A comprehensive, computer-model-based approach for diagnosis and treatment of complex acid–base disorders in critically-ill patients

Wolf, Matthew B.; DeLand, Edward Charles

doi:10.1007/s10877-011-9320-2

Cited by 13 publications

(7 citation statements)

References 18 publications

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“…Here, the pH of the closed system is no longer insensitive to the dilution and the the open system is additionally buffered by the erythrocytes. Plotting the dependency of the HCO 3 − for the open system together with comparison to Figge-Fencl and recent Wolf [ 13 ] (reduced to plasma and erythrocyte compartments) models reveals, that the Combined model shows a perfect fit to measured values, as reproduced in [ 22 ] (Fig. 4b ).…”

Section: Resultssupporting

confidence: 53%

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Modern and traditional approaches combined into an effective gray-box mathematical model of full-blood acid-base

Ježek

Kofránek

2018

Theor Biol Med Model

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BackgroundThe acidity of human body fluids, expressed by the pH, is physiologically regulated in a narrow range, which is required for the proper function of cellular metabolism. Acid-base disorders are common especially in intensive care, and the acid-base status is one of the vital clinical signs for the patient management. Because acid-base balance is connected to many bodily processes and regulations, complex mathematical models are needed to get insight into the mixed disorders and to act accordingly. The goal of this study is to develop a full-blood acid-base model, designed to be further integrated into more complex human physiology models.ResultsWe have developed computationally simple and robust full-blood model, yet thorough enough to cover most of the common pathologies. Thanks to its simplicity and usage of Modelica language, it is suitable to be embedded within more elaborate systems. We achieved the simplification by a combination of behavioral Siggaard-Andersen’s traditional approach for erythrocyte modeling and the mechanistic Stewart’s physicochemical approach for plasma modeling. The resulting model is capable of providing variations in arterial pCO2, base excess, strong ion difference, hematocrit, plasma protein, phosphates and hemodilution/hemoconcentration, but insensitive to DPG and CO concentrations.ConclusionsThis study presents a straightforward unification of Siggaard-Andersen’s and Stewart’s acid-base models. The resulting full-blood acid-base model is designed to be a core part of a complex dynamic whole-body acid-base and gas transfer model.Electronic supplementary materialThe online version of this article (10.1186/s12976-018-0086-9) contains supplementary material, which is available to authorized users.

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Section: Resultssupporting

confidence: 53%

“…where pH HCT1 = pH SA and pH HCT0 = pH PC . Note that pH HCT1 does not represent the pH inside an erythrocyte, as modeled by Raftos et al, Rees et al or Wolf and DeLand [ 11 – 13 ]. In contrast, it is a limit of the pH outside erythrocytes, as the hematocrit of this theoretical compartment (the ratio of erythrocytes) approaches 1.…”

Section: Methodsmentioning

confidence: 99%

Modern and traditional approaches combined into an effective gray-box mathematical model of full-blood acid-base

Ježek

Kofránek

2018

Theor Biol Med Model

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“…The remaining equations account for the physico-chemical properties of blood, including the solubility of O 2 and CO 2 in plasma and red blood cells (18r-21r), the fractions of plasma and erythrocyte (22r, 23r), and a modified form [45] of the empirical relationship relating pH in the plasma and red blood cells, derived by Funder and Weith [13], to describe the link between plasma and red blood cell acid-base status without the need to represent electrolyte transport across cell membranes. This simplification means that the model cannot calculate values of electrolytes in the plasma and red blood cells, as can newer models by Wolf [54,55].…”

Section: Mathematical Models Of Acid-basementioning

confidence: 99%

Determining the appropriate model complexity for patient-specific advice on mechanical ventilation

Rees

Karbing

2017

Biomedical Engineering / Biomedizinische Technik

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Mathematical physiological models can be applied in medical decision support systems. To do so requires consideration of the necessary model complexity. Models that simulate changes in the individual patient are required, meaning that models should have a complexity where parameters can be uniquely identified at the bedside from clinical data and where the models adequately represent the individual patient's (patho)physiology. This paper describes the models included in a system for providing decision support for mechanical ventilation. Models of pulmonary gas exchange, respiratory mechanics, acid-base, and respiratory control are described. The parameters of these models are presented along with the necessary clinical data required for their estimation and the parameter estimation process. In doing so, the paper highlights the need for simple, minimal models for application at the bedside, directed toward well-defined clinical problems.

