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Hofmaenner DA, Singer M. Challenging management dogma where evidence is non-existent, weak, or outdated: part II. Intensive Care Med 2024:10.1007/s00134-024-07634-x. [PMID: 39320462 DOI: 10.1007/s00134-024-07634-x] [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: 07/06/2024] [Accepted: 08/24/2024] [Indexed: 09/26/2024]
Abstract
Many dogmas influence daily clinical practice, and critical care medicine is no exception. We previously highlighted the weak, questionable, and often contrary evidence base underpinning four established medical managements-loop diuretics for acute heart failure, routine use of heparin thromboprophylaxis, rate of sodium correction for hyponatremia, and 'every hour counts' for treating bacterial meningitis. We now provide four further examples in this "Dogma II" piece (a week's course of antibiotics, diabetic ketoacidosis algorithms, sodium bicarbonate to improve ventricular contractility during severe metabolic acidosis, and phosphate replacement for hypophosphatemia) where routine practice warrants re-appraisal.
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Affiliation(s)
- Daniel A Hofmaenner
- Bloomsbury Institute of Intensive Care Medicine, University College London, London, UK
- Institute of Intensive Care Medicine, University Hospital Zurich, Zurich, Switzerland
| | - Mervyn Singer
- Bloomsbury Institute of Intensive Care Medicine, University College London, London, UK.
- Division of Medicine, Bloomsbury Institute of Intensive Care Medicine, University College London, London, UK.
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2
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Claure-Del Granado R, Prudencio-Ribera VC, Gupta V, Yang J, Kashani K, Malhotra R. Bicarbonate-Based Solution for the Management of Established Acute Kidney Injury: A Pilot Open-Label Observation Study. Cureus 2023; 15:e42127. [PMID: 37476296 PMCID: PMC10355685 DOI: 10.7759/cureus.42127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/18/2023] [Indexed: 07/22/2023] Open
Abstract
Background Administration of intravenous (IV) solutions constitutes a key component of acute kidney injury (AKI) management. However, the optimal IV fluid solution in the setting of AKI remains uncertain. In this study, we assessed whether the use of bicarbonate-containing solution in patients with established AKI is associated with early renal recovery as compared to bicarbonate-free solutions. Methods We performed an open-label observational pilot study in 59 patients with established AKI. IV fluid solutions that were used include bicarbonate-based solution with low chloride content (80 mEq/L of 8% sodium bicarbonate in a solution that contains 77 mEq/L of sodium, 77 mEq/L of chloride and 25 g/L of glucose) or solutions without bicarbonate with high chloride content (0.9% normal saline, 0.45% half-saline, normal ringer, or 4% succinylated gelatine). We evaluated the association of IV fluids type with renal recovery. Results The median age of study participants was 66 years (inter-quartile range (IQR) 37-85), and 59% (n=35) were men. The prevalence of diabetes and chronic kidney disease (CKD) stages 1-3 were 34% (n=20) and 39% (n=23), respectively. Patients who received bicarbonate-based IV solutions had a greater reduction of serum creatinine (sCr) per day (delta sCr) as compared with patients who received bicarbonate-free solutions (-0.29±0.47 vs. 0.07±0.42; p=0.007). The renal recovery was faster in patients who received bicarbonate-based solutions as compared to the bicarbonate-free group (days from peak sCr to baseline sCr: 5.6±2.1 vs. 7.6±2.8; p < 0.001, respectively). Conclusions We observed faster renal recovery in patients with established AKI who received the bicarbonate-based solution with low chloride content. Our study findings require confirmation in larger cohorts.
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Affiliation(s)
- Rolando Claure-Del Granado
- Division of Nephrology, Department of Medicine, Hospital Obrero No. 2 - Caja Nacional de Salud (CNS) Universidad Mayor de San Simon, Cochabamba, BOL
| | | | - Vineet Gupta
- Medicine/Hospital Medicine, University of California San Diego School of Medicine, San Diego, USA
| | - Jason Yang
- Medicine, University of California San Diego School of Medicine, San Diego, USA
| | - Kianoush Kashani
- Pulmonary and Critical Care Medicine, Mayo Clinic, Rochester, USA
- Nephrology and Hypertension, Mayo Clinic, Rochester, USA
| | - Rakesh Malhotra
- Division of Nephrology and Hypertension, Department of Medicine, University of California San Diego School of Medicine, San Diego, USA
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Peng J, Zhao J, Tang Q, Wang J, Song W, Lu X, Huang X, Chen G, Zheng W, Zhang L, Han Y, Yan C, Wan Q, Chen L. Low intensity near-infrared light promotes bone regeneration via circadian clock protein cryptochrome 1. Int J Oral Sci 2022; 14:53. [PMID: 36376275 PMCID: PMC9663728 DOI: 10.1038/s41368-022-00207-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 09/04/2022] [Accepted: 10/12/2022] [Indexed: 11/16/2022] Open
Abstract
Bone regeneration remains a great clinical challenge. Low intensity near-infrared (NIR) light showed strong potential to promote tissue regeneration, offering a promising strategy for bone defect regeneration. However, the effect and underlying mechanism of NIR on bone regeneration remain unclear. We demonstrated that bone regeneration in the rat skull defect model was significantly accelerated with low-intensity NIR stimulation. In vitro studies showed that NIR stimulation could promote the osteoblast differentiation in bone mesenchymal stem cells (BMSCs) and MC3T3-E1 cells, which was associated with increased ubiquitination of the core circadian clock protein Cryptochrome 1 (CRY1) in the nucleus. We found that the reduction of CRY1 induced by NIR light activated the bone morphogenetic protein (BMP) signaling pathways, promoting SMAD1/5/9 phosphorylation and increasing the expression levels of Runx2 and Osterix. NIR light treatment may act through sodium voltage-gated channel Scn4a, which may be a potential responder of NIR light to accelerate bone regeneration. Together, these findings suggest that low-intensity NIR light may promote in situ bone regeneration in a CRY1-dependent manner, providing a novel, efficient and non-invasive strategy to promote bone regeneration for clinical bone defects.
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Ali ES, Lipońska A, O'Hara BP, Amici DR, Torno MD, Gao P, Asara JM, Yap MNF, Mendillo ML, Ben-Sahra I. The mTORC1-SLC4A7 axis stimulates bicarbonate import to enhance de novo nucleotide synthesis. Mol Cell 2022; 82:3284-3298.e7. [PMID: 35772404 PMCID: PMC9444906 DOI: 10.1016/j.molcel.2022.06.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 05/15/2022] [Accepted: 06/07/2022] [Indexed: 12/12/2022]
Abstract
Bicarbonate (HCO3-) ions maintain pH homeostasis in eukaryotic cells and serve as a carbonyl donor to support cellular metabolism. However, whether the abundance of HCO3- is regulated or harnessed to promote cell growth is unknown. The mechanistic target of rapamycin complex 1 (mTORC1) adjusts cellular metabolism to support biomass production and cell growth. We find that mTORC1 stimulates the intracellular transport of HCO3- to promote nucleotide synthesis through the selective translational regulation of the sodium bicarbonate cotransporter SLC4A7. Downstream of mTORC1, SLC4A7 mRNA translation required the S6K-dependent phosphorylation of the translation factor eIF4B. In mTORC1-driven cells, loss of SLC4A7 resulted in reduced cell and tumor growth and decreased flux through de novo purine and pyrimidine synthesis in human cells and tumors without altering the intracellular pH. Thus, mTORC1 signaling, through the control of SLC4A7 expression, harnesses environmental bicarbonate to promote anabolic metabolism, cell biomass, and growth.
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Affiliation(s)
- Eunus S Ali
- Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL 60611, USA
| | - Anna Lipońska
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Brendan P O'Hara
- Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL 60611, USA
| | - David R Amici
- Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL 60611, USA
| | - Michael D Torno
- Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL 60611, USA
| | - Peng Gao
- Metabolomics Core Facility, Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL 60611, USA
| | - John M Asara
- Mass Spectrometry Core, Beth Israel Deaconess Medical Center, Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Mee-Ngan F Yap
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Marc L Mendillo
- Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL 60611, USA
| | - Issam Ben-Sahra
- Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL 60611, USA.
