The effect of pH on platelet and coagulation factor activities.

After observing that lavage of the stomach with alkaline solutions has a beneficial effect on the control of gastric hemorrhage, we examined the platelet and coagulation factor activities under conditions of lower and elevated pH. The results showed that change of the pH from acidosis to 7.0 and even to slight alkalosis induces platelet aggregation, platelet calcium and serotonin release, as well as platelet factor II availability. The prothrombin and partial thromboplastin times approached normal levels, whereas the fibrinogen level did not change significantly. The results obtained may serve as an explanation for the control of the intragastric bleeding in patients treated by maintenance of their gastric pH at 7.0.