Acid base

OBJECTIVE: The objective of this review is to discuss acid-base physiology, describe the essential steps for interpreting an arterial blood gas and relevant laboratory tests, and review the 4 distinct types of acid-base disorders. DATA SOURCES: A comprehensive literature search and resultant bibliography review of PubMed from inception through March 7, 2023. STUDY SELECTION AND DATA EXTRACTION: Relevant English-language articles were extracted and evaluated...

The late Peter Stewart developed an approach to the analysis of acid-base disturbances in biological systems based on basic physical-chemical principles. His key argument was that the traditional carbon dioxide/bicarbonate analysis with just the use of the Henderson-Hasselbalch equation does not account for the important role in the regulation of H(+) concentration played by strong ions, weak acids and water itself. Acceptance of his analysis has been limited because it requires a complicated set of calculations to account for all the variables and it does not provide simple clinical guidance...

Metabolic acid-base disorders are comnom clinical problems in ICU patients. Arterial blood gas analysis and anion gap (AG) are important laboratory data in approaching acid-base interpretation. When measuring the AG, several factors such as albumin have influence on unmeasured anions and unmeasured cations. If a patient has hypoalbuminemia, the AG should be adjusted according to the albumin level. High AG metabolic acidoses including lactic acidosis, ketoacidosis, and ingestion of toxic alcohols are common in ICU patients...

Evaluation of acid-base status depends on accurate measurement of acid-base variables and their appropriate assessment. Currently, 3 approaches are utilized for assessing acid-base variables. The physiological or traditional approach, pioneered by Henderson and Van Slyke in the early 1900s, considers acids as H+ donors and bases as H+ acceptors. The acid-base status is conceived as resulting from the interaction of net H+ balance with body buffers and relies on the H2 CO3 /HCO3 - buffer pair for its assessment...

No abstract text is available yet for this article.

No abstract text is available yet for this article.

PURPOSE: Sepsis is a significant threat in the intensive care unit (ICU) worldwide because it has high morbidity and mortality rates. Early recognition and diagnosis of sepsis are essential for the prevention of adverse outcomes. The present study aimed to quantitatively assess the association between serum anion gap (AG) levels and 30- and 90-day all-cause mortality among sepsis patients. METHODS: Clinical data of patients diagnosed with sepsis were extracted from the Medical Information Mart for Intensive Care III (MIMIC III) database...

Acid-base disorders are common in the intensive care unit. By utilizing a systematic approach to their diagnosis, it is easy to identify both simple and mixed disturbances. These disorders are divided into four major categories: metabolic acidosis, metabolic alkalosis, respiratory acidosis, and respiratory alkalosis. Metabolic acidosis is subdivided into anion gap and non-gap acidosis. Distinguishing between these is helpful in establishing the cause of the acidosis. Anion gap acidosis, caused by the accumulation of organic anions from sepsis, diabetes, alcohol use, and numerous drugs and toxins, is usually present on admission to the intensive care unit...

Metabolic alkalosis is a widespread acid-base disturbance, especially in hospitalized patients. It is characterized by the primary elevation of serum bicarbonate and arterial pH, along with a compensatory increase in Pco2 consequent to adaptive hypoventilation. The pathogenesis of metabolic alkalosis involves either a loss of fixed acid or a net accumulation of bicarbonate within the extracellular fluid. The loss of acid may be via the gastrointestinal tract or the kidney, whereas the sources of excess alkali may be via oral or parenteral alkali intake...

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2021. Other selected articles can be found online at https://www.biomedcentral.com/collections/annualupdate2021 . Further information about the Annual Update in Intensive Care and Emergency Medicine is available from https://link.springer.com/bookseries/8901 .

We discuss the use of urine electrolytes and urine osmolality in the clinical diagnosis of patients with fluid, electrolytes, and acid-base disorders, emphasizing their physiological basis, their utility, and the caveats and limitations in their use. While our focus is on information obtained from measurements in the urine, clinical diagnosis in these patients must integrate information obtained from the history, the physical examination, and other laboratory data.