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Abstract
Lactic acidosis occurs commonly and can be a marker of significant physiologic derangements. However what an elevated lactate level and acidemia connotes and what should be done about it is subject to inconsistent interpretations. This review examines the varied etiologies of lactic acidosis, the physiologic consequences, and the known effects of its treatment with sodium bicarbonate. Lactic acidosis is often assumed to be a marker of hypoperfusion, but it can also result from medications, organ dysfunction, and sepsis even in the absence of malperfusion. Acidemia causes deleterious effects in almost every organ system, but it can also have positive effects, increasing localized blood flow and oxygen delivery, as well as providing protection against hypoxic cellular injury. The use of sodium bicarbonate to correct severe acidemia may be tempting to clinicians, but previous studies have failed to show improved patient outcomes following bicarbonate administration. Bicarbonate use is known to decrease vasomotor tone, decrease myocardial contractility, and induce intracellular acidosis. This suggests that mild to moderate acidemia does not require correction. Most recently, a randomized control trial found a survival benefit in a subgroup of critically ill patients with serum pH levels <7.2 with concomitant acute kidney injury. There is no known benefit of correcting serum pH levels ≥ 7.2, and sparse evidence supports bicarbonate use <7.2. If administered, bicarbonate is best given as a slow IV infusion in the setting of adequate ventilation and calcium replacement to mitigate its untoward effects.
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Wang T, Yi L, Zhang H, Wang T, Xi J, Zeng L, He J, Zhang Z, Ma P. Risk Potential for Organ Dysfunction Associated With Sodium Bicarbonate Therapy in Critically Ill Patients With Hemodynamic Worsening. Front Med (Lausanne) 2021; 8:665907. [PMID: 34307402 PMCID: PMC8292723 DOI: 10.3389/fmed.2021.665907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 06/11/2021] [Indexed: 02/05/2023] Open
Abstract
Background: The role of sodium bicarbonate therapy (SBT) remains controversial. This study aimed to investigate whether hemodynamic status before SBT contributed to the heterogeneous outcomes associated with SBT in acute critically ill patients. Methods: We obtained data from patients with metabolic acidosis from the Medical Information Mart for Intensive Care (MIMIC)-III database. Propensity score matching (PSM) was applied to match the SBT group with the control group. Logistic regression and Cox regression were used to analyze a composite of newly "developed or exacerbated organ dysfunction" (d/eOD) within 7 days of ICU admission and 28-day mortality associated with SBT for metabolic acidosis. Results: A total of 1,765 patients with metabolic acidosis were enrolled, and 332 pairs obtained by PSM were applied to the final analyses in the study. An increased incidence of newly d/eOD was observed in the SB group compared with the control group (54.8 vs. 44.6%, p < 0.01). Multivariable logistic regression indicated that the adjusted OR of SBT for this composite outcome was no longer significant [OR (95% CI): 1.39 (0.9, 1.85); p = 0.164]. This effect of SBT did not change with the quintiles stratified by pH. Interestingly, SBT was associated with an increased risk of the composite of newly d/eOD in the subgroup of patients with worsening hemodynamics before SBT [adjusted OR (95% CI): 3.6 (1.84, 7.22), p < 0.001]. Moreover, the risk potential for this composite of outcomes was significantly increased in patients characterized by both worsening [adjusted OR (95% CI): 2.91 (1.54, 5.47), p < 0.001] and unchanged hemodynamics [adjusted OR (95% CI): 1.94 (1.01, 3.72), p = 0.046] compared to patients with improved hemodynamics before SBT. Our study failed to demonstrate an association between SBT and 28-day mortality in acute critically ill patients with metabolic acidosis. Conclusions: Our findings did not demonstrate an association between SBT and outcomes in critically ill patients with metabolic acidosis. However, patients with either worsening or unchanged hemodynamic status in initial resuscitation had a significantly higher risk potential of newly d/eOD subsequent to SBT.
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Affiliation(s)
- Tiehua Wang
- Critical Care Medicine Department, Peking University Third Hospital, Beijing, China
| | - Lingxian Yi
- Critical Care Medicine Department, Strategic Support Force Characteristic Medical Center of People's Liberation Army, Beijing, China
| | - Hua Zhang
- Research Center of Clinical Epidemiology, Peking University Third Hospital, Beijing, China
| | - Tianhao Wang
- Emergency Department, The 8th Medical Centre of Chinese People's Liberation Army (PLA) General Hospital, Beijing, China
| | - Jingjing Xi
- Critical Care Medicine Department, Peking University Third Hospital, Beijing, China
| | - Lin Zeng
- Research Center of Clinical Epidemiology, Peking University Third Hospital, Beijing, China
| | - Junlin He
- Department of Medical Affairs, Shanghai Palan DataRx Co. Ltd., Shanghai, China
| | - Zhongheng Zhang
- Department of Emergency Medicine, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Penglin Ma
- Critical Care Medicine Department, Peking University Third Hospital, Beijing, China
- Critical Care Medicine Department, Guiqian International General Hospital, Guiyang, China
- *Correspondence: Penglin Ma
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7
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Jung B, Jaber S. The Janus faces of bicarbonate therapy in the ICU. Intensive Care Med 2019; 46:516-518. [PMID: 31713059 DOI: 10.1007/s00134-019-05835-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 10/17/2019] [Indexed: 12/31/2022]
Affiliation(s)
- Boris Jung
- Département de Médecine Intensive et Réanimation, CHU Montpellier, 34000, Montpellier, France.,PhyMedExp, INSERM U1046, CNRS, UMR 9214, Centre Hospitalier Universitaire Montpellier, University of Montpellier, 34295, Montpellier Cedex 5, France
| | - Samir Jaber
- PhyMedExp, INSERM U1046, CNRS, UMR 9214, Centre Hospitalier Universitaire Montpellier, University of Montpellier, 34295, Montpellier Cedex 5, France. .,Intensive Care Unit, Anesthesiology and Intensive Care, Anesthesia and Critical Care Department B, Saint Eloi Teaching Hospital, Centre Hospitalier Universitaire Montpellier, University Montpellier, 1, 80 Avenue Augustin Fliche, 34295, Montpellier Cedex 5, France.
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8
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Fujii T, Udy A, Licari E, Romero L, Bellomo R. Sodium bicarbonate therapy for critically ill patients with metabolic acidosis: A scoping and a systematic review. J Crit Care 2019; 51:184-191. [DOI: 10.1016/j.jcrc.2019.02.027] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 02/21/2019] [Accepted: 02/25/2019] [Indexed: 01/31/2023]
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Wasiluk T, Roueinfar M, Hiryak K, Torsiello M, Miner A, Lee J, Venditto M, Terzaghi W, Lucent D, VanWert AL. Simultaneous expression of ClopHensor and SLC26A3 reveals the nature of endogenous oxalate transport in CHO cells. Biol Open 2019; 8:bio.041665. [PMID: 30837228 PMCID: PMC6504001 DOI: 10.1242/bio.041665] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
ClopHensor, a fluorescent fusion protein, is a dual function biosensor that has been utilized as a tool for the simultaneous measurement of intracellular chloride and pH in cells. ClopHensor has traditionally been used in conjunction with fluorescence microscopy for single cell measurements. Here, we present a promising multi-well format advancement for the use of ClopHensor as a potential high-throughput method capable of measuring fluorescence signal intensity across a well of confluent cells with highly reproducible results. Using this system, we gained mechanistic insight into an endogenous oxalate transporter in Chinese hamster ovary (CHO) cells expressing ClopHensor and the human chloride transporter, SLC26A3. SLC26A3, a known anion exchanger, has been proposed to play a role in colonic oxalate absorption in humans. Our attempt to study the role of SLC26A3 in oxalate transport revealed the presence of an endogenous oxalate transporter in CHO cells. This transporter was strongly inhibited by niflumate, and exhibited clear saturability. Use of ClopHensor in a multi-well cell assay allowed us to quickly demonstrate that the endogenous oxalate transporter was unable to exchange chloride for bicarbonate, unlike SLC26A3.
