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Object and Purpose: Acid-base disorders in dairy herds can be diagnosed by determining urinary net base excretion (NBE). Modifications of this method are the differential NBE (dNBE) with determination of the urinary concentration-independent base-acid ratio (BAR) and the simplified NBE test with reduced urine volume (sNBE). The aim of this study was to compare these methods among themselves and as a pooled test, in their assessment of cow group acid base status as well as to derive recommendations for practical use., Animals, Material, and Methods: The concentrations of NBE, dNBE, and sNBE were measured in urine samples derived from 855 German-Holstein cows in 127 cow groups at different stages of lactation. BAR was then calculated. dNBE and BAR were determined both individually per cow and as a pool of a group. Mixed linear models were used to examine the relationship between the mean of the individual animal values and the pool sample result of a group for these two parameters. In addition, all groups were evaluated with respect to acidotic or alkalotic load based on their single animal results of the respective methods, the mean values formed from them, and the measured pool result. By using the single animal BAR as reference, the sensitivity and specificity of the different methods were calculated., Results: The calculated mean values of the individual measurements of dNBE and BAR differed from the measured value in the pool sample, especially in low and high measurement ranges. In the group assessment, NBE showed the best combined sensitivity and specificity for the detection of acid base disorders. The dNBE pool assay showed satisfactory specificity with respect to acidosis and alkalosis, while the sNBE on an individual animal basis and the BAR determination in the pool showed satisfactory sensitivity with respect to acidosis., Conclusions and Clinical Relevance: It was shown that NBE determined in individual animal samples is well suited for the assessment of acid base status of cow groups and can therefore be recommended for practical use. The determination of dNBE as well as BAR as a pool test is not sufficient for the detection of alkalotic load in cow groups but may help to confirm an existing acidotic load., Competing Interests: Die Autoren erklären, dass keine geschützten, finanziellen, beruflichen oder anderweitigen Interessen an einem Produkt oder einer Firma bestehen, welche die in dieser Veröffentlichung genannten Inhalte oder Meinungen beeinflussen können., (Thieme. All rights reserved.)

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, P v CO 2 , 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., (© 2023 British Small Animal Veterinary Association.)

Background: Enteral hydration in cattle is most commonly performed as a bolus (B) via the ororuminal route, although continuous flow (CF) administration via the nasoesophageal route represents a viable alternative. Currently, no study has compared the effectiveness of these two methods. This study aimed to compare the efficiency of enteral hydration using CF and B to correct water, electrolyte and acid-base imbalances in cows., Methods: Protocols for the induction of dehydration were applied twice to eight healthy cows, with an interval of 1 week. In a crossover design, two types of enteral hydration were performed using the same electrolyte solution and volume equal to 12% of bodyweight (BW): CF (10 mL/kg/h, between 0 and 12 hours) and B (6% BW, twice, at 0 and 6 hours). Clinical and blood variables were determined at -24, 0, 6, 12 and 24 hours and compared using repeated-measures ANOVA., Results: Induced moderate dehydration and hypochloremic metabolic alkalosis were corrected after 12 hours using the two hydration methods, with no differences observed between the methods., Limitations: The study was conducted with induced rather than natural imbalances, so the findings should be interpreted cautiously., Conclusion: Enteral CF hydration is as effective as B hydration in reversing dehydration and correcting electrolyte and acid-base imbalances., (© 2023 British Veterinary Association.)

Background: Surgical abdominal emergencies in calves are associated with a guarded prognosis and have the potential for complex metabolic derangements including acid-base imbalances., Objectives: To perform a comprehensive analysis of acid-base status and to assess the prognostic relevance of preoperative clinicopathologic variables in calves undergoing abdominal surgery., Animals: Hospital-based study samples of 535 (dataset 1; DS1) and 83 calves (dataset 2; DS2)., Methods: Retrospective (DS1) and prospective (DS2) case series., Results: In DS1, acidemia (pH <7.33) was present in 49.9%, whereas alkalemia (pH >7.37) was present in 30.7% of calves. Plasma L-lactate, chloride, and serum inorganic phosphorus concentration accounted for 51.9%, 11.6% and 9.4% of the variation of venous blood pH, respectively. Classification tree analysis indicated that a negative outcome (death or euthanasia during hospitalization) was associated with venous pO 2  ≤33.6 mm Hg, anion gap >18.3 and >22.9 mEq/L, serum albumin concentration ≤36.5 and ≤29.4 g/L, serum urea concentration >4.4 mmol/L, and plasma ionized calcium concentration ≤1.26 mmol/L. The area under the receiver operating characteristic curve of this model was 0.85 (95% CI: 0.82-0.89, P < .001) and the resulting sensitivity and specificity for the prediction of nonsurvival at the optimal probability cut-point of 0.5 was 89.8% and 65.7%, respectively. In DS2 the model had a similar sensitivity and specificity of 90.5% and 70%, respectively., Conclusions and Clinical Importance: Clinicopathologic imbalances and associated changes of acid-base status are common in calves with surgical abdominal emergencies and have clinical utility for the prediction of a negative postoperative outcome., (© 2023 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC. on behalf of the American College of Veterinary Internal Medicine.)

In clinical medicine, evaluation of acid-base balance can be a valuable diagnostic and monitoring tool. Blood gas machines need very small volumes of blood and provide immediate results, making them ideal for use in the emergency room and intensive care setting. This review outlines the stepwise approach to assessment of acid-base balance in dogs, common causes of acid-base abnormalities, and the general approach to treatment., Competing Interests: Disclosure The author has nothing to disclose., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Objectives: To investigate the acid-base status of sick goats using the simplified strong ion difference (sSID) approach, to establish the quantitative contribution of sSID variables to changes in blood pH and HCO 3 - and to determine whether clinical, acid-base, and biochemical variables on admission are associated with the mortality of sick goats., Animals: One hundred forty-three sick goats., Methods: Retrospective study. Calculated sSID variables included SID using 6 electrolytes unmeasured strong ions (USI) and the total nonvolatile buffer ion concentration in plasma (A tot ). The relationship between measured blood pH and HCO 3 - , and the sSID variables was examined using forward stepwise linear regression. Cox proportional hazard models were constructed to assess associations between potential predictor variables and mortality of goats during hospitalization., Results: Hypocapnia, hypokalemia, hyperchloremia, hyperlactatemia, and hyperproteinemia were common abnormalities identified in sick goats. Respiratory alkalosis, strong ion acidosis, and A tot acidosis were acid-base disorders frequently encountered in sick goats. In sick goats, the sSID variables explained 97% and 100% of the changes in blood pH and HCO 3 - , respectively. The results indicated that changes in the respiratory rate (<16 respirations per minute), USI, and pH at admission were associated with increased hazard of hospital mortality in sick goats., Conclusions and Clinical Importance: The sSID approach is a useful methodology to quantify acid-base disorders in goats and to determine the mechanisms of their development. Clinicians should consider calculation of USI in sick goats as part of the battery of information required to establish prognosis., (© 2020 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)

