***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: BACKGROUND The aim of the present study was to evaluate the efficacy of alpha-human atrial natriuretic peptide ( hANP ) in cardiac surgery under cardiopulmonary bypass ( CPB ) .  METHODS AND RESULTS A prospect i ve r and omized study was conducted with 150 patients who underwent scheduled coronary artery bypass grafting  to compare a group of patients receiving 0.02 microg x kg(-1 ) x min(-1 ) of hANP from the initiation of CPB with a group not receiving hANP .  Hemodynamics , levels of atrial and brain natriuretic peptides ( BNP ) , angiotensin-II and aldosterone , renin activity , and left ventricular ( LV ) function were examined . The hANP group showed significantly lower renin activity and lower levels of angiotensin-II and aldosterone during the early postoperative period , compared with the non-hANP group . The incidence of postoperative ventricular arrhythmia and the postoperative peak level of creatine kinase-MB were significantly lower in the hANP group . BNP at 1 month after surgery and measures of LV function were also significantly lower in the hANP group . CONCLUSIONS Low-dose continuous infusion of hANP during cardiac surgery not only had a compensatory effect for the imperfections of CPB during the early postoperative period but also an inhibitory effect on postoperative LV remodeling and a reduction in ischemia/reperfusion injury . hANP should be part of the postoperative care for cardiac surgery BACKGROUND We evaluated the effects of human atrial natriuretic peptide ( hANP ) during cardiopulmonary bypass ( CPB ) . METHODS Forty patients undergoing coronary artery bypass grafting were investigated . A group of patients given hANP for 24 hours from the start of CPB ( hANP group ) was compared with a non-hANP group . Parameters examined were hemodynamics , urine volume , dosage of furosemide , respiratory index , pleural effusion , ANP , cyclic guanosine monophosphate , renin activity ( renin ) , angiotensin-II , aldosterone , and glomerular filtration rate . RESULTS Central venous pressure , systemic vascular resistance index , and pulmonary vascular resistance index were significantly lower in the hANP group than in the non-hANP group . The hANP group showed significantly higher levels of ANP , cyclic guanosine monophosphate , glomerular filtration rate , and respiratory index , and significantly lower levels of renin , angiotensin-II , aldosterone , and pleural effusion , as compared with the non-hANP group . The dosage of furosemide was significantly lower and the urine volume was significantly larger in the hANP group . CONCLUSIONS hANP can satisfactorily compensate for the shortcomings of CPB by decreasing the peripheral vascular resistance , suppressing the renin-angiotensin-aldosterone system , and exerting a strong diuretic effect Atrial natriuretic factor ( ANF ) ameliorates renal damage in animal models of acute ischemic renal failure . Consequently , ANF could blunt acute tubular necrosis related to ischemia that occurs frequently in cadaveric renal transplants . Ten pairs of cadaveric kidneys were transplanted into 20 recipients . Paired recipients received either alpha-human ANF ( hANF ) or vehicle alone in a prospect i ve , double-blind protocol . Upon revascularization of the allograft , either hANF or vehicle was administered intravenously as a 50-micrograms bolus , followed by a 4-h infusion ( 0.1 microgram/kg/min ) . Glomerular filtration rate ( [125I]iothalamate clearance ) was measured between 4 and 7 days posttransplant and again between 14 and 21 days posttransplant . Serum creatinine was measured daily when patients were in the hospital , then twice weekly as patients were examined in the outpatient clinic . Between the groups , there was no significant difference in age of the recipients or donors , cold ischemia time , or histocompatibility leukocyte antigen match . Infusion of hANF had no adverse effects . When subjects receiving hANF were compared with those treated with vehicle alone , there were no significant differences in serum creatinine or glomerular filtration rate . Three hANF and four vehicle recipients required dialysis postoperatively . At 1 month posttransplant , 19 of 20 patients had functioning allografts ; an allograft from one hANF recipient never functioned . It was concluded that hANF , when given by the protocol of this study , had no beneficial effect on the outcome of cadaveric renal transplantation in humans This study was performed to investigate the effects of atrial natriuretic peptide ( ANP ) and mannitol on renal blood flow ( RBF ) and radiocontrast-induced nephropathy ( RCIN ) in human subjects with chronic renal failure . ANP preserves glomerular filtration rate or RBF ( or both ) in severe animal models of acute renal failure . Radiocontrast is known to substantially decrease RBF and can induce acute renal failure .  