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Affiliation(s)
- Teresa Wasiluk
- Department of Biology, College of Science and Engineering, Wilkes University, Wilkes-Barre, PA 18766, USA
| | - Mina Roueinfar
- Department of Electrical Engineering and Physics, College of Science and Engineering, Wilkes University, Wilkes-Barre, PA 18766, USA
| | - Kayla Hiryak
- Department of Pharmaceutical Sciences, Nesbitt School of Pharmacy, Wilkes University, Wilkes-Barre, PA 18766, USA
| | - Maria Torsiello
- Department of Pharmaceutical Sciences, Nesbitt School of Pharmacy, Wilkes University, Wilkes-Barre, PA 18766, USA
| | - Alexander Miner
- Department of Biology, College of Science and Engineering, Wilkes University, Wilkes-Barre, PA 18766, USA
| | - Jennifer Lee
- Department of Pharmaceutical Sciences, Nesbitt School of Pharmacy, Wilkes University, Wilkes-Barre, PA 18766, USA
| | - Michael Venditto
- Department of Pharmaceutical Sciences, Nesbitt School of Pharmacy, Wilkes University, Wilkes-Barre, PA 18766, USA
| | - William Terzaghi
- Department of Biology, College of Science and Engineering, Wilkes University, Wilkes-Barre, PA 18766, USA
| | - Del Lucent
- Department of Electrical Engineering and Physics, College of Science and Engineering, Wilkes University, Wilkes-Barre, PA 18766, USA
| | - Adam L VanWert
- Department of Pharmaceutical Sciences, Nesbitt School of Pharmacy, Wilkes University, Wilkes-Barre, PA 18766, USA
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Rosenstein PG, Tennent-Brown BS, Hughes D. Clinical use of plasma lactate concentration. Part 2: Prognostic and diagnostic utility and the clinical management of hyperlactatemia. J Vet Emerg Crit Care (San Antonio) 2018. [PMID: 29533517 DOI: 10.1111/vec.12706] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
OBJECTIVE To review the current literature pertaining to the use of lactate as a prognostic indicator and therapeutic guide, the utility of measuring lactate concentrations in body fluids other than blood or plasma, and the clinical management of hyperlactatemia in dogs, cats, and horses. DATA SOURCES Articles were retrieved without date restrictions primarily via PubMed, Scopus, and CAB Abstracts as well as by manual selection. HUMAN AND VETERINARY DATA SYNTHESIS Increased plasma lactate concentrations are associated with increased morbidity and mortality. In populations with high mortality, hyperlactatemia is moderately predictive in identifying nonsurvivors. Importantly, eulactatemia predicts survival better than hyperlactatemia predicts death. Consecutive lactate measurements and calculated relative measures appear to outperform single measurements. The use of lactate as a therapeutic guide has shown promising results in people but is relatively uninvestigated in veterinary species. Increased lactate concentrations in body fluids other than blood should raise the index of suspicion for septic or malignant processes. Management of hyperlactatemia should target the underlying cause. CONCLUSION Lactate is a valuable triage and risk stratification tool that can be used to separate patients into higher and lower risk categories. The utility of lactate concentration as a therapeutic target and the measurement of lactate in body fluids shows promise but requires further research.
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Affiliation(s)
- Patricia G Rosenstein
- Department of Veterinary Clinical Sciences, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Werribee, Victoria, Australia
| | - Brett S Tennent-Brown
- Department of Veterinary Clinical Sciences, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Werribee, Victoria, Australia
| | - Dez Hughes
- Department of Veterinary Clinical Sciences, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Werribee, Victoria, Australia
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Zhao R, Najmi M, Aluri S, Spray DC, Goldman ID. Concentrative Transport of Antifolates Mediated by the Proton-Coupled Folate Transporter (SLC46A1); Augmentation by a HEPES Buffer. Mol Pharmacol 2018; 93:208-215. [PMID: 29326243 DOI: 10.1124/mol.117.110445] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 01/08/2018] [Indexed: 11/22/2022] Open
Abstract
The proton-coupled folate transporter (PCFT) is ubiquitously expressed in solid tumors to which it delivers antifolates, particularly pemetrexed, into cancer cells. Studies of PCFT-mediated transport, to date, have focused exclusively on the influx of folates and antifolates. This article addresses the impact of PCFT on concentrative transport, critical to the formation of the active polyglutamate congeners, and at pH levels relevant to the tumor microenvironment. An HeLa-derived cell line was employed, in which folate-specific transport was mediated exclusively by PCFT. At pH 7.0, there was a substantial chemical gradient for methotrexate that decreased as the extracellular pH was increased. A chemical gradient was still detected at pH 7.4 in the usual HEPES-based transport buffer in contrast to what was observed in a bicarbonate/CO2-buffered medium. This antifolate gradient correlated with an alkaline intracellular pH in the former (pH 7.85), but not the latter (pH 7.39), buffer and was abolished by the protonophore carbonyl cyanide-4-(trifluoromethoxy)phenylhydrazone. The gradient in HEPES buffer at pH 7.4 was the result of the activity of Na+/H+ exchanger(s); it was eliminated by inhibitors of Na+/H+ exchanger (s) or Na+/K+ ATPase. An antifolate chemical gradient was also detected in bicarbonate buffer at pH 6.9 versus 7.4, also suppressed by carbonyl cyanide-4-(trifluoromethoxy)phenylhydrazone. When the membrane potential is considered, PCFT generates substantial transmembrane electrochemical-potential gradients at extracellular pH levels relevant to the tumor microenvironment. The augmentation of intracellular pH, when cells are in a HEPES buffer, should be taken into consideration in studies that encompass all proton-coupled transporter families.
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Affiliation(s)
- Rongbao Zhao
- Departments of Molecular Pharmacology (R.Z., M.N., S.A., I.D.G.), Medicine (R.Z., I.D.G.), and Dominick P. Purpura Department of Neuroscience (D.C.S.), Albert Einstein College of Medicine, Bronx, New York
| | - Mitra Najmi
- Departments of Molecular Pharmacology (R.Z., M.N., S.A., I.D.G.), Medicine (R.Z., I.D.G.), and Dominick P. Purpura Department of Neuroscience (D.C.S.), Albert Einstein College of Medicine, Bronx, New York
| | - Srinivas Aluri
- Departments of Molecular Pharmacology (R.Z., M.N., S.A., I.D.G.), Medicine (R.Z., I.D.G.), and Dominick P. Purpura Department of Neuroscience (D.C.S.), Albert Einstein College of Medicine, Bronx, New York
| | - David C Spray
- Departments of Molecular Pharmacology (R.Z., M.N., S.A., I.D.G.), Medicine (R.Z., I.D.G.), and Dominick P. Purpura Department of Neuroscience (D.C.S.), Albert Einstein College of Medicine, Bronx, New York
| | - I David Goldman
- Departments of Molecular Pharmacology (R.Z., M.N., S.A., I.D.G.), Medicine (R.Z., I.D.G.), and Dominick P. Purpura Department of Neuroscience (D.C.S.), Albert Einstein College of Medicine, Bronx, New York
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12
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Collins A, Sahni R. Uses and misuses of sodium bicarbonate in the neonatal intensive care unit. Semin Fetal Neonatal Med 2017; 22:336-341. [PMID: 28801177 DOI: 10.1016/j.siny.2017.07.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Over the past several decades, bicarbonate therapy continues to be used routinely in the treatment of acute metabolic acidosis in critically ill neonates despite the lack of evidence for its effectiveness in the treatment of acid-base imbalance, and evidence indicating that it may be detrimental. Clinicians often feel compelled to use bicarbonate since acidosis implies a need for such therapy and thus the justification for its use is based on hearsay rather than science. This review summarizes the evidence and refutes the clinical practice of administering sodium bicarbonate to treat metabolic acidosis associated with several specific clinical syndromes in neonates.
