consensus definition of septic shock requires hypotension after adequate fluid challenge or vasopressor requirement . Some patients with septic shock present with hypotension and hyperlactatemia greater than 2 mmol/L ( tissue dysoxic shock ) , whereas others have hypotension alone with normal lactate ( vasoplegic shock ) . Objective The objective of this study was to determine differences in outcomes of patients with tissue dysoxic versus vasoplegic septic shock . Methods This was a secondary analysis of a large , multicenter r and omized controlled trial . Inclusion criteria were suspected infection , two or more systemic inflammatory response criteria , and systolic blood pressure less than 90 mmHg after a fluid bolus . Patients were categorized by presence of vasoplegic or tissue dysoxic shock . Demographics and Sequential Organ Failure Assessment scores were evaluated between the groups . The primary outcome was in-hospital mortality . Results A total of 247 patients were included , 90 patients with vasoplegic shock and 
    Output:
    
Crossover trials suggest that achieving higher blood pressure targets by increasing vasopressor doses increases heart rate and cardiac index with no effect on serum lactate .
Our findings underscore the paucity of clinical evidence to guide the administration of vasopressors in critically ill patients with septic shock .