***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: Thirty-six patients with preoperative renal dysfunction were studied to evaluate the effects of dopamine ( D ) and dopamine-nitroprusside ( DN ) on renal function during cardiopulmonary bypass ( CPB ) . No differences from the control group ( C ) were found in creatinine clearance , fractional sodium excretion , osmolarity and free-water clearance . Sodium output/intake ratio during CPB was higher in group D than in groups C and DN ( P less than 0.05 ) ; water output/intake ratio was higher in group D than in group C ( P less than 0.05 ) . Urine lysozime levels and alpha-glycosidase/creatinine ratios increased similarly in the three groups , suggesting ischemic tubular cell damage . No patients showed acute postoperative renal failure or a worsening of their renal dysfunction . The data suggest an increased water and sodium excretion during CPB with a dopamine infusion , possibly result ing from a renal vasodilator effect that was abolished by simultaneous nitroprusside administration We report the use of dopamine in renal doses ( 5 micrograms/kg/min ) to prevent contrast induced nephropathy ( CIN ) .  Forty patients with diabetes mellitus who were undergoing coronary angiography were r and omly divided into two groups . Gr I ( 20 patients ) was infused with dopamine starting 30 min before cardiac catheterization and continued for 6 h thereafter . Gr II ( 20 patients ) did not receive dopamine . Baseline blood chemistry was performed before catheterization and then repeated 24 h after the procedure . The mean age and sex distribution were similar in both the groups .  Urograffin  ( 76 % ; 120 - 150 ml ) was used in all the cases . The mean serum creatinine and blood urea nitrogen ( BUN ) levels in Gr I patients before catheterization were 1.5 + /- 0.32 mg % and 16.3 + /- 8.05 mg % , respectively . The corresponding values for Gr II were 1.52 + /- 0.68 mg % and 19.6 + /- 13.4 mg % , respectively . After angiography , Gr I patients did not show significant changes in renal parameters ( serum creatinine , 1.37 + /- 0.25 mg % and BUN , 14.7 + /- 5.5 mg % ) while Gr II patients showed a significant rise ( serum creatinine , 1.96 + /- 1.2 mg % and BUN , 23.25 + /- 12.7 mg % ; P = 0.01 and P = 0.05 , respectively ) . Ten patients in Gr II ( 50 % ) developed a 25 % rise in serum creatinine levels within 24 h of injection of the contrast . None of the patients developed renal failure severe enough to warrant dialysis . Hence alterations of renal function are common after cardiac catheterization . Dopamine in renal doses appears to be an effective means to prevent deterioration in renal function induced by contrast Previous studies suggest a role for renal vasoconstriction in the pathogenesis of radiocontrast-induced nephropathy ( RCIN ) . A renal vasodilator such as dopamine may be protective . However , the effect of dopamine on renal blood flow ( RBF ) in patients with chronic renal failure ( CRF ) is controversial . Patients with CRF of diabetic ( DM ) or nondiabetic ( NDM ) origin were hydrated with 0.45 % NaCl intravenously at 100 mL/h for 12 h and then r and omized to either 0.45 % NaCl IV at 100 mL/h ( Group 1 ) or dopamine IV at 2 micrograms/kg/min in 0.45 % NaCl at 100 mL/h for 2 h during and after cardiac catheterization . Mean arterial pressure ( MAP ) , cardiac output ( CO ) , and RBF were measured at baseline ( t = 0 ) , after 5 min of vehicle ( Group 1 ) or dopamine ( Group 2 ) but before ionic radiocontrast ( t = 5 min ) , after ventriculogram ( t = 15 min ) , and after coronary angiography ( t = 65 min ) . Serum creatinine ( SCr ) was measured at baseline and 24 and 48 h after cardiac catheterization . RCIN was defined as a 25 % increase of SCr above baseline 48 h after cardiac catheterization . Baseline characteristics demonstrated the groups to be equivalent in age , SCr , creatinine clearance , CO , MAP , RBF , and radiocontrast dose administered . The incidence of RCIN was not different between Group 1 and Group 2 ( Group 1 , 6 of 15 patients ; Group 2 , 5 of 15 patients ) . Dopamine infusion was associated with