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Affiliation(s)
- Amélie Collins
- Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Rakesh Sahni
- Columbia University College of Physicians and Surgeons, New York, NY, USA.
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13
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Cho JS, Soh S, Shim JK, Kang S, Choi H, Kwak YL. Effect of perioperative sodium bicarbonate administration on renal function following cardiac surgery for infective endocarditis: a randomized, placebo-controlled trial. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2017; 21:3. [PMID: 28057030 PMCID: PMC5217446 DOI: 10.1186/s13054-016-1591-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 12/12/2016] [Indexed: 12/18/2022]
Abstract
Background Patients with infective endocarditis (IE) have an elevated risk of renal dysfunction because of extensive systemic inflammation and use of nephrotoxic antibiotics. In this randomized, placebo-controlled trial, we investigated whether perioperative sodium bicarbonate administration could attenuate postoperative renal dysfunction in patients with IE undergoing cardiac surgery. Methods Seventy patients randomly received sodium chloride (n = 35) or sodium bicarbonate (n = 35). Sodium bicarbonate was administered as a 0.5 mmol/kg loading dose for 1 h commencing with anesthetic induction, followed by a 0.15 mmol/kg/h infusion for 23 h. The primary outcome was peak serum creatinine (SCr) level during the first 48 h postoperatively. The incidence of acute kidney injury, SCr level, estimated glomerular filtration rate, and major morbidity endpoints were assessed postoperatively. Results The peak SCr during the first 48 h postoperatively (bicarbonate vs. control: 1.01 (0.74, 1.37) mg/dl vs. 0.88 (0.76, 1.27) mg/dl, P = 0.474) and the incidence of acute kidney injury (bicarbonate vs. control: 29% vs. 23%, P = 0.584) were similar in both groups. The postoperative increase in SCr above baseline was greater in the bicarbonate group than in the control group on postoperative day 2 (0.21 (0.07, 0.33) mg/dl vs. 0.06 (0.00, 0.23) mg/dl, P = 0.028) and postoperative day 5 (0.23 (0.08, 0.36) mg/dl vs. 0.06 (0.00, 0.23) mg/dl, P = 0.017). Conclusions Perioperative sodium bicarbonate administration had no favorable impact on postoperative renal function and outcomes in patients with IE undergoing cardiac surgery. Instead, it was associated with possibly harmful renal effects, illustrated by a greater increase in SCr postoperatively, compared to control. Trial registration ClinicalTrials.gov, NCT01920126. Registered on 31 July 2013. Electronic supplementary material The online version of this article (doi:10.1186/s13054-016-1591-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jin Sun Cho
- Department of Anesthesiology and Pain Medicine, Yonsei Cardiovascular Hospital, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, Republic of Korea
| | - Sarah Soh
- Department of Anesthesiology and Pain Medicine, Yonsei Cardiovascular Hospital, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, Republic of Korea
| | - Jae-Kwang Shim
- Department of Anesthesiology and Pain Medicine, Yonsei Cardiovascular Hospital, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, Republic of Korea.,Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Sanghwa Kang
- Department of Anesthesiology and Pain Medicine, National Health Insurance Corporation Ilsan Hospital, Gyeonggi-do, Republic of Korea
| | - Haegi Choi
- Department of Anesthesiology and Pain Medicine, Yonsei Cardiovascular Hospital, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, Republic of Korea
| | - Young-Lan Kwak
- Department of Anesthesiology and Pain Medicine, Yonsei Cardiovascular Hospital, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, Republic of Korea. .,Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Seoul, Republic of Korea.
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Mason TG, Kraut JA. Treatment of Acidified Blood Using Reduced Osmolarity Mixed-Base Solutions. Front Physiol 2016; 7:625. [PMID: 28082905 PMCID: PMC5183630 DOI: 10.3389/fphys.2016.00625] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 11/29/2016] [Indexed: 01/30/2023] Open
Abstract
We hypothesize that reduced osmolarity mixed-base (ROMB) solutions can potentially serve as customizable treatments for acidoses, going beyond standard solutions in clinical use, such as 1.0 M sodium bicarbonate. Through in silico quantitative modeling, by treating acidified canine blood using ROMB solutions, and by performing blood-gas and optical microscopy measurements in vitro, we demonstrate that ROMB solutions having a high proportion of a strong base, such as disodium carbonate or sodium hydroxide, can be effective in reducing carbon dioxide pressure PCO2 while raising pH and bicarbonate ion concentration without causing significant osmotic damage to red blood cells, which can occur during rapid administration of hypertonic solutions of weak bases. These results suggest that a ROMB solution, which is composed mostly of a strong base, could be administered in a safe and effective manner, when compared to a hypertonic solution of sodium bicarbonate. Because of the reduced osmolarity and the customizable content of strong base in ROMB solutions, this approach differs from prior approaches involving hypertonic solutions that only considered a single molar ratio of strong to weak base. Our calculations and measurements suggest that custom-tailored ROMB solutions merit consideration as potentially efficacious treatments for specific types of acidosis, particularly acute metabolic acidosis and acute respiratory acidosis.
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Affiliation(s)
- Thomas G Mason
- Department of Chemistry and Biochemistry, University of California, Los AngelesLos Angeles, CA, USA; Department of Physics and Astronomy, University of California, Los AngelesLos Angeles, CA, USA
| | - Jeffrey A Kraut
- Medical and Research Services, Veterans Health Administration Greater Los Angeles Area Healthcare SystemLos Angeles, CA, USA; Division of Nephrology, Veterans Health Administration Greater Los Angeles Area Healthcare SystemLos Angeles, CA, USA; Membrane Biology Laboratory, David Geffen School of Medicine, University of California, Los AngelesLos Angeles, CA, USA
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15
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Reinwald Y, Leonard KHL, Henstock JR, Whiteley JP, Osborne JM, Waters SL, Levesque P, El Haj AJ. Evaluation of the growth environment of a hydrostatic force bioreactor for preconditioning of tissue-engineered constructs. Tissue Eng Part C Methods 2015; 21:1-14. [PMID: 24967717 DOI: 10.1089/ten.tec.2013.0476] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Bioreactors have been widely acknowledged as valuable tools to provide a growth environment for engineering tissues and to investigate the effect of physical forces on cells and cell-scaffold constructs. However, evaluation of the bioreactor environment during culture is critical to defining outcomes. In this study, the performance of a hydrostatic force bioreactor was examined by experimental measurements of changes in dissolved oxygen (O2), carbon dioxide (CO2), and pH after mechanical stimulation and the determination of physical forces (pressure and stress) in the bioreactor through mathematical modeling and numerical simulation. To determine the effect of hydrostatic pressure on bone formation, chick femur skeletal cell-seeded hydrogels were subjected to cyclic hydrostatic pressure at 0-270 kPa and 1 Hz for 1 h daily (5 days per week) over a period of 14 days. At the start of mechanical stimulation, dissolved O2 and CO2 in the medium increased and the pH of the medium decreased, but remained within human physiological ranges. Changes in physiological parameters (O2, CO2, and pH) were reversible when medium samples were placed in a standard cell culture incubator. In addition, computational modeling showed that the distribution and magnitude of physical forces depends on the shape and position of the cell-hydrogel constructs in the tissue culture format. Finally, hydrostatic pressure was seen to enhance mineralization of chick femur skeletal cell-seeded hydrogels.
