Hypoproteinemia, strong-ion difference, and acid-base status in critically ill patients

Abstract

The present study was a prospective, nonrandomized, observational examination of the relationship among hypoproteinemia and electrolyte and acid-base status in a critical care population of patients. A total of 219 arterial blood samples reviewed from 91 patients was analyzed for arterial blood gas, electrolytes, lactate, and total protein. Plasma strong-ion difference ([SID]) was calculated from [Na+] + [K+] - [Cl-] - [La-]. Total protein concentration was used to derive the total concentration of weak acid ([A]tot). [A]tot encompassed a range of 18.7 to 9.0 meq/l, whereas [SID] varied from 48.1 to 26.6 meq/l and was directly correlated with [A]tot. The decline in [SID] was primarily attributable to an increase in [Cl-]. A direct correlation was also noted between PCO2 and [SID], but not between PCO2 and [A]tot. The decrease in [SID] and PCO2 was such that neither [H+] nor [HCO-3] changed significantly with [A]tot.

Das Säure-Basen-Modell nach Stewart

“…Im Gegensatz zur klassischen Anionenlücke berücksichtigt die SIG alle Elektrolyte und die schwachen Säuren. Auch beim Gesunden finden sich immer ungemessene Anionen im Serum (vermutlich zwischen 2 und 6 mmol/L), wobei der Normwert laborabhängig ist [7,[46][47][48][49]. Hier handelt es sich zum Teil um anorganische Säuren als Abbauprodukte von Aminosäuren und Nukleinsäuren.…”

Reference Intervals for Anion Gap and Strong Ion Difference in Pregnancy: A Pilot Study

“…Previously, Kirschbaum and Peng (11) had observed a correlation between the decreased anion gap and albumin levels in proteinuric hypertensive gravidas compared with patients without proteinuria, but we could not demonstrate any correlation between anion gap and albumin during the prepartum period in normal pregnancy. Also, we hypothesize that the [Cl − ] was maintained because of balanced and counteracting influences of low protein levels, which should increase [Cl − ] (19), and hypocapnia, which might decrease [Cl − ] (20) (see the Appendix for a more complete discussion). Also as anticipated, plasma albumin concentration was significantly lower in the prepartum state compared to postpartum.…”

“…We studied 112 women during pregnancy or postpartum in a cross-sectional fashion (6 first trimester, [weeks [6][7][8][9][10][11][12], 47 mid-trimester [weeks [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28], 59, third trimester [weeks 29 to term], and 13 women postpartum). Normotensive healthy subjects undergoing uneventful pregnancies were recruited consecutively during routine prenatal clinic visits; exclusions included a history or presence of hypertension, diabetes, renal disease, and disorders requiring the chronic use of medications.…”

How Should Acid-Base Disorders Be Diagnosed and Managed?

“…Most critically ill patients are hypoalbuminemic, and many are also hypophosphatemic. 48 Consequently, the gap may be normal in the presence of unmeasured anions. Figge and colleagues have provided us with a useful variant known as the corrected (for albumin) anion gap (AGC) 49 :…”