Background: Use of different analyzers to measure electrolytes in the same horse can lead to different interpretation of acid-base balance when using the simplified strong ion difference (sSID) approach., Objective: Investigate the level of agreement between 2 analyzers in determining electrolytes concentrations, sSID variables, and acid-base disorders in sick horses., Animals: One hundred twenty-four hospitalized horses., Methods: Retrospective study using paired samples. Electrolytes were measured using a Beckman Coulter AU480 Chemistry analyzer (PBMA) and a Nova Biomedical Stat Profile (WBGA), respectively. Calculated sSID variables included strong ion difference, SID 4 ; unmeasured strong ions, USI; and total nonvolatile buffer ion concentration in plasma (A tot ). Agreement between analyzers was explored using Passing-Bablok regression and Bland-Altman analysis. Kappa (κ) test evaluated the level of agreement between analyzers in detecting acid-base disorders., Results: Methodologic differences were identified in measured Na + and Cl - and calculated values of SID 4 and USI. Mean bias (95% limits of agreement) for Na + , Cl - , SID 4 , and USI were: -1.2 mmol/L (-9.2 to 6.8), 4.4 mmol/L (-4.4 to 13), -5.4 mmol/L (-13 to 2), and -6.2 mmol/L (-14 to 1.7), respectively. The intraclass correlation coefficient for SID 4 and USI was .55 (95%CI: -0.2 to 0.8) and .2 (95%CI: -0.15 to 0.48), respectively. There was a poor agreement between analyzers for detection of SID 4 (κ = 0.20, 95%CI, 0.1 to 0.31) or USI abnormalities (κ = -0.04, 95%CI, -0.11 to 0.02)., Conclusions and Clinical Importance: Differences between analyzer methodology in measuring electrolytes led to a poor agreement between the diagnosis of acid-base disorders in sick horses when using the sSID approach., (© 2020 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)

Background: Early recognition and management of acid-base, fluid, and electrolyte disorders are crucial for the maintenance of health and performance in equine athletes., Objectives: To analyze changes in acid-base and electrolyte status associated with exercise during cross-country competitions at different levels using traditional and quantitative approaches., Animals: Thirty-eight eventing horses., Methods: Prospective observational study. Jugular venous blood samples were collected before and after the cross-country test of 25 international eventing competitions ranging from 2-star (formerly 1-star) to 5-star (formerly 4-star) level. Blood gas analysis was performed to determine pH, pCO 2 , Na + , Cl - , and K + and calculate HCO 3 - , tCO 2 base excess (BE ECF ), anion gap (AG), strong ion difference calculated from Na + , K + , Cl - , and lactate - (SID 4 ), strong ion difference calculated from Na + , K + , and Cl - (SID 3 ), strong ion gap (SIG), and total nonvolatile weak buffer concentration (A tot ). Postexercise acid-base imbalances, diagnosed on the basis of the traditional approach, and the simplified strong ion model were compared., Results: Significant decreases in pH, Cl - , SID 4 , pCO 2 , HCO 3 - , tCO 2 , and BE ECF as well as increases in K + , SID 3 , AG, TP, and A tot were observed between pre- and postexercise samples. The changes in acid-base parameters were significantly affected by the competition level. Using the strong ion approach, a higher proportion of horses was diagnosed with postexercise metabolic acidosis., Conclusions and Clinical Importance: Regarding the complex acid-base changes in horses competing at cross-country competitions, the quantitative approach provided a more detailed analysis of the different factors contributing to acid-base balance than did the traditional approach., (© 2020 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.)

Background: The strong ion model (SIM) is an alternative paradigm in the characterization of acid-base disturbances particularly in complex disorders., Hypothesis/objectives: To compare the acid-base changes in dogs with parvoviral enteritis (PE) using the Henderson-Hasselbalch (HH) approach, with 2 strong ion approaches., Animals: Forty-four dogs with PE, and 16 age-matched control dogs., Methods: Prospective controlled observational study. Acid-base status was evaluated using the HH model, Fencl-Stewart (FS) approach and a validated strong ion model (VDM). The acid-base changes according to each model were classified and compared. Statistical correlations between pH, CO 2 , and various SIM variables were performed, as well as between the sum of effects (SOE) of the SIM and the individual variables comprising the SOE., Results: The HH model identified acid-base disorders in 31/44 cases of which 16/31 were mixed with metabolic acidosis and concurrent respiratory alkalosis the most common (10/31). Using the FS approach, metabolic changes were present 36/42 cases, with changes in free water (FW), chloride, and unmeasured anions (UA) being the most prevalent. Both FW and UA correlated well with pH; however, UA were most consistently abnormal in severe acidemia. Similarly to the HH, the VDM detected acid-base disturbances in 28/44 cases. Major contributors to the acid-base changes were hyponatremia, hypochloremia, and A tot acidosis because of elevated globulins and increased UA., Conclusions and Clinical Importance: Acid-base changes are common and complex in dogs with PE, and were easier to understand using a SIM paradigm. Increases in UA have not been documented in PE in dogs., (© 2020 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.)

Equine asthma syndrome is an allergic, inflammatory airway disease that usually affects older horses. Respiratory acidosis is an acid-base imbalance caused by alveolar hypoventilation. The acid-base balance may be assessed using the Henderson-Hasselbalch equation as well as the Stewart model. The authors hypothesized that systemic respiratory acidosis changes the ionic concentrations affecting water dissociation. The study group included 16 Warmblood, mixed breed horses of both sexes with a history of severe equine asthma, and 10 healthy horses were used as controls. Arterial and venous blood were collected from all the horses. The pH, pO 2 , and pCO 2 and HCO 3- were assessed in the arterial blood. Na, K, Cl, albumin, and P inorganic (P i ) were assessed in the venous blood. The obtained results were used to calculate the anion gap (AG), modified AG, actual strong ion difference (SID a ), weak non-volatile acids, and effective strong ion difference (SID e ) values for all the horses. A systemic, compensatory respiratory acidosis was diagnosed in the study group. The concentration of Na in the blood serum in the study group was significantly higher, whereas the concentration of Cl was significantly lower than the values in the control group. The SID a and SID e values calculated in the horses from the study group were significantly higher than those in the control group. Significantly higher SID a and SID e values confirm the presence of ionic changes that affect water dissociation in the course of respiratory acidosis in horses. The SID a and SID e values may be useful in the diagnosis and treatment of respiratory acidosis in horses, which warrant further investigation., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Objectives: Electrolyte disorders have been individually associated with mortality in small populations of cats with specific conditions, but the associations and interactions between electrolyte disturbances and outcome have not been evaluated in a large, heterogeneous population. It was hypothesized that abnormalities of sodium, chloride, potassium and calcium concentrations would be independently and proportionately associated with death from natural causes and with all-cause mortality in cats., Methods: An electronic database containing 7064 electrolyte profiles was constructed to assess the association between disorders of sodium, potassium, corrected-chloride and ionized calcium concentrations with non-survival by multivariable modelling. A second database containing 2388 records was used to validate the models constructed from the first database., Results: All four electrolytes assessed had non-linear U-shaped associations with case fatality rates, wherein concentrations clustered around the reference interval had the lowest case fatality rates, while progressively abnormal concentrations were associated with proportionately increased risk of non-survival (area under the receiver operator characteristic curve [AUROC] 0.689) or death (AUROC 0.750)., Conclusions and Relevance: Multivariable modelling suggested that these electrolyte disturbances were associated with non-survival and with death from natural causes independent of each other. The present study suggests that measurement of electrolyte concentrations is an important component of the assessment of cats in emergency rooms or intensive care units. Future studies should focus on confirming these associations in a prospective manner accounting for disease severity.

