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Lindinger MI. Total Carbon Dioxide in Adult Standardbred and Thoroughbred Horses. J Equine Vet Sci 2021; 106:103730. [PMID: 34670689 DOI: 10.1016/j.jevs.2021.103730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 08/02/2021] [Accepted: 08/08/2021] [Indexed: 10/20/2022]
Abstract
The TCO2 (total carbon dioxide) test is performed on the blood of racehorses as a means of combatting the practice of administering alkalizing agents for the purpose of enhancing performance. The purposes of this review are to present an overview of the factors contributing to TCO2 and to review the literature regarding TCO2 in adult Standardbred and Thoroughbred horses to demonstrate the range of variability of TCO2 in horses. Most of the research published on the topic of TCO2 or bicarbonate measurement in racehorses was accessed and reviewed. PubMed and Google Scholar were the primary search engines used to source the relevant literature. The main physicochemical factors that contribute to changes in TCO2 in horses at rest are changes in strong ions concentration, followed by changes in weak acid (i.e. plasma albumin) concentrations. There is a wide normal distribution of TCO2 in horses ranging from 23 mmol/L to 38 mmol/L. Independent of administration of alkalizing agents, blood TCO2 is affected mainly by feeding, time of day (diurnal variation), season and exercise. There are few studies that have reported hour-by-hour changes in TCO2. Racehorse population studies suffer from lack of validation regarding whether or not a horse was administered an alkalizing agent. It is concluded that the normal range of TCO2 in non-alkalized Standardbred and Thoroughbred horses is significantly wider than has been appreciated, that periods of elevated TCO2 appear to be normal for many horses at rest, and that a TCO2 test alone is not definitive for the purposes of determining of an alkalizing agent has been administered to a horse.
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Zingg T, Bhattacharya B, Maerz LL. Metabolic acidosis and the role of unmeasured anions in critical illness and injury. J Surg Res 2017; 224:5-17. [PMID: 29506851 DOI: 10.1016/j.jss.2017.11.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 09/04/2017] [Accepted: 11/03/2017] [Indexed: 12/31/2022]
Abstract
Acid-base disorders are frequently present in critically ill patients. Metabolic acidosis is associated with increased mortality, but it is unclear whether as a marker of the severity of the disease process or as a direct effector. The understanding of the metabolic component of acid-base derangements has evolved over time, and several theories and models for precise quantification and interpretation have been postulated during the last century. Unmeasured anions are the footprints of dissociated fixed acids and may be responsible for a significant component of metabolic acidosis. Their nature, origin, and prognostic value are incompletely understood. This review provides a historical overview of how the understanding of the metabolic component of acid-base disorders has evolved over time and describes the theoretical models and their corresponding tools applicable to clinical practice, with an emphasis on the role of unmeasured anions in general and several specific settings.
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Affiliation(s)
- Tobias Zingg
- Department of Surgery, Section of General Surgery, Trauma & Surgical Critical Care, Yale University School of Medicine, New Haven, Connecticut.
| | - Bishwajit Bhattacharya
- Department of Surgery, Section of General Surgery, Trauma & Surgical Critical Care, Yale University School of Medicine, New Haven, Connecticut
| | - Linda L Maerz
- Department of Surgery, Section of General Surgery, Trauma & Surgical Critical Care, Yale University School of Medicine, New Haven, Connecticut
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Schiavo A, Renis M, Polverino M, Iannuzzi A, Polverino F. Acid-base balance, serum electrolytes and need for non-invasive ventilation in patients with hypercapnic acute exacerbation of chronic obstructive pulmonary disease admitted to an internal medicine ward. Multidiscip Respir Med 2016; 11:23. [PMID: 27226896 PMCID: PMC4879756 DOI: 10.1186/s40248-016-0063-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 04/29/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Hypoventilation produces or worsens respiratory acidosis in patients with hypercapnia due to acute exacerbations of chronic obstructive pulmonary disease (AECOPD). In these patients acid-base and hydroelectrolite balance are closely related. Aim of the present study was to evaluate acid-base and hydroelectrolite alterations in these subjects and the effect of non-invasive ventilation and pharmacological treatment. METHODS We retrospectively analysed 110 patients consecutively admitted to the Internal Medicine ward of Cava de' Tirreni Hospital for acute exacerbation of hypercapnic chronic obstructive pulmonary disease. On admission all patients received oxygen with a Venturi mask to maintain arterial oxygen saturation at least >90 %, and received appropriate pharmacological treatment. Non-Invasive Ventilation (NIV) was started when, despite optimal therapy, patients had severe dyspnea, increased work of breathing and respiratory acidosis. Based on Arterial Blood Gas (ABG) data, we divided the 110 patients in 3 groups: A = 51 patients with compensated respiratory acidosis; B = 36 patients with respiratory acidosis + metabolic alkalosis; and C = 23 patients with respiratory acidosis + metabolic acidosis. 