scholarly journals Strong Ion Difference: ‘ὃ οὐ κινούμενον κινεῖ’* or the unmoved physicochemical mover

2021 ◽  
Author(s):  
Ioannis Vasileiadis ◽  
Emmanouil Alevrakis ◽  
Nikolaos Gialelis
Keyword(s):  
Strong Ion Difference

Total weak acid concentration and effective dissociation constant of nonvolatile buffers in human plasma

2001 ◽  
Vol 91 (3) ◽  
pp. 1364-1371 ◽  
Author(s):  
Peter D. Constable
Keyword(s):  
Dissociation Constant ◽  
Human Plasma ◽  
Total Concentration ◽  
Weak Acid ◽  
Strong Ion Difference ◽  
Acid Base ◽  
Horse Plasma ◽  
Using Data ◽  
Species Specific

The strong ion approach provides a quantitative physicochemical method for describing the mechanism for an acid-base disturbance. The approach requires species-specific values for the total concentration of plasma nonvolatile buffers (Atot) and the effective dissociation constant for plasma nonvolatile buffers ( K a), but these values have not been determined for human plasma. Accordingly, the purpose of this study was to calculate accurate Atot and K a values using data obtained from in vitro strong ion titration and CO2tonometry. The calculated values for Atot (24.1 mmol/l) and K a (1.05 × 10−7) were significantly ( P < 0.05) different from the experimentally determined values for horse plasma and differed from the empirically assumed values for human plasma (Atot = 19.0 meq/l and K a = 3.0 × 10−7). The derivatives of pH with respect to the three independent variables [strong ion difference (SID), Pco 2, and Atot] of the strong ion approach were calculated as follows: [Formula: see text] [Formula: see text], [Formula: see text]where S is solubility of CO2 in plasma. The derivatives provide a useful method for calculating the effect of independent changes in SID+, Pco 2, and Atot on plasma pH. The calculated values for Atot and K a should facilitate application of the strong ion approach to acid-base disturbances in humans.

scholarly journals Contribution of red blood cells to the compensation for hypocapnic alkalosis through plasmatic strong ion difference variations

Critical Care ◽  
2011 ◽  
Vol 15 (S1) ◽  
Author(s):  
T Langer ◽  
L Zani ◽  
E Carlesso ◽  
A Protti ◽  
P Caironi ◽  
...  
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Strong Ion Difference ◽  
Hypocapnic Alkalosis

Acid-Base and Ionic Exchanges at Gills and Kidney After Exhaustive Exercise in the Rainbow Trout

1988 ◽  
Vol 136 (1) ◽  
pp. 461-481 ◽  
Author(s):  
CHRIS M. WOOD
Keyword(s):  
Rainbow Trout ◽  
Exhaustive Exercise ◽  
Strong Ion Difference ◽  
Dynamic Modulation ◽  
Extracellular Acidosis ◽  
Titratable Acid ◽  
Na Efflux ◽  
Net Flux ◽  
Ionic Exchanges ◽  
Net Fluxes

Unidirectional Na+ and Cl− fluxes, net fluxes of Na+, Cl−, other ions, titratable acid (TA), ammonia and acidic equivalents (net H+) across the gills, together with the comparable renal fluxes, were monitored throughout a 24-h period after exhaustive exercise (simple chasing) in the rainbow trout. The gills were the major site of flux. The renal excretion of [TA-HCO3−], ammonia, lactate and most electrolytes increased after exercise, coincident with diuresis. Relative to the gills, the kidney accounted for only 8% of net H+ flux, 0–15% of net electrolyte losses and 50% of lactate loss, though the latter was negligibly small. Approximately 1000 μequiv kg−1 of net H+ were transported across the gills to the water during the first 4h, and then fully recovered over the subsequent 8h, coincident with periods of extracellular acidosis and alkalosis recorded in previous studies. Ammonia efflux increased during the first 4h; changes in titratable acid flux and extracellular PNHNH3 and NH4+ levels suggest that this elevation occurred partially as NH3 diffusion in the first hour, and thereafter mainly as NH4+ exchange. Small net Na+ losses (≊300 μequivkg−1), moderate net K+ losses (≊600 μequiv kg−1) and large net Cl− losses (≊1200 μequiv kg−1) correlated well with previously reported plasma changes; only the Na+ deficit was fully corrected by 24 h. Na+ influx was stimulated and Cl− influx inhibited during the 0–4 h period of net H+ excretion, whereas Na+ influx returned to control levels and Cl− influx increased during the 4–12 h period of net H+ uptake. These data indicate dynamic modulation of Na+/NH4+,H+ and C1−/HCO3−,OH− exchanges; however, an excess of Cl− over Na+ efflux also contributed to net H+ excretion. Acidic equivalent flux correlated well with [Na+-Cl−] net flux, in accord with strong ion difference theory.