Twenty consecutive patients with chronic renal failure ( 60 % with diabetes ) were r and omized in a prospect i ve , double-blind fashion to receive either ANP ( 50 micrograms bolus , then 1 microgram/min infusion ) or mannitol ( 15 % at 100 ml/hr ) for 2 hours before and during cardiac catheterization with diatrizoate . Baseline serum creatinine level ( ANP 2.4 + /- 0.7 mg/dl , mannitol 2.5 + /- 0.8 mg/dl ) , medications , and quantity of radiocontrast were similar in both groups . Direct measurements of RBF were made with thermodilution catheters placed in the left renal vein . RBF rose significantly ( p less than 0.05 ) , to 198 % of baseline at 15 minutes and 166 % of baseline at 65 minutes in the group receiving ANP and remained stable in the group receiving mannitol .  ANP levels rose significantly from baseline at 5 , 15 , 65 and 120 minutes in both groups ( p less than 0.05 ) . Acute renal failure defined as a 0.5 mg/dl rise of creatinine within 24 hours of cardiac catheterization , developed only in patients with diabetes mellitus and was similar in both experimental groups ( ANP , 50 % ; mannitol , 30 % ) . Only patients with diabetes mellitus responded with an increase in RBF after a 5-minute infusion of either ANP or mannitol ( diabetes , 165 % + /- 28 % baseline ; no diabetes , 96 % + /- 8 % baseline ) ( p less than 0.05 ) . In conclusion , RBF was maintained or increased despite administration of radiocontrast , a documented renal vasoconstrictor . Patients with diabetes mellitus had a renal vasodilatory response to drug infusion . Acute renal failure occurred to a similar extent in both groups . Plasma ANP levels rose significantly in both groups . Mannitol may induce ANP release , thus contributing to mannitol 's renal effects Acute renal failure is a serious problem following heart transplantation . In first uncontrolled clinical trials , Urodilatin revealed beneficial effects in the prophylaxis and therapy of acute renal failure following heart and liver transplantation . Here , we present the first r and omized , placebo-controlled , double-blind study on 24 patients following heart transplantation to investigate whether prophylactic i.v .  Urodilatin infusion can prevent acute renal failure requiring renal replacement therapy . Postoperative drug management was characterized by intravenous application of high furosemide , cyclosporine , and vancomycin doses . Urodilatin infusion was started postoperatively with a dose of 40 ng / kg bw / min for 6 days . 6 of the 12 patients in the Urodilatin group and 6 of the 12 patients in the placebo group had a stable diuresis ( 3 - 4 l / day ) during the study period of 6 days . In contrast , the remaining 6 patients of each group developed oliguria / anuria and required subsequent hemofiltration / hemodialysis . Cumulative duration of hemofiltration ( 88 + /- 7.39 hours in the placebo treated patients versus 44 + /- 5.35 hours in the Urodilatin treated patients , p < 0 . 05 ) as well as frequency of hemodialysis ( 3.0 + /- 0.49 times in the placebo group vs 1.2 + /- 0.29 times in the Urodilatin group , p < 0 . 05 ) were significantly reduced using Urodilatin .  Mean arterial blood pressure was stable during the Urodilatin infusion period and was not different to that observed in placebo patients . We conclude that Urodilatin does not reduce the incidence of acute renal failure and the subsequent requirement for hemofiltration / hemodialysis in our patient population , but seems to reduce the duration of hemofiltration and frequency of hemodialysis compared to the placebo group Summary Renal failure after heart transplantation ( HTx ) still remains a serious problem , especially when cyclosporin A is used for immunosuppression in the early postoperative therapy . To preserve good renal function without reducing immunosuppressive cyclosporin A