Disturbances of extracellular potassium (K) homeostasis in calves with severe neonatal diarrhea have been studied extensively. Although total body depletion of this predominantly intracellular electrolyte is generally thought to occur in diarrheic calves, the mechanisms through which K depletion occurs are poorly understood. The aim of this study was to investigate how intracellular K homeostasis is affected by dehydration and acidemia, the 2 most important metabolic disturbances in calves with naturally occurring diarrhea. Twenty-seven calves with naturally occurring neonatal diarrhea, pronounced dehydration, and acidemia, and 2 groups of 10 healthy control calves were included in this study. Blood samples and muscle biopsies were obtained immediately before initiation of treatment (T 0 ) and after complete rehydration and correction of acidemia (T 1 ) from diarrheic calves. Blood samples were used to perform blood gas, blood biochemical, and hematological analyses and to determine K content in erythrocytes. Muscle biopsies were used to determine muscle tissue K content and tissue dry matter. Controls were used to determine values for erythrocyte and muscle tissue K content in healthy neonatal calves for comparison with diarrheic calves. As defined by the inclusion criteria, diarrheic calves showed pronounced acidemia and dehydration at T 0 . Mean muscle tissue K content and tissue dry matter remained unchanged between sampling times and did not differ from values measured in healthy control calves. Erythrocyte K content increased from 73.63 ± 13.73 to 77.64 ± 15.97 mmol/L (±standard deviation) but was associated with a concomitant decline in erythrocyte volume. Values measured at both sampling times in diarrheic calves did not differ from erythrocyte K measured in healthy control calves. The plasma K concentration (median [interquartile range]) decreased from 5.44 [4.76-6.17] to 4.16 [3.99-4.31] mmol/L between T 0 and T 1 . Although changes in plasma [K] were associated with the degree of dehydration, neither dehydration nor acidemia was associated with changes of K content in muscle tissue or erythrocytes. In conclusion, severe dehydration and acidemia in diarrheic calves were not associated with notable changes in K content of muscle tissue or erythrocytes. These results do not support the concept of pronounced K depletion occurring in calves with neonatal diarrhea. Erythrocytes are a poor surrogate tissue in which to measure changes of intracellular K content in diarrheic calves because of concomitant changes in erythrocyte volume that complicate the interpretation of results., (Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Metabolic acid-base disorders are common in emergency and critically ill patients. Clinicians may have difficulty recognizing their presence when multiple acid-base derangements are present in a single patient simultaneously. The anion gap and the strong ion gap concepts are useful calculations to identify the components of complex metabolic acid-base associated to the presence of unmeasured anions. This article presents their definition, normal values, indications, limitations, and guidelines for interpretation of changes in the clinical setting., (Copyright © 2016 Elsevier Inc. All rights reserved.)

The incidence of respiratory acid-base abnormalities in the critical care unit (CCU) is unknown, although respiratory alkalosis is suspected to be common in this population. Abnormal carbon dioxide tension can have many physiologic effects, and changes in Pco 2 may have a significant impact on outcome. Monitoring Pco 2 in CCU patients is an important aspect of critical patient assessment, and identification of respiratory acid-base abnormalities can be valuable as a diagnostic tool. Treatment of respiratory acid-base disorders is largely focused on resolution of the primary disease, although mechanical ventilation may be indicated in cases with severe respiratory acidosis., (Published by Elsevier Inc.)

Respiratory alkalosis, or primary hypocapnia, occurs when alveolar ventilation exceeds that required to eliminate the carbon dioxide produced by tissues. Concurrent decreases in Paco 2 , increases in pH, and compensatory decreases in blood HCO 3 - levels are associated with respiratory alkalosis. Respiratory alkalosis can be acute or chronic, with metabolic compensation initially consisting of cellular uptake of HCO 3 - and buffering by intracellular phosphates and proteins. Chronic respiratory alkalosis results in longer-lasting decreases in renal reabsorption of HCO 3 - ; the arterial pH can approach near-normal values., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Because of the role of the kidneys in maintaining homeostasis in the body, kidney disease leads to derangements of fluid, electrolyte, and acid-base balance. The most effective therapy of a uremic crisis is careful management of fluid balance, which involves thoughtful assessment of hydration, a fluid treatment plan personalized for the specific patient, and repeated and frequent reassessment of fluid and electrolyte balance. Disorders of sodium, chloride, potassium, calcium, and phosphorus are commonly encountered in kidney disease and some may be life-threatening. Treatment of metabolic acidosis and nutritional support is frequently needed., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Chloride is an essential element, playing important roles in digestion, muscular activity, regulation of body fluids, and acid-base balance. As the most abundant anion in extracellular fluid, chloride plays a major role in maintaining electroneutrality. Chloride is intrinsically linked to sodium in maintaining osmolality and fluid balance and has an inverse relationship with bicarbonate in maintaining acid-base balance. It is likely because of these close ties that chloride does not get the individual attention it deserves; we can use these facts to simplify and interpret changes in serum chloride concentrations., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Hydrogen concentration is a critical determinant of many physiologic functions and is tightly regulated. Any alteration in acid-base equilibrium sets into motion a compensatory response by either the lungs or the kidneys. The compensatory response attempts to return the ratio between Pco 2 and [HCO 3 - ] to normal and thereby minimize the pH change. A primary increase or decrease in one component is associated with a predictable compensatory change in the same direction in the other component, and the expected compensation can be estimated clinically in dogs and cats., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Fluid therapy is generally the most life saving and important therapeutic measure in a critical pet suffering from dehydration due to gastrointestinal losses (vomiting and/or diarrhea). Fluid therapy should be personalized to the patient's history, complaint, physical examination and laboratory findings. It is directed to the patients needs and modified based of the physical and laboratory findings until fluid therapy resuscitation end points are achieved., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Acid-base balance is one of the most vigorously regulated variables of the body, including genital organs. Subacute ruminal acidosis is a common disturbance in dairy cows that disturbs several biochemical indices in the blood, cerebrospinal fluid, and urine. The possible negative effects of metabolic acidosis on the follicular fluid (FF) composition and, subsequently, on oocyte quality, are not fully elucidated. This study aimed to evaluate the changes in acid-base balance (ABB) in FF and blood during acute metabolic acidosis in dairy heifers. Ten Holstein heifers were stimulated with FSH in eight decreasing doses at 12-hour intervals (D0-D3). Acidosis was induced by oral administration of sucrose at 9 g/kg of body weight, dissolved in 10 L of warm tap water, at D3. Samples were collected from each cow at 0, 8, 12, 16, 24, 32, 40, and 48 hours after treatment. Samples of FF, obtained by transvaginal follicular aspiration, and peripheral blood were examined for ABB parameters: pH, pCO 2 , pO 2 , HCO 3 - , and base excess (BE). A significant decrease in pH, HCO 3 - , and BE values in the blood, as well as FF, occurred after sucrose treatment. The lowest pH values occurred in blood at 16 hours, and in FF at 24 hours, after treatment (7.30 ± 0.05 and 7.33 ± 0.05, respectively). The lowest HCO 3 - values in blood (18.75 ± 3.2 mmol/L) and FF (18.07 ± 2.84 mmol/L) occurred 24 hours after treatment, as did the lowest BE values (-6.61 ± 3.7 mmol/L and -7.53 ± 3.89 mmol/L, in blood and FF, respectively). Significant correlations for HCO 3 - (r = 0.928), BE (r = 0.946), pH (r = 0.889), and pCO 2 (r = 0.522) existed between blood and FF samples. The results demonstrated that metabolic acute acidosis substantially influences the characteristics of both serum and FF., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Reasons for Performing Study: Acid-base imbalances observed in human paediatric patients are associated with outcome. Likewise, neonatal foals may have different acid-base imbalances associated with diagnosis or prognosis., Objectives: To determine acid-base imbalances by the quantitative method in ill neonatal foals and assess their association with diagnosis and prognosis., Study Design: Observational prospective clinical study., Methods: This study included 65 ill neonatal foals (32 septic, 33 nonseptic) admitted to an equine referral hospital from 2005 to 2011with acid-base parameters determined on admission and a control group of 33 healthy neonatal foals. Blood pH, pCO 2 , sodium, potassium, chloride, L-lactate, albumin and phosphate concentrations were determined. Bicarbonate, globulin, measured strong ion difference (SID m ), nonvolatile weak buffer concentrations (A tot ), base excess and its components were calculated. Analysis of covariance (ANCOVA) and multiple linear regression statistical analyses were performed. Results are summarised as mean ± s.d. for normally distributed variables and median [25-75th percentiles] for non-normally distributed ones., Results: A total of 63% of ill foals had respiratory alkalosis and 58.5% had SID m acidosis. The combination of both alterations was detected in 21 of 65 ill foals and abnormal pH was found in 24 of 65. Compared with healthy foals, ill foals had significantly lower SID m (nonseptic 31.6 ± 6.3 [P<0.01] and septic 32.0 ± 6.4 [P<0.01] vs. control 40.3 ± 3.1 mmol/l), potassium (nonseptic 3.5 [3.3-3.8; P<0.01] and septic 3.6 [3.2-4.3; P = 0.01] vs. control 4.2 [3.8-4.5] mEq/l) and higher L-lactate (nonseptic 5.1 ± 4.2 [P = 0.01] and septic 5.0 ± 3.7 [P = 0.03] vs. control 2.5 ± 1.3 mmol/l). Significantly higher L-lactate and venous pCO 2 were found in nonsurviving (6.4 ± 3.5 mmol/l [P = 0.04] and 51 ± 13 mmHg [P<0.01]) compared with surviving foals., Conclusions: The most common acid-base imbalances observed in ill foals were respiratory alkalosis, SID m acidosis or mixed respiratory alkalosis with strong ion acidosis. Increased venous pCO 2 and blood L-lactate concentration were associated with poor outcome., (© 2015 EVJ Ltd.)