55 patients received only conventional therapy and 55 had conventional therapy plus NIV. RESULTS The use of NIV support was lower in the patients belonging to group B than in those belonging to group A and C (25 %, vs 47 % and 96 % respectively; p < 0.01). A statistically significant association was found between pCO2 values and serum chloride concentrations both in the entire cohort and in the three separate groups. CONCLUSIONS Our study shows that in hypercapnic respiratory acidosis due to AECOPD, differently from previous studies, the metabolic alkalosis is not a negative prognostic factor neither determines greater NIV support need, whereas the metabolic acidosis in addition to respiratory acidosis is an unfavourable element, since it determines an increased need of NIV and invasive mechanical ventilation support.
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Affiliation(s)
- Alfonso Schiavo
- Division of Internal Medicine, Cava de' Tirreni Hospital, University of Salerno, Cava de' Tirreni, SA, Italy
| | - Maurizio Renis
- Division of Internal Medicine, Cava de' Tirreni Hospital, University of Salerno, Cava de' Tirreni, SA, Italy
| | - Mario Polverino
- Division of Pulmonary Medicine, Scafati Hospital, Salerno, Italy
| | | | - Francesca Polverino
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA USA
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Aristizábal-Salazar RE, Calvo-Torres LF, Valencia-Arango LA, Montoya-Cañon M, Barbosa-Gantiva O, Hincapié-Baena V. Equilibrio ácido-base: el mejor enfoque clínico. COLOMBIAN JOURNAL OF ANESTHESIOLOGY 2015. [DOI: 10.1016/j.rca.2015.04.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Aristizábal-Salazar RE, Calvo-Torres LF, Valencia-Arango LA, Montoya-Cañon M, Barbosa-Gantiva O, Hincapié-Baena V. Acid–base equilibrium: The best clinical approach. COLOMBIAN JOURNAL OF ANESTHESIOLOGY 2015. [DOI: 10.1016/j.rcae.2015.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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Arzapalo M. Association of elevated levels of plasma chloride, in severity and mortality, in adult patients in the ICU. Crit Care 2015. [PMCID: PMC4471245 DOI: 10.1186/cc14440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Acid-base equilibrium: The best clinical approach☆. COLOMBIAN JOURNAL OF ANESTHESIOLOGY 2015. [DOI: 10.1097/01819236-201543030-00008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Burchell RK, Schoeman JP, Leisewitz AL. The central role of chloride in the metabolic acid-base changes in canine parvoviral enteritis. Vet J 2014; 200:152-6. [PMID: 24613416 PMCID: PMC7128572 DOI: 10.1016/j.tvjl.2014.01.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 01/19/2014] [Accepted: 01/24/2014] [Indexed: 11/24/2022]
Abstract
The acid–base disturbances in canine parvoviral (CPV) enteritis are not well described. In addition, the mechanisms causing these perturbations have not been fully elucidated. The purpose of the present study was to assess acid–base changes in puppies suffering from CPV enteritis, using a modified strong ion model (SIM). The hypothesis of the study was that severe acid–base disturbances would be present and that the SIM would provide insights into pathological mechanisms, which have not been fully appreciated by the Henderson–Hasselbalch model. The study analysed retrospective data, obtained from 42 puppies with confirmed CPV enteritis and 10 healthy control dogs. The CPV-enteritis group had been allocated a clinical score, to allow classification of the data according to clinical severity. The effects of changes in free water, chloride, l-lactate, albumin and phosphate were calculated, using a modification of the base excess algorithm. When the data were summated for each patient, and correlated to each individual component, the most important contributor to the metabolic acid–base changes, according to the SIM, was chloride (P < 0.001). Severely-affected animals tended to demonstrate hypochloraemic alkalosis, whereas mildly-affected puppies had a hyperchloraemic acidosis (P = 0.007). In conclusion, the acid–base disturbances in CPV enteritis are multifactorial and complex, with the SIM providing information in terms of the origin of these changes.
