#11 SYSTEMIC CONSEQUENCES OF OXIDATIVE STRESS
FOLLOWING AORTIC SURGERY CORRELATE WITH THE DEGREE OF ANTIOXIDANT
DEFENSES.
Gaston Cornu-Labat, MD, Michael Serra, PhD, Karthikeshwar
Kasirajan, MD, Walter E. McGregor, MD, Arthur Smith, BS,Mark K.
Hirko, MD, John J. Turner, MD, and Jeffrey R. Rubin, MD
Forum Health, Western Reserve Care System, Youngstown, OH
Objective: The aim of this study was to prospectively
evaluate the correlation between the level of antioxidant defenses
and the severity of pulmonary dysfunction following aortic surgery.
Method: 24 consecutive patients undergoing elective aortic
surgery for aneurysmal or occlusive disease were studied. The
antioxidant defenses were quantified before and 24 hours after the
surgery, using an UV-absorbency spectroscopic assay that measures the
capacity of plasma to quench the production of a free radical (Total
Antioxidant Capacity). The severity of pulmonary dysfunction was
evaluated by serial chest radiographs and blood gas samples. Using
ten objective radiologic criteria, the etiology and degree of
pulmonary edema were determined, confirmed by the patient's
hemodynamic profile. Changes in the pulmonary gas exchange were
based upon alterations in the oxygenation ratio (PaO2/FiO2).
Patients' demographics, risk factors, type of disease, cross-clamp
time, estimated blood loss and ICU and hospital stay were considered
in the analysis.
Results: Significant evidence of oxidative stress was found
in the decline in the antioxidant capacity after the operation
(p=0.001). Significant evidence of increased capillary leak
pulmonary edema and pulmonary dysfunction were found. These were
most evident in the immediate postoperative period (p=<0.001 for
the radiographic evidence of pulmonary edema and p=<0.001 for the
oxygenation ratio). A weak to moderate correlation was found between
the antioxidant capacity and degree of oxidative stress when compared
to the severity of pulmonary dysfunction, strongest in the immediate
postoperative period (r=-0.37; p=0.06). No correlation was found
between patients' demographics, risk factors, type of disease,
technical aspects of the surgery, hospital and ICU stays and
antioxidant capacity or degree of oxidative stress.
Conclusion: Some degree of systemic inflammatory response,
manifest by acute lung injury, is present in most patients undergoing
aortic surgery. Our study suggests an association between the
severity of lung injury and the level of antioxidant defenses and
oxidative stress. A prospective study with supplementation of
antioxidant defenses in an attempt to further improve the outcome
following this type of surgery is in order.
