Differential effects of human atrial natriuretic peptide and furosemide on glomerular filtration rate and renal oxygen consumption in humans.
OBJECTIVE
Imbalance in the renal medullary oxygen supply/demand 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 filtration rate and renal oxygen consumption in humans are, however, controversial. We evaluated the effects of h-ANP and furosemide on renal oxygen consumption, glomerular filtration rate, and renal hemodynamics in humans.


METHODS
Prospective two-agent interventional study in a university hospital cardiothoracic ICU.


METHODS
Nineteen uncomplicated, mechanically ventilated postcardiac surgery patients with normal renal function.


METHODS
h-ANP (25 and 50 ng/kg per minute, n=10) or furosemide (0.5 mg/kg per hour, n=9).


RESULTS
Renal plasma flow and glomerular filtration rate were measured using the infusion clearance technique for (51)Cr-labeled EDTA and paraaminohippurate, corrected for by renal extraction of PAH. h-ANP increased glomerular filtration rate, renal filtration fraction, fractional excretion of sodium, and urine flow. This was accompanied by an increase in tubular sodium reabsorption (9%) and renal oxygen consumption (26%). Furosemide infusion caused a 10- and 15-fold increase in urine flow and fractional excretion of sodium, respectively, accompanied by a decrease in tubular sodium reabsorption (-28%), renal oxygen consumption (-23%), glomerular filtration rate and filtration fraction (-12% and -7%, respectively).


CONCLUSIONS
The filtered load of sodium is an important determinant of renal oxygen consumption. h-ANP improves glomerular filtration rate but does not have energy-conserving tubular effects. In contrast, furosemide decreases tubular sodium reabsorption and renal oxygen consumption and thus has the potential to improve the oxygen supply/demand relationship in clinical ischemic acute renal failure.
Swärd
Kristina
K
Department of Cardiothoracic Anesthesia and Intensive Care, Sahlgrenska University Hospital, 41345 Gothenburg, Sweden.
Valsson
Felix
F
Sellgren
Johan
J
Ricksten
Sven-Erik
SE
D058186:Acute Kidney Injury / Q000517:prevention & control*; D000368:Aged; D009320:Atrial Natriuretic Factor / Q000494:pharmacology / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects; D001026:Coronary Artery Bypass; D004232:Diuretics / Q000494:pharmacology / Q000627:therapeutic use*; D005260:Female; D005665:Furosemide / Q000494:pharmacology / Q000627:therapeutic use*; D005919:Glomerular Filtration Rate / Q000187:drug effects; D006801:Humans; D007668:Kidney / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000187:drug effects; D011183:Postoperative Complications / Q000517:prevention & control*; D012079:Renal Circulation / Q000187:drug effects; D012964:Sodium / Q000378:metabolism
D004232:Diuretics; D005665:Furosemide; D009320:Atrial Natriuretic Factor; D012964:Sodium