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Affiliation(s)
- Richard K Burchell
- Department of Companion Animal Clinical Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort 0110, South Africa.
| | - Johan P Schoeman
- Department of Companion Animal Clinical Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort 0110, South Africa
| | - Andrew L Leisewitz
- Department of Companion Animal Clinical Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort 0110, South Africa
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Strong ion difference and gap predict outcomes after adult burn injury. J Trauma Acute Care Surg 2013; 75:555-60; discussion 560-1. [PMID: 24064866 DOI: 10.1097/ta.0b013e3182a53a03] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The strong ion difference (SID) (apparent [SIDa] and effective [SIDe]) and strong ion gap (SIG) provide a comprehensive method of evaluating acid-base status in critically ill patients. The SID is the difference between strong cations and strong anions in plasma, while the SIG demonstrates the presence of unmeasured ions. This approach accounts for changes in a patient's protein status, which is particularly important in those with burn injuries. We hypothesized that the SIDa, SIDe, and SIG during the first 72 hours after admission would be predictive of mortality in burn patients. METHODS This study is a retrospective review of adults with 20% or greater total body surface area burns admitted during a 7-year period to a regional burn center. SIDa, SIDe, and SIG were calculated at admission and for the first 3 days. These results were then compared with Acute Physiology and Chronic Health Evaluation II (APACHE II) and sepsis-related organ failure assessment (SOFA) scores. RESULTS A total of 113 patients met the criteria and had full data sets, with mean ± SEM age of 45.4 ± 1.4 years and total body surface area burn of 41.4% ± 1.6%. Mortality was 27.4%. At admission, APACHE II remained most predictive of mortality (p = 0.006). However, admission SIG (SIDa - SIDe) was also predictive of mortality on multivariate analysis (odds ratio, 1.11). Day 1 SIDa (Na+ + K+ + Ca2+ + Mg2+ - Cl-) and SIDe ([1,000 × 2.46 × 10(-11) × PaCO2/10(-pH)] + [[albumin] × (0.123 × pH - 0.631)] + [[PO4] × (0.309) × pH - 0.469)]) were also associated with mortality (odds ratio, 1.16 and 1.13 respectively), and SIDe with length of stay and ventilator days (p < 0.05). CONCLUSION The SID and SIG are predictive of mortality, hospital length of stay, and ventilator days in adult burn patients. They also elucidate complex acid-base disorders. LEVEL OF EVIDENCE Prognostic study, level II.
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Terzano C, Di Stefano F, Conti V, Di Nicola M, Paone G, Petroianni A, Ricci A. Mixed acid-base disorders, hydroelectrolyte imbalance and lactate production in hypercapnic respiratory failure: the role of noninvasive ventilation. PLoS One 2012; 7:e35245. [PMID: 22539963 PMCID: PMC3335154 DOI: 10.1371/journal.pone.0035245] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2011] [Accepted: 03/12/2012] [Indexed: 12/05/2022] Open
Abstract
Background Hypercapnic Chronic Obstructive Pulmonary Disease (COPD) exacerbation in patients with comorbidities and multidrug therapy is complicated by mixed acid-base, hydro-electrolyte and lactate disorders. Aim of this study was to determine the relationships of these disorders with the requirement for and duration of noninvasive ventilation (NIV) when treating hypercapnic respiratory failure. Methods Sixty-seven consecutive patients who were hospitalized for hypercapnic COPD exacerbation had their clinical condition, respiratory function, blood chemistry, arterial blood gases, blood lactate and volemic state assessed. Heart and respiratory rates, pH, PaO2 and PaCO2 and blood lactate were checked at the 1st, 2nd, 6th and 24th hours after starting NIV. Results Nine patients were transferred to the intensive care unit. NIV was performed in 11/17 (64.7%) mixed respiratory acidosis–metabolic alkalosis, 10/36 (27.8%) respiratory acidosis and 3/5 (60%) mixed respiratory-metabolic acidosis patients (p = 0.026), with durations of 45.1±9.8, 36.2±8.9 and 53.3±4.1 hours, respectively (p = 0.016). The duration of ventilation was associated with higher blood lactate (p<0.001), lower pH (p = 0.016), lower serum sodium (p = 0.014) and lower chloride (p = 0.038). Hyponatremia without hypervolemic hypochloremia occurred in 11 respiratory acidosis patients. Hypovolemic hyponatremia with hypochloremia and hypokalemia occurred in 10 mixed respiratory acidosis–metabolic alkalosis patients, and euvolemic hypochloremia occurred in the other 7 patients with this mixed acid-base disorder. Conclusions Mixed acid-base and lactate disorders during hypercapnic COPD exacerbations predict the need for and longer duration of NIV. The combination of mixed acid-base disorders and hydro-electrolyte disturbances should be further investigated.
