Dilutional acidosis

Where do the protons come from?

Luciano Gattinoni, E. Carlesso, G. Maiocchi, F. Polli, P. Cadringher

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Purpose: To investigate the mechanism of acidosis developing after saline infusion (dilutional acidosis or hyperchloremic acidosis). Methods: We simulated normal extracellular fluid dilution by infusing distilled water, normal saline and lactated Ringer's solution. Simulations were performed either in a closed system or in a system open to alveolar gases using software based on the standard laws of mass action and mass conservation. In vitro experiments diluting human plasma were performed to validate the model. Results: In our computerized model with constant pKs, diluting extracellular fluid modeled as a closed system with distilled water, normal saline or lactated Ringer's solution is not associated with any pH modification, since all its determinants (strong ion difference, CO2 content and weak acid concentration) decrease at the same degree, maintaining their relative proportions unchanged. Experimental data confirmed the simulation results for normal saline and lactated Ringer's solution, whereas distilled water dilution caused pH to increase. This is due to the increase of carbonic pK induced by the dramatic decrease of ionic strength. Acidosis developed only when the system was open to gases due to the increased CO2 content, both in its dissociated (bicarbonate) and undissociated form (dissolved CO2). Conclusions: The increase in proton concentration observed after dilution of the extracellular system derives from the reaction of CO2 hydration, which occurs only when the system is open to the gases. Both Stewart's approach and the traditional approach may account for these results.

Original languageEnglish
Pages (from-to)2033-2043
Number of pages11
JournalIntensive Care Medicine
Volume35
Issue number12
DOIs
Publication statusPublished - Dec 2009

Fingerprint

Acidosis
Protons
Gases
Extracellular Fluid
Bicarbonates
Computer Simulation
Osmolar Concentration
Software
Ions
Acids
Water
Ringer's lactate
Ringer's solution
Saline Waters

Keywords

  • Acid-base equilibrium
  • CO content
  • Metabolic acidosis
  • Stewart's approach
  • Volume resuscitation

ASJC Scopus subject areas

  • Critical Care and Intensive Care Medicine

Cite this

Gattinoni, L., Carlesso, E., Maiocchi, G., Polli, F., & Cadringher, P. (2009). Dilutional acidosis: Where do the protons come from? Intensive Care Medicine, 35(12), 2033-2043. https://doi.org/10.1007/s00134-009-1653-7

Dilutional acidosis : Where do the protons come from? / Gattinoni, Luciano; Carlesso, E.; Maiocchi, G.; Polli, F.; Cadringher, P.

In: Intensive Care Medicine, Vol. 35, No. 12, 12.2009, p. 2033-2043.

Research output: Contribution to journalArticle

Gattinoni, L, Carlesso, E, Maiocchi, G, Polli, F & Cadringher, P 2009, 'Dilutional acidosis: Where do the protons come from?', Intensive Care Medicine, vol. 35, no. 12, pp. 2033-2043. https://doi.org/10.1007/s00134-009-1653-7
Gattinoni, Luciano ; Carlesso, E. ; Maiocchi, G. ; Polli, F. ; Cadringher, P. / Dilutional acidosis : Where do the protons come from?. In: Intensive Care Medicine. 2009 ; Vol. 35, No. 12. pp. 2033-2043.
@article{8ef1093a792a409da77ff5efe86a279b,
title = "Dilutional acidosis: Where do the protons come from?",
abstract = "Purpose: To investigate the mechanism of acidosis developing after saline infusion (dilutional acidosis or hyperchloremic acidosis). Methods: We simulated normal extracellular fluid dilution by infusing distilled water, normal saline and lactated Ringer's solution. Simulations were performed either in a closed system or in a system open to alveolar gases using software based on the standard laws of mass action and mass conservation. In vitro experiments diluting human plasma were performed to validate the model. Results: In our computerized model with constant pKs, diluting extracellular fluid modeled as a closed system with distilled water, normal saline or lactated Ringer's solution is not associated with any pH modification, since all its determinants (strong ion difference, CO2 content and weak acid concentration) decrease at the same degree, maintaining their relative proportions unchanged. Experimental data confirmed the simulation results for normal saline and lactated Ringer's solution, whereas distilled water dilution caused pH to increase. This is due to the increase of carbonic pK induced by the dramatic decrease of ionic strength. Acidosis developed only when the system was open to gases due to the increased CO2 content, both in its dissociated (bicarbonate) and undissociated form (dissolved CO2). Conclusions: The increase in proton concentration observed after dilution of the extracellular system derives from the reaction of CO2 hydration, which occurs only when the system is open to the gases. Both Stewart's approach and the traditional approach may account for these results.",
keywords = "Acid-base equilibrium, CO content, Metabolic acidosis, Stewart's approach, Volume resuscitation",
author = "Luciano Gattinoni and E. Carlesso and G. Maiocchi and F. Polli and P. Cadringher",
year = "2009",
month = "12",
doi = "10.1007/s00134-009-1653-7",
language = "English",
volume = "35",
pages = "2033--2043",
journal = "Intensive Care Medicine",
issn = "0342-4642",
publisher = "Springer Verlag",
number = "12",

