Induced Hypotension
During anesthesia with induced hypotension, a substantial reduction
in GFR and the urine flow rate is common. However, when the duration of hypotension
is less than 2 hours, no permanent impairment in renal function occurs, even in elderly
patients.[111]
Vasodilator agents used to induce
hypotension differ in their effect on RBF. Administration of sodium nitroprusside
decreases renal vascular resistance but tends to shunt blood flow away from the kidney.
Moreover, its administration is associated with marked renin-angiotensin activation
and catecholamine release, which results in rebound hypertension if the infusion
is suddenly discontinued. Nitroglycerin decreases RBF less than sodium nitroprusside
does.[112]
The selective DA1
dopaminergic
agonist fenoldopam is capable of providing induced hypotension without any significant
decrease in RBF.[113]