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Affiliation(s)
- Claudio Terzano
- Fondazione Eleonora Lorillard Spencer Cenci, Sapienza University of Rome, Rome, Italy
| | - Fabio Di Stefano
- Fondazione Eleonora Lorillard Spencer Cenci, Sapienza University of Rome, Rome, Italy
| | - Vittoria Conti
- Fondazione Eleonora Lorillard Spencer Cenci, Sapienza University of Rome, Rome, Italy
- * E-mail:
| | - Marta Di Nicola
- Laboratory of Biostatistics, Department of Biomedical Science, University “G. d'Annunzio” of Chieti-Pescara, Chieti, Italy
| | - Gregorino Paone
- Fondazione Eleonora Lorillard Spencer Cenci, Sapienza University of Rome, Rome, Italy
| | - Angelo Petroianni
- Fondazione Eleonora Lorillard Spencer Cenci, Sapienza University of Rome, Rome, Italy
| | - Alberto Ricci
- Fondazione Eleonora Lorillard Spencer Cenci, Sapienza University of Rome, Rome, Italy
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Asuero AG, Michałowski T. Comprehensive Formulation of Titration Curves for Complex Acid-Base Systems and Its Analytical Implications. Crit Rev Anal Chem 2011. [DOI: 10.1080/10408347.2011.559440] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Dzierba AL, Abraham P. A practical approach to understanding acid-base abnormalities in critical illness. J Pharm Pract 2011; 24:17-26. [PMID: 21507871 DOI: 10.1177/0897190010388153] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Acid-base disorders are common in the critically ill. Arterial blood gas (ABG) analysis is frequently used to identify and manage acid-base disturbances. Using a systematic problem-solving approach to acid-base disturbances will facilitate the identification and assess the progression and severity of the metabolic and respiratory abnormality. The intent of this review is to examine acid-base physiology and regulation, provide a method to evaluate a patient's acid-base disorder, and provide therapeutic interventions.
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Affiliation(s)
- Amy L Dzierba
- NewYork-Presbyterian Hospital, Columbia University, New York, NY, USA.
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Wolf MB, DeLand EC. A mathematical model of blood-interstitial acid-base balance: application to dilution acidosis and acid-base status. J Appl Physiol (1985) 2011; 110:988-1002. [DOI: 10.1152/japplphysiol.00514.2010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We developed mathematical models that predict equilibrium distribution of water and electrolytes (proteins and simple ions), metabolites, and other species between plasma and erythrocyte fluids (blood) and interstitial fluid. The models use physicochemical principles of electroneutrality in a fluid compartment and osmotic equilibrium between compartments and transmembrane Donnan relationships for mobile species. Across the erythrocyte membrane, the significant mobile species Cl−is assumed to reach electrochemical equilibrium, whereas Na+and K+distributions are away from equilibrium because of the Na+/K+pump, but movement from this steady state is restricted because of their effective short-term impermeability. Across the capillary membrane separating plasma and interstitial fluid, Na+, K+, Ca2+, Mg2+, Cl−, and H+are mobile and establish Donnan equilibrium distribution ratios. In each compartment, attainment of equilibrium by carbonates, phosphates, proteins, and metabolites is determined by their reactions with H+. These relationships produce the recognized exchange of Cl−and bicarbonate across the erythrocyte membrane. The blood submodel was validated by its close predictions of in vitro experimental data, blood pH, pH-dependent ratio of H+, Cl−, and HCO3−concentrations in erythrocytes to that in plasma, and blood hematocrit. The blood-interstitial model was validated against available in vivo laboratory data from humans with respiratory acid-base disorders. Model predictions were used to gain understanding of the important acid-base disorder caused by addition of saline solutions. Blood model results were used as a basis for estimating errors in base excess predictions in blood by the traditional approach of Siggaard-Andersen (acid-base status) and more recent approaches by others using measured blood pH and Pco2values. Blood-interstitial model predictions were also used as a basis for assessing prediction errors of extracellular acid-base status values, such as by the standard base excess approach. Hence, these new models can give considerable insight into the physicochemical mechanisms producing acid-base disorders and aid in their diagnoses.
