INCREASE IN ANTIOXIDANT CAPACITY OF PLASMA DURING PROPOFOL ANESTHESIA

We have examined the effect of total intravenous anesthesia (TIVA) usi ng a continuous propofol infusion on the antioxidant capacity of plasm a in 18 neurosurgical al patients who required cerebrospinal fluid shu nting, Patients were premedicated with hydroxyzine, alprazolam, and at ropine. Anesthesia was induced intravenously with propofol 1.5 mg kg(- 1) and sufentanil 0.15-0.3 mu g kg(-1). Tracheal intubation was facili tated with atracurium 0.5 mg kg(-1). Anesthesia was maintained with a continuous propofol infusion at an increasing rate from 6 to 12 mg kg( -1) h(-1) under controlled ventilation (FiO(2) = 0.4 in air). In all p atients, arterial blood samples were drawn before induction of anesthe sia and during surgery for measurement of blood propofol concentration and plasma antioxidant capacity, which was assessed as the ability to inhibit lipid peroxidation, Lipid peroxidation was induced in vitro b y exposing a linoleic acid microemulsion to hemoglobin-generated oxofe rryl radicals, and assessed by ultraweak chemiluminescence in the abse nce (central) and the presence of the plasma samples. The antioxidant capacity of plasma, measured by the inhibition of Light emission and e xpressed as a percentage of control, increased significantly from 39.8 +/- 2% (mean +/- SEM) to 44.7 +/- 2.4% during anesthesia (Wilcoxon te st, p < 0.001), No correlation was observed between this increased res istance to lipid peroxidation and blood propofol concentrations (Spear man test, r = 0.07, NS). We conclude that the capacity of plasma to in hibit lipid peroxidation increases in patients during TIVA maintained with a continuous propofol infusion.