Reduced blood pH causes bleeding

Hemorrhage, due to a reduction in the coaguability of blood, is a common cause of morbidity and mortality among trauma victims and the critically ill in general. Reduced blood pH (acidosis) is also common in these patient groups. Previous studies have shown that acidosis is an independent risk factor for development of reduced blood coaguability and hemorrhage-associated death. 

However, it remains unclear if acidosis is merely an epiphenomenon in this context or if it has a causative role. The notion that reduced blood pH can cause reduced blood coaguability and consequent hemorrhage is now given credence by the results of laboratory studies conducted by researchers at Lund University Hospital in Sweden. 

This group adjusted the pH of blood from healthy volunteers with hydrochloric acid to give samples of blood with pH ranging from 6.8 to 7.4 and examined the coaguability of these pH-adjusted blood samples, using the technique of rotating thromboelastography. They found a strong correlation (p <0.00001, r = 0.89) between pH and impairment of coagulation. 

Compared with blood of normal pH (7.4), clot formation time was increased by 168 % if pH was reduced to 6.8. This reduction in blood coaguability was reversed if pH of blood was returned to normal with addition of a trometamol (THAM) buffer. This work suggests that normalization of blood pH might be vital for the optimal treatment of severely bleeding patients.