We measured urinary and plasma level of prostaglandins during cardiopulmonary bypass (CPB) and their clinical significance. The urinary levels of NAG was also measured at the same time.
Urinary and plasma levels of TXB
2 and 6keto PGF
1α were increased upon initiation of CPB. The urinary NAG level increased significantly (p<0.001). Plasma TXB
2 levels as expected from the urinary TXB
2 and 2, 3dinor-TXB
2 level was higher than the measured plasma TXB
2 concentration, showing increasese in TXB
2 originating from the kidney. However Plasma 6ketoPGF
1α as expected from the urinary 6ketoPGF
1α level was same to the measured plasma 6ketoPGF
1α concentration, showing no increased in 6ketoPGF
1α originating from the kidney.
It is possible that the elevation of urinary TXB
2 level is due to the massive increase in TXA
2 originating from the kidney when a hypoxic condition is indused by hypotension and lowered perfusion in the kidney, in addition to the increased excretion of platelet derived TXA
2 during CPB.
Furthermore, the significant correlation (r=0.77, p<0.01) was observed in NAG and urinary TXB
2, thus the increased production of TXA
2 appears to inhibit the functions of the renal proximal tubules.
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