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Affiliation(s)
- Matthew B. Wolf
- Department of Pharmacology, Physiology, and Neuroscience, University of South Carolina, Columbia, South Carolina; and
| | - Edward C. DeLand
- Department of Surgery, University of California at Los Angeles, Westwood, California
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Anstey CM. Estimating the net effect of unmeasured ions in human extracellular fluid using a new mathematical model. Part I: Theoretical considerations. Anaesth Intensive Care 2010; 38:862-9. [PMID: 20865870 DOI: 10.1177/0310057x1003800509] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A theoretical framework for the formulation of a derived variable to be used for the prediction of the net effect of unmeasured charged species present in human extracellular fluid was explored. This new variable was based on contemporary strong ion and classical buffer base theories and tested against the standard base excess using simulation. It proved to be more accurate in predicting the existence of unmeasured charged species in the extracellular fluid when disturbances of either strong ions, weak acids or both were present.
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Affiliation(s)
- C M Anstey
- Department of Critical Care Medicine, Sunshine Coast Hospital, Nambour Queensland, Australia.
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The standard strong ion difference, standard total titratable base, and their relationship to the Boston compensation rules and the Van Slyke equation for extracellular fluid. J Clin Monit Comput 2010; 24:177-88. [DOI: 10.1007/s10877-010-9231-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2010] [Accepted: 03/09/2010] [Indexed: 11/27/2022]
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Aman J, Nurmohamed SA, Vervloet MG, Groeneveld ABJ. Metabolic effects of citrate- vs bicarbonate-based substitution fluid in continuous venovenous hemofiltration: a prospective sequential cohort study. J Crit Care 2009; 25:120-7. [PMID: 19427760 DOI: 10.1016/j.jcrc.2009.02.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Revised: 02/16/2009] [Accepted: 02/22/2009] [Indexed: 11/16/2022]
Abstract
BACKGROUND Studies investigating the metabolic effects of citrate-based substitution fluids are lacking. This study aims to compare the effect of citrate- vs bicarbonate-based substitution fluid used during continuous venovenous hemofiltration (CVVH) for acute kidney injury on acid-base balance and electrolytes in critically ill patients. METHODS This was a prospective sequential cohort study in patients with a contraindication for systemic anticoagulation. The first cohort was treated by bicarbonate-based CVVH (n = 10) and the second cohort was treated by CVVH with citrate-based substitution fluid (n = 19). Flow of the latter was coupled to blood flow, and ionized calcium concentrations were monitored and kept constant by calcium-glubionate infusion. RESULTS No major differences between the 2 groups were found in baseline acid-base parameters. In both groups, arterial pH increased after initiation of treatment and normalized on the average within 18 hours in either group. No differences were found in bicarbonate concentrations. Electrolyte control was comparable for the groups. CONCLUSION Citrate-based substitution fluid is comparable to bicarbonate-based substitution fluid during CVVH in critically ill patients with acute kidney injury, concerning acid-base balance and electrolyte control. This implies complete conversion of citrate to bicarbonate in the patients studied.
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Affiliation(s)
- Jurjan Aman
- Department of Intensive Care, VU University Medical Centre, PO Box 7057, 1007 MB Amsterdam, The Netherlands.
