N-acetylcysteine increases liver blood flow and improves liver function inseptic shock patients: Results of a prospective, randomized, double-blind study

Objective: In septic shack, decreased splanchnic blood flow is reported, de spite adequate systemic hemodynamics. N-acetylcysteine (NAC) was found to i ncrease hepatosplanchnic blood flow in experimental settings. In septic sho ck patients, NAC improved the clearance of indocyanine green and the relati onship of systemic oxygen consumption to oxygen demand. We investigated the influence of NAC on liver blood flow, hepatosplanchnic oxygen transport-re lated variables, and liver function during early septic shock. Design: Prospective, randomized, double-blind study, Setting: Septic shock patients admitted to an interdisciplinary surgical in tensive care unit. Patients: We examined 60 septic shock patients within 24 hrs after onset of sepsis. They were conventionally resuscitated with volume and inotropes an d were in stable condition, A gastric tonometer was inserted into the stoma ch and a catheter into the hepatic vein, Microsomal liver function was asse ssed by using the plasma appearance of monoethylglycinexylidide (MEGX). Interventions: Subjects randomly received either a bolus of 150 mg/kg iv NA G over 15 mins and a subsequent continuous infusion of 12.5 mg/kg/hr NAC ov er 90 mins (n = 30) or placebo (n = 30), Measurements and Main Results: Measurements were performed before (baseline ) and 60 mins after beginning the infusion (infusion), After NAG, a signifi cant increase in absolute liver blood flow index (2.7 vs. 3.3 L/min/m(2); p = .01) and cardiac index (5.0 vs. 5.7 L/min/m(2); p = .02) was observed. F ractional liver blood flow index (cardiac index-related river blood flow in dex) did not change. The difference between arterial and gastric mucosal ca rbon dioxide tension decreased (p = .05) and MEGX increased (p = .04). Live r blood flow index and MEGX correlated significantly (r(s) = .57; p less th an or equal to .01). Conclusions: After NAG treatment, hepatosplanchnic flow and function improv ed and may, therefore, suggest enhanced nutritive blood flow. The increase of liver blood flow index was not caused by redistribution to the hepatospl anchnic area, but by an increase of cardiac index. Because of its correlati on with liver blood flow index, MEGX may be helpful in identifying patients who benefit from NAC treatment in early septic shock.