ALTERATION OF RENAL BLOOD-FLOW DURING EPIDURAL-ANESTHESIA IN NORMAL SUBJECTS

The cardiovascular consequences of epidural anesthesia secondary to sy mpathetic blockade are well documented; however, their repercussions o n renal hemodynamics in humans have not been reported. We investigated the effect of epidural anesthesia on renal blood flow (RBF) in 13 hea lthy volunteers 18-45 yr of age. RBF was measured using paraaminohippu rate clearance before and after bilateral T6 epidural sensory block (t o ensure adequate sympathetic renal nerve blockade). Epidural anesthes ia was established using 22 +/- 3 mt of 2% plain lidocaine (without ep inephrine) via L1-L2 epidural catheter; urine output was measured usin g a three-way Foley catheter. Mean arterial pressure remained greater than or equal to 70 mm Hg in all subjects without any pharmacologic in tervention. Mean RBF before epidural anesthesia was 16.1 +/- 6.8 mL.kg (-1).min(-1) and 14.3 +/- 2.9 mL.kg(-1).min(-1) after bilateral T6 epi dural blockade. We conclude that the institution of epidural anesthesi a in healthy subjects does not result in a significant change in RBF ( P > 0.25).