Effects of prophylactic fenoldopam infusion on renal blood flow and renal tubular function during acute hypovolemia in anesthetized dogs

Abstract

Fenoldopam ablated the tubular prerenal response to profound hypovolemia and maintained renal blood flow, glomerular filtration rate, and natriuresis without causing hypotension. This suggests that fenoldopam may have a renoprotective effect in acute ischemic injury.

A comparison between fenoldopam and low-dose dopamine in early renal dysfunction of critically ill patients*

“…Fenoldopam produces a selective renal vasodilation at 0.03 g/kg/min, and the greatest increase in renal blood flow is observed between 0.03 and 0.1 g/kg/min. In an experimental setting by using a dose-finding regimen, no significant decrease in blood pressure was observed during infusion of fenoldopam at 0.1 g/kg/min (27). This is consistent with the findings of Murphy et al (28), who observed a Ͼ10 mm Hg reduction of diastolic blood pressure only in one of 17 patients with essential hypertension.…”

Effect of Fenoldopam Continuous Infusion on Glomerular Filtration Rate and Fractional Excretion of Sodium in Healthy Dogs

“…The study in cats that identified increased FeNa and UOP showed inconsistent changes in creatinine clearance, making it difficult to assess whether the increased UOP was truly secondary to increased GFR or to changes in sodium excretion . Another study on anesthetized dogs indicated that fenoldopam administration maintained normal FeNa in the face of hypotension because of partial exsanguination, an effect that was not produced by saline administration alone . The results of our study suggest that both natriuresis and increased GFR may be involved in increasing UOP.…”

“…In the same study, creatinine clearance, used as an estimate of GFR, initially decreased but subsequently increased by 6 hours, making it difficult to assess whether the increased UOP seen was secondary to increased GFR or to changes in sodium excretion. In an experimental model of partial exsanguination in anesthetized dogs, fenoldopam administration maintained RBF, GFR, and natriuresis despite systemic hypotension, whereas these variables failed to be maintained by saline administration alone . Thus far, studies in both human and veterinary medicine have identified variable changes in GFR with fenoldopam infusion, and the mechanism of increased UOP after fenoldopam infusion remains unknown.…”

Effect of fenoldopam on renal function after nephrotomy in normal dogs

“…Fenoldopam mesylate has been reported to be a potent renal vasodilator in several species, resulting in increased RBF, decreased renal vascular resistance, and increased GFR 12,13 . A renoprotective effect has been reported in dogs with acute hypovolemia, hypotension, and nephrotoxic acute renal failure 17‐19 . Fenoldopam doses used in earlier studies were similar to the dose we used.…”

“…Fenoldopam produces renal effects at low doses (0.03 μg/kg/min) and is effective as an antihypertensive agent as well as positively affecting renal function at higher doses (0.1 to 0.3 μg/kg/min) without cardiovascular changes in either hypertensive or normotensive humans 16 . In dogs, fenoldopam preserved RBF during hypotension and hypovolemia and prevented decreased GFR associated with acute nephrotoxicity 17‐19 . Renal vasodilator effects have been reported in both normal, conscious, and anesthetized dogs 20,21 .…”