Base excess (BE): reloaded.

The base excess value (BE, mmol/L), not standard base excess (SBE), correctly calculated including pH, pCO2 (mmHg), sO2 (%) and cHb (g/dl) is a diagnostic tool for several in vivo events, e.g., mortality after multiple trauma or shock, acidosis, bleeding, clotting, artificial ventilation. In everyday clinical practice a few microlitres of blood (arterial, mixed venous or venous) are sufficient for optimal diagnostics of any metabolic acidosis or alkalosis.The same applies to a therapeutic tool-then referred to as potential base excess (BEpot)-for several in vitro assessments, e.g., solutions for infusion, sodium bicarbonate, blood products, packed red blood cells, plasma. Thus, BE or BEpot has been a parameter with exceptional clinical significance since 2007.

Urinary acid-base excretion deciphers high acid load from colonic bicarbonate loss in intestinal failure patients with ileocolonic anastomosis - Guidance for composition of parenteral support.

BACKGROUND & AIMS: Acid-base disturbances are common in short bowel (SB) patients due to increased intestinal bicarbonate loss. However, the resulting systemic acid load has not been quantified. Base excess is used to monitor metabolic acid-base disturbances but inadequately reflects the acid load. Our aim was to investigate the systemic acid/base load in SB-patients to obtain quantitative estimates to guide the composition of parenteral support. METHODS: We calculated total acid load in SB patients by summing 24-h urinary net acid excretion (NAE) and the provision of base equivalents in parenteral support. We then compared differences among anatomical SB-types: jejunostomy (SB-J), jejunocolostomy (SB-JC), and jejunoileostomy (SB-JIC). 47 urine samples from 34 SB patients were analyzed for bicarbonate (HCO3-), ammonium (NH4+), and titratable acid (TA) concentrations. NAE was calculated as (TA + NH4+) - HCO3-. Mixed-effects repeated-measures models were used to statistically examine differences between SB-types and associations with parenteral nutrition and NAE. A healthy cohort served as control. RESULTS: In comparison to SB-J, SB-JC patients had a 4.1 mmoL/l lower base excess (95% CI: -6.3 to -1.8) and an 84.5 mmol/day higher total acid load (CI: 41.3 to 127.7). There were no significant differences between SB-JIC and SB-J regarding base excess, NAE, or total acid load. Higher amounts of infused acetate, sodium, and chloride, but not the acetate/chloride ratio, were associated with lower NAE and higher base excess. CONCLUSIONS: Due to increased colonic bicarbonate loss, patients with SB-JC have a ∼4.4-fold higher acid load than healthy controls. The ion transport mechanisms mediating this bicarbonate loss from the remaining colon need further experimental investigation. NAE could be a useful tool to adjust base infusion in SB.

A basic solution for a complex problem: does treatment of metabolic acidosis slow CKD progression?

PURPOSE OF THIS REVIEW: Metabolic acidosis is frequently encountered in patients with chronic kidney disease (CKD), with increasing prevalence as kidney function worsens. Treating electrolyte disturbances is the sine qua non of Nephrologists, and alkali therapy to normalize serum bicarbonate levels and slow progression of kidney disease has been embedded in clinical practice guidelines for decades on the basis of animal models and controversial clinical trials. This review will critically appraise the literature base for this recommendation and determine whether the available evidence supports this common practice, which is a timely endeavor considering the impending demotion of metabolic acidosis treatment from recommendation to practice point in forthcoming KDIGO guidelines. RECENT FINDINGS: Earlier, open-label, studies supporting the utility of sodium bicarbonate therapy to slow progression of chronic kidney disease have been challenged by more recent, blinded, studies failing to show benefit on CKD progression. This was further demonstrated in the absence of concomitant sodium administration with the hydrochloric acid binder veverimer, which failed to demonstrate benefit on renal death, end stage kidney disease or 40% reduction in estimated glomerular filtration rate in a large multicenter trial. SUMMARY: The current body of literature does not support the routine treatment of metabolic acidosis in patients with CKD and the authors agree with the forthcoming KDIGO guidelines to de-emphasize this common practice.

