Dilutional acidosis: is there a role for the strong ion difference?

Excerpt

Sir: I read with great interest the article by Gattinoni et al. [1] on the chemical mechanism of dilutional acidosis. The authors employed simulation and in vitro experiments in order to evaluate the effects of dilution on separated plasma acid-base parameters. They have demonstrated that, in a system closed to ventilation, dilution via a solution with SID = 0 (pure water, normal saline and Ringer’s lactated) reduces all the presumably independent acid-base parameters, i.e., SID [total CO₂ content] and [A _tot]. They further asserted that the acidosis imposed on the system by the reduction in SID is offset by the alkaloses caused by the simultaneous reduction in [total CO₂ content] and [A _tot], and therefore pH does not change. However, when the system opens to ventilation, equilibration with the gas phase CO₂ in the alveoli leads to an increase in the [total CO₂ content], while other variables remain unaffected. They concluded that dilutional acidosis should be solely attributed to increased [total CO₂ content] [1]. …