Objective: To describe the prevalence and possible causes of hypochloremia in the local hospital cat population., Material and Methods: Retrospective study consisting of two parts. Data were collected from the local electronic medical records database using the search terms "chloride" and "cats" (part A), and "blood gas analysis" and "cats" (part B). The medical records of the hypochloremic cats were then reviewed to determine prior treatment or infusions and to identify major underlying disease processes. Part A included an age and gender matched non-hypochloremic control group, whereas in part B acid-base status was assessed., Results: Hypochloremia was detected in 367 (27%) of 1363 blood samples. The application of a correction formula to adjust for free water changes decreased the number of hypochloremic cats to 253 (19%). Only a minority had received glucocorticoids or loop diuretics and the prevalence of vomiting was 44%. Common associated disorders were gastrointestinal and respiratory diseases, as well as azotemia and diabetes mellitus. Polyuria/polydipsia, dehydration, prednisolone or furosemide pretreatment, azotemia and diabetes mellitus increased, whereas fluid therapy and the diagnosis of neoplasia decreased the prevalence of hypochloremia. An inverse correlation was found between corrected chloride and standardized base excess (rs = -0.597, p = 0.001) as well as anion gap (rs = -0.4, p = 0.026). 99% of the hypochloremic cats had derangements of acid-base balance., Conclusion: Hypochloremia is a common electrolyte disorder in the local cat population. The correction formula is necessary to adjust for changes in plasma osmolality. Although associated with metabolic alkalosis, most of the hypochloremic cats have a normal or decreased pH. The inverse correlation of chloride and anion gap als well as the high proportion of azotemic or diabetic animals support the concept of compensatory acidosis induced hypochloremia., Clinical Relevance: Hypochloremia should prompt the clinician to performe blood-gas analysis. Diabetes mellitus (especially ketoacidosis) and renal disease should be included in current algorithms for the evaluation of hypochloremic patients.

The changes in ocean chemistry stemming from anthropogenic CO2 release--termed ocean acidification (OA)--are predicted to have wide-ranging effects on fish and ultimately threaten global populations. The ability of fish to adapt to environmental change is currently unknown, but phenotypic plasticity has been highlighted as a crucial factor in determining species resilience. Here we show that red drum, a long-lived estuarine-dependent fish species native to the Gulf of Mexico, exhibit respiratory plasticity that increases CO2 excretion capacity when acclimated to OA conditions. Specifically, fish exposed to 14 days of 1000 µatm CO2 had a 32% reduction in branchial diffusion distance and increased expression of two putative CO2 channel proteins--rhag and rhcg1. No changes were observed in the erythrocyte CO2 transport pathways. Surprisingly, no significant changes in blood chemistry were observed between acclimated and acutely challenged animals; however, a non-significant 30 % drop in the magnitude of plasma C(CO2) elevation was observed. Reduced diffusion distance also comes with the cost of increased diffusive water loss, which would require greater osmoregulatory investment by the animal. OA exposure induced increased gill Na(+), K(+) ATPase activity and intestinal nkcc2 expression, supporting both the presumed osmotic stress and increased osmoregulatory investment. However, no differences in standard metabolic rate, maximum metabolic rate or aerobic scope were detected between control and OA acclimated individuals. Similarly, no differences in critical swim speed were detected between groups, suggesting the energetic cost related to respiratory plasticity is negligible against background metabolism. The current study demonstrated that red drum exhibit respiratory plasticity with only mild physiological trade-offs; however, this plasticity is insufficient to fully offset the OA-induced acid-base disturbance and as such is unlikely to impact species resilience.

This study reports electrolyte and acid/base disturbances observed in clinical cases receiving autologous transfusion of blood processed by a cell salvage device. The records of 12 client-owned dogs that received an autologous transfusion via a cell salvage device with pre- and post-autologous transfusion blood work available were reviewed. Blood work from the 12 case dogs was compared to blood work from 12 control dogs with similar diseases. Control dogs received similar surgical treatment and were administered a similar volume per kg of packed red blood cells as case dogs, but did not undergo autologous transfusion. Case dogs that received autologous transfusion via a cell salvage device were significantly more likely to experience a decrease in ionized calcium and magnesium levels post-transfusion than were control dogs. Calcium and magnesium levels should be closely monitored during and after autologous transfusion. Calcium and/or magnesium supplementation may be required.

Background: The quantitative effect of strong electrolytes, unmeasured strong anions (UAs), pCO2, and plasma protein concentrations in determining plasma pH can be demonstrated using the physicochemical approach. Plasma anion gap (AG) and strong ion gap (SIG) are used to assess UAs in different species., Hypotheses: Strong ions are a major factor influencing changes in plasma pH of hospitalized foals. AG and SIG accurately predict severe hyper-L-lactatemia ([L-lac(-)] > 7 mmol/L)., Animals: Seven hundred and ninety three hospitalized foals < 7 days old., Methods: Retrospective study. The relationship between measured pH and physicochemical variables, and the relationship between plasma [L-lac(-)] and AG and SIG, were determined using regression analyses. Optimal AG and SIG cut points to predict hyper-L-lactatemia were identified using an ROC curve analysis., Results: Combined, the measured strong ion difference and SIG accounted for 54-69% of the changes in the measured arterial pH of hospitalized foals. AG and SIG were significantly associated with plasma [L-lac(-)] (P < .0001). The receiver operator characteristics (ROC) AUC of AG and SIG for prediction of severe hyper-L-lactatemia were 0.89 (95%CI, 0.8-0.95; P < .0001) and 0.90 (95%CI, 0.81-0.96; P < .0001), respectively. Severe hyper-L-lactatemia was best predicted by AG > 27 mmol/L (sensitivity 80%, 95%CI, 56-94, specificity 85%, 95%CI, 73-93; P < .0001) and SIG <-15 mmol/L (sensitivity 90%, 95%CI, 68-98; specificity 80%; 95%CI, 68-90; P < .0001)., Conclusion and Clinical Relevance: Altered concentrations of strong ions (Na(+), K(+), Cl(-)) and UAs were the primary cause of acidemia of hospitalized foals. AG and SIG were good predictors of hyper-L-lactatemia and could be used as surrogate tests., (Copyright © 2015 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.)

