Kinetics of acid-base parameters in conventional hemodialysis

Details about the acid-base changes in hemodialysis are scarce in the literature but are potentially relevant to adequate management of patients. We addressed the acid-base kinetics during hemodialysis and throughout the interdialytic period in a cross-sectional study of adults undergoing conventional hemodialysis. Samples for blood gas analysis were obtained from the arterial limb of the arteriovenous fistula before the first session of the week (HD1), immediately at the end of HD1, and on sequential collections at 15, 30, 45, 60, and 120 min post-HD1. Additional blood samples were collected after ∼20 h following the end of the first dialysis and immediately prior to the initiation of the second dialysis of the week. Thirty adult patients were analyzed (55±15 years, 50% men, 23% diabetic; dialysis vintage 69±53 months). Mean serum bicarbonate levels increased at the end of HD1 (22.3±2.7 mEq/L vs 17.5±2.3 mEq/L, P<0.001) and remained stable until 20 h after the end of the session. The mean values of pCO2 before HD1 were below reference and at 60 and 120 min post-HD1 were significantly lower than at the start (31.3±2.7 mmHg and 30.9±3.7 mmHg vs 34.3±4.1 mmHg, P=0.041 and P=0.010, respectively). The only point of collection in which mean values of pCO2 were above 35 mmHg was 20 h post-dialysis. Serum bicarbonate levels remained stable for at least 20 h after the dialysis sessions, a finding that may have therapeutic implications. During dialysis, the respiratory response for correction of metabolic acidosis (i.e., pCO2 elevation) was impaired.

Impacto del componente hiperclorémico de la acidosis metabólica en el estado de hidratación y en el tratamiento de la cetoacidosis diabética / Impact of the hyperchloremic component of metabolic acidosis on the patient's hydration status and the treatment of diabetic ketoacidosis

Introducción. La cetoacidosis diabética (CAD) se caracteriza por acidosis metabólica (AM) con anión restante (AR) elevado, aunque, ocasionalmente, puede presentar hipercloremia. Se postuló que la presencia de hipercloremia inicial podría reflejar un mejor estado de hidratación; sin embargo, su prevalencia y su impacto en el tratamiento de la CAD se desconoce. Objetivos. Determinar la prevalencia de AM con componente hiperclorémico previo al inicio del tratamiento y evaluar si su presencia se asocia con mejor estado de hidratación y con menor tiempo de salida de la CAD, en comparación con los pacientes con AR elevado exclusivo. Pacientes y métodos. Se agruparon los pacientes internados con CAD (período entre enero de 2014 y junio de 2016) según presentaran, al ingresar, AM con AR elevado exclusivo o con hipercloremia y se compararon sus variables clínicas, de laboratorio y la respuesta al tratamiento. Resultados. Se incluyeron 40 pacientes -amp;#91;17 varones, mediana de edad: 14,5 años (2,4-18)-amp;#93;, 22 con AM con componente hiperclorémico (prevalencia de 55%) y 18 con AR elevado exclusivo. La presencia de hipercloremia no se asoció con mejor estado de hidratación (porcentaje de déficit de peso en ambos grupos: 4,9%; p= 0,81) ni con una respuesta terapéutica más rápida (con componente hiperclorémico: 9,5 horas; con AR elevado exclusivo: 11 horas; p= 0,64). Conclusiones. En niños con CAD, la prevalencia de AM con componente hiperclorémico fue del 55% y no se asoció con un mejor estado de hidratación ni con una salida más temprana de la descompensación metabólica.

Introduction. Diabetic ketoacidosis (DKA) is characterized by metabolic acidosis (MA) with a high anion gap (AG), although, occasionally, it can present with hyperchloremia. It has been postulated that the early presence of hyperchloremia could reflect a better hydration status; however, its prevalence and impact on DKA treatment remain unknown. Objectives. To determine the prevalence of the hyperchloremic component in MA prior to treatment and to assess whether it is associated with a better hydration status and a shorter recovery time from DKA compared to patients with high AG only. Patients and Methods. Patients hospitalized with DKA (between January 2014 and June 2016) were grouped according to whether they were admitted with MA with high AG only. or with hyperchloremia, and clinical and laboratory outcome measures and response to treatment were compared. Results. Forty patients (17 males, median age: 14.5 years -amp;#91;2.4-18-amp;#93;) were included; 22 with hyperchloremic metabolic acidosis (prevalence of 55%) and 18 with metabolic acidosis with high AG only. The presence of hyperchloremia was not associated with a better hydration status (weight loss percentage in both groups: 4.9%; p= 0.81) nor with a faster treatment response (MA with a hyperchloremic component: 9.5 hours; MA with high AG only: 11 hours; p= 0.64). Conclusions. The prevalence of MA with a hyperchloremic component among children with DKA was 55% and was not associated with a better hydration status nor with a faster recovery from the metabolic decompensation.

