Hypotensive anesthesia with propofol and remifentanil: protective effect of alpha-tocopherol on renal function

Abstract Study objective To determine the effect of α -tocopherol in patients receiving hypotensive anesthesia with propofol-remifentanil. Study design Prospective, randomized study. Setting University hospital. Patients 66 ASA physical status I and II patients, aged 32 to 56 years, scheduled for nasal polypectomy. Interventions Patients were allocated into two groups, the treatment and the control groups (T group and C group). T group received α -tocopherol 300 mg orally 5 to 6 hours before surgery. Measurements Sampling times and measurements were done before hypotension (t 0 ), 45 minutes after starting hypotension ( t 1 ), 90 minutes after starting hypotension (t 2 ), 45 minutes after recovery of normotension (t 3 ), and 24 hours after surgery (t 4 ). Renal function was assessed by testing glomerular and tubular functions: glomerular filtration rate, fractional excretion of sodium (FE NA ); fractional excretion of urea (FE UN ); and urinary N -acetyl-1- β -D-glucosoaminidase (NAG) index (NAG i ). Main results Glomerular filtration rate values remained unchanged in all patient populations. Fractional excretion of sodium was within reference ranges in both groups at times t 0 , t 1 , and t 2 . At time t 3 , a significant FE NA peak was observed. At this time, FE NA was significantly higher in C group than T group ( P UN time course was similar to the FE NA trend. At time t 4 , FE NA and FE UN returned to basal values. At time t 3 , NAG i was also increased without significant intergroup differences ( P P P 0 , t 1 , t 2 in C group, respectively; P P P 0 , t 1 , and t 2 in T group, respectively). Conclusions In patients without any renal disease, hypotensive anesthesia with propofol and remifentanil results in a transient tubular dysfunction, which appears to be minimized by the preoperative administration of α -tocopherol.