***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 Both dopamine and norepinephrine are recommended as first-line vasopressor agents in the treatment of shock . There is a continuing controversy about whether one agent is superior to the other . METHODS In this multicenter , r and omized trial , we assigned patients with shock to receive either dopamine or norepinephrine as first-line vasopressor therapy to restore and maintain blood pressure . When blood pressure could not be maintained with a dose of 20 microg per kilogram of body weight per minute for dopamine or a dose of 0.19 microg per kilogram per minute for norepinephrine , open-label norepinephrine , epinephrine , or vasopressin could be added . The primary outcome was the rate of death at 28 days after r and omization ; secondary end points included the number of days without need for organ support and the occurrence of adverse events . RESULTS The trial included 1679 patients , of whom 858 were assigned to dopamine and 821 to norepinephrine . The baseline characteristics of the groups were similar . There was no significant between-group difference in the rate of death at 28 days ( 52.5 % in the dopamine group and 48.5 % in the norepinephrine group ; odds ratio with dopamine , 1.17 ; 95 % confidence interval , 0.97 to 1.42 ; P=0.10 ) . However , there were more arrhythmic events among the patients treated with dopamine than among those treated with norepinephrine ( 207 events [ 24.1 % ] vs. 102 events [ 12.4 % ] , P<0.001 ) . A subgroup analysis showed that dopamine , as compared with norepinephrine , was associated with an increased rate of death at 28 days among the 280 patients with cardiogenic shock but not among the 1044 patients with septic shock or the 263 with hypovolemic shock ( P=0.03 for cardiogenic shock , P=0.19 for septic shock , and P=0.84 for hypovolemic shock , in Kaplan-Meier analyses ) . CONCLUSIONS Although there was no significant difference in the rate of death between patients with shock who were treated with dopamine as the first-line vasopressor agent and those who were treated with norepinephrine , the use of dopamine was associated with a greater number of adverse events . ( Clinical Trials.gov number , NCT00314704 . Objectives : Dopamine , a natural catecholamine with hypophysiotropic properties , is used as a first choice drug for inotropic and vasoactive support in pediatric intensive care . In infants and children , the pituitary gl and plays a crucial role as a regulator of growth , metabolism , maturation and , possibly , immune function . We evaluated the effect of dopamine infusion ( 5 & mgr;g/kg/min iv ) on the dynamics of prolactin , growth hormone , and thyrotropin secretion and on the thyroid axis in critically ill infants and children . Design : Prospect i ve , r and omized , controlled , open‐labeled , clinical study . Setting : Intensive care unit of a university hospital over a 9‐month period . Patients and Methods : The study population consisted of infants and children recovering from cardiovascular surgery . The group was stratified into two age groups ( infants aged 12 to 90 days [ n = 18 ] and children aged 0.3 to 6.7 yrs [ n = 15 ] ) and was studied dynamically ( blood sampling every 20 mins for 3 hrs ) on two consecutive days , after r and omization for dopamine withdrawal on the first or the second day . Serum prolactin , growth hormone , insulin‐like growth factor‐1 , thyrotropin , thyroxine ( T4 ) , triiodothyronine ( T3 ) , and reverse triiodothyronine ( reverse T3 ) concentrations were measured . Measurements and Main Results : In the newborns  , dopamine was found to suppress prolactin , growth hormone , and thyrotropin secretion consistently , rebound releases starting within 20 mins after dopamine withdrawal . One day later , prolactin concentrations were ten times higher , pulsatile growth hormone secretion was augmented , thyrotropin was unchanged , but T3 was increased by 30 % and the T3/reverse T3 ratio was inverted . In the children  , dopamine suppressed prolactin and thyrotropin ( but not growth hormone ) secretion , rebound releases starting within 20 mins after dopamine withdrawal . One day later , prolactin concentrations were at least twice as high , thyrotropin was increased ten‐fold , T4 was augmented