BACKGROUND
Hypertonic/hyperoncotic fluids may reduce overall fluid requirements and tissue edema, improve perfusion and reduce the incidence of paraplegia associated with aortic cross-clamping and subsequent reperfusion.
OBJECTIVE
We evaluated potential benefits of a hypertonic saline acetate solution on reperfusion injury following ischemia. We examined blood flow and plasma antioxidant status, spinal cord and skeletal muscle above and below the cross-clamp, as well as in the liver and the kidney.
METHOD
The aorta of anesthetized swine (n=5-6/group) was cross-clamped at the level of T9 for 30 min; animals were infused with 4 ml/kg of hypertonic acetate dextran (HAD) or 8.4% NaHCO3 (Control). Pigs were euthanatized 1h later.
RESULTS
As blood flow fell to zero in lower spinal cord and muscle, it doubled in the upper cord and increased 6-fold in upper muscle. Upon reperfusion, blood flow in all regions returned to baseline levels, with no statistical differences between HAD and Controls. Lipid peroxidation in plasma was lower in HAD than Controls. Lower muscle had 41% lower glutathione levels and significantly lower activities of the antioxidant enzymes glutathione peroxidase and reductase, catalase, superoxide dismutase versus upper muscle. The lower spinal cord had 2.5 fold higher malondialdehyde levels and 50% higher catalase activity than upper spinal cord. Within a tissue, any significant differences in antioxidant status or evidence of lipid peroxidation favored HAD over Control.
CONCLUSION
HAD offered only minor advantages over NaHCO3 with respect to blood flow and antioxidant status of spinal cord and muscle following this period of aortic cross-clamping and reperfusion.
KEYWORDS:
ischemia/reperfusion; hypertonic saline; blood flow; oxidant stress; swine