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Affiliation(s)
- Yvonne Reinwald
- 1 Institute of Science and Technology in Medicine, University of Keele , Stoke-on-Trent, United Kingdom
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The Use of Sodium Bicarbonate in the Treatment of Acidosis in Sepsis: A Literature Update on a Long Term Debate. Crit Care Res Pract 2015; 2015:605830. [PMID: 26294968 PMCID: PMC4534594 DOI: 10.1155/2015/605830] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2015] [Revised: 06/29/2015] [Accepted: 07/01/2015] [Indexed: 12/29/2022] Open
Abstract
Introduction. Sepsis and its consequences such as metabolic acidosis are resulting in increased mortality. Although correction of metabolic acidosis with sodium bicarbonate seems a reasonable approach, there is ongoing debate regarding the role of bicarbonates as a therapeutic option. Methods. We conducted a PubMed literature search in order to identify published literature related to the effects of sodium bicarbonate treatment on metabolic acidosis due to sepsis. The search included all articles published in English in the last 35 years. Results. There is ongoing debate regarding the use of bicarbonates for the treatment of acidosis in sepsis, but there is a trend towards not using bicarbonate in sepsis patients with arterial blood gas pH > 7.15. Conclusions. Routine use of bicarbonate for treatment of severe acidemia and lactic acidosis due to sepsis is subject of controversy, and current opinion does not favor routine use of bicarbonates. However, available evidence is inconclusive, and more studies are required to determine the potential benefit, if any, of bicarbonate therapy in the sepsis patient with acidosis.
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Interaction of sodium bicarbonate and Na+/H+ exchanger inhibition in the treatment of acute metabolic acidosis in pigs. Crit Care Med 2015; 43:e160-9. [PMID: 25785519 DOI: 10.1097/ccm.0000000000000962] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
OBJECTIVE Administration of NaHCO3 does not improve cellular function or reduce the mortality of acute lactic acidosis. This might be related to aggravation of intracellular acidosis, but it could also be due to activation of Na+/H+ exchanger with a deleterious increment in intracellular calcium ([Ca2+]i). This study examined the impact of coadministration of NaHCO3 and a selective inhibitor of Na+/H+ exchanger, sabiporide on cardiovascular function, changes in proinflammatory cytokines, and organ function in a model of acute lactic acidosis produced by hemorrhagic hypotension followed by infusion of lactic acid. DESIGN Experimental, prospective study. SETTING Medical Center research laboratory. SUBJECTS Male Yorkshire pigs. INTERVENTIONS Anesthetized pigs were subjected to hypovolemia for 30 minutes and followed by DL-lactic acid infusion, and then either saline or sodium bicarbonate was infused. MEASUREMENTS AND MAIN RESULTS Hypovolemia followed by a DL-lactic acid infusion resulted in severe acidemia with a blood pH~6.8. Administration of NaHCO3 did not improve cardiovascular performance or decrease the levels of proinflammatory responses, whereas administration of sabiporide prior to acid or NaHCO3 infusion improved cardiopulmonary performance and blood oxygenation, reduced nuclear factor-κB activation, neutrophil accumulation, and proinflammatory cytokine production, and attenuated organ injury. Exposure of rat cardiac myocytes to a pH of 7.2 led to a marked increase of [Ca2+]i, and release of lactate dehydrogenase from cells which were further augmented after increase in external pH by addition of NaHCO3. Both the increase in [Ca2+]i and release of lactate dehydrogenase were attenuated in the presence of sabiporide. CONCLUSIONS Coadministration of Na/H exchanger inhibitor with sodium bicarbonate improves cardiovascular performances, reduces proinflammatory responses, and attenuates organ injury. This improvement in these variables appears to be related to prevention of a rise in intracellular calcium occurring after both exposures to acid and bicarbonate.
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The effect of bicarbonate administration via continuous venovenous hemofiltration on acid-base parameters in ventilated patients. BIOMED RESEARCH INTERNATIONAL 2015; 2015:901590. [PMID: 25648653 PMCID: PMC4306401 DOI: 10.1155/2015/901590] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 12/08/2014] [Accepted: 12/22/2014] [Indexed: 11/18/2022]
Abstract
Background. Acute kidney injury (AKI) and metabolic acidosis are common in the intensive care unit. The effect of bicarbonate administration on acid-base parameters is unclear in those receiving continuous venovenous hemofiltration (CVVH) and mechanical ventilatory support. Methods. Metabolic and ventilatory parameters were prospectively examined in 19 ventilated subjects for up to 96 hours following CVVH initiation for AKI at an academic tertiary care center. Mixed linear regression modeling was performed to measure changes in pH, partial pressure of carbon dioxide (pCO2), serum bicarbonate, and base excess over time. Results. During the 96-hour study period, pCO2 levels remained stable overall (initial pCO2 42.0 ± 14.6 versus end-study pCO2 43.8 ± 16.1 mmHg; P = 0.13 for interaction with time), for those with initial pCO2 ≤40 mmHg (31.3 ± 5.7 versus 35.0 ± 4.8; P = 0.06) and for those with initial pCO2 >40 mmHg (52.7 ± 12.8 versus 53.4 ± 19.2; P = 0.57). pCO2 decreased during the immediate hours following CVVH initiation (42.0 ± 14.6 versus 37.3 ± 12.6 mmHg), though this change was nonsignificant (P = 0.052). Conclusions. We did not detect a significant increase in pCO2 in response to the administration of bicarbonate via CVVH in a ventilated population. Additional studies of larger populations are needed to confirm this finding.
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Efficient Extra- and Intracellular Alkalinization Improves Cardiovascular Functions in Severe Lactic Acidosis Induced by Hemorrhagic Shock. Anesthesiology 2014; 120:926-34. [DOI: 10.1097/aln.0000000000000077] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Abstract
Background:
Lactic acidosis is associated with cardiovascular failure. Buffering with sodium bicarbonate is proposed in severe lactic acidosis. Bicarbonate induces carbon dioxide generation and hypocalcemia, both cardiovascular depressant factors. The authors thus investigated the cardiovascular and metabolic effects of an adapted sodium bicarbonate therapy, including prevention of carbon dioxide increase with hyperventilation and ionized calcium decrease with calcium administration.
Methods:
Lactic acidosis was induced by hemorrhagic shock. Twenty animals were randomized into five groups: (1) standard resuscitation with blood retransfusion and norepinephrine (2) adapted sodium bicarbonate therapy (3) nonadapted sodium bicarbonate therapy (4) standard resuscitation plus calcium administration (5) hyperventilation. Evaluation was focused in vivo on extracellular pH, on intracellular pH estimated by P31 nuclear magnetic resonance and on myocardial contractility by conductance catheter. Aortic rings and mesenteric arteries were isolated and mounted in a myograph, after which arterial contractility was measured.
Results:
All animals in the hyperventilation group died prematurely and were not included in the statistical analysis. When compared with sham rats, shock induced extracellular (median, 7.13; interquartile range, [0.10] vs. 7.30 [0.01]; P = 0.0007) and intracellular acidosis (7.26 [0.18] vs. 7.05 [0.13]; P = 0.0001), hyperlactatemia (7.30 [0.01] vs. 7.13 [0.10]; P = 0.0008), depressed myocardial elastance (2.87 [1.31] vs. 0.5 [0.53] mmHg/μl; P = 0.0001), and vascular hyporesponsiveness to vasoconstrictors. Compared with nonadapted therapy, adapted bicarbonate therapy normalized extracellular pH (7.03 [0.12] vs. 7.36 [0.04]; P < 0.05), increased intracellular pH to supraphysiological values, improved myocardial elastance (1.68 [0.41] vs. 0.72 [0.44] mmHg/μl; P < 0.05), and improved aortic and mesenteric vasoreactivity.
Conclusions:
A therapeutic strategy based on alkalinization with sodium bicarbonate along with hyperventilation and calcium administration increases pH and improves cardiovascular function.