Adaptação metabólica diante de hipercapnia persistente aguda em pacientes submetidos à ventilação mecânica por síndrome do desconforto respiratório agudo / Metabolic acid-base adaptation triggered by acute persistent hypercapnia in mechanically ventilated patients with acute respiratory distress syndrome

RESUMO Objetivo: A hipercapnia resultante da ventilação protetora na síndrome do desconforto respiratório agudo desencadeia uma compensação metabólica do pH que ainda não foi completamente caracterizada. Nosso objetivo foi descrever esta compensação metabólica. Métodos: Os dados foram recuperados a partir de uma base de dados registrada de forma prospectiva. Foram obtidas as variáveis dos pacientes no momento da admissão e quando da instalação da hipercapnia até o terceiro dia após sua instalação. Analisamos 41 pacientes com síndrome do desconforto respiratório agudo, incluindo 26 com hipercapnia persistente (pressão parcial de gás carbônico acima de 50mmHg por mais de 24 horas) e 15 sem hipercapnia (Grupo Controle). Para a realização da análise, utilizamos uma abordagem físico-química quantitativa do metabolismo acidobásico. Resultados: As médias de idade dos Grupos com Hipercapnia e Controle foram, respectivamente, de 48 ± 18 anos e 44 ± 14 anos. Após a indução da hipercapnia, o pH diminuiu acentuadamente e melhorou gradualmente nas 72 horas seguintes, de forma coerente com os aumentos observados no excesso de base padrão. A adaptação metabólica acidobásica ocorreu em razão de diminuições do lactato sérico e do strong ion gap e de aumentos na diferença aparente de strong ions inorgânicos. Além do mais, a elevação da diferença aparente de strong ions inorgânicos ocorreu por conta de ligeiros aumentos séricos de sódio, magnésio, potássio e cálcio. O cloreto sérico não diminuiu por até 72 horas após o início da hipercapnia. Conclusão: A adaptação metabólica acidobásica, que é desencadeada pela hipercapnia aguda persistente em pacientes com síndrome do desconforto respiratório agudo, foi complexa. Mais ainda, aumentos mais rápidos no excesso de base padrão em pacientes com hipercapnia envolveram diminuições séricas de lactato e íons não medidos, e aumentos na diferença aparente de strong ions inorgânicos, por meio de ligeiros aumentos séricos de sódio, magnésio, cálcio e potássio. Não ocorreu redução do cloreto sérico.

ABSTRACT Objective: Hypercapnia resulting from protective ventilation in acute respiratory distress syndrome triggers metabolic pH compensation, which is not entirely characterized. We aimed to describe this metabolic compensation. Methods: The data were retrieved from a prospective collected database. Variables from patients' admission and from hypercapnia installation until the third day after installation were gathered. Forty-one patients with acute respiratory distress syndrome were analyzed, including twenty-six with persistent hypercapnia (PaCO2 > 50mmHg > 24 hours) and 15 non-hypercapnic (control group). An acid-base quantitative physicochemical approach was used for the analysis. Results: The mean ages in the hypercapnic and control groups were 48 ± 18 years and 44 ± 14 years, respectively. After the induction of hypercapnia, pH markedly decreased and gradually improved in the ensuing 72 hours, consistent with increases in the standard base excess. The metabolic acid-base adaptation occurred because of decreases in the serum lactate and strong ion gap and increases in the inorganic apparent strong ion difference. Furthermore, the elevation in the inorganic apparent strong ion difference occurred due to slight increases in serum sodium, magnesium, potassium and calcium. Serum chloride did not decrease for up to 72 hours after the initiation of hypercapnia. Conclusion: In this explanatory study, the results indicate that metabolic acid-base adaptation, which is triggered by acute persistent hypercapnia in patients with acute respiratory distress syndrome, is complex. Furthermore, further rapid increases in the standard base excess of hypercapnic patients involve decreases in serum lactate and unmeasured anions and increases in the inorganic apparent strong ion difference by means of slight increases in serum sodium, magnesium, calcium, and potassium. Serum chloride is not reduced.

