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Part III: Minimum Quality Threshold in Preclinical Sepsis Studies (MQTiPSS) for Fluid Resuscitation and Antimicrobial Therapy Endpoints. Shock 2019; 51:33-43. [DOI: 10.1097/shk.0000000000001209] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Abstract
PURPOSE OF REVIEW This review explores the contemporary definition of the term 'balanced crystalloid' and outlines optimal design features and their underlying rationale. RECENT FINDINGS Crystalloid interstitial expansion is unavoidable, but also occurs with colloids when there is endothelial glycocalyx dysfunction. Reduced chloride exposure may lessen kidney dysfunction and injury with a possible mortality benefit. Exact balance from an acid-base perspective is achieved with a crystalloid strong ion difference of 24 mEq/l. This can be done simply by replacing 24 mEq/l of chloride in 0.9% sodium chloride with bicarbonate or organic anion bicarbonate substitutes. Potassium, calcium and magnesium additives are probably unnecessary. Large volumes of mildly hypotonic crystalloids such as lactated Ringer's solution reduce extracellular tonicity in volunteers and increase intracranial pressure in nonbrain-injured experimental animals. A total cation concentration of 154 mmol/l with accompanying anions provides isotonicity. Of the commercial crystalloids, Ringer's acetate solution is close to balanced from both acid-base and tonicity perspectives, and there is little current evidence of acetate toxicity in the context of volume loading, in contrast to renal replacement. SUMMARY The case for balanced crystalloids is growing but unproven. A large randomized controlled trial of balanced crystalloids versus 0.9% sodium chloride is the next step.
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The European Consensus Statement on intraoperative fluid therapy in children: a step in the right direction. Eur J Anaesthesiol 2011; 28:618-9. [PMID: 21822076 DOI: 10.1097/eja.0b013e328345c96d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Morgan TJ, Vellaichamy M, Cowley DM, Weier SL, Venkatesh B, Jonest MA. Equivalent Metabolic Acidosis with Four Colloids and Saline on Ex Vivo Haemodilution. Anaesth Intensive Care 2009; 37:407-14. [DOI: 10.1177/0310057x0903700304] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Colloid infusions can cause metabolic acidosis. Mechanisms and relative severity with different colloids are incompletely understood. We compared haemodilution acid-base effects of 4% albumin, 3.5% polygeline, 4% succinylated gelatin (all weak acid colloids, strong ion difference 12 mEq/l, 17.6 mEq/l and 34 mEq/l respectively), 6% hetastarch (non-weak acid colloid, strong ion difference zero) and 0.9% saline (crystalloid, strong ion difference zero). Gelatin weak acid properties were tracked via the strong ion gap. Four-step ex vivo dilutions of pre-oxygenated human venous blood were performed to a final [Hb] near 50% baseline. With each fluid, base excess fell to approximately −13 mEq/l. Base excess/[Hb] relationships across dilution were linear and direct (R2 ≥0.96), slopes and intercepts closely resembling saline. Baseline strong ion gap was −0.3 (2.1) mEq/l. Post-dilution increases occurred in three groups: small with saline, hetastarch and albumin (to 3.5 (02) mEq/l, 4.3 (0.3) mEq/l, 3.3 (1.4) mEq/l respectively), intermediate with polygeline (to 12.2 (0.9) mEq/l) and greatest with succinylated gelatin (to 20.8 (1.4) mEq/l). We conclude that, despite colloid weak acid activity ranging from zero (hydroxyethyl starch) to greater than that of albumin with both gelatin preparations, ex vivo dilution causes a metabolic acidosis of identical severity to saline in each case. This uniformity reflects modifications to the albumin and gelatin saline vehicles, in part aimed at pH correction. By proportionally increasing the strong ion difference, these modifications counter deviations from pure saline effects caused by colloid weak acid activity. Extrapolation in vivo requires further investigation.
