RESUMEN
<p><b>OBJECTIVE</b>To observe changes of thromboxane B2 (TXB2), 6-keto-prostaglandin F1 alpha(6-Keto-PGF1 alpha) and TXB2/6-Keto-PGF1 alpha (T/P) in lungs of rats drowned in hypothermic sea water and to assess their influence on the blood-gas.</p><p><b>METHODS</b>Rats of different groups were drowned nearly to death in hypothermic sea water and then taken out of the water rapidly, observed at room temperature, after that the following steps were taken in 5, 15, 30, 60, 240 min and 360 min groups, that were 1 ml arterial blood taken from left heart for blood-gas analysis including pH, PaO2 and PaCO2, rectal temperature observed; at last, the ratio of left dry lungs with left wet lungs was assessed, TXB2 and 6-Keto-PGF1 alpha in right lungs were examined in all above groups and dead group(14 rats dead, only 4 examined).</p><p><b>RESULTS</b>The rectal temperature[(20.13 +/- 0.48) degree C], pH(6.68 +/- 0.03), PaO2[(45.00 +/- 6.30) mm Hg)], TXB2[(97.46 +/- 17.46) ng/L] and 6-Keto-PGF1 alpha[(25.59 +/- 8.12) ng/L] dropped to the lowest point in the 5 minutes group(P < 0.01), while PaCO2[(89.18 +/- 5.10) mm Hg] reached the highest point(P < 0.01), all above items from 5 minutes group then showed a recovering tendency, but only the pH in 240 minutes and 360 minutes groups as well as TXB2 in 360 minutes group and dead group reached near the level of normal control groups (P > 0.05); T/P had a rising tendency and reached the highest point in the 360 minutes group.</p><p><b>CONCLUSIONS</b>The production and secretion of TXB2 and 6-Keto-PGF1 alpha were influenced by hypothermia, hypoxemia and acidosis, the imbalance of T/P could be one of factors influencing the improvement of blood gas index.</p>