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“…Hence, a module has been developed (see APPENDIX B) to allow users to simply determine the effects of fluid infusions and urinary losses on whole-body fluid and electrolyte (acid-base) balance. In addition, this new CIPE model will be incorporated into a diagnostic module in the same way as before for the IPE model (38). This latter step will allow accurate diagnostic, acid-base predictions in disease processes such as diabetic ketoacidosis, nephrotic syndrome and others where cellular volume is compromised.…”

Section: Model Developmentmentioning

confidence: 99%

“…They showed (38) that their model could be used along with laboratory blood-chemistry values to predict both the abnormal fluid and electrolyte distribution and acid-base status in critically ill patients. However, the lack of a cellular compartment limited this tool to the study of disease processes lacking significant osmolarity changes.…”

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confidence: 99%

Whole body acid-base and fluid-electrolyte balance: a mathematical model

Wolf

2013

American Journal of Physiology-Renal Physiology

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Wolf MB. Whole body acid-base and fluid-electrolyte balance: a mathematical model. Am J Physiol Renal Physiol 305: F1118-F1131, 2013. First published July 24, 2013 doi:10.1152/ajprenal.00195.2013.-A cellular compartment was added to our previous mathematical model of steady-state acid-base and fluid-electrolyte chemistry to gain further understanding and aid diagnosis of complex disorders involving cellular involvement in critically ill patients. An important hypothesis to be validated was that the thermodynamic, standard free-energy of cellular H ϩ and Na ϩ pumps remained constant under all conditions. In addition, a hydrostatic-osmotic pressure balance was assumed to describe fluid exchange between plasma and interstitial fluid, including incorporation of compliance curves of vascular and interstitial spaces. The description of the cellular compartment was validated by close comparison of measured and model-predicted cellular pH and electrolyte changes in vitro and in vivo. The new description of plasma-interstitial fluid exchange was validated using measured changes in fluid volumes after isoosmotic and hyperosmotic fluid infusions of NaCl and NaHCO 3. The validated model was used to explain the role of cells in the mechanism of saline or dilutional acidosis and acid-base effects of acidic or basic fluid infusions and the acid-base disorder due to potassium depletion. A module was created that would allow users, who do not possess the software, to determine, for free, the results of fluid infusions and urinary losses of water and solutes to the whole body. mathematical model; acid-base balance; fluid and electrolyte balance; potassium depletion; saline acidosis A TRUE UNDERSTANDING OF THE physiological effects of disease processes and attendant fluid infusions and losses requires consideration of the distribution of water, protein, electrolytes, and electrically neutral solutes among all the body fluids. Many simple analytical solutions to subsets of this physicochemical problem have been used since the time of Henderson (22), but they have yielded only limited understanding.Recently, Wolf and DeLand (39) developed a model of the steady-state water and electrolyte exchanges between interstitial fluid (I), plasma (P), and erythrocytes (E). They showed (38) that their model could be used along with laboratory blood-chemistry values to predict both the abnormal fluid and electrolyte distribution and acid-base status in critically ill patients. However, the lack of a cellular compartment limited this tool to the study of disease processes lacking significant osmolarity changes. Another shortcoming was an incomplete description of the forces moving water between plasma and interstitial fluid.Hence, the aims of the present study were to expand and modify the previous IPE model (39) by 1) adding a parenchymal cell compartment, 2) incorporating a more explicit description of the forces leading to plasma-interstitial water distribution, 3) providing much more extensive validation of both water and electrolyte distrib...

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A comprehensive, computer-model-based approach for diagnosis and treatment of complex acid–base disorders in critically-ill patients

Cited by 13 publications

References 18 publications

Modern and traditional approaches combined into an effective gray-box mathematical model of full-blood acid-base

Modern and traditional approaches combined into an effective gray-box mathematical model of full-blood acid-base

Determining the appropriate model complexity for patient-specific advice on mechanical ventilation

Whole body acid-base and fluid-electrolyte balance: a mathematical model

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