by 14 % , T3 by 30 % and the T3/reverse T3 ratio had doubled . Neither in newborns nor in children did dopamine withdrawal appear to affect the low serum insulin‐like growth factor‐1 concentrations . Conclusions : The data indicate that dopamine infusion induces or aggravates partial hypopituitarism and the euthyroid sick syndrome in critically ill infants and children . ( Crit Care Med 1994 ; 22:1747–1753 Dopamine is a naturally occurring catecholamine with actions in the central nervous system and endocrine systems , including inhibition of prolactin release from the pituitary gl and . Prolactin secretion has been shown to be increased in response to physiological stress , while hypoprolactinaemia is associated with a reduction in the cellular immune response . We have investigated the effects of low-dose infusion of dopamine 2.5 micrograms kg-1 min-1 on serum concentrations of prolactin in critically ill patients . Six hours after commencing the dopamine infusion , mean serum prolactin concentration had decreased from 746.95 to 128.9 mu . litre-1 ( normal range 84 - 488 mu . litre-1 ) . This represented a mean reduction of 79.2 % , with 35 % of patients exhibiting a subnormal concentration while receiving dopamine . This reduction was reversed after cessation of dopamine and reproducible on re-institution . This suppression of the release of dopamine  may be a detrimental side effect of low-dose dopamine infusion in critically ill patients Objective To measure the blood flow distribution and regional oxygen transport in hyperdynamic septic shock during hypotension and after correction by vasopressor doses of dopamine or norepinephrine . Design Prospect i ve , r and omized , controlled trial . Setting Tertiary care center . Patients Ten patients with hyperdynamic septic shock ( ages ranging from 45.1 ± 16.6 yrs ) and a control group of 11 postoperative cardiac surgery patients ( ages ranging from 54.8 ± 7.9 yrs ) . Interventions Systemic and regional hemodynamics and oxygen transport were measured in ten patients with hyperdynamic septic shock during hypotension and after vasopressor therapy ( norepinephrine or dopamine )  . Oxygen consumption ( Vo2 ) was measured by indirect calorimetry and splanchnic and leg blood flow with indocyanine green infusion . Measurements and Main Results Splanchnic blood flow and ( Vo2 ( p<.05 ) were increased in septic shock during hypotension and during vasopressor therapy . Both dopamine and norepinephrine  increased systemic blood flow and Vo2 independently of the arterial lactate level . Despite the relatively small changes in systemic oxygen transport , major regional changes occurred in oxygen delivery and Vo2 , and these changes were unpredictable from systemic changes . Conclusions Regional changes in oxygen transport in septic shock can not be predicted from the changes in the whole body . The increased oxygen dem and in the splanchnic region is the main risk factor for splanchnic tissue hypoxia in speptic shock . ( Crit Care Med 1993 ; 21:1296–1303 The optimum septic shock vasopressor support strategy is currently debated . This study was performed to evaluate the efficacy and safety of norepinephrine ( NE ) and dopamine ( DA ) as the initial vasopressor in septic shock patients who were managed with a specific treatment protocol . A prospect i ve , r and omized , open-label , clinical trial was used in a medical intensive care unit comparing DA with NE as the initial vasopressor in fluid-resuscitated 252 adult patients with septic shock . If the maximum dose of the initial vasopressor was unable to maintain the hemodynamic goal , then fixed-dose vasopressin was added to each regimen . If additional vasopressor support was needed to achieve the hemodynamic goal , then phenylephrine was added . The primary efficacy end point was all-cause 28-day mortality . Secondary end points included organ dysfunction , hospital and intensive care unit length of stay , and safety ( primarily occurrence of arrhythmias ) . The 28-day mortality rate was 50 % ( 67/134 ) with DA as the initial vasopressor compared with 43 % ( 51/118 ) for NE treatment ( P = 0.282 ) . There was a significantly greater incidence of sinus tachycardia with DA ( 24.6 % ; 33/134 ) than NE ( 5.9 % ; 7/118 ) and arrhythmias noted with DA