Intra- and inter-day variability in plasma tCO2 concentration in sedentary horses

2014 ◽  
Vol 10 (1) ◽  
pp. 39-47
Author(s):  
B.E. Bergstrom ◽  
J.H. Foreman ◽  
C.R. Foreman ◽  
A.M. Barger
Keyword(s):  
Blood Test ◽  
Indoor Environment ◽  
Early Morning ◽  
Time Of Day ◽  
Individual Variability ◽  
Strong Ion Difference ◽  
Serum Chemistry ◽  
Blood Samples ◽  
Early Afternoon ◽  
Glass Tubes

Sodium bicarbonate and other alkalinising solutions (‘milkshakes’) have been given to horses surreptitiously before exercise to provide exogenous buffering effects. After an initial positive blood test, some accused horse trainers claim that their horses ‘naturally test high’, so some jurisdictions allow a secured quarantine in which the horse is tested multiple times. The objective of this experiment was to determine the intra- and inter-day variability of plasma total CO2 (tCO2) and other plasma strong ions in a group of sedentary horses housed similarly to a quarantine period. The hypothesis was that plasma tCO2 would not remain constant over a multi-day monitoring interval, but would vary measurably during that interval. Eight sedentary (unconditioned) horses were studied for 2 weeks. Horses were acclimated to a climate-controlled indoor environment and an alfalfa-only diet for a minimum of 10 days prior to sampling. Horses were sampled 3 times daily for 5 consecutive days at 7:00, 11:00 and 15:00 h. Blood samples were collected directly into 10 ml heparinised evacuated glass tubes by jugular venipuncture using a double-ended 0.91 mm needle. Samples were chilled until concentrations of plasma tCO2, Na+, K+, and Cl-, were determined within 1-3 h of sampling using an automated serum chemistry analyzer which was calibrated daily using commercial reagents obtained from the manufacturer as well as externally-obtained NIST-traceable calibrating solutions. Mean results documented mild variations in mean plasma tCO2 (range 28.9-31.6 mmol/l), but individual horses’ plasma tCO2 ranged over 4-7 units. Results showed that there was considerable intra- and inter-individual variability in plasma tCO2. Mean pooled tCO2 and measured strong ion difference (SIDm) differed by time-of-day, with both late morning and early afternoon values lower than early morning values (P<0.001). There was a strong positive linear relationship between plasma SIDm and tCO2 (r=0.75, P<0.001).

Physicochemical analysis of phasic menstrual cycle effects on acid-base balance

2001 ◽  
Vol 280 (2) ◽  
pp. R481-R487 ◽  
Author(s):  
Robert J. Preston ◽  
Aaron P. Heenan ◽  
Larry A. Wolfe
Keyword(s):  
Menstrual Cycle ◽  
Ventilatory Threshold ◽  
Physicochemical Analysis ◽  
Carbon Dioxide Tension ◽  
Weak Acid ◽  
Ion Concentration ◽  
Strong Ion Difference ◽  
Acid Base Balance ◽  
Hydrogen Ion Concentration ◽  
Base Balance

In accordance with Stewart's physicochemical approach, the three independent determinants of plasma hydrogen ion concentration ([H+]) were measured at rest and during exercise in the follicular (FP) and luteal phase (LP) of the human menstrual cycle. Healthy, physically active women with similar physical characteristics were tested during either the FP ( n = 14) or LP ( n = 14). Arterialized blood samples were obtained at rest and after 5 min of upright cycling at both 70 and 110% of the ventilatory threshold (TVent). Measurements included plasma [H+], arterial carbon dioxide tension (PaCO2 ), total weak acid ([ATot]) as reflected by total protein, and the strong-ion difference ([SID]). The transition from rest to exercise in both groups resulted in a significant increase in [H+] at 70% TVentversus rest and at 110% TVent versus both rest and 70% TVent. No significant between-group differences were observed for [H+] at rest or in response to exercise. At rest in the LP, [ATot] and PaCO2 were significantly lower (acts to decrease [H+]) compared with the FP. This effect was offset by a reduction in [SID] (acts to increase [H+]). After the transition from rest to exercise, significantly lower [ATot] during the LP was again observed. Although the [SID] and PaCO2 were not significantly different between groups, trends for changes in these two variables were similar to changes in the resting state. In conclusion, mechanisms regulating [H+] exhibit phase-related differences to ensure [H+] is relatively constant regardless of progesterone-mediated ventilatory changes during the LP.