No abstract text is available yet for this article.

BACKGROUND: The etiology of acute metabolic acidosis (aMA) is heterogeneous, and the consequences are potentially life-threatening. The aim of this article was to summarize the causes and management of aMA from a clinician's perspective. SUMMARY: We performed a systematic search on PubMed, applying the following search terms: "acute metabolic acidosis," "lactic acidosis," "metformin" AND "acidosis," "unbalanced solutions" AND "acidosis," "bicarbonate" AND "acidosis" AND "outcome," "acute metabolic acidosis" AND "management," and "acute metabolic acidosis" AND "renal replacement therapy (RRT)/dialysis...

L-lactic acidosis (L-LA) is the most common cause of metabolic acidosis in the critical care setting, which has been associated with a large increase in mortality. The purpose of this article is to provide clinicians with an overview of the biochemical and metabolic background required to understand the different pathophysiological mechanisms that may lead to the development of L-LA. We propose a classification based on whether the pathophysiology of L-LA is due predominantly to increased production or decreased removal of L-lactic acid...

This paper describes the interactions between ventilation and acid-base balance under a variety of conditions including rest, exercise, altitude, pregnancy, and various muscle, respiratory, cardiac, and renal pathologies. We introduce the physicochemical approach to assessing acid-base status and demonstrate how this approach can be used to quantify the origins of acid-base disorders using examples from the literature. The relationships between chemoreceptor and metaboreceptor control of ventilation and acid-base balance summarized here for adults, youth, and in various pathological conditions...

No abstract text is available yet for this article.

Measurements made in the blood, part of the extracellular compartment, are used in the clinical assessment of acid-base disorders; however, intracellular events determine much of the metabolic importance of these disorders. Intracellular and interstitial compartment acid-base balance is complex and varies in different tissues. This review considers the determination of extracellular pH in the context of ion transport processes at the interface of cells and the interstitial fluid, and between epithelial cells lining the transcellular contents of the gastrointestinal and urinary tracts that open to the external environment...

Physicochemical models have played an important role in understanding, diagnosing, and treating acid-base disorders for more than 100 years. This review focuses on recent complex models, solved using computers, and shows how these models provide new understanding and diagnostic approaches in acid-base disorders. These advanced models use the following physicochemical principles: (1) chemical equilibrium, (2) conservation of mass, (3) electroneutrality, and (4) osmotic equilibrium to describe the steady-state distribution of H2 O and ions in the four major body-fluid spaces, cells, interstitium, plasma, and erythrocytes, and show how this distribution is changed by fluid infusions and losses through renal and gastrointestinal physiological processes...

Although students initially learn of ionic buffering in basic chemistry, buffering and acid-base transport in biology often is relegated to specialized classes, discussions, or situations. That said, for physiology, nephrology, pulmonology, and anesthesiology, these basic principles often are critically important for mechanistic understanding, medical treatments, and assessing therapy effectiveness. This short introductory perspective focuses on basic chemistry and transport of buffers and acid-base equivalents, provides an outline of basic science acid-base concepts, tools used to monitor intracellular pH, model cellular responses to pH buffer changes, and the more recent development and use of genetically encoded pH-indicators...

Metabolic acidosis is a disorder frequently encountered in emergency medicine and intensive care medicine. As literature has been enriched with new data concerning the management of metabolic acidosis, the French Intensive Care Society (Société de Réanimation de Langue Française [SRLF]) and the French Emergency Medicine Society (Société Française de Médecine d'Urgence [SFMU]) have developed formalized recommendations from experts using the GRADE methodology. The fields of diagnostic strategy, patient assessment, and referral and therapeutic management were addressed and 29 recommendations were made: 4 recommendations were strong (Grade 1), 10 were weak (Grade 2), and 15 were experts' opinions...