[The mechanism of hemorrhage following phosphorus burns and the effect of calcium gluconate].

Objective: To investigate the mechanism of hemorrhagic tendency after phosphorus poisoning.

Methods: 45% phosphoric acid and 20 mg/cm2 phosphorus were used to produce burn injury in rabbits. The total content of phosphorus remaining on the wound and 7-day mortality were similar in both groups.

Results: The results showed that plasma free calcium contents were significantly lower in both phosphorus groups than healthy and thermal burn controls (0.80 vs 1.40 mol/l, P < 0.01). The free calcium content of platelet was lowered to 116-140 nmol/l, which was significantly lower than that of healthy control (285 nmol/l) and thermal injury group (480-504 nmol/l). Concomitantly, the platelet aggregation rate was lowered to 1.29% and 10.78% in phosphoric acid group and phosphorus group, respectively, while it was 67.01% in healthy control and 82.1%-84.9% in thermal injury group; the difference was statistically significant.

Conclusion: Calcium therapy brought back intracellular and extracellular free calcium contents to normal in phosphorus burn group. Also platelet aggregation rate approached normal level after calcium therapy. The results suggest that the bleeding tendency after phosphorus burn is due to combination of phosphorus with intracellular and extracellular calcium of platelets, thus inhibiting aggregation of platelets.