Acid-base balance of dairy cows and its relationship with alcoholic stability and mineral composition of milk / Equilíbrio ácido-base de vacas leiteiras e sua relação com a estabilidade alcoólica e composição mineral do leite

This study aimed to associate the occurrence of acid-base disorders with the alcoholic stability of milk from animals in the field, and to evaluate differences between the mineral composition of milk that was both stable and unstable in alcohol. The sample comprised 96 dairy cows, where the milk and blood of each corresponding animal was collected. The mineral composition of stable and unstable milk in alcohol was different and may be related to acid-base disturbances. The average amount of phosphate was lower in the milk that was unstable in alcohol, while potassium was greater. Frequency of the alcoholically unstable milk cases was higher in the cows with acid-base disturbances. Respiratory alkalosis was the disorder that was most observed.

Esse trabalho teve como objetivo associar a ocorrência de distúrbios ácido-base com a estabilidade alcoólica do leite de animais a campo, bem como avaliar diferenças entre a composição mineral de leites estáveis e instáveis ao álcool. A amostragem compreendeu 96 vacas leiteiras, das quais o leite e o sangue correspondente de cada animal foram coletados. A composição mineral entre leites estáveis e instáveis ao álcool foi diferente e também pode estar relacionada aos distúrbios ácido-básicos. A quantidade média de fosfato foi menor no leite instável ao álcool, enquanto a de potássio foi maior. A frequência de amostras de leite com instabilidade alcoólica foi maior nas vacas com distúrbios ácido-básicos. A alcalose respiratória foi o desequilíbrio mais observado.

Ânion gap corrigido para albumina, fosfato e lactato é um bom preditor de íon gap forte em pacientes enfermos graves: estudo de coorte em nicho / Anion gap corrected for albumin, phosphate and lactate is a good predictor of strong ion gap in critically ill patients: a nested cohort study

OBJETIVO: Ânion gap corrigido e íon gap forte são usados comumente para estimar os ânions não medidos. Avaliamos o desempenho do ânion gap corrigido para albumina, fosfato e lactato na predição do íon gap forte em uma população mista de pacientes enfermos graves. Formulamos a hipótese de que o ânion gap corrigido para albumina, fosfato e lactato seria um bom preditor do íon gap forte, independentemente da presença de acidose metabólica. Além disso, avaliamos o impacto do íon gap forte por ocasião da admissão na mortalidade hospitalar. MÉTODOS: Incluímos 84 pacientes gravemente enfermos. A correlação e a concordância entre o ânion gap corrigido para albumina, fosfato e lactato e o íon gap forte foi avaliada utilizando-se os testes de correlação de Pearson, regressão linear, plot de Bland-Altman e pelo cálculo do coeficiente de correlação interclasse. Foram realizadas duas análises de subgrupos: uma para pacientes com excesso de base <-2mEq/L (grupo com baixo excesso de base) e outro grupo de pacientes com excesso de base >-2mEq/L (grupo com alto excesso de base). Foi realizada uma regressão logística para avaliar a associação entre os níveis de íon gap forte na admissão e a mortalidade hospitalar. RESULTADOS: Houve correlação muito forte e uma boa concordância entre o ânion gap corrigido para albumina, fosfato e lactato e o íon gap forte na população geral (r2=0,94; bias 1,40; limites de concordância de -0,75 a 3,57). A correlação foi também elevada nos grupos com baixo excesso de base (r2=0,94) e alto excesso de base (r2=0,92). Estavam presentes níveis elevados de íon gap forte em 66% da população total e 42% dos casos do grupo alto excesso de. ...