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Sodium bicarbonate use in shock and cardiac arrest: attitudes of pediatric acute care physicians. Crit Care Med 2013; 41:2188-95. [PMID: 23760153 DOI: 10.1097/ccm.0b013e31828a6669] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES To evaluate the preferences and self-reported practices of pediatric acute care physicians with respect to sodium bicarbonate administration to infants and children in shock or cardiac arrest. DESIGN National survey study utilizing a self-administered questionnaire. SETTING Thirteen Canadian pediatric tertiary care centers. SUBJECTS Canadian pediatric critical care physicians, pediatric emergency physicians, and trainees in these subspecialties. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Survey items were evaluated based on Yes/No responses, frequency responses, and Likert scales. Overall response rate was 53% (151/284) with 49.0% (74/151) citing pediatric critical care as their primary practice. 82.0% of respondents (123/150) indicated they would administer sodium bicarbonate as part of ongoing resuscitation for septic shock, whereas 58.3% (88/151) would administer sodium bicarbonate in a cardiac arrest scenario (p=0.004). 47.3% (71/150) selected a pH threshold at or below which they would administer sodium bicarbonate (mean, 6.94±0.013; median, 7.00; range, 6.50-7.20; interquartile range, 6.90-7.00), whereas 20.5% (31/151) selected a base excess threshold (mean, -15.62±0.78; median, -16; range, -20 to -4; interquartile range, -20 to -14). Both pH and duration of resuscitation were strongly associated with the decision to administer sodium bicarbonate (p<0.0001). Respondents' perceptions regarding a colleague's likelihood of administering sodium bicarbonate to the same patient under the same circumstances reflect an acknowledgment of disparate practices with respect to sodium bicarbonate use. 53.0% (79/149) felt current American Heart Association guidelines help them in deciding whether to administer sodium bicarbonate to critically ill patients, and 84% would support a randomized trial. CONCLUSION Differences of opinion exist among pediatric acute care physicians with respect to the timing and appropriateness of sodium bicarbonate administration during resuscitation. Most indicated they would support moving forward with a clinical trial.
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22
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Khan AA, Surrao DC. The importance of bicarbonate and nonbicarbonate buffer systems in batch and continuous flow bioreactors for articular cartilage tissue engineering. Tissue Eng Part C Methods 2011; 18:358-68. [PMID: 22092352 DOI: 10.1089/ten.tec.2011.0137] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
In cartilage tissue engineering an optimized culture system, maintaining an appropriate extracellular environment (e.g., pH of media), can increase cell proliferation and extracellular matrix (ECM) accumulation. We have previously reported on a continuous-flow bioreactor that improves tissue growth by supplying the cells with a near infinite supply of medium. Previous studies have observed that acidic environments reduce ECM synthesis and chondrocyte proliferation. Hence, in this study we investigated the combined effects of a continuous culture system (bioreactor) together with additional buffering agents (e.g., sodium bicarbonate [NaHCO₃]) on cartilaginous tissue growth in vitro. Isolated bovine chondrocytes were grown in three-dimensional cultures, either in static conditions or in a continuous-flow bioreactor, in media with or without NaHCO₃. Tissue constructs cultivated in the bioreactor with NaHCO₃-supplemented media were characterized with significantly increased (p<0.05) ECM accumulation (glycosaminoglycans a 98-fold increase; collagen a 25-fold increase) and a 13-fold increase in cell proliferation, in comparison with static cultures. Additionally, constructs grown in the bioreactor with NaHCO₃-supplemented media were significantly thicker than all other constructs (p<0.05). Further, the chondrocytes from the primary construct expanded and synthesized ECM, forming a secondary construct without a separate expansion phase, with a diameter and thickness of 4 mm and 0.72 mm respectively. Tissue outgrowth was negligible in all other culturing conditions. Thus this study demonstrates the advantage of employing a continuous flow bioreactor coupled with NaHCO₃ supplemented media for articular cartilage tissue engineering.
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Affiliation(s)
- Aasma A Khan
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, Oxfordshire, United Kingdom.
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23
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Trenholm S, Baldridge WH. The effect of aminosulfonate buffers on the light responses and intracellular pH of goldfish retinal horizontal cells. J Neurochem 2010; 115:102-11. [PMID: 20633206 DOI: 10.1111/j.1471-4159.2010.06906.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Retinal horizontal cell feedback acts as a gain control at the first synapse in the visual system and generates center-surround receptive fields in the outer retina. One model of feedback proposes that elevation of protons in the photoreceptor synaptic cleft produces feedback. Most evidence supporting the proton model has depended on the effect of proton buffers, in particular aminosulfonates, but these agents could potentially have effects other than external pH regulation. We therefore determined if the effects of aminosulfonates on horizontal cell rollback, an indicator of feedback, were consistent with external proton buffering. Intracellular recording from horizontal cells in isolated goldfish retina revealed that rollback was blocked only by aminosulfonates with an acid dissociation constant suited for buffering at the pH (7.5) of the Ringer's solution. In isolated goldfish horizontal cells, aminosulfonates, even those that did not block rollback, altered intracellular pH. This suggests that the effect of aminosulfonates on rollback is not because of changing intracellular pH. Measures of both intracellular and extracellular pH revealed that treatment with either glutamate or kainate resulted in acidification. As glutamate produced both internal and external acidification, intracellular and extracellular horizontal cell pH would be expected to increase in response to light, a change consistent with the proton model of feedback.
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Affiliation(s)
- Stuart Trenholm
- Neuroscience Institute, Department of Anatomy & Neurobiology, Dalhousie University, Halifax, Nova Scotia, Canada
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Abstract
BACKGROUND Lactic acidosis (LA) is common in hospitalized patients and is associated with poor clinical outcomes. There have been major recent advances in our understanding of lactate generation and physiology. However, treatment of LA is an area of controversy and uncertainty, and the use of agents to raise pH is not clearly beneficial. AIM AND METHODS We reviewed animal and human studies on the pathogenesis, impact, and treatment of LA, published in the English language and available through the PubMed/MEDLINE database. Our aim was to clarify the physiology of the generation of LA, its impact on outcomes, and the different treatment modalities available. We also examined relevant data regarding LA induced by medications commonly prescribed by hospitalists: biguanides, nucleoside analog reverse-transcriptase inhibitors (NRTIs), linezolid, and lorazepam. RESULTS/CONCLUSIONS Lactic acid is a marker of tissue ischemia but it also may accumulate without tissue hypoperfusion. In the latter circumstance, lactic acid accumulation may be an adaptive mechanism-a novel possibility quite in contrast to the traditional view of lactic acid as only a marker of tissue ischemia. Studies on the treatment of LA with sodium bicarbonate or other buffers fail to show consistent clinical benefit. Severe acidemia in the setting of LA is a particularly poorly studied area. In the settings of medication-induced LA, optimal treatment, apart from prompt cessation of the offending agent, is still unclear.
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Affiliation(s)
- Jean-Sebastien Rachoin
- Division of Nephrology, Department of Medicine, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Cooper University Hospital, Camden, New Jersey 08103, USA.