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Abdel-Razeq SS, Kaplan LJ. Hyperchloremic Metabolic Acidosis: More than Just a Simple Dilutional Effect. Intensive Care Med 2009. [DOI: 10.1007/978-0-387-92278-2_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Moll W, Gros G. Combined glycolytic production of lactate(-) and ATP(4-) derived protons (= dissociated lactic acid) is the only cause of metabolic acidosis of exercise--a note on the OH(-) absorbing function of lactate (1-) production. J Appl Physiol (1985) 2008; 105:366-7. [PMID: 18680794 DOI: 10.1152/japplphysiol.zdg-8016-pcpcomm.2008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Abstract
The cell-to-cell lactate shuttle was introduced in 1984 and has been repeatedly supported by studies using a variety of experimental approaches. Because of its large mass and metabolic capacity, skeletal muscle is probably the major component of the lactate shuttle in terms of both production and consumption. Muscles exercising in a steady state are avid consumers of lactate, using most of the lactate as an oxidative fuel. Cardiac muscle is highly oxidative and readily uses lactate as a fuel. Lactate is a major gluconeogenic substrate for the liver; the use of lactate to form glucose increases when blood lactate concentration is elevated. Illustrative of the widespread shuttling of lactate, even the brain takes up lactate when the blood level is increased. Recently, an intracellular lactate shuttle has also been proposed. Although disagreements abound, current evidence suggests that lactate is the primary end-product of glycolysis at cellular sites remote from mitochondria. This lactate could subsequently diffuse to areas adjacent to mitochondria. Evidence is against lactate oxidation within the mitochondrial matrix, but a viable hypothesis is that lactate could be converted to pyruvate by a lactate oxidation complex with lactate dehydrogenase located on the outer surface of the inner mitochondrial membrane. In another controversial area, the role of lactic acid in acid-base balance has been hotly debated in recent times. Careful analysis reveals that lactate, not lactic acid, is the substrate/product of metabolic reactions. One view is that lactate formation alleviates acidosis, whereas another is that lactate is a causative factor in acidosis. Surprisingly, there is little direct mechanistic evidence regarding cause and effect in acid-base balance. However, there is insufficient evidence to discard the term "lactic acidosis."
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Affiliation(s)
- L Bruce Gladden
- Department of Kinesiology, Auburn University, Auburn, AL 36849-5323, USA.
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Kurtz I, Kraut J, Ornekian V, Nguyen MK. Acid-base analysis: a critique of the Stewart and bicarbonate-centered approaches. Am J Physiol Renal Physiol 2008; 294:F1009-31. [PMID: 18184741 DOI: 10.1152/ajprenal.00475.2007] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
When approaching the analysis of disorders of acid-base balance, physical chemists, physiologists, and clinicians, tend to focus on different aspects of the relevant phenomenology. The physical chemist focuses on a quantitative understanding of proton hydration and aqueous proton transfer reactions that alter the acidity of a given solution. The physiologist focuses on molecular, cellular, and whole organ transport processes that modulate the acidity of a given body fluid compartment. The clinician emphasizes the diagnosis, clinical causes, and most appropriate treatment of acid-base disturbances. Historically, two different conceptual frameworks have evolved among clinicians and physiologists for interpreting acid-base phenomena. The traditional or bicarbonate-centered framework relies quantitatively on the Henderson-Hasselbalch equation, whereas the Stewart or strong ion approach utilizes either the original Stewart equation or its simplified version derived by Constable. In this review, the concepts underlying the bicarbonate-centered and Stewart formulations are analyzed in detail, emphasizing the differences in how each approach characterizes acid-base phenomenology at the molecular level, tissue level, and in the clinical realm. A quantitative comparison of the equations that are currently used in the literature to calculate H+concentration ([H+]) is included to clear up some of the misconceptions that currently exist in this area. Our analysis demonstrates that while the principle of electroneutrality plays a central role in the strong ion formulation, electroneutrality mechanistically does not dictate a specific [H+], and the strong ion and bicarbonate-centered approaches are quantitatively identical even in the presence of nonbicarbonate buffers. Finally, our analysis indicates that the bicarbonate-centered approach utilizing the Henderson-Hasselbalch equation is a mechanistic formulation that reflects the underlying acid-base phenomenology.
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Abstract
BACKGROUND Intensivists spend much of their time managing problems related to fluids, electrolytes, and blood pH. Recent advances in the understanding of acid-base physiology have resulted from the application of basic physical-chemical principles of aqueous solutions to blood plasma. All changes in blood pH, in health and in disease, occur through changes in three variables: carbon dioxide, relative electrolyte concentrations, and total weak acid concentrations. However, while this quantitative approach has enjoyed widespread use among researchers, clinicians are reluctant to employ it. Recent advances have brought a measure of parity between the newer and the older, descriptive approach to acid-base physiology. DATA SYNTHESIS Case-based review of the literature. CONCLUSION Both quantitative and traditional approaches can be easily combined to result in a powerful tool for bedside acid-base analysis.