treatment ( 19.4 % ; 26/134 ) compared with NE treatment ( 3.4 % ; 4/118 ; P < 0.0001 ) , respectively . Logistic regression analysis identified Acute Physiologic and Chronic Health Evaluation II score ( P < 0.0001 ) and arrhythmia ( P < 0.015 ) as significant predictors of outcome . In this protocol -directed vasopressor support strategy for septic shock , DA and NE were equally effective as initial agents as judged by 28-day mortality rates . However , there were significantly more cardiac arrhythmias with DA treatment . Patients receiving  DA should be monitored for the development of cardiac arrhythmias ( NCT00604019 ) Abstract Objective To determine whether infusion of dopamine modulates cellular immune functions and survival during systemic inflammation . Design and setting R and omized animal study , university research laboratory , Level I trauma center . SubjectsMale NMRI mice . Interventions Mice were subjected to laparotomy ( sham intervention , LAP ) or  polymicrobial sepsis induced by cecal ligation and puncture ( CLP ) . Mice in each of these conditions received either an intraperitoneal infusion of 0.9 % saline ( CLP/saline ; LAP/saline ) or an intraperitoneal infusion of dopamine ( 1.0 μg/kg/min i.p . , CLP/DOP ; LAP/DOP ) . Metabolic data and survival were monitored 24 h and 48 h after onset of sepsis , and animals were terminated 48 h after induction of sepsis to determine splenocyte apoptosis ( Annexin V binding capacity ) , splenocyte proliferation ( 3H-Thymidine incorporation assay ) , splenocyte IL-2 , IL-6 and IFN-γ release ( ELISA ) and leukocyte distribution ( WBC ; CD3 , CD4 , CD8 , B220 , F4/80 , NK1.1 ) . Measurements and results Infusion of dopamine in septic mice increased splenocyte apoptosis and decreased splenocyte proliferation and IL-2 release of septic mice . Furthermore , an inhibitory effect of dopamine infusion on splenocyte proliferation and the release of the TH1-cytokines IL-2 and IFN-γ was observed in sham operated control mice . These effects were paralleled by a decreased survival  of dopamine-treated septic animals ( 47 % vs. 67 % ) . Treatment with DOP did not affect sepsis-induced changes of leukocyte distribution . Conclusions We conclude that dopamine is capable of modulating cellular immune functions in a murine model of sepsis Objective To determine the incidence , cost , and outcome of severe sepsis in the United States . Design Observational cohort study . Setting All nonfederal hospitals ( n = 847 ) in seven U.S. states . Patients All patients ( n = 192,980 ) meeting criteria for severe sepsis based on the International Classification of Diseases , Ninth Revision , Clinical Modification . Interventions None . Measurements and Main Results We linked all 1995 state hospital discharge records ( n = 6,621,559 ) from seven large states with population and hospital data from the U.S. Census , the Centers for Disease Control , the Health Care Financing Administration , and the American Hospital Association . We defined severe sepsis as documented infection and acute organ dysfunction using criteria based on the International Classification of Diseases , Ninth Revision , Clinical Modification . We vali date d these criteria against prospect i ve clinical and physiologic criteria in a subset of five hospitals . We generated national age- and gender-adjusted estimates of incidence , cost , and outcome . We identified 192,980 cases , yielding national estimates of 751,000 cases ( 3.0 cases per 1,000 population and 2.26 cases per 100 hospital discharges ) , of whom 383,000 ( 51.1 % ) received intensive care and an additional 130,000 ( 17.3 % ) were ventilated in an intermediate care unit or cared for in a coronary care unit . Incidence increased > 100-fold with age ( 0.2/1,000 in children to 26.2/1,000 in those > 85 yrs old 
    Output:
    
A subgroup analysis that pooled studies in which all the r and omized patients had septic shock demonstrated that  norepinephrine improved in-hospital or 28-day mortality ; however , the results were no longer statistically significant .
Conclusions : The analysis of the pooled studies that included a critically ill population with shock predominantly secondary to sepsis showed superiority of norepinephrine over dopamine for in-hospital or 28-day mortality