a significant increase in RBF at 5 min ( Group 1 , 110 + /- 13 % ; Group 2 , 193 + /- 40 % at t = 5 , p < .05 ) . RBF remained elevated throughout the catheterization in Group 2 . ( ABSTRACT TRUNCATED AT 250 WORDS To evaluate whether the intact hypoxic drive from the carotid bodies during sustained hypoxia is required for the generation of hypoxic depression of ventilation ( VE ) , 16 volunteers were exposed to two consecutive periods of isocapnic hypoxia ( first period 20 min ; second period 5 min ; end-tidal PO2 45 Torr ) separated by 6 min of normoxia . In study A , saline was given . In study B , 3 micrograms.kg-1.min-1 i.v . dopamine ( DA ) , a carotid body inhibitor , was given during the first hypoxic exposure followed by saline during normoxia and the second hypoxic exposure . In study C , 20 min of normoxia with DA preceded 6 min of normoxia and 5 min of hypoxia without DA . The first peak hypoxic VE ( PHV ) in study A was approximately 100 % above normoxic VE . After 20 min of hypoxia , VE declined to 60 % above normoxic VE . The second PHV in study A was only 60 % of the first PHV . We relate this delayed recovery from hypoxia to " ongoing " effects of hypoxic depression . During DA infusion , the changes in VE due to sustained hypoxia were insignificant ( study B ) . The second PHV in study B was not different from the PHV after air breathing in studies A and C. This indicates that the recovery from sustained hypoxia with a suppressed carotid body drive was complete within 6 min . Our results show that despite central hypoxia the absence of ventilatory changes during 20 min of isocapnic hypoxia due to intravenous DA prevented the generation of central hypoxic depression and the depression of a subsequent hypoxic response We prospect ively studied the effects of renal protection intervention in 17 patients with preoperative abnormal renal function ( plasma creatinine > 1.5 mg/dL ) scheduled for elective coronary surgery . Patients were r and omized to either dopamine 2.0 micro g [ center dot ] kg-1 [ center dot ] min-1 ( Group 1 , n = 10 ) or perfusion pressure > 70 mm Hg during cardiopulmonary bypass ( CPB ) ( Group 2 , n = 7 ) . Glomerular filtration rate and effective renal plasma flow were measured with inulin and 125 I-hippuran clearances before the induction of anesthesia , after sternotomy and before CPB , during hypo- and normothermic CPB , after sternal closure , and 1 h postoperatively . Plasma and urine electrolytes were measured , and free water , osmolar , and creatinine clearances , as well as fractional excretion of sodium and potassium , were calculated before and after surgery . Significant differences between groups were found before CPB for glomerular filtration rate ( higher in Group 1 ) , urine output ( 2.0 vs 0.29 mL/min in Group 1 versus Group 2 ) , urinary creatinine ( 66 vs 175 mg/dL ) , urinary osmolarity ( 370 vs 627 mOsm/L ) , osmolar clearance ( 2.1 vs 0.7 mL/min ) , and urinary potassium ( 33 vs 71 mEq/L ) . There were no differences between groups during hypo- and normothermic CPB . After CPB , the only difference was a slightly higher urinary creatinine in Group 2 . Renal plasma flow was lower than normal in all patients before the induction of anesthesia . A nonsignificant trend toward increased flow was seen during hypothermic CPB . Filtration fraction was high before CPB , which suggests efferent arteriolar vasoconstriction , descending toward normal during and after CPB . The same pattern of changes was present in both groups . In conclusion , there were no clinical ly relevant differences between the two treatment modalities during and after CPB . However , significant differences were observed before CPB , when dopamine seemed to partially revert renal vasoconstriction . Implication s : Two protective interventions were compared in patients undergoing heart surgery to prevent deterioration of renal function  ;  these were dopamine infusion throughout the operation and phenylephrine infusion during cardiopulmonary bypass . We found clinical ly relevant differences only during surgery before cardiopulmonary bypass The potential