A 4.75-year old Simmental cow was presented with symptoms of colic and ileus. The clinical signs and blood analysis resulted in the diagnosis of suspected primary hypoadrenocorticism (Addison's disease). Although Addison's disease has been frequently described in other domestic mammals, to our knowledge, this disease has not previously been reported in cattle.

Obtaining and interpreting blood gas and electrolyte levels is essential in the management of perioperative veterinary patients. Metabolic and electrolyte alterations are common in critically ill surgical patients, and can lead to alterations in cardiovascular function, neurologic status, respiratory function, and even response to various drug therapies. Several common perioperative conditions are discussed in this article, including metabolic disturbances, electrolyte abnormalities (hyponatremia and hypernatremia, hyperkalemia), and respiratory abnormalities., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Ketoacidosis during pregnancy carries significant risk of intrauterine fetal demise, but little is known about the impact of ketoacids on the ovine fetus. We report a case series of maternal ketoacidosis in ewes. Maternal ketoacidosis may result in biochemical and acid-base fetal abnormalities associated with changes in feto-placental unit perfusion.

To determine the reference level of central venous oxygen saturation (ScvO2) and clinical efficacy of central venous blood gas analysis, partial pressures of oxygen and carbon dioxide, pH, oxygen saturation, base excess (B.E.) and HCO3 concentration were compared between simultaneously obtained central venous and arterial blood samples from conscious healthy 6 dogs and 5 cats. Comparisons between arteriovenous samples were performed by a paired t-test and Bland-Altman analysis. Between arteriovenous samples, B.E. showed good agreement, but there were significant differences in other parameters in the dogs, and no good agreement was detected in cats. The ScvO2 in dogs and cats were 82.3 ± 3.5 and 62.4 ± 13.5%, respectively. Central venous blood gas analysis is indispensable, especially in cats.

Background: Electrochemical approach to the assessment of acid-base states should provide a better mechanistic explanation of the metabolic component than methods that consider only pH and carbon dioxide., Hypothesis/objectives: Simplified strong ion equation (SSIE), using published dog-specific values, would predict the measured serum pH of diseased dogs., Animals: Ten dogs, hospitalized for various reasons., Methods: Prospective study of a convenience sample of a consecutive series of dogs admitted to the Massey University Veterinary Teaching Hospital (MUVTH), from which serum biochemistry and blood gas analyses were performed at the same time. Serum pH was calculated (Hcal+) using the SSIE, and published values for the concentration and dissociation constant for the nonvolatile weak acids (Atot and Ka ), and subsequently Hcal+ was compared with the dog's actual pH (Hmeasured+). To determine the source of discordance between Hcal+ and Hmeasured+, the calculations were repeated using a series of substituted values for Atot and Ka ., Results: The Hcal+ did not approximate the Hmeasured+ for any dog (P = 0.499, r(2) = 0.068), and was consistently more basic. Substituted values Atot and Ka did not significantly improve the accuracy (r(2) = 0.169 to <0.001). Substituting the effective SID (Atot-[HCO3-]) produced a strong association between Hcal+ and Hmeasured+ (r(2) = 0.977)., Conclusions and Clinical Importance: Using the simplified strong ion equation and the published values for Atot and Ka does not appear to provide a quantitative explanation for the acid-base status of dogs. Efficacy of substituting the effective SID in the simplified strong ion equation suggests the error lies in calculating the SID., (Copyright © 2015 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.)

Objective: To review magnesium physiology including absorption, excretion, and function within the body, causes of magnesium abnormalities, and the current applications of magnesium monitoring and therapy in people and animals., Etiology: Magnesium plays a pivotal role in energy production and specific functions in every cell in the body. Disorders of magnesium can be correlated with severity of disease, length of hospital stay, and recovery of the septic patient. Hypermagnesemia is seen infrequently in people and animals with significant consequences reported. Hypomagnesemia is more common in critically ill people and animals, and can be associated with platelet, immune system, neurological, and cardiovascular dysfunction as well as alterations in insulin responsiveness and electrolyte imbalance., Diagnosis: Measurement of serum ionized magnesium in critically or chronically ill veterinary patients is practical and provides information necessary for stabilization and treatment. Tissue magnesium concentrations may be assessed using nuclear magnetic resonance spectroscopy as well as through the application of fluorescent dye techniques., Therapy: Magnesium infusions may play a therapeutic role in reperfusion injury, myocardial ischemia, cerebral infarcts, systemic inflammatory response syndromes, tetanus, digitalis toxicity, bronchospasms, hypercoagulable states, and as an adjunct to specific anesthetic or analgesic protocols. Further veterinary studies are needed to establish the frequency and importance of magnesium disorders in animals and the potential benefit of magnesium infusions as a therapeutic adjunct to specific diseases., Prognosis: The prognosis for most patients with magnesium disorders is variable and largely dependent on the underlying cause of the disorder., (© Veterinary Emergency and Critical Care Society 2014.)

The aim of this study was to analyze disorders of acid-base balance in calves with chronic diarrhea caused by mixed, viral, bacterial and Cryptosporydium parvum infection. We compared results ob- tained with the classic model (Henderson-Hasselbalch) and strong ion approach (the Steward model). The study included 36 calves aged between 14 and 21 days. The calves were allocated to three groups: I - (control) non-diarrheic calves, group II - animals with compensated acid-base imbalance and group III calves with compensated acid-base disorders and hypoalbuminemia. Plasma concentrations of Na+, K+, Cl-, C12+, Mg2+, P, albumin and lactate were measured. In the classic model, acid-base balance was determined on the basis of blood pH, pCO2, HCO3-, BE and anion gap. In the strong ion model, strong ion difference (SID), effective strong anion difference, total plasma concentration of nonvolatile buffers (A(Tot)) and strong ion gap (SIG) were measured. The control calves and the animals from groups II and III did not differ significantly in terms of their blood pH. The plasma concentration of HCO3-, BE and partial pressure of CO2 in animals from the two groups with chronic diarrhea were significantly higher than those found in the controls. The highest BE (6.03 mmol/l) was documented in calves from group II. The animals from this group presented compensation resulted from activation of metabolic mechanisms. The calves with hypoal- buminemia (group III) showed lower plasma concentrations of albumin (15.37 g/L), Cl (74.94 mmol/L), Mg2+ (0.53 mmol/L), P (1.41 mmol/L) and higher value of anion gap (39.03 mmol/L). This group III presented significantly higher SID3 (71.89 mmol/L), SID7 (72.92 mmol/L) and SIG (43.53 mmol/L) values than animals from the remaining groups (P < 0.01), whereas A(Tot) (6.82 mmol/L) were significantly lower. The main finding of the correlation study was the excellent relationship between the AGcorr and SID3, SID7, SIG. In conclusion, chronic diarrhea leads to numerous water-electrolyte disorders. Characterization of acid-base disturbance in these cases suggests that classic model have some limitations. This model can not be recommended for use whenever serum albumin or phosphate concentrations are markedly abnormal.