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25
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Tricyclic antidepressant toxicity treated with massive sodium bicarbonate. Am J Emerg Med 2009; 27:1168.e3-7. [DOI: 10.1016/j.ajem.2008.11.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2008] [Revised: 11/21/2008] [Accepted: 11/25/2008] [Indexed: 11/20/2022] Open
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Koch A, Kaske M. Clinical efficacy of intravenous hypertonic saline solution or hypertonic bicarbonate solution in the treatment of inappetent calves with neonatal diarrhea. J Vet Intern Med 2008; 22:202-11. [PMID: 18289311 PMCID: PMC7166734 DOI: 10.1111/j.1939-1676.2007.0029.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Background: The clinical efficacy of IV administered hypertonic saline solution and hypertonic bicarbonate solution (HBS) in the treatment of inappetent diarrheic calves has not been compared yet. Hypothesis: HBS is more advantageous than hypertonic saline in the treatment of calves with severe metabolic acidosis. Animals: Twenty‐eight dehydrated, inappetent calves with neonatal diarrhea. Methods: In 2 consecutive clinical studies, calves were initially treated with saline (5.85%; 5 mL/kg body weight [BW] over 4 minutes; study I: N = 16) or bicarbonate solution (8.4%; 10 mL/kg BW over 8 minutes; study II: N = 12), respectively, followed by oral administration of 3 L isotonic electrolyte solution 5 minutes after injection. Clinical and laboratory variables were monitored for 72 hours. Results: Treatment failed in 6 calves of study I and in 1 calf of study II as indicated by a deterioration of the general condition. All treatment failures had more severe metabolic acidosis compared with successfully treated calves before treatment. In the latter, rehydration was completed within 18 hours after injection; metabolic acidosis was corrected within 24 hours (study I) and 6 hours (study II) after injection. Conclusions and Clinical Importance: Diarrheic calves with slight metabolic acidosis (base excess [BE] >−10 mM) can be treated successfully with hypertonic saline. HBS is appropriate in calves without respiratory problems with more severe metabolic acidosis (BE up to −20 mM). Intensive care of the calves is required to ensure a sufficient oral fluid intake after the initial IV treatment.
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Affiliation(s)
- A Koch
- Clinic for Cattle, University of Veterinary Medicine Hannover, Hannover, Germany
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27
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Abstract
The correct identification of the cause, and ideally the individual acid, responsible for metabolic acidosis in the critically ill ensures rational management. In Part 2 of this review, we examine the elevated (corrected) anion gap acidoses (lactic, ketones, uraemic and toxin ingestion) and contrast them with nonelevated conditions (bicarbonate wasting, renal tubular acidoses and iatrogenic hyperchloraemia) using readily available base excess and anion gap techniques. The potentially erroneous interpretation of elevated lactate signifying cell ischaemia is highlighted. We provide diagnostic and therapeutic guidance when faced with a high anion gap acidosis, for example pyroglutamate, in the common clinical scenario 'I can't identify the acid--but I know it's there'. The evidence that metabolic acidosis affects outcomes and thus warrants correction is considered and we provide management guidance including extracorporeal removal and fomepizole therapy.
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Affiliation(s)
- C G Morris
- Intensive Care Medicine and Anaesthesia, Derby Hospitals Foundation Trust, Derby Royal Infirmary, London Road, Derby DE1 2QY, UK.
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28
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Effect of Tris-Hydroxymethyl Aminomethane on intracellular pH depends on the extracellular non-bicarbonate buffering capacity. Transl Res 2007; 150:350-6. [PMID: 18022597 DOI: 10.1016/j.trsl.2007.05.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2007] [Revised: 05/08/2007] [Accepted: 05/13/2007] [Indexed: 11/23/2022]
Abstract
The effect of Tris-Hydroxymethyl Aminomethane (THAM) on intracellular pH (pHi) is unknown. We previously demonstrated that the effect of sodium bicarbonate on pHi depends on the non-bicarbonate buffering system. First, human hepatocytes from hepatocytes cell culture (HepG2) were perfused with an acidotic artificial medium containing 5-mmol/L (H5) or 30-mmol/L (H30) concentrations of 4-(2-hydroxyethyl)-1-piperazineethane sulfonic acid (HEPES), a non-bicarbonate buffer. We studied the effect of THAM on the pHi in both conditions. We repeated the same protocol using an acidotic human blood with a 5% or 40% hematocrit. The pHi was measured with the pH-sensitive fluorescent dye bis-carboxyethyl carboxy-fluorescein (BCECF). Gas analysis was performed before and during the alkaline infusion. The results showed that THAM caused an intracellular alkalization that was higher when the non-bicarbonate buffer concentration was low (0.45 +/- 0.21 and 0.22 +/- 0.14 pH units with H5 and H30, respectively). A significant relationship was found between changes in pHi and changes in PCO(2). Similar results were obtained with the human blood. In conclusion, the intracellular alkalizing effect of THAM is caused by the induced decrease of PCO(2) linked to the extracellular non-bicarbonate buffer capacity: The smaller the concentration of extracellular non-bicarbonate buffer, the higher the PCO(2) decrease caused by THAM.
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Abstract
Lactic acidosis is frequently encountered in the intensive care unit. It occurs when there is an imbalance between production and clearance of lactate. Although lactic acidosis is often associated with a high anion gap and is generally defined as a lactate level >5 mmol/L and a serum pH <7.35, the presence of hypoalbuminemia may mask the anion gap and concomitant alkalosis may raise the pH. The causes of lactic acidosis are traditionally divided into impaired tissue oxygenation (Type A) and disorders in which tissue oxygenation is maintained (Type B). Lactate level is often used as a prognostic indicator and may be predictive of a favorable outcome if it normalizes within 48 hours. The routine measurement of serum lactate, however, should not determine therapeutic interventions. Unfortunately, treatment options remain limited and should be aimed at discontinuation of any offending drugs, treatment of the underlying pathology, and maintenance of organ perfusion. The mainstay of therapy of lactic acidosis remains prevention.
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Affiliation(s)
- Pamela J Fall
- Section of Nephrology, Hypertension and Transplantation, Department of Medicine, Medical College of Georgia, Augusta 30912, USA
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30
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Harvey B, Hickman C, Hinson G, Ralph T, Mayer A. Severe lactic acidosis complicating metformin overdose successfully treated with high-volume venovenous hemofiltration and aggressive alkalinization. Pediatr Crit Care Med 2005; 6:598-601. [PMID: 16148825 DOI: 10.1097/01.pcc.0000162451.47034.4f] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE In this report of a near-fatal metformin ingestion successfully treated with alkalinization and high-volume hemofiltration, we discuss the management of severe lactic acidosis and demonstrate that early aggressive intervention resulted in a positive outcome. DESIGN Case report. SETTING A tertiary pediatric intensive care unit. PATIENT The patient was a healthy 14-yr-old female found by a sibling following a seizure of unknown duration, thought to be secondary to hypoglycemia as a consequence of a self-ingestion of metformin, atenolol, and diclofenac. She responded well to advanced resuscitation but progressively developed severe lactic acidosis, bradycardia, and hypotension in addition to persistent hypoglycemia. The peak lactate level was 37.5 mmol/L with an albumin corrected anion gap of 65 mmol/L. INTERVENTIONS She was treated with high-volume venovenous hemofiltration and aggressive alkalinization therapy. The latter facilitated control of severe acidosis, whereas the hemofiltration removed the ingested drugs in addition to endogenously produced lactate precipitated by metformin. CONCLUSIONS In this case, early and aggressive treatment of the acidosis and cardiovascular compromise with inotropes, venovenous hemofiltration, and large doses of sodium bicarbonate in metformin overdose resulted in a successful outcome even in the presence of severe acidosis and very high lactate levels.