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Affiliation(s)
- T. J. Morgan
- Adult Intensive Care Unit and Department of Chemical Pathology, Mater Health Services, Brisbane, Queensland, Australia
- Intensive Care Unit, Mater Adult Hospital, Mater Health Services
| | - M. Vellaichamy
- Adult Intensive Care Unit and Department of Chemical Pathology, Mater Health Services, Brisbane, Queensland, Australia
- Intensive Care Unit, Toowoomba General Hospital, Toowoomba
| | - D. M. Cowley
- Adult Intensive Care Unit and Department of Chemical Pathology, Mater Health Services, Brisbane, Queensland, Australia
- Chemical Pathology, Mater Health Services Pathology, Mater Health Services
| | - S. L. Weier
- Adult Intensive Care Unit and Department of Chemical Pathology, Mater Health Services, Brisbane, Queensland, Australia
- Mater Health service Pathology, Mater Health Services
| | - B. Venkatesh
- Adult Intensive Care Unit and Department of Chemical Pathology, Mater Health Services, Brisbane, Queensland, Australia
- Intensive Care, Intensive Care Units, Princess Alexandra and Wesley Hospitals, University of Queensland
| | - M. A. Jonest
- Adult Intensive Care Unit and Department of Chemical Pathology, Mater Health Services, Brisbane, Queensland, Australia
- Queensland Clinical Trials Centre, University of Queensland, Princess Alexandra Hospital
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Morgan TJ, Power G, Venkatesh B, Jones MA. Acid-base effects of a bicarbonate-balanced priming fluid during cardiopulmonary bypass: comparison with Plasma-Lyte 148. A randomised single-blinded study. Anaesth Intensive Care 2009; 36:822-9. [PMID: 19115651 DOI: 10.1177/0310057x0803600611] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Fluid-induced metabolic acidosis can be harmful and can complicate cardiopulmonary bypass. In an attempt to prevent this disturbance, we designed a bicarbonate-based crystalloid circuit prime balanced on physico-chemical principles with a strong ion difference of 24 mEq/l and compared its acid-base effects with those of Plasma-Lyte 148, a multiple electrolyte replacement solution containing acetate plus gluconate totalling 50 mEq/l. Twenty patients with normal acid-base status undergoing elective cardiac surgery were randomised 1:1 to a 2 litre prime of either bicarbonate-balanced fluid or Plasma-Lyte 148. With the trial fluid, metabolic acid-base status was normal following bypass initiation (standard base excess 0.1 (1.3) mEq/l, mean, SD), whereas Plasma-Lyte 148 produced a slight metabolic acidosis (standard base excess -2.2 (2.1) mEq/l). Estimated group difference after baseline adjustment was 3.6 mEq/l (95% confidence interval 2.1 to 5.1 mEq/l, P=0.0001). By late bypass, mean standard base excess in both groups was normal (0.8 (2.2) mEq/l vs. -0.8 (1.3) mEq/l, P=0.5). Strong ion gap values were unaltered with the trial fluid, but with Plasma-Lyte 148 increased significantly on bypass initiation (15.2 (2.5) mEq/l vs. 2.5 (1.5) mEq/l, P < 0.0001), remaining elevated in late bypass (8.4 (3.4) mEq/l vs. 5.8 (2.4) mEq/l, P < 0.05). We conclude that a bicarbonate-based crystalloid with a strong ion difference of 24 mEq/l is balanced for cardiopulmonary bypass in patients with normal acid-base status, whereas Plasma-Lyte 148 triggers a surge of unmeasured anions, persisting throughout bypass. These are likely to be gluconate and/or acetate. Whether surges of exogenous anions during bypass can be harmful requires further study.
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Affiliation(s)
- T J Morgan
- Department of Anaesthesia, Princess Alexandra Hospital, Brisbane, Queensland, Australia
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Ochola J, Venkatesh B. Rational Approach to Fluid Therapy in Acute Diabetic Ketoacidosis. Intensive Care Med 2009. [DOI: 10.1007/978-0-387-92278-2_24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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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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