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Affiliation(s)
- John A Kellum
- Clinical Research, Investigation, and Systems Modeling of Acute Illness (CRISMA) Laboratory and the Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
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Abstract
OBJECTIVE Development of a two-buffer model which simulates the acid-base properties of blood and allows comparison of the different acidbase concepts according to Stewart and to Siggaard-Andersen. METHODS The two-buffer model consisted of different aqueous solutions of bicarbonate/CO(2) (pCO(2), sCO(2), pK(1)), HEPES buffer (A(tot), pK(a)) and electrolytes. These were used to calculate the pH from the independent variables according to Stewart - strong ion difference (SID), pCO(2) and total concentration of the weak acids (A(tot)) - from which all other dependent variables (cHCO(3)(-), cA(-), BB, BE) were obtained and compared with the measured values. RESULTS The normal pH (7.408) was calculated from the normal values for SID (48 mmol/l), pCO(2) (40 mmHg) and A(tot) (45.2 mmol/l) and agreed perfectly with the measured value (7.409+/-0.001). This was also valid for all calculated and measured pH values when the SID was varied: non-respiratory alkalosis ( upward arrow) or acidosis ( downward arrow), pCO(2):respiratory acidosis ( upward arrow) or alkalosis ( downward arrow) and A(tot):hyperproteinemic acidosis ( upward arrow) or hypoproteinemic alkalosis ( downward arrow) were varied and the sum of the buffer bases (BB) was always equal to the SID. All changes and hence BE were also equal, providing that A(tot) was normal. This was not the case, however, if A(tot) was outside the normal range, when BE was then the difference from the normal BB at the respective reference point. Whereas the deviation of the measured pCO(2) was acceptable (1.74+/-0.86 mmHg), this was not the case for the SID (-6.18+/-3.58 mmol/l) calculated from the measured ion concentrations (Na, K, Ca, Cl). CONCLUSIONS Despite controversial discussions, both concepts are much closer than might be expected. Whereas in the Stewart approach the focus of analysis is on plasma, with the Siggaard-Andersen approach it is on blood. Hence, a combined analysis of the blood gases (pH, pCO(2), pO(2), sO(2), cHb, BE) and of the strong ion gap (SIG) may be useful.
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Affiliation(s)
- W Lang
- Institut für Physiologie und Pathophysiologie, Johannes Gutenberg-Universität Mainz, Duesbergweg 6, 55128 Mainz.
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Story DA, Morimatsu H, Bellomo R. Hyperchloremic Acidosis in the Critically Ill: One of the Strong-Ion Acidoses? Anesth Analg 2006; 103:144-8, table of contents. [PMID: 16790643 DOI: 10.1213/01.ane.0000221449.67354.52] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Decreases in plasma bicarbonate are associated with hyperchloremic acidosis and lactic acidosis. According to the Stewart approach to acid-base physiology, the strong-ion difference regulates plasma bicarbonate, with chloride and lactate being the only strong anions routinely measured in clinical chemistry. We hypothesized that the plasma strong-ion difference, both with and without lactate, would have a stronger association with plasma bicarbonate than plasma chloride alone would have with bicarbonate. We used plasma acid-base data from 300 critically ill patients. The correlation with bicarbonate became progressively weaker (P < 0.001): all measured strong ions, r = 0.60; measured strong ions without lactate, r = 0.42; chloride alone, r = -0.27. In a subgroup of 26 patients with traditional hyperchloremic acidosis (base excess < -2 mmol/L and anion gap <17 mmol/L), the measured strong-ion difference (without lactate) had a stronger correlation (P < 0.001) with bicarbonate than chloride had: r = 0.85 versus r = -0.60. We conclude that hyperchloremic acidosis and lactic acidosis are strong-ion acidoses. Hyperchloremia should be viewed relative to the plasma strong cations. A practical conclusion is that both managing and preventing acid-base disorders with IV fluid therapy involves manipulating each of the plasma strong ions, particularly sodium and chloride.