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Affiliation(s)
- Ben Harvey
- Paediatric Intensive Care Unit, Sheffield Children's Hospital, Western Bank, Sheffield, UK
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Waldman SD, Couto DC, Omelon SJ, Kandel RA. Long-term intermittent compressive stimulation improves the composition and mechanical properties of tissue-engineered cartilage. ACTA ACUST UNITED AC 2005; 10:1633-40. [PMID: 15684672 DOI: 10.1089/ten.2004.10.1633] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Tissue engineering of articular cartilage is a promising alternative for cartilage repair. However, it has been difficult to develop tissue in vitro that mimicks native cartilage. Cartilaginous tissue formed in vitro does not accumulate enough extracellular matrix, is deficient in collagen, and possesses only a fraction of the mechanical properties of native cartilage. In this study, we investigated whether long-term intermittent compressive stimulation would improve the quality of the generated tissue. Chondrocyte cultures were established on the surface of porous calcium polyphosphate substrates and allowed to form cartilaginous tissue. In vitro-formed tissues were subjected to different stimulation protocols for 1 week. The optimal mechanical stimulation parameters identified in this short-term study were then applied to the cultures for up to 4 weeks. Mechanical stimulation applied at a 5% compressive amplitude at a frequency of 1 Hz for 400 cycles every second day resulted in the greatest increase in collagen synthesis (37 +/- 9% over control) while not significantly affecting proteoglycan synthesis (2 +/- 8% over control). This condition, applied to the chondrocyte cultures for 4 weeks, resulted in a significant increase in the amount of tissue that formed (stimulated, 2.4 +/- 0.2 mg dry wt; unstimulated, 1.61 +/- 0.08 mg dry wt). Stimulated tissues contained approximately 40% more collagen (stimulated, 590 +/- 58 microg; unstimulated, 420 +/- 42 microg), and 30% more proteoglycans (stimulated, 393 +/- 34 microg; unstimulated, 302 +/- 32 microg) as well as displaying a 2- to 3-fold increase in compressive mechanical properties (maximal equilibrium stress: stimulated, 10 +/- 1 kPa; unstimulated, 5 +/- 1 kPa; maximal equilibrium modulus: stimulated, 80 +/- 23 kPa; unstimulated, 24 +/- 6 kPa). The results of this study demonstrate that intermittent mechanical stimulation can increase collagen synthesis and, when applied over a 4-week period, can accelerate extracellular matrix accumulation as well as improve the material properties of the developed tissue. Interestingly, only short periods of mechanical stimulation (6 min every second day) were needed to affect the quality of cartilaginous tissue formed in vitro.
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Affiliation(s)
- Stephen D Waldman
- CIHR-Bioengineering of Skeletal Tissues Team, Mount Sinai Hospital and University of Toronto, Toronto, Ontario, Canada.
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Zhou FQ. Pyruvate in the correction of intracellular acidosis: a metabolic basis as a novel superior buffer. Am J Nephrol 2005; 25:55-63. [PMID: 15731550 DOI: 10.1159/000084141] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2004] [Accepted: 01/06/2005] [Indexed: 01/18/2023]
Abstract
The review focuses on biochemical metabolisms of conventional buffers and emphasizes advantages of sodium pyruvate (Pyr) in the correction of intracellular acidosis. Exogenous lactate (Lac) as an alternative of natural buffer, bicarbonate, consumes intracellular protons on an equimolar basis, regenerating bicarbonate anions in plasma while the completion of gluconeogenesis and/or oxidation occurs via tricarboxylic-acid cycle in mitochondria mainly in liver and kidney, or heart. The general assumption that Lac is 'metabolized to bicarbonate' in liver to serve as a buffer has been questioned. Pyr as a novel buffer would be superior to conventional ones in the correction of metabolic acidosis. Several likely biochemical mechanisms of Pyr action are discussed. Experimental evidence, in vivo, strongly suggested that Pyr would be particularly efficient in the correction of severe acidemia: type A lactic acidosis, hypercapnia with cardiac arrest, and diabetic and alcoholic ketoacidosis in animal experiments and clinic settings. Because of its multi-cytoprotection, Pyrs not only correct acidosis, but also benefit theunderlying dysfunction of vital organs. In addition, Pyr is also a potential buffer component of dialysis solutions. However, the instability of Pyr in aqueous solutions restricts its clinical applications as a therapeutic agent. Attempts to create a stable Pyr preparation are needed.
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Gehlbach BK, Schmidt GA. Bench-to-bedside review: treating acid-base abnormalities in the intensive care unit - the role of buffers. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2004; 8:259-65. [PMID: 15312208 PMCID: PMC522834 DOI: 10.1186/cc2865] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The recognition and management of acid-base disorders is a commonplace activity for intensivists. Despite the frequency with which non-bicarbonate-losing forms of metabolic acidosis such as lactic acidosis occurs in critically ill patients, treatment is controversial. This article describes the properties of several buffering agents and reviews the evidence for their clinical efficacy. The evidence supporting and refuting attempts to correct arterial pH through the administration of currently available buffers is presented.
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Affiliation(s)
- Brian K Gehlbach
- Instructor of Medicine, Section of Pulmonary and Critical Care, University of Chicago, Chicago, Illinois, USA
| | - Gregory A Schmidt
- Professor of Medicine, Section of Pulmonary and Critical Care, University of Chicago, Chicago, Illinois, USA
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Abstract
Metabolic acidosis is characterized by a decrease of the blood pH associated with a decrease in the bicarbonate concentration. This may be secondary to a decrease in the strong ion difference or to an increase in the weak acids concentration, mainly the inorganic phosphorus. From a conceptual point of view, two types of nontoxic metabolic acidosis must be differentiated: the mineral metabolic acidosis that reveals the presence of an excess of nonmetabolizable anions, and the organic metabolic acidosis that reveals an excess of metabolizable anions. Significance and consequences of these two types of acidosis are radically different. Mineral acidosis is not caused by a failure in the energy metabolic pathways, and its treatment is mainly symptomatic by correcting the blood pH (alkali therapy) or accelerating the elimination of excessive mineral anions (renal replacement therapy). On the other hand, organic acidosis gives evidence that a severe underlying metabolic distress is in process. No reliable argument exists to prove that this acidosis is harmful under these conditions in humans. Experimental data even show that hypoxic cells are able to survive only if the medium is kept acidic. The management of an acute organic metabolic acidosis is therefore primarily based on the cause of the acidosis, and no scientific argument exists to justify the correction of the acid-base imbalance in this context.
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Affiliation(s)
- Jacques Levraut
- Departemente d'Anesthesie Reanimation Est, Hopital Saint Roch-5, rue Pierre Devoluy, F-06006, Nice.
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Magdesian KG, Madigan JE. Volume replacement in the neonatal ICU: Crystalloids and colloids. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s1534-7516(03)000210] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Heijnen BHM, Elkhaloufi Y, Straatsburg IH, Van Gulik TM. Influence of acidosis and hypoxia on liver ischemia and reperfusion injury in an in vivo rat model. J Appl Physiol (1985) 2002; 93:319-23. [PMID: 12070220 DOI: 10.1152/japplphysiol.01112.2001] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The contribution of acidosis to the development of reperfusion injury is controversial. In this study, we examined the effects of respiratory acidosis and hypoxia in a frequently used in vivo liver ischemia and reperfusion (I/R) injury rat model. Rats were anesthetized with intraperitoneal anesthetics and subjected to partial liver ischemia (70%) for 60 min and subsequent reperfusion for 90 min under the following conditions: 1) no acidosis and normoxia, maintained by controlled ventilation; 2) acidosis and normoxia, maintained by passive supply with oxygen; 3) no acidosis and hypoxia, maintained by bicarbonate administration without respiratory support; and 4) acidosis and hypoxia, i.e., without respiratory support or pH correction. Changes in plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were measured as parameters of hepatocellular injury, and bile secretion was monitored. AST and ALT levels were lowest in the ventilated rats and highest in the bicarbonate-treated rats. No differences in bile secretion were found between groups. Our results suggest that respiratory acidosis significantly enhanced liver I/R injury under normoxic conditions, whereas respiratory acidosis significantly reduced liver I/R injury under hypoxic conditions.
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Affiliation(s)
- Bob H M Heijnen
- Surgical Laboratory, Academic Medical Center, 1105 AZ Amsterdam, The Netherlands.
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Abstract
Despite the lack of evidence for its effectiveness in the treatment of acid-base disturbances in critically ill patients of all ages, and despite several lines of evidence that indicate it might be dangerous, bicarbonate therapy is used routinely in many neonatal intensive care units. The justification for the persistent use of this controversial therapy comes from a variety of sources, many based more in philosophy than in science. Clinicians contemplating the use of bicarbonate therapy should consider what they expect the intervention to accomplish and what evidence exists that their therapeutic objective will be met. Without rigorous scientific support for this therapy, it should be considered of unproven value and, therefore, experimental.
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Affiliation(s)
- Amer N Ammari
- Division of Neonatal-Perinatal Medicine, Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA.
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