treatment , we administered urodilatin ( CDD/ANP-95 - 126 ) in a long-term , low-dose infusion in addition to the usual medication after heart transplantation . From November 1990 to June 1991 , 51 patients ( 46 male and 5 female ; mean age 48 years ) were treated with a 620 ng/kg bw·min infusion for 96 h after HTx . The renal function and hemodynamic parameters of these urodilatin-treated patients were compared in this sequential study with 40 patients ( 33 male and 7 female ; mean age 49 years ) who had undergone HTx previously from May to November , 1990 , as controls . In this phase IIa study , both groups did not differ significantly with respect to age , sex , indication for HTx , and preoperative renal function . In comparison with controls patients treated with urodilatin had a significantly better renal function : a reduction in the peak plasma creatinine ( PC values day 4 : 1.5 ± 0.11 vs. 2.19 ± 0.19 mg/dl ; P = 0.002 ) , a lower peak serum urea ( SU values day 4 : 109 ± 8 vs. 154.7 ± 8.94 mg/dl ; P = 0.0036 ) , and a lower incidence of hemodialysis ( 6 % vs. 10 % ) were observed . Adequate diuresis was maintained in spite of the reduction of furosemide by more than 60 % ( P = 0.005 ) on each day of urodilatin infusion in comparison with controls . The mean central venous pressure was significantly lower by about 50 % ( P = 0.02 ) during the administration of urodilatin in spite of reduced vasodilator medication with nitroglycerin . From this phase IIa study , we may conclude that urodilatin could be an important drug in intensive care treatment . For patients undergoing HTx , this peptide seems to be indicated for the improvement of renal function and cardiovascular status , especially in postoperative therapy using high-dose cyclosporin A treatment Many therapeutic measures have been employed to prevent or at least ameliorate postoperative renal impairment following liver transplantation . Recent clinical phase II studies have demonstrated that the new natriuretic peptide urodilatin has beneficial effects on renal function following heart and liver transplantation . The present study reports the first prospect i ve r and omized placebo-controlled trial of prophylactic urodilatin administration following liver transplantation . Seventy consecutive recipients of primary liver transplants were included in the study following r and omization , and 33 patients continuously received urodilatin  at a dose of 20 ng/kg/min for 7 d. The remaining 37 patients received a placebo infusion for the same time period . The course of serum creatinine and urea did not differ between the two groups nor did the daily urine production . However , the urodilatin group showed a higher preoperative median serum creatinine and a significant reduction on days 1 and 2 , whereas this observation was not made in the placebo group . Furthermore , less furosemide was administered to the patients in the urodilatin group during the first 2 d. The incidence of postoperative hemodialysis and the number of treatments did not differ between the groups either ( urodilatin group 4 , vs. placebo group 6 and 22 for both groups , respectively ) . Side effects of the urodilatin therapy were not detected . The prophylactic low-dose urodilatin administration result ed in a trend towards amelioration of the renal function , but did not result in significant differences between the two experimental groups . Further studies , using higher doses , will be required to define the value of urodilatin for prevention of renal impairment after liver transplantation Objective Imbalance in the renal medullary oxygen supply/dem and relationship can cause hypoxic medullary damage and ischemic acute renal failure . Human atrial natriuretic peptide ( h-ANP ) increases glomerular filtration rate in clinical acute renal failure . This would increase renal oxygen consumption due to increased tubular load of sodium . Loop diuretics are commonly used in acute renal failure . Data on the effects of loop diuretics on glomerular 
    Output:
    
For the treatment of established AKI , ANP , particularly in high doses , was associated with a trend toward increased mortality and more adverse events .
Analysis of the existing literature suggests ANP might be associated with beneficial clinical effects when administered in patients undergoing major surgery such as cardiovascular surgery .