M. Kretzschmar et al., REDUCTION OF ISCHEMIA-REPERFUSION SYNDROME AFTER ABDOMINAL AORTIC ANEURYSMECTOMY BY N-ACETYLCYSTEINE BUT NOT MANNITOL, Acta anaesthesiologica Scandinavica, 40(6), 1996, pp. 657-664
Background: Abdominal aortic aneurysmectomy results in a general ische
mia-reperfusion syndrome accompanied by an acute rise in mean pulmonar
y artery pressure (MPAP). Severe and sometimes fatal postoperative car
diopulmonary complications have been described. Methods: This pilot st
udy examined whether N-acetyl-cysteine (NAC), a precursor of the most
important physiological antioxidant glutathione (reduced form: GSH; ox
idized form: GSSG), or the hydroxyl radical scavenger mannitol (MAN) m
odifies these events. The patients received 150 mg/kg b.m. NAC (n=9) 3
0 minutes before infrarenal aortic clamping or 500 mg/kg b.m. MAN (n=1
0) 10 minutes before declamping. 11 patients had no additional treatme
nt (control). Results: In the control group, a significant increase in
plasma levels of oxidized glutathione and lipid peroxides was observe
d after declamping. Additionally, a significant increase in plasma lev
els of the stable metabolites of thromboxane (TXB(2)) and prostacyclin
(6-keto-PGF(1 alpha)) was measurable after declamping. There was a tr
ansient 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 intrap
ulmonary shunt fraction. Relative to the control group, NAC pretreatme
nt led to a complete lack of changes in plasma lipid peroxide, thrombo
xane and prostacyclin levels after declamping; there was a significant
increase in plasma GSH concentration persisting over a period of 12 h
ours. MPAP, PVR and Q(S)/Q(T) values were unchanged. MAN pretreatment
showed similar effects on the parameters obtained in the acute phase a
fter declamping like the control group. Conclusions: Pretreatment with
NAG, but not mannitol, may help prevent ischemia-reperfusion syndrome
following aortic clamping.