Background: Profiles from serum biochemical analyzers include the concentration of strong electrolytes (including l-lactate), total carbon dioxide (tCO2 ), and total protein. These variables are associated with changes in acid-base balance. Application of physicochemical principles may allow predicting acid-base balance from serum biochemistry without measuring whole blood pH and pCO2 ., Objectives: The purpose of the study was to determine if the acid-base status of critically ill horses could be accurately predicted using variables included in standard serum biochemical profiles., Methods: Two jugular venous blood samples were prospectively obtained from critically ill horses and foals. Samples were analyzed using a whole blood gas and pH analyzer (BG) and a serum biochemistry multi analyzer system (AMAS). Linear regression, Deming regression, and Bland-Altman plots were used for method comparison and P < .05 was considered significant., Results: Values from 70 horses and foals for Na, K, Cl, and total protein concentrations, and consequently the calculated variables used for acid base interpretation, were different between the AMAS and BG analyzer. Using physicochemical principles, BG results accurately predicted pH, whereas the AMAS results did not when a fixed value for pCO2 was used., Conclusions: Measurement of pCO2 is required in critically ill horses for accurate prediction of whole blood pH. Differences in the measured values of Na and Cl concentration exist when measured in serum by the AMAS and in whole blood or plasma by BG, indicating that the accurate prediction of whole blood pH is analyzer-dependent. Application of physicochemical principles to plasma or serum provides a practical method to evaluate analyzer accuracy., (© 2014 American Society for Veterinary Clinical Pathology.)

Objective: To compare the diagnostic performance of the traditional approach to acid-base analysis with the Stewart approach and a semiquantitative approach., Design: Prospective cohort study., Setting: University teaching hospital., Animals: A total number of 84 dogs and 14 cats presenting to a university teaching hospital emergency room., Procedures: All dogs and cats in which venous blood samples for acid-base, lactate, and serum biochemical analysis were all collected within 60 minutes of each other, over a 5-month enrollment period. Acid-base analysis was performed using the traditional approach, Stewart approach, and a semiquantitative approach., Results: Traditional acid-base analysis identified respiratory acid-base abnormalities in 14/98 animals and metabolic acid-base abnormalities in 67/98. A mixed disorder of metabolic acidosis and respiratory alkalosis was most common occurring in 29/98 patients. The Stewart approach identified metabolic abnormalities in 82/98 patients; strong ion difference abnormalities were evident in 68/98 cases; an increased strong ion gap acidosis was identified in 49/98 cases; and changes in the quantity of weak acids in 25/98 cases. The semiquantitative approach identified abnormalities in all cases evaluated. Of the 14 patients with a primary respiratory acid-base abnormality, the Stewart approach identified metabolic abnormalities in 9 and the semiquantitative approach found abnormalities in all animals., Conclusions and Clinical Relevance: The physicochemical approaches diagnosed more acid-base abnormalities in this population than the traditional approach although many of the abnormalities identified were small and of unknown clinical relevance. The physicochemical approaches may provide greater insight as to the underlying etiology of abnormalities, which maybe of particular relevance to cases with changes in albumin and/or phosphorus concentration., (© Veterinary Emergency and Critical Care Society 2014.)

Objective: To compare the traditional (HH) and quantitative approaches used for the evaluation of the acid-base balance in hypoalbuminemic dogs., Design: Prospective observational study., Setting: ICU of a veterinary teaching hospital., Animals: One hundred and five client-owned dogs., Measurements and Main Results: Jugular venous blood samples were collected from each patient on admission to determine: total plasma protein (TP), albumin (Alb), blood urea nitrogen (BUN), glucose (Glu), hematocrit (HCT), Na(+) , Cl(-) , K(+) , phosphate (Pi ), pH, PvCO2, bicarbonate (HCO3 (-) ), anion gap (AG), adjusted anion gap for albumin (AGalb ) or phosphate (AGalb-phos ), standardized base excess (SBE), strong ion difference (SID), concentration of nonvolatile weak buffers (Atot ), and strong ion gap (SIG). Patients were divided in 2 groups according to the severity of the hypoalbuminemia: mild (Alb = 21-25 g/L) and severe (Alb ≤20 g/L). All parameters were compared among groups. Patients with severe hypoalbuminemia showed significant decrease in TP (P = 0.011), Atot (P = 0.050), and a significant increase in adjusted AG (P = 0.048) and the magnitude of SIG (P = 0.011) compared to animals with mild hypoalbuminemia. According to the HH approach, the most frequent imbalances were simple disorders (51.4%), primarily metabolic acidosis (84.7%) associated with a high AG acidosis. However, when using the quantitative method, 58.1% of patients had complex disorders, with SIG acidosis (74.3%) and Atot alkalosis (33.3%) as the most frequent acid-base imbalances. Agreement between methods only matched in 32 cases (kappa < 0.20)., Conclusions: The agreement between the HH and quantitative methods for interpretation of acid-base balance was poor and many imbalances detected using the quantitative approach were missed using the HH approach. Further studies are necessary to confirm the clinical utility of using the quantitative approach in the decision-making process of the severely ill hypoalbuminemic patients., (© Veterinary Emergency and Critical Care Society 2014.)

The acid-base disturbances in canine parvoviral (CPV) enteritis are not well described. In addition, the mechanisms causing these perturbations have not been fully elucidated. The purpose of the present study was to assess acid-base changes in puppies suffering from CPV enteritis, using a modified strong ion model (SIM). The hypothesis of the study was that severe acid-base disturbances would be present and that the SIM would provide insights into pathological mechanisms, which have not been fully appreciated by the Henderson-Hasselbalch model. The study analysed retrospective data, obtained from 42 puppies with confirmed CPV enteritis and 10 healthy control dogs. The CPV-enteritis group had been allocated a clinical score, to allow classification of the data according to clinical severity. The effects of changes in free water, chloride, l-lactate, albumin and phosphate were calculated, using a modification of the base excess algorithm. When the data were summated for each patient, and correlated to each individual component, the most important contributor to the metabolic acid-base changes, according to the SIM, was chloride (P<0.001). Severely-affected animals tended to demonstrate hypochloraemic alkalosis, whereas mildly-affected puppies had a hyperchloraemic acidosis (P=0.007). In conclusion, the acid-base disturbances in CPV enteritis are multifactorial and complex, with the SIM providing information in terms of the origin of these changes., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Low dietary K levels have been associated with increasing renal Ca excretion in humans, indicating a higher risk of calcium oxalate (CaOx) urolith formation. Therefore, the present study aimed to investigate whether dietary K also affects the urine composition of cats. A total of eight adult cats were fed diets containing 0·31 % native K and 0·50, 0·75 and 1·00 % K from KCl or KHCO₃ and were evaluated for the effects of dietary K. High dietary K levels were found to elevate urinary K concentrations (P<0·001). Renal Ca excretion was higher in cats fed the KCl diets than in those fed the KHCO₃ diets (P=0·026), while urinary oxalate concentrations were generally lower in cats fed the KCl diets and only dependent on dietary K levels in cats fed the KHCO₃ diets (P<0·05). Fasting urine pH increased with higher dietary K levels (P=0·022), reaching values of 6·38 (1·00 % KCl) and 7·65 (1·00 % KHCO₃). K retention was markedly negative after feeding the cats with the basal diet (-197 mg/d) and the 0·50 % KCl diet (-131 mg/d), while the cats tended to maintain their balance on being fed the highest-KCl diet (-23·3 mg/d). In contrast, K from KHCO₃ was more efficiently retained (P=0·018), with K retention being between -82·5 and 52·5 mg/d. In conclusion, the dietary inclusion of KHCO₃ instead of KCl as K source could be beneficial for the prevention of CaOx urolith formation in cats, since there is an association between a lower renal Ca excretion and a generally higher urine pH. The utilisation of K is distinctly influenced by the K salt, which may be especially practically relevant when using diets with low K levels.