}

TY - JOUR

T1 - Dilutional acidosis

T2 - Where do the protons come from?

AU - Gattinoni, Luciano

AU - Carlesso, E.

AU - Maiocchi, G.

AU - Polli, F.

AU - Cadringher, P.

PY - 2009/12

Y1 - 2009/12

N2 - Purpose: To investigate the mechanism of acidosis developing after saline infusion (dilutional acidosis or hyperchloremic acidosis). Methods: We simulated normal extracellular fluid dilution by infusing distilled water, normal saline and lactated Ringer's solution. Simulations were performed either in a closed system or in a system open to alveolar gases using software based on the standard laws of mass action and mass conservation. In vitro experiments diluting human plasma were performed to validate the model. Results: In our computerized model with constant pKs, diluting extracellular fluid modeled as a closed system with distilled water, normal saline or lactated Ringer's solution is not associated with any pH modification, since all its determinants (strong ion difference, CO2 content and weak acid concentration) decrease at the same degree, maintaining their relative proportions unchanged. Experimental data confirmed the simulation results for normal saline and lactated Ringer's solution, whereas distilled water dilution caused pH to increase. This is due to the increase of carbonic pK induced by the dramatic decrease of ionic strength. Acidosis developed only when the system was open to gases due to the increased CO2 content, both in its dissociated (bicarbonate) and undissociated form (dissolved CO2). Conclusions: The increase in proton concentration observed after dilution of the extracellular system derives from the reaction of CO2 hydration, which occurs only when the system is open to the gases. Both Stewart's approach and the traditional approach may account for these results.

AB - Purpose: To investigate the mechanism of acidosis developing after saline infusion (dilutional acidosis or hyperchloremic acidosis). Methods: We simulated normal extracellular fluid dilution by infusing distilled water, normal saline and lactated Ringer's solution. Simulations were performed either in a closed system or in a system open to alveolar gases using software based on the standard laws of mass action and mass conservation. In vitro experiments diluting human plasma were performed to validate the model. Results: In our computerized model with constant pKs, diluting extracellular fluid modeled as a closed system with distilled water, normal saline or lactated Ringer's solution is not associated with any pH modification, since all its determinants (strong ion difference, CO2 content and weak acid concentration) decrease at the same degree, maintaining their relative proportions unchanged. Experimental data confirmed the simulation results for normal saline and lactated Ringer's solution, whereas distilled water dilution caused pH to increase. This is due to the increase of carbonic pK induced by the dramatic decrease of ionic strength. Acidosis developed only when the system was open to gases due to the increased CO2 content, both in its dissociated (bicarbonate) and undissociated form (dissolved CO2). Conclusions: The increase in proton concentration observed after dilution of the extracellular system derives from the reaction of CO2 hydration, which occurs only when the system is open to the gases. Both Stewart's approach and the traditional approach may account for these results.

KW - Acid-base equilibrium

KW - CO content

KW - Metabolic acidosis

KW - Stewart's approach

KW - Volume resuscitation

UR - http://www.scopus.com/inward/record.url?scp=70949087375&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=70949087375&partnerID=8YFLogxK

U2 - 10.1007/s00134-009-1653-7

DO - 10.1007/s00134-009-1653-7

M3 - Article

VL - 35

SP - 2033

EP - 2043

JO - Intensive Care Medicine

JF - Intensive Care Medicine

SN - 0342-4642

IS - 12

ER -