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Background and Objectives: This study aimed at evaluating acute radiological contrast effects in fluid restriction situations, observing renal and cardiovascular effects after intra-arterial injection of high osmolarity radiological contrast., Methods: Participated in this study 16 dogs anesthetized with sodium thiopental (15 mg.kg-1) and fentanyl (0.03 mL.kg-1), followed by continuous infusion of 40 microg.kg-1.min-1 (sodium thiopental) and 0.1 microg.kg-1.min-1 (fentanyl). Hydration was achieved with 5% glucose solution (0.03 mL.kg-1.min-1) and ventilation was mechanically controlled with compressed air. The following attributes were evaluated: heart rate (HR); mean blood pressure (MBP); inferior vena cava pressure (IVP); cardiac output (CO); hematocrit (Ht); effective renal plasma flow (ERPF); renal blood flow (RBF); glomerular filtration rate (GFR); filtration fraction; renal vascular resistance (RVR), urinary volume (UV); plasma and urinary osmolarity; osmolar clearance; free water clearance; sodium and potassium clearance; plasma sodium and potassium; sodium and potassium urinary fractional excretion and rectal temperature. These attributes were evaluated in four moments: 30 (M1), 60 (M2), 90 (M3) and 120 (M4) minutes after sodium para-aminohipurate and creatinine administration (beginning of experiment). In moment 2, G1 received intra-arterial 0.9% saline (1.24 mL.kg-1) and G2 received intra-arterial radiological contrast (1.4 mL.kg-1)., Results: Group G1 has presented increased HR, ERPF, RBF, plasma osmolarity, sodium clearance and sodium urinary excretion, in addition to decreased urinary osmolarity, plasma sodium, potassium clearance and rectal temperature. Group G2 has presented increased HR, RVR, UV, osmolar clearance, sodium clearance and sodium urinary and fractional excretion; there has also been decrease in hematocrit, glomerular filtration rate, filtration fraction, urinary osmolarity, free water clearance, urinary sodium and potassium, plasma potassium and rectal temperature., Conclusions: This study has concluded that intra-arterial radiological contrast has promoted a two-phase effect on renal function. Initially it has promoted increased diuresis and sodium excretion but then the hemodynamic conditions impaired, and consequently renal function impaired, with increased renal vascular resistance and decreased glomerular filtration rate.

Background and Objectives: Dopamine infusion for renal protection is controversial. This study aimed at observing the effects of dopamine, hypertonic solution and the association of both in dogs with water restriction, emulating preoperative fast., Methods: The following renal function parameters were studied in 32 dogs anesthetized with sodium pentobarbital and fentanyl: effective renal plasma flow (sodium para-aminohippurate clearance), glomerular filtration rate (creatinine clearance), sodium, potassium and osmolar clearance, sodium and potassium fractional excretion and renal vascular resistance. Cardiovascular parameters were: mean blood pressure, heart rate, inferior vena cava pressure, cardiac index, hematocrit and peripheral vascular resistance index. Animals were randomly distributed in four experimental groups: Group 1 - G1 (n = 8) - control group; Group 2 - G2 (n = 8) - dopamine infusion (2 microg kg(-1) min(-1)); Group 3 - G3 (n = 8) - 7.5% sodium chloride (2 ml kg(-1)) and Group 4 - G4 (n = 8) - association of dopamine (2 microg kg(-1) min(-1)) and 7.5% sodium chloride (2 ml kg(-1)). Groups underwent four experimental stages lasting 30 minutes each, and involving moments M1, M2, M3 and M4., Results: Dopamine group (G2) had mean blood pressure, renal vascular resistance and potassium excretion decrease. Hypertonic sodium chloride group (G3) had cardiac index, urinary volume, sodium and potassium clearance, sodium and potassium urinary excretion and sodium fractional excretion increase. Group receiving the association of hypertonic solution and dopamine (G4) had heart rate, cardiac index, effective renal plasma flow and sodium urinary excretion increase; there has also been systemic vascular resistance and plasma potassium index decrease., Conclusions: Our conclusion was that hypertonic sodium chloride solution was able to improve hemodynamic conditions and, as a consequence, renal function of dogs under 12-hour water restriction. The same was not true for 2 microg kg(-1) min(-1) dopamine which, in a similar situation, has not increased diuresis and sodium excretion.