OBJECTIVE: Corrected anion gap and strong ion gap are commonly used to estimate unmeasured anions. We evaluated the performance of the anion gap corrected for albumin, phosphate and lactate in predicting strong ion gap in a mixed population of critically ill patients. We hypothesized that anion gap corrected for albumin, phosphate and lactate would be a good predictor of strong ion gap, independent of the presence of metabolic acidosis. In addition, we evaluated the impact of strong ion gap at admission on hospital mortality. METHODS: We included 84 critically ill patients. Correlation and agreement between the anion gap corrected for albumin, phosphate and lactate and strong ion gap was evaluated by the Pearson correlation test, linear regression, a Bland-Altman plot and calculating interclass correlation coefficient. Two subgroup analyses were performed: one in patients with base-excess <-2mEq/L (low BE group - lBE) and the other in patients with base-excess >-2mEq/L (high BE group - hBE). A logistic regression was performed to evaluate the association between admission strong ion gap levels and hospital mortality. RESULTS: There was a very strong correlation and a good agreement between anion gap corrected for albumin, phosphate and lactate and strong ion gap in the general population (r2=0.94; bias 1.40; limits of agreement -0.75 to 3.57). Correlation was also high in the lBE group (r2=0.94) and in the hBE group (r2=0.92). High levels of strong ion gap were present in 66% of the whole population and 42% of the cases in the hBE group. Strong ion gap was not associated with hospital mortality by logistic regression. CONCLUSION: Anion gap corrected for albumin, phosphate and lactate and strong ion gap have an excellent correlation. Unmeasured anions are frequently elevated in critically ill patients with normal base-excess. However, there was no association between unmeasured anions and hospital mortality. .

Entendendo os distúrbios hidroeletrolíticos e o equilíbrio ácido-básico / Understanding hydroeletrolytic disturbances and acid-basic balance

Os distúrbios hidroeletrolíticos e o equilíbrio ácido-básico são frequentes no dia a dia de especialidades clínicas e cirúrgicas. O entendimento da sua fisiopatologia é essencial para o seu tratamento adequado. Este artigo discursa sobre os distúrbios hidroeletrolíticos e os do equilíbrio ácido-básico mais comuns.

Electrolyte disorders and acid-base balance occur on a daily basis in both clinical and surgical specialties. The pathophysiological understanding of these disorders is essential for their appropriate treatment. This article addresses the most common electrolyte and acid-base disorders.

Cloreto e status hidroeletrolítico e ácido-básico: importância clínica da determinação laboratorial / Chloride and hydroelectrolytic and acid base status: clinical importance of laboratorial determination

Apesar de o cloreto ser um exame amplamente disponível e solicitado em instituições de saúde, a maior pane dos médicos crê ser difícil interpretar seus resultados, estabelecer correlações com outros parâmetros laboratoriais associados e tomar decisões terapêuticas baseadas no mesmo. Devido à complexidade de sua homeostase e à intrincada correlação com o status hidroeletrolítico e ácido-básico, poucos médicos se sentem efetivamente aptos a aproveitar a valiosa informação clínica que ele pode revelar. Isto é agravado pela rarefeita bibliografia objetiva sobre o tema. Os autores desta revisão não foram capazes de encontrar nenhum capítulo especificamente dedicado ao cloreto nos principais livros-texto de Fisiologia, Clínica Médica e Nefrologia, disponíveis, à exceção de três revisões bibliográficas no Medline. Não obstante, tentamos organizar a informação tão claramente quanto possível, com o objetivo de tornar o cloreto uma ferramenta útil aos nossos colegas profissionais de saúde.

Even though chloride is a widely available and requested test in health institutions, most part of physicians find it difficult to interpret its results, establish correlations with other laboratory linked parameters and take therapeutic decisions based on it. Due to the complexity of its homeostatic balance and intrincated correlation to hydroelectrolytic and acid base status, few doctors feel actually able to fully profit from the valuable clinical information it can unfold. This is aggravated by the scarce objective bibliography on the issue. The authors of this review were not able to find any chapters specifically dedicated to chloride on major Physiology, Internal Medicine and Nephrology textbooks, but only three reviews on Medline. Nevertheless, we managed to organize the information as clearly as possible with the aim of making chloride test an useful tool to our fellow health professionals.

Métodos para identificar o limiar anaeróbio em indivíduos com diabete tipo 2 e em indivíduos não-diabéticos / Methods to identify the anaerobic threshold for type-2 diabetic and non-diabetic subjects / Métodos para identificar el umbral anaeróbico en individuos con diabetes tipo 2 y en individuos no diabéticos