Background: The quantitative effect of strong electrolytes, unmeasured anions (UAs), pCO2 , and plasma protein concentrations in determining plasma pH and bicarbonate (HCO3 (-) ) can be demonstrated using the physicochemical approach. Demeanor of calves with diarrhea is associated with acidemia, dehydration, and hyper-d-lactatemia., Hypothesis: Unmeasured anions are a major factor influencing changes in plasma pH and HCO3 (-) of calves with diarrhea and UAs and strong UAs, estimated by anion gap (AG) and strong ion gap (SIG), respectively, are more strongly associated with alteration of demeanor compared to other acid-base variables., Animals: A total of 264 calves with diarrhea from two data sets (DS1 and DS2)., Methods: Retrospective study. Forward stepwise regression was performed to determine the relationship between measured pH or HCO3 (-) , and physicochemical variables. A two-way ANOVA was performed to investigate the association between acid-base variables and attitude (bright, obtunded, and stuporous), posture (standing, sternal or lateral recumbency), and strength of suckling reflex (strong, weak, or absent)., Results: Increased strong UAs estimated by SIG was the most important contributor to changes in measured pH and HCO3 (-) (DS1: r(2) 66 and 59%, DS2: 39 and 42%, P < .0001). SIG and AG were correlated to deteriorating calf demeanor for all three clinical scoring categories: attitude, posture, and suckle reflex (P < .0001)., Conclusion and Clinical Relevance: Elevated concentrations of strong UAs were the primary cause of acidemia and had an important influence on the demeanor of calves with diarrhea. These findings emphasize the importance of the calculation of UAs when evaluating acid-base abnormalities in calves., (Copyright © 2013 by the American College of Veterinary Internal Medicine.)

Acid-base abnormalities are common in critically ill veterinary patients. Rapid recognition of disturbances can be helpful in identifying the underlying cause of the patient's clinical signs, directing diagnostics, and monitoring response to therapy. If acid-base disturbances are left unidentified and untreated, severe physiologic consequences can result, including cardiovascular and neurologic dysfunction, protein and enzyme dysfunction, and electrolyte derangements. Treatment of acid-base disorders is aimed at correcting the underlying disease process., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Arterial and venous blood gases provide useful information regarding pulmonary function as well as acid-base balance. The goal of this article is to discuss the collection of blood gases, common errors in analysis, and what information can be gleaned from a blood gas analysis., (© 2013 Elsevier Inc. All rights reserved.)

Background: The quantitative effect of strong electrolytes, pCO2 , and plasma protein concentration in determining plasma pH and bicarbonate concentrations can be demonstrated with the physicochemical approach. Plasma anion gap (AG) and strong ion gap (SIG) are used to assess the presence or absence of unmeasured anions., Hypotheses: The physicochemical approach is useful for detection and explanation of acid-base disorders in horses with colitis. AG and SIG accurately predict hyperlactatemia in horses with colitis., Animals: Fifty-four horses with acute colitis and diarrhea., Methods: Retrospective study. Physicochemical variables were calculated for each patient. ROC curves were generated to analyze sensitivity and specificity of AG and SIG for predicting hyperlactatemia., Results: Physicochemical interpretation of acid-base events indicated that strong ion metabolic acidosis was present in 39 (72%) horses. Mixed strong ion acidosis and decreased weak acid (hypoproteinemia) alkalosis was concomitantly present in 17 (30%) patients. The sensitivity and specificity of AG and SIG to predict hyperlactatemia (L-lactate > 5 mEq/L) were 100% (95% CI, 66.4-100; P < .0001) and 84.4% (95% CI, 70.5-93.5 P < .0001). Area under the ROC curve for AG and SIG for predicting hyperlactatemia was 0.95 (95% CI, 0.86-0.99) and 0.93 (95% CI, 0.83-0.99), respectively., Conclusion and Clinical Relevance: These results emphasize the importance of strong ions and proteins in the maintenance of the acid-base equilibria. AG and SIG were considered good predictors of clinically relevant hyperlactatemia., (Copyright © 2013 by the American College of Veterinary Internal Medicine.)

Objective: To determine the correlation between plasma lactate concentration and base excess at the time of hospital admission and evaluate each variable as a predictor of gastric necrosis or outcome in dogs with gastric dilatation-volvulus (GDV)., Design: Retrospective case series., Animals: 78 dogs., Procedures: For each dog, various data, including plasma lactate concentration and base excess at the time of hospital admission, surgical or necropsy findings, and outcome, were collected from medical records., Results: Gastric necrosis was identified in 12 dogs at the time of surgery and in 4 dogs at necropsy. Sixty-five (83%) dogs survived to hospital discharge, whereas 13 (17%) dogs died or were euthanized. Of the 65 survivors and 8 nonsurvivors that underwent surgery, gastric necrosis was detected in 8 and 4 dogs, respectively. Via receiver operating characteristic curve analysis, an initial plasma lactate concentration cutoff of 7.4 mmol/L was 82% accurate for predicting gastric necrosis (sensitivity, 50%; specificity, 88%) and 88% accurate for predicting outcome (sensitivity, 75%; specificity, 89%). Among all dogs, the correlation between initial plasma lactate concentration and base excess was significant, although base excess was a poor discriminator for predicting gastric necrosis or outcome (area under the receiver operating characteristic curve, 0.571 and 0.565, respectively)., Conclusions and Clinical Relevance: In dogs with GDV, plasma lactate concentration at the time of hospital admission was a good predictor of gastric necrosis and outcome. However, despite the correlation between initial base excess and plasma lactate concentration, base excess should not be used for prediction of gastric necrosis or outcome in those patients.

The acid-base balance parameters (ABB) of blood are used in the diagnostics and therapy of acidosis or alkalosis type disorders. Nowadays, some reports on the attempts to use the body cavity fluid for the diagnostics of the ABB disorders have appeared in the human medicine. The study has aimed at comparing the acid-base balance parameters (ABB): pH, pCO2, and HCO3(-) determined in the arterial blood and the fluid from the peritoneal cavity in dogs. The study was carried out on 20 dogs suffering from ascites developed as a result of the chronic renal failure. 1 ml of full blood was drawn from each dog from its femoral artery to a heparinized syringe equipped with a needle with an internal diameter of 0.7 mm and the puncture of the abdominal cavity was carried out in the white line. In the sample of arterial blood and the sample of the abdominal cavity fluid drawn the ABB parameters were determined. In the group examined, the ABB parameters determined for the arterial blood and the fluid had comparable numeric values and the same nature of the ABB disorder diagnosed on the basis of them. The conclusions are as follows: the results of the effusion fluid gasometry depend on the mechanism of the fluid formation and, in the case when it comes from the developed capillary network, a pressure of gases and remaining ABB parameters are similar to those determined for the arterial blood.