Modified del Nido cardioplegia is associated with low incidence of low main strong ion difference and hyperchloremia in pediatric patients after cardiac surgery.

PURPOSE: The aims of this study were (1) to determine the associations of cardioplegic solutions with postoperative main strong ion difference (mSID), which is the difference between sodium ion concentration and chloride ion concentration ([Cl-]) and (2) to determine the associations of cardioplegic solutions with markers of organ dysfunction. METHODS: In this retrospective cohort study, patients aged <5 years who underwent cardiac surgery in a tertiary teaching hospital were included. Patients were classified on the basis of the type of cardioplegic solution: modified del Nido cardioplegia (mDNC) and conventional cardioplegia (CC). The effects of mDNC on postoperative mSID and markers of organ functions were examined using propensity-matched analysis. RESULTS: A total of 500 cases were included. mDNC solution was used in 163 patients (32.6%). After propensity score matching, patients in the mDNC group (n = 152) had significantly higher minimum mSID [28 (26, 30) mEq/L vs. 27 (25, 29) mEq/L, p = 0.02] and lower maximum [Cl-] [112 (109, 114) mEq/L vs. 113 (111, 117) mEq/L, p < 0.001] than patients in the CC group (n = 304). The incidences of low mSID and hyperchloremia in the mDNC group were significantly lower than those in the CC group (63.8 vs. 75.7%, p = 0.01 and 63.2 vs. 79.3%, p < 0.001, respectively). There was no significant difference in the incidence of postoperative acute kidney injury and B-type natriuretic peptide level between the two groups. CONCLUSION: The use of modified del Nido cardioplegia may reduce the incidence of abnormal mSID and hyperchloremia compared with the use of a chloride-rich cardioplegic solution.

Alactic base excess (ABE): a novel internal milieu parameter-its concept and clinical importance.

Inspired by the Stewart-Figge acid-base approach, Gattinoni et al. recently introduced a new internal milieu parameter known as alactic base excess (ABE). The authors defined ABE as the sum of lactate and standard base excess. In the context of sepsis, ABE has been proposed as a valuable marker to discern between metabolic acidosis resulting from the accumulation of lactate and the retention of fixed acids, which can occur in cases of renal failure. Multiple studies have demonstrated that a negative ABE value (<-3 mmol/L) represents an early marker of renal dysfunction, and significantly correlates with higher mortality rates in septic patients. In conclusion, ABE is a simple and useful parameter that can be used to better interpret a patient's acid-base status, assess renal function, and general prognosis in sepsis. By incorporating ABE into clinical practice, healthcare professionals can enhance their understanding of the complex acid-base imbalances in their patients and tailor more individualized, effective treatment plans.

Quantifying pH-induced changes in plasma strong ion difference during experimental acidosis: clinical implications for base excess interpretation.

