Reduction of ischemia-reperfusion syndrome after abdominal aortic aneurysmectomy by N-acetylcysteine but not mannitol.
BACKGROUND
Abdominal aortic aneurysmectomy results in a general ischemia-reperfusion syndrome accompanied by an acute rise in mean pulmonary artery pressure (MPAP). Severe and sometimes fatal postoperative cardiopulmonary complications have been described.


METHODS
This pilot study examined whether N-acetyl-cysteine (NAC), a precursor of the most important physiological antioxidant glutathione (reduced form: GSH; oxidized form: GSSG), or the hydroxyl radical scavenger mannitol (MAN) modifies these events. The patients received 150 mg/ kg b.m.NAC (n = 9) 30 minutes before infrarenal aortic clamping or 500 mg/kg b.m. MAN (n = 10) 10 minutes before declamping. 11 patients had no additional treatment (control).


RESULTS
In the control group, a significant increase in plasma levels of oxidized glutathione and lipid peroxides was observed after declamping. Additionally, a significant increase in plasma levels of the stable metabolites of thromboxane (TXB2) and prostacyclin (6-keto-PGF1 alpha) was measureable after declamping. There was a transient increase in MPAP and pulmonary vascular resistance (PVR), both of which returned to normal values within 20 minutes. Six hours after surgery, pulmonary dysfunction was manifest by increase in the intrapulmonary shunt fraction. Relative to the control group, NAC pretreatment led to a complete lack of changes in plasma lipid peroxide, thromboxane and prostacyclin levels after declamping; there was a significant increase in plasma GSH concentration persisting over a period of 12 hours. MPAP, PVR and Qs/QT values were unchanged. MAN pretreatment showed similar effects on the parameters obtained in the acute phase after declamping like the control group.


CONCLUSIONS
Pretreatment with NAC, but not mannitol, may help prevent ischemia-reperfusion syndrome following aortic clamping.
Kretzschmar
M
M
Clinic of Anesthesiology and Intensive Care Medicine, Friedrich Schiller University, Jena, Germany.
Klein
U
U
Palutke
M
M
Schirrmeister
W
W
D000111:Acetylcysteine / Q000008:administration & dosage*; D000368:Aged; D017544:Aortic Aneurysm, Abdominal / Q000601:surgery*; D011464:Epoprostenol / Q000097:blood; D016166:Free Radical Scavengers / Q000008:administration & dosage*; D006439:Hemodynamics; D006801:Humans; D008353:Mannitol / Q000008:administration & dosage*; D008875:Middle Aged; D018384:Oxidative Stress; D010865:Pilot Projects; D011183:Postoperative Complications; D015427:Reperfusion Injury / Q000097:blood / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D013928:Thromboxane A2 / Q000097:blood
D016166:Free Radical Scavengers; D008353:Mannitol; D013928:Thromboxane A2; D011464:Epoprostenol; D000111:Acetylcysteine