Background: Changes in water balance and the presence of unmeasured anions perturb the inverse relationship between serum chloride (Cl) and bicarbonate (HCO(3) ) concentrations in people, affecting accurate interpretation of acid-base status., Objectives: The aim of this study was to demonstrate that corrected serum Cl and predicted HCO(3) concentrations, based on serum sodium (Na) concentration and anion gap (AG), would be inversely correlated and could be used to better characterize causes of acid-base disorders in dogs., Methods: In this retrospective study, electrolyte data from dogs with at least one abnormality in serum Na, Cl, or HCO(3) concentrations were analyzed. Profiles were classified before and after calculations using 2 methods, a modified Feldman and an institutional method, to correct Cl concentration and predict HCO(3) concentrations based on Na concentration and AG. Dogs were classified as low (L), normal (N), or high (H) based on Cl (first letter) and HCO(3) (second letter) concentrations, as follows: LL, LN, LH, NL, NN, NH, HL, HN, or HH., Results: For profiles from 261 dogs, reclassifying corrected Cl and predicted HCO(3) concentrations resulted in a shift from the initial classification into a different one in 73% of dogs; in most cases, the shift was to LH, NN, or HL categories. Albumin concentration was a significant factor in acid-base balance., Conclusions: When interpreting acid-base status based on results of a standard biochemical panel, erroneous conclusions can be drawn if concentrations of Na, unmeasured anions, and albumin are not taken into account. The inverse relationship between serum Cl and HCO(3) concentrations may be used to identify frequent acid-base disorders as well as to unmask abnormalities obscured by irregularities in water balance or AG., (© 2012 American Society for Veterinary Clinical Pathology.)

Objective: To evaluate the ability of admission base excess (ABE) to predict blood transfusion requirement and mortality in dogs following blunt trauma., Design: Retrospective study 2007-2009., Setting: University Veterinary Teaching Hospital., Animals: Fifty-two dogs admitted to the intensive care unit for treatment following blunt trauma., Measurements and Main Results: Animals requiring red blood cell transfusion (N = 8) had significantly lower ABE than those not requiring transfusion (N = 44; median base excess [BE] = -8.4 versus -4.7, P = .0034), while there was no difference in admission packed cell volume (PCV) or age. Animals that died or were euthanized due to progression of signs (N = 5) had lower median ABE than those that survived (N = 47; median BE = -7.3 versus -4.9, P = 0.018). Admission PCV and age were not significantly different between survivors and nonsurvivors. Receiver operator characteristic curve analysis showed an ABE cutoff of -6.6 was 88% sensitive and 73% specific for transfusion requirement (P < 0.001), and a cutoff of -7.3 was 81% sensitive and 80% specific for survival (P < 0.001). Multivariate logistic regression analysis demonstrated that ABE was a predictor of transfusion requirement that was independent of overall severity of injury as measured by the Animal Triage Trauma (ATT) score, but a similar analysis showed that only ATT was an independent predictor of survival., Conclusions: The ABE in dogs with blunt trauma was a predictor of mortality and blood transfusion requirement within 24 hours., (© Veterinary Emergency and Critical Care Society 2012.)

Eleven Murciano-Granadina goats in late pregnancy were separated into two groups (1) control (n=6) and (2) fasting for 72 h to induce pregnancy toxaemia (n=5). Venous blood was taken daily to determine acid-base and electrolyte parameters. Significant decreases in blood pH, bicarbonate concentration and base excess, and a significant increase in anion gap were observed after 24h of fasting. These changes were significantly correlated with non-esterified fatty acid concentration. No significant changes were observed in pCO(2), and electrolyte or lactate concentrations. Clinical signs of pregnancy toxaemia in fasted goats appeared by 72h post-fasting. These signs and the changes in acid-base balance disappeared once feed was reintroduced. Blood pH, bicarbonate concentration, base excess and anion gap could be indicators of early pregnancy toxaemia in goats., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Chronic kidney disease (CKD) occurs commonly in older dogs and cats. Advances in diagnostics, staging, and treatment are associated with increased quality and quantity of life. Dietary modification has been shown to increase survival and quality of life and involves more than protein restriction as diets modified for use with CKD are lower in phosphorous and sodium, potassium and B-vitamin replete, and alkalinizing, and they contain n3-fatty acids. Additionally, recognition and management of CKD-associated diseases such as systemic arterial hypertension, proteinuria, and anemia benefit patients. This article summarizes staging and management of CKD in dogs and cats.

The aim of this study was to determine whether or not canine lymphoma could be associated with a clinically relevant type B hyperlactatemia (> 2.5 mmol/L). The medical database from the University of Montreal Veterinary Medical Teaching Hospital was searched for confirmed cases of canine lymphoma with a blood lactate measurement. Information retrieved included stage, clinical observations compatible with causes of type A and B hyperlactatemia other than cancer, hepatic involvement, and drugs administered. Twenty (40%) dogs were hyperlactatemic. Five dogs (10%) were classified as having cancer-related hyperlactatemia. Seventy-five percent of hyperlactatemic dogs had clinical evidence of type A hyperlactatemia. In addition to lymphoma, 70% of hyperlactatemic dogs had evidence of an additional cause of type B hyperlactatemia. A significant association (P = 0.01) was identified between corticosteroid administration and hyperlactatemia. Cytological, echographic, and/or biochemical tests revealed hepatic changes in all hyperlactatemic dogs. Lymphoma alone may not be sufficient to explain clinically relevant hyperlactatemia in dogs.

Classically, the acid-base balance (ABB) is described by the Henderson-Hasselbach equation, where the blood pH is a result of a metabolic components--the HCO3(-) concentration and a respiratory component--pCO2. The Stewart model assumes that the proper understanding of the organisms ABB is based on an analysis of: pCO2, Strong Ion difference (SID)--the difference strong cation and anion concentrations in the blood serum, and the Acid total (Atot)--the total concentration of nonvolatile weak acids. Right sided heart failure in dogs causes serious haemodynamic disorders in the form of peripheral stasis leading to formation of transudates in body cavities, which in turn causes ABB respiratory and metabolic disorders. The study was aimed at analysing the ABB parameters with the use of the classic method and the Stewart model in dogs with the right sided heart failure and a comparison of both methods for the purpose of their diagnostic and therapeutic utility. The study was conducted on 10 dogs with diagnosed right sided heart failure. Arterial and venous blood was drawn from the animals. Analysis of pH, pCO2 and HCO3(-) was performed from samples of arterial blood. Concentrations of Na+, K+, Cl(-), P(inorganic), albumins and lactate were determined from venous blood samples and values of Strong Ion difference of Na+, K+ and Cl(-) (SID3), Strong Ion difference of Na+, K+, Cl(-) and lactate (SID4), Atot, Strong Ion difference effective (SIDe) and Strong Ion Gap (SIG4) were calculated. The conclusions are as follows: 1) diagnosis of ABB disorders on the basis of the Stewart model showed metabolic alkalosis in all dogs examined, 2) in cases of circulatory system diseases, methodology based on the Stewart model should be applied for ABB disorder diagnosis, 3) if a diagnosis of ABB disorders is necessary, determination of pH, pCO2 and HCO3(-) as well as concentrations of albumins and P(inorganic) should be determined on a routine basis, 4) for ABB disorder diagnosis, the classic model should be used only when the concentrations of albumins and P(inorganic) are normal.