It is commonly assumed that changes in plasma strong ion difference (SID) result in equal changes in whole blood base excess (BE). However, at varying pH, albumin ionic-binding and transerythrocyte shifts alter the SID of plasma without affecting that of whole blood (SIDwb), i.e., the BE. We hypothesize that, during acidosis, 1) an expected plasma SID (SIDexp) reflecting electrolytes redistribution can be predicted from albumin and hemoglobin's charges, and 2) only deviations in SID from SIDexp reflect changes in SIDwb, and therefore, BE. We equilibrated whole blood of 18 healthy subjects (albumin = 4.8 ± 0.2 g/dL, hemoglobin = 14.2 ± 0.9 g/dL), 18 septic patients with hypoalbuminemia and anemia (albumin = 3.1 ± 0.5 g/dL, hemoglobin = 10.4 ± 0.8 g/dL), and 10 healthy subjects after in vitro-induced isolated anemia (albumin = 5.0 ± 0.2 g/dL, hemoglobin = 7.0 ± 0.9 g/dL) with varying CO2 concentrations (2-20%). Plasma SID increased by 12.7 ± 2.1, 9.3 ± 1.7, and 7.8 ± 1.6 mEq/L, respectively (P < 0.01) and its agreement (bias[limits of agreement]) with SIDexp was strong: 0.5[-1.9; 2.8], 0.9[-0.9; 2.6], and 0.3[-1.4; 2.1] mEq/L, respectively. Separately, we added 7.5 or 15 mEq/L of lactic or hydrochloric acid to whole blood of 10 healthy subjects obtaining BE of -6.6 ± 1.7, -13.4 ± 2.2, -6.8 ± 1.8, and -13.6 ± 2.1 mEq/L, respectively. The agreement between ΔBE and ΔSID was weak (2.6[-1.1; 6.3] mEq/L), worsening with varying CO2 (2-20%): 6.3[-2.7; 15.2] mEq/L. Conversely, ΔSIDwb (the deviation of SID from SIDexp) agreed strongly with ΔBE at both constant and varying CO2: -0.1[-2.0; 1.7], and -0.5[-2.4; 1.5] mEq/L, respectively. We conclude that BE reflects only changes in plasma SID that are not expected from electrolytes redistribution, the latter being predictable from albumin and hemoglobin's charges.NEW & NOTEWORTHY This paper challenges the assumed equivalence between changes in plasma strong ion difference (SID) and whole blood base excess (BE) during in vitro acidosis. We highlight that redistribution of strong ions, in the form of albumin ionic-binding and transerythrocyte shifts, alters SID without affecting BE. We demonstrate that these expected SID alterations are predictable from albumin and hemoglobin's charges, or from the noncarbonic whole blood buffer value, allowing a better interpretation of SID and BE during in vitro acidosis.

A Systematic Approach to Understanding Acid-Base Disorders in the Critically Ill.

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. DATA SYNTHESIS: Critically ill patients are prone to significant acid-base disorders that can adversely affect clinical outcomes. Assessing these acid-base abnormalities can be complex because of dynamic aberrations in plasma proteins, electrolytes, extracellular volume, concomitant therapies, and use of mechanical ventilation. This article provides a systematic approach to acid-base abnormalities which is necessary to facilitate prompt identification of acid-base disturbances and prevent untoward morbidity and mortality. RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE: Many acid-base disorders result from medication therapy or are treated with medications. Pharmacists are uniquely poised as the medication experts on the multidisciplinary team to assist with acid-base assessments in the context of pharmacotherapy. CONCLUSION: The use of a systematic approach to address acid-base disorders can be performed by all pharmacists to improve pharmacotherapy and optimize patient outcomes.

Biochemical Alterations Associated With the Severity of COVID-19 in Sub-Saharan Black African Individuals.

BACKGROUND: Biochemical markers are essential in the monitoring and the clinical care of patients as they inform clinicians. Here, we characterized biochemical alterations in sub-Saharan Black African individuals with COVID-19. METHODS: The study includes COVID-19 patients cared for at the Akanda Army Hospital in Libreville (Gabon). A total of 2237 patient records were extracted and reviewed. Patients were classified based on hospital admission (intensive care unit [ICU], internal medicine ward, and outpatient). RESULTS: One thousand six hundred seventy-one were included in the study. ICU patients were significantly older than non-ICU hospitalized patients (P < 0.001) and outpatients (P < 0.0001). Hyperglycemic patients had 6.4 odds of being in ICU (P < 0.0001). Patients with abnormally high urea had 54.7 odds of being in ICU (P < 0.0001). Patients with abnormally high aspartate aminotransferase (AST) (>33 IU/L) had 3.5 odds of being in ICU (P < 0.0001). Hyperlactatemia (>246 IU/L) odds in ICU patients were 14 (P < 0.0001). The odds of abnormally high alkaline phosphatase (ALP) (>147 IU/L) in ICU patients were 4.6 (P < 0.0001). Odds for hypochloremia (<98 mmol/L) were 1.6 in ICU (P < 0.05). Dysnatremia patients (<135 or >145 mmol/L) had 9.5 odds of being found in ICU patients (P < 0.0001). The odds of potassium imbalance (<3.6 or >5 mmol/L) in ICU patients were 12.2 (P < 0.0001). CONCLUSIONS: COVID-19-associated biochemical alterations observed in the Black African population are similar to those observed in other populations, and the association between COVID-19 severity, hyperglycemia, and multi-organ affection is confirmed.

