Traditionally
sodium bicarbonate has been the
buffer of first choice in the treatment of
metabolic acidosis. This treatment, however, involves risks of developing a hyperosmolar state, a high
sodium concentration in the blood, increased arterial
carbon dioxide tension and, as a result of the latter, intracellular and intracerebral
acidosis and also cerebral oedema. The buffering effect occurs slowly and as a consequence of this, and of the titration curve of
sodium bicarbonate, overcorrection of
metabolic acidosis is often seen.
Tris buffer was introduced as an alternative and has been claimed to solve most of these problems, but on the other hand it entails a very high risk of peripheral
venous thrombosis and thrombophlebitic lesions owing to its local irritative effect. In order to overcome these disadvantages a new mixture of Tris,
acetate,
bicarbonate and
phosphate has been designed. In the studies described it was shown to have an adequate buffering effect and to provide a
solution to most of the problems connected with buffering of
metabolic acidosis. The new
Tris buffer mixture has a buffering effect in blood equivalent to 0.5 mol/l
sodium bicarbonate, although its
sodium content has been decreased to one-third of pure
sodium bicarbonate. Its administration also results in predictable buffering in cerebrospinal fluid and skeletal muscle. In a clinical study it was demonstrated that the new
Tris buffer mixture results in sufficient and adequate buffering without significant side-effects.