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Affiliation(s)
- David A Story
- Department of Anaesthesia, University of Melbourne, Austin Health, Heidelberg, Victoria, Australia.
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26
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Abstract
Recent advances in acid-base physiology and in the epidemiology of acid-base disorders have refined our understanding of the basic control mechanisms that determine blood pH in health and disease. These refinements have also brought parity between the newer, quantitative and older, descriptive approaches to acid-base physiology. This review explores how the new and older approaches to acid-base physiology can be reconciled and combined to result in a powerful bedside tool. A case based tutorial is also provided.
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Affiliation(s)
- John A Kellum
- The CRISMA (Clinical Research Investigation and Systems Modeling of Acute Illness) Laboratory, Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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27
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Abstract
We summarize all original research in the field of critical care nephrology published in 2004 or accepted for publication in Critical Care and, when considered relevant or directly linked to this research, in other journals. Articles were grouped into four categories to facilitate a rapid overview. First, regarding the definition of acute renal failure (ARF), the RIFLE criteria (risk, injury, failure, loss, ESKD [end-stage kidney disease]) for diagnosis of ARF were defined by the Acute Dialysis Quality Initiative workgroup and applied in clinical practice by some authors. The second category is acid-base disorders in ARF; the Stewart-Figge quantitative approach to acidosis in critically ill patients has been utilized by two groups of researchers, with similar results but different conclusions. In the third category - blood markers during ARF - cystatin C as an early marker of ARF and procalcitonin as a sepsis marker during continuous venovenous haemofiltration were examined. Finally, in the extracorporeal treatment of ARF, the ability of two types of high cutoff haemofilters to influence blood levels of middle- and high-molecular-weight toxins showed promise.
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Affiliation(s)
- Zaccaria Ricci
- Consultant, Department of Anesthesiology and Intensive Care, University of Rome 'La Sapienza', Rome, Italy
| | - Claudio Ronco
- Head, Department of Nephrology, Dialysis and Transplantation, S Bortolo Hospital, Vicenza, Italy
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Morgan TJ. The meaning of acid-base abnormalities in the intensive care unit: part III -- effects of fluid administration. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2004; 9:204-11. [PMID: 15774079 PMCID: PMC1175908 DOI: 10.1186/cc2946] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Stewart's quantitative physical chemical approach enables us to understand the acid–base properties of intravenous fluids. In Stewart's analysis, the three independent acid–base variables are partial CO2 tension, the total concentration of nonvolatile weak acid (ATOT), and the strong ion difference (SID). Raising and lowering ATOT while holding SID constant cause metabolic acidosis and alkalosis, respectively. Lowering and raising plasma SID while clamping ATOT cause metabolic acidosis and alkalosis, respectively. Fluid infusion causes acid–base effects by forcing extracellular SID and ATOT toward the SID and ATOT of the administered fluid. Thus, fluids with vastly differing pH can have the same acid–base effects. The stimulus is strongest when large volumes are administered, as in correction of hypovolaemia, acute normovolaemic haemodilution, and cardiopulmonary bypass. Zero SID crystalloids such as saline cause a 'dilutional' acidosis by lowering extracellular SID enough to overwhelm the metabolic alkalosis of ATOT dilution. A balanced crystalloid must reduce extracellular SID at a rate that precisely counteracts the ATOT dilutional alkalosis. Experimentally, the crystalloid SID required is 24 mEq/l. When organic anions such as L-lactate are added to fluids they can be regarded as weak ions that do not contribute to fluid SID, provided they are metabolized on infusion. With colloids the presence of ATOT is an additional consideration. Albumin and gelatin preparations contain ATOT, whereas starch preparations do not. Hextend is a hetastarch preparation balanced with L-lactate. It reduces or eliminates infusion related metabolic acidosis, may improve gastric mucosal blood flow, and increases survival in experimental endotoxaemia. Stored whole blood has a very high effective SID because of the added preservative. Large volume transfusion thus causes metabolic alkalosis after metabolism of contained citrate, a tendency that is reduced but not eliminated with packed red cells. Thus, Stewart's approach not only explains fluid induced acid–base phenomena but also provides a framework for the design of fluids for specific acid–base effects.
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Affiliation(s)
- Thomas J Morgan
- Adult Intensive Care, Mater Misericordiae Hospitals, Brisbane, Australia.
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