Association between peri-transplant acid-base parameters and graft dysfunction types in kidney transplantation.

Perioperative acid-base disturbance could be informative regarding the possible slow graft function (SGF) or delayed graft function (DGF) development. There is a lack of data regarding the relationship between perioperative acid-base parameters and graft dysfunction in kidney transplant (KT) recipients. We aim to determine the incidence of graft dysfunction types and the association between them and acid-base parameters. We performed a prospective, cohort study on 54 adults, KT recipients, between 1st of January 2019 and 31st of December 2019. Graft function was defined and classified in three categories: immediate graft function (IGF) (serum creatinine < 3 mg/dL at day 5 after KT), SGF (serum creatinine ≥ 3mg/dL at day 5 or ≥ 2.5mg dL at day 7 after KT) and DGF (the need for at least one dialysis treatment in the first week after kidney transplantation). Among the 54 KT recipients, the incidence of SGF and DGF was 13% and 11.1%, respectively. SGF was significantly associated with lower intraoperative pH (7.26± 0.05 vs 7.35± 0.06, p= 0.004), preoperative and intraoperative base excess (BE) [-7.0 (-10.0 ߝ -6.0) vs -3.4 (-7.8 ߝ - 2.1) mmol/L, p= 0.04 and -10.3 (-11.0 ߝ -9.1) vs -4.0 (-6.3 ߝ - 3.0) mmol/L, p= 0.002, respectively] and serum bicarbonate (HCO3-) (16.0± 2.7 vs 19.3± 3.4 mmol/L, p= 0.01 and 14.1± 1.9 vs 18.8± 3.2 mmol/L, p= 0.002 respectively), compared to IGF. DGF was significantly associated with lower intraoperative values of pH (7.27± 0.05 vs 7.35± 0.06, p= 0.003), BE [-7.1 (-10.9 ߝ -6.1) vs -4.0 (-6.3 ߝ - 3.0) mmol/L, p= 0.02] and HCO3- (15.9± 2.4 vs 18.8± 3.2 mmol/L, p=0.02) compared to IGF. No differences were observed between SGF and DGF patients in any of the perioperative acid-base parameters. In conclusion we found that kidney graft dysfunction types are associated with perioperative acid-base parameters and perioperative metabolic acidosis could provide important information to predict SGF or DGF occurrence.

A modified Gamblegram for the visual representation of acid-base disorders according to the Stewart-Figge approach.

The Gamblegram consists of two bars, each of which represents the sum of the charges of individual positively and negatively charged ions and is commonly used for visualizing changes in acid-base and electrolyte charges. However, according to the Stewart-Figge theory, the metabolic independent acid-base variables include the strong ion difference ([SID]) and the total concentrations of weak acids (albumin and inorganic phosphate), which are not shown in the conventional Gamblegram. Thus, the Gamblegram in its current form is unsuitable for visualizing acid-base perturbations using the Stewart-Figge approach. To overcome this problem the following modifications are proposed: 1) The positive bar is represented exclusively by strong ion difference ([SID]) 2) The negative bar is comprised of [HCO3̄], unmeasured ion charge ([X]) and albumin and inorganic phosphate charges which are considered proportional to their total concentrations assuming a standard pH of 7.4 (0.28⋅[Albumin] (g/l) and 1.8⋅[Phosphate] (mmol/l), respectively). The proposed method treats [HCO3̄] as a global index of the metabolic acid-base status, whose concentration is expressed as a function of the Stewart-Figge independent acid-base variables ([SID], [Albumin], [Phosphate] and [X]).

Effect of different hypoxic and hypobaric interventions on blood gas and erythrocyte-related indicators in rats. / ä¸åŒç¼ºæ°§å¹²é¢„å¯¹ä½ŽåŽ‹ä½Žæ°§æ¨¡åž‹é¼ è¡€æ°”åŠçº¢ç»†èƒžç›¸å ³æŒ‡æ ‡çš„å½±å“.