Fundamento: Apesar de o limiar anaeróbio (LAn) ser utilizado na avaliação funcional de diferentes populações, estudos comparando métodos para sua identificação em diabéticos tipo-2 tem sido pouco realizados. Objetivo: Comparar protocolos de identificação do LAn em indivíduos diabéticos tipo 2 e em não-diabéticos, e analisar respostas relacionadas ao equilíbrio ácido-básico em intensidades relativas ao LAn. MÉTODOS: Diabéticos tipo 2 (n=10; 54,5±9,5 anos; 30,1±5,0 kg/m²) e jovens não-diabéticos (n=10; 36,6±12,8 anos; 23,9±5,0 kg/m²) realizaram teste incremental (TI) em ciclo ergômetro. O aumento desproporcional no equivalente ventilatório de oxigênio (VE/VO2) e lactatemia ([lac]) identificaram intensidades (Watts-W) correspondentes aos limiares ventilatório (LV) e de lactato (LL), respectivamente. A intensidade correspondente à menor glicemia ([glic]) foi considerada limiar glicêmico individual (LGI). O LAn também foi determinado por ajuste polinomial das razões VE/Watts (LV VE/W) e [lac]/Watts (LL[lac]/W), as quais identificaram intensidades acima das quais um aumento desproporcional na VE e [lac] ocorreram. Resultados: Não foram observadas diferenças entre LL, LV, LG, LL[lac]/W e LV VE/W em diabéticos (85,0±32,1; 88,0±31,7; 86,0±33,8; 82,0±20,9 e 90,2±22,2W) e não-diabéticos (139,0±39,0; 133,0±42,7; 140,8±36,4; 122,7±44,3 e 133,0±39,1W). Contudo os valores de LAn diferiram significativamente entre grupos (p<0.001). A técnica de Bland-Altman confirmou concordância entre os protocolos. Reduções significativas no pH e pCO2 em paralelo a um aumento na [lac], pO2 e VE foram observadas em intensidades supra limiares. Conclusão: Os protocolos apresentaram, para ambos os grupos estudados, concordância na identificação do LAn, que se mostrou como uma intensidade de exercício acima da qual ocorre perda de equilíbrio ácido-básico.

Background: In spite of Anaerobic Threshold (AT) to be widely used on exercise evaluation for different populations, there are few studies comparing methods to identify AT for individuals with type-2 diabetes. Objective: To compare methods of AT determination on type-2 diabetics (T2D) and non-diabetic (ND) subjects and verify the acid-base balance as related to AT intensity. METHODS: T2D (n=10; 54.5±9.5 yr; 30.1±5.0 kg/m²) and younger ND (n=10; 36.6±12.8 yr; 23.9±5.0 kg/m²) performed an incremental test (IT) on a cycle ergometer. The over-proportional increase in VE/VO2 and blood lactate ([lac]) identified the ventilatory (VT) and lactate thresholds (LT) respectively. The workload corresponding to the lower blood glucose ([gluc]) during test identified the individual glucose threshold (IGT). The AT was also determined by polynomial adjustment of the VE/Workload and [lac]/Workload responses to identify exercise intensities above which an over-proportional increase in VE and [lac] did occur and were named VT VE/W and LT[lac]/W. Results: The workload (Watts-W) corresponding to LT, VT, IGT, LT Lac/W and VT VE/W of diabetics (85.0±32.1; 88.0±31.7; 86.0±33.8; 82.0±20.9 and 90.2±22.2W) and non-diabetics (139.0±39.0; 133.0±42.7; 140.8±36.4; 122.7±44.3 and 133.0±39.1W) differed between groups (p<0.001), but not within groups. Thus it was evidenced an agreement among the studied methods. The pH and pCO2 were significantly decreased in parallel to the increase in [lac], pO2 and VE at supra AT intensities. Conclusion: The AT intensities, as determined by different methods both for diabetics and non-diabetic individuals, were in agreement to each other and identified exercise intensities above which the acid-basic balance is disrupted.

Fundamento: A pesar de que el umbral anaeróbico (UAn) se utiliza en la evaluación funcional de diferentes poblaciones, pocos estudios que comparen métodos para su identificación en diabéticos tipo 2 están siendo realizados. Objetivo: Comparar protocolos de identificación del UAn en individuos diabéticos tipo 2 y en no diabéticos, y analizar respuestas relacionadas al equilibrio ácido-base en intensidades relativas al UAn. MÉTODOS: Diabéticos tipo 2 (n=10; 54,5±9,5 años; 30,1±5,0 kg/m²) y jóvenes no diabéticos (n=10; 36,6±12,8 años; 23,9±5,0 kg/m²) realizaron un test incremental (TI) en ciclo ergómetro. El aumento desproporcionado en el equivalente ventilatorio de oxígeno (VE/VO2) y lactatemia ([lac]) identificó intensidades (Watts-