renal vasodilatory effect of dopamine in improving renal function after arteriography was studied . Sixty patients with preexisting renal insufficiency were prospect ively r and omized into two groups . Patients in the treated group ( n = 30 ) received an infusion of dopamine for 12 hours starting at the beginning of arteriography . Patients who received placebo infusion with arteriography  ( n = 30 ) served as controls . The study was conducted in two different time intervals . In the first interval , serum creatinine levels and 12-hour creatinine clearance values were obtained before and immediately after arteriography in 12 patients in the dopamine group and 13 patients in the control group . In the second interval , the same variables were measured before arteriography and for 3 consecutive days after arteriography in 18 patients in the dopamine group and 17 patients in the control group . Serum creatinine levels became significantly elevated in the control group on the 1st day and remained so on the 3rd day after arteriography , whereas the dopamine group did not show significant elevation of these levels . Creatinine clearance decreased in the control group on the 1st day , but this deterioration was not sustained on the 3rd day . In the dopamine group , there was no deterioration in creatinine clearance on either day , and mean effective renal plasma flow during and after arteriography was greater BACKGROUND Acute renal failure occurring in the postoperative period , requiring dialysis after cardiac surgery is an important risk factor for an early mortality , and the overall mortality of this complication is as high as 40 % to 60 % . Dialysis in the early postoperative period is often complicated by acute hemodynamic , metabolic , and hematologic effects that adversely affect cardiopulmonary function in patients stabilizing from recent surgery . The purpose of this study was to avoid the need for dialysis by infusion of the solution of mannitol , furosemide , and dopamine in the early postoperative period in oliguric renal failure . METHODS One hundred patients with postoperative oliguric or anuric renal failure despite adequate postoperative cardiac output and hemodynamic function were r and omized . Forty patients ( group A ) were given intermittent doses of diuretics ( furosemide , bumetadine , and ethracrynic acid ) and fluids .  Sixty patients ( group B ) were given continuous infusion of the solution of mannitol , furosemide , and dopamine ; the infusion was started within 6 hours ( mean 3.5 hours ) in subgroup B1 ( n = 30 ) , and later than 6 hours ( mean 7.5 hours ) in subgroup B2 ( n = 30 ) after the onset of renal failure . RESULTS Diuresis occurred in 93.3 % of group B ( n = 56 ) versus 10 % in group A ( n = 4 ; patients with preop normal renal function ) . Ninety percent of group A ( n = 36 ) required dialysis versus only 6.7 % of group B ( n = 4 ; patients with preexisting renal disease of subgroup B2 ) . Renal function returned to preoperative normal ( serum creatinine 0.9 + /- 0.05 , p < 0.0001 ) or baseline value ( serum creatinine 2.5 + /- 0.01 , p < 0.0001 ) after first postoperative week in subgroup B1 and third postoperative week in subgroup B2 . CONCLUSIONS Infusion of solution of mannitol , furosemide , and dopamine promoted diuresis in patients with acute postoperative renal failure with adequate postoperative cardiac output and had decreased the need for dialysis in the majority of patients . Early administration of this solution in acute renal failure caused early restoration of renal function to normal or baseline status . It remains to be determined whether routine administration of this solution in the early postoperative period for oliguric renal failure influences the long-term mortality and morbidity in those patients who do require dialysis INTRODUCTION The purpose of our study was to evaluate the relationship between the state of splanchnic perfusion and morbidity and mortality in the hemodynamically unstable trauma patient ac 
    Output:
    
The results of this meta- analysis confirms that low-dose dopamine has no reno-protective effect .