Strong ion difference in urine: A measure of proton excretion or of the net plasma charge alteration?

Abstract

Strong ion difference in urine: A measure of proton excretion or of the net plasma charge alteration? How to cite this article: Alevrakis E, Gialelis N, Vasileiadis I. Strong ion difference in urine: A measure of proton excretion or of the net plasma charge alteration?.

Strong ion difference: “ὃ οὐ κινούμενον κινεῖ”a or the unmoved physico‐chemical mover

“…After carefully studying Prof. Bie's commentary, 1 one realizes that from the scientific debate—which stemmed from our published article 2 presenting an interpretive approach to urine [SID] according to Stewart's view and extended to a broader critique of his approach on the overall regulation of acid‐base balance in the body—remains but a single point of divergence, which does not truly make it so difficult to accept Stewart's view, as it seems to justify the persistent adherence to what is called the classical view of acid‐base disorders. This is the active proton transfer .…”

Strong ion difference: Inconsistencies lining up

“…SID is ‘the sum of all strong base cation concentrations minus the sum of all strong acid anion concentrations’, 2 in clinical practice often ([Na + ] + [K + ] − [Cl − ]) in mmol/l. Subsequently, the concept was extended to renal function, and recently this was the focus of an editorial in the journal, 4 henceforth the editorial . The arguments in the editorial are difficult to follow mainly because (a) they seem to violate the fundamental principle of electroneutrality, (b) they question the mere existence of transmembrane transport of protons and bicarbonate ions and (c) they include peculiar cause‐effect relationships for which there are little documentation in the literature.…”

Stewart's approach: Just a heresy or another lens into acid‐base physiology?

“…We thank Prof. Bie for his interest in our article 1 as well as for his criticisms, 2 which gave us the opportunity to, more extensively, address an issue which still concerns the international scientific community, and which has both ardent supporters and fierce opponents.…”

“…On the whole, our Editorial 1 did not intend to take a stand in favour of one or the other view regarding the renal response in compensating acid‐base disorders, but to present, in addition to the conventional view about renal acid excretion in the form of NH 4 + , the Stewart's physicochemical approach 3 on the subject. Also, we had no intention to present exact numerical values but to make clear the conceptual difference between the two pathophysiological views.…”