OBJECTIVES: To explore the effects of hypoxic and hypobaric conditions on blood gas and erythrocyte-related indicators in rats. METHODS: SD male rats were exposed to low-pressure hypoxic conditions simulating an altitude of 6500 m in a small or a large experimental cabin. Abdominal aortic blood samples were collected and blood gas indicators, red blood cells (RBCs) count, and hemoglobin (Hb) content were measured. The effects of exposure to different hypoxia times, different hypoxia modes, normal oxygen recovery after hypoxia, and re-hypoxia after hypoxia preconditioning on blood gas indicators, RBCs count and Hb content were investigated. RESULTS: The effect of blood gas indicators was correlated with the length of exposure time of hypoxia and the reoxygenation after leaving the cabin. Hypoxia caused acid-base imbalance and its severity was associated with the duration of hypoxia; hypoxia also led to an increase in RBCs count and Hb content, and the increase was also related to the time exposed to hypoxia. The effects of reoxygenation on acid-base imbalance in rats caged in a small animal cabin were more severe that those in a large experimental cabin. Acetazolamide alleviated the effects of reoxygenation after leaving the cabin. Different hypoxia modes and administration of acetazolamide had little effect on RBCs count and Hb content. Normal oxygen recovery can alleviate the reoxygenation and acid-base imbalance of hypoxic rats after leaving the cabin and improve the increase in red blood cell and hemoglobin content caused by hypoxia. The improvement of hypoxia preconditioning on post hypoxia reoxygenation is not significant, but it can alleviate the acid-base imbalance caused by hypoxia in rats and to some extent improve the increase in red blood cell and hemoglobin content caused by hypoxia. CONCLUSIONS: Due to excessive ventilation and elevated RBCs count and Hb content after hypoxia reoxygenation, oxygen partial pressure and other oxygenation indicators in hypoxic rats are prone to become abnormal, while blood gas acid-base balance indicators are relatively stable, which are more suitable for evaluating the degree of hypoxia injury and related pharmacological effects in rats.

Evaluating a low anion gap: A practical approach.

In teaching and in practice, little attention is given to a low anion gap. This oversight can result in a missed opportunity to diagnose acute or chronic disorders requiring treatment. In this article, we review the constituents of the anion gap, build a differential diagnosis for a low anion gap using case examples, and provide a stepwise approach to diagnostic testing to evaluate this abnormal finding.

Fluid Management during Continuous Renal Replacement Therapy: A Case-Based Approach.

Continuous renal replacement therapy (CRRT) is frequently used for fluid management of critically ill patients with acute or chronic kidney failure. There is significant practice variation worldwide in fluid management during CRRT. Multiple clinical studies have suggested that both the magnitude and duration of fluid overload are associated with morbidity and mortality in critically ill patients. Therefore, timely and effective fluid management with CRRT is paramount in managing critically ill patients with fluid overload. While the optimal method of fluid management during CRRT is still unclear and warrants further investigation, observational data have suggested a U-shape relationship between net ultrafiltration rate and mortality. Furthermore, recent clinical data have underpinned a significant gap in prescribed versus achieved fluid balance during CRRT, which is also associated with mortality. This review uses a case-based approach to discuss two fluid management strategies based on net ultrafiltration rate and fluid balance goals during CRRT and harmonizes operational definitions.

Metabolic Acid-Base Disorders.

Metabolic acid-base disturbances are frequently encountered in the emergency department, and many of these patients are critically ill. In the evaluation of patients with these maladies, it is important for the emergency clinician to determine the cause, which can usually be elicited from a thorough history and physical examination. There are several mnemonics that can be used to form an appropriate list of potential causes. Most of the time, the management of these patients requires no specific treatment of the acid-base status but, rather, requires treatment of the underlying disorder that is causing the acid-base disturbance.

Acid-base and electrolyte evaluation in dogs with upper GI obstruction: 115 dogs (2015-2021).