A simplified strong ion model for acid-base equilibria: application to horse plasma

1997 ◽  
Vol 83 (1) ◽  
pp. 297-311 ◽  
Author(s):  
Peter D. Constable
Keyword(s):  
Human Plasma ◽  
Practical Method ◽  
Published Data ◽  
Strong Ion Difference ◽  
Weak Acids ◽  
Acid Base ◽  
Plasma Protein Concentration ◽  
Horse Plasma ◽  
Hasselbalch Equation

Constable, Peter D. A simplified strong ion model for acid-base equilibria: application to horse plasma. J. Appl. Physiol. 83(1): 297–311, 1997.—The Henderson-Hasselbalch equation and Stewart’s strong ion model are currently used to describe mammalian acid-base equilibria. Anomalies exist when the Henderson-Hasselbalch equation is applied to plasma, whereas the strong ion model does not provide a practical method for determining the total plasma concentration of nonvolatile weak acids ([Atot]) and the effective dissociation constant for plasma weak acids ( K a). A simplified strong ion model, which was developed from the assumption that plasma ions act as strong ions, volatile buffer ions ([Formula: see text]), or nonvolatile buffer ions, indicates that plasma pH is determined by five independent variables:[Formula: see text], strong ion difference, concentration of individual nonvolatile plasma buffers (albumin, globulin, and phosphate), ionic strength, and temperature. The simplified strong ion model conveys on a fundamental level the mechanism for change in acid-base status, explains many of the anomalies when the Henderson-Hasselbalch equation is applied to plasma, is conceptually and algebraically simpler than Stewart’s strong ion model, and provides a practical in vitro method for determining [Atot] and K a of plasma. Application of the simplified strong ion model to CO2-tonometered horse plasma produced values for [Atot] (15.0 ± 3.1 meq/l) and K a(2.22 ± 0.32 × 10−7 eq/l) that were significantly different from the values commonly assumed for human plasma ([Atot] = 20.0 meq/l, K a = 3.0 × 10−7 eq/l). Moreover, application of the experimentally determined values for [Atot] and K a to published data for the horse (known [Formula: see text], strong ion difference, and plasma protein concentration) predicted plasma pH more accurately than the values for [Atot] and K a commonly assumed for human plasma. Species-specific values for [Atot] and K a should be experimentally determined when the simplified strong ion model (or strong ion model) is used to describe acid-base equilibria.

Low non-carbonic buffer power amplifies acute respiratory acid-base disorders in septic patients: an in-vitro study

2021 ◽  
Author(s):  
Thomas Langer ◽  
Serena Brusatori ◽  
Eleonora Carlesso ◽  
Francesco Zadek ◽  
Paolo Brambilla ◽  
...  
Keyword(s):  
Whole Blood ◽  
In Vitro Study ◽  
Blood Gases ◽  
Hemoglobin Concentration ◽  
Strong Ion Difference ◽  
Strongly Correlated ◽  
Acid Base ◽  
Buffer Power ◽  
Ph Variations

Rationale: Septic patients have typically reduced concentrations of hemoglobin and albumin, the major components of non-carbonic buffer power(β). This could expose patients to high pH variations during acid-base disorders. Objectives: To compare, in-vitro, non-carbonic β of septic patients with that of healthy volunteers, and evaluate its distinct components. Methods: Whole blood and isolated plasma of 18 septic patients and 18 controls were equilibrated with different CO2 mixtures. Blood gases, pH and electrolytes were measured. Non-carbonic β and non-carbonic β due to variations in Strong Ion Difference (βSID) were calculated for whole blood. Non-carbonic β and non-carbonic β normalized for albumin concentrations (βNORM) were calculated for isolated plasma. Representative values at pH=7.40 were compared. Albumin proteoforms were evaluated via two-dimensional electrophoresis. Measurements and Main Results: Hemoglobin and albumin concentrations were significantly lower in septic patients. Septic patients had lower non-carbonic β both of whole blood (22.0±1.9 vs. 31.6±2.1 mmol/L, p<0.01) and plasma (0.5±1.0 vs. 3.7±0.8 mmol/L, p<0.01). Non-carbonic βSID was lower in patients (16.8±1.9 vs. 24.4±1.9 mmol/L, p<0.01) and strongly correlated with hemoglobin concentration (r=0.94, p<0.01). Non-carbonic βNORM was lower in patients (0.01 [-0.01 - 0.04] vs. 0.08 [0.06 - 0.09] mmol/g, p<0.01). Septic patients and controls showed different amounts of albumin proteoforms. Conclusions: Septic patients are exposed to higher pH variations for any given change in CO2 due to lower concentrations of non-carbonic buffers and, possibly, an altered buffering function of albumin. In both septic patients and healthy controls, electrolyte shifts are the major buffering mechanism during respiratory acid-base disorders.

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