OBJECTIVES: Metabolic alkalosis, although uncommon in small animals, has been previously associated with gastrointestinal obstructions. Depending on the population and disease process evaluated, previous prevalence of metabolic alkalosis is reported as ranging from 2% to 45% in canine patients. The objective of this study was to determine the prevalence of metabolic alkalosis and other acid-base and electrolyte disorders in a cohort of dogs with a confirmed upper gastrointestinal obstruction. MATERIALS AND METHODS: Electronic medical records were reviewed to identify dogs who presented for vomiting with evidence of an upper gastrointestinal obstruction from January 2015 to October 2021. Patients were enrolled only if a preoperative venous blood gas was obtained and analysed in house. Traditional acid-base analysis was utilised to determine an acid-base status before relieving the obstruction. When available, post-operative venous acid-base status was determined within 24 hours after surgery, and compared to preoperative results. RESULTS: A total of 115 dogs were included in the study. Twenty-five out of 115 (22%) dogs displayed either a simple metabolic alkalosis or a mixed acid-base disturbance before surgery. Twenty-seven out of 115 dogs (37%) had a normal acid-base status at entry. Seventy-one dogs had pre- and post-operative venous blood gas results available. Metabolic alkalosis was resolved in nearly all patients post-operatively, with no patients displaying a simple metabolic alkalosis. A mixed metabolic acidosis and respiratory alkalosis was the most common condition post-operatively, found in 25 of 71 (35%) dogs. Severe derangements of electrolytes were infrequent preoperatively (3/115; 2.6%). A majority of patients in this study exhibited hypokalaemia (64.4%), hypochloraemia (72.8%) and hyponatraemia (77.4%) on preoperative venous blood gases. Venous pH, Pv CO2 , bicarbonate and base excess were significantly higher preoperatively when compared to the post-operative results. CLINICAL SIGNIFICANCE: This study found the prevalence of pre-operative metabolic alkalosis in dogs with a documented upper gastrointestinal obstruction to be lower than previously reported. Surgical or endoscopic alleviation of the upper gastrointestinal obstruction resulted in resolution of metabolic alkalosis in nearly all patients.

Carbon dioxide reduction by photosynthesis undetectable even during phytoplankton blooms in two lakes.

Lakes located in the boreal region are generally supersaturated with carbon dioxide (CO2), which emerges from inflowing inorganic carbon from the surrounding watershed and from mineralization of allochthonous organic carbon. While these CO2 sources gained a lot of attention, processes that reduce the amount of CO2 have been less studied. We therefore examined the CO2 reduction capacity during times of phytoplankton blooms. We investigated partial pressure of CO2 (pCO2) in two lakes at times of blooms dominated by the cyanobacterium Gloeotrichia echinulata (Erken, Sweden) or by the nuisance alga Gonyostomum semen (Erssjön, Sweden) during two years. Our results showed that pCO2 and phytoplankton densities remained unrelated in the two lakes even during blooms. We suggest that physical factors, such as wind-induced water column mixing and import of inorganic carbon via inflowing waters suppressed the phytoplankton signal on pCO2. These results advance our understanding of carbon cycling in lakes and highlight the importance of detailed lake studies for more precise estimates of local, regional and global carbon budgets.

Point-of-Care Verification of Blood Culture Volume in Neonates: A Feasibility Trial.

BACKGROUND: Blood cultures remain the gold standard for the diagnosis of sepsis. However, volumes of blood submitted for cultures often do not match the recommended values. We propose a simple intervention aimed to verify the volume of blood sampled using a scale. This study was undertaken in preparation for a future, multicenter, pre- and post-intervention trial. Our primary objective was to test the feasibility (uptake and retention) of this future intervention. MATERIALS AND METHODS: This study was conducted at a neonatal department in Warsaw, Poland, over a period of eight months (May to December 2020). Before starting the study, we undertook an educational intervention focused on obtaining adequate blood volumes for culture. The culture bottles that were weighed in advance were distributed in all blood collection areas. Blood volume was verified by weighing the bottle immediately after blood inoculation. The calculated value was communicated to the collecting clinician and recorded. The primary outcome measure was the percentage of blood culture submissions for which the blood volume inoculated into the bottles was determined by weighing. RESULTS: During the study period, 244 blood samples were collected for culture, out of which 205 samples were weighed (84.0%, CI95 [78.8% to 88.4%]). This high proportion remained stable throughout the study period. We have not observed any adverse events related to the study. CONCLUSIONS: The point-of-care verification of blood culture volume using a scale was feasible to implement. Since we have met our pre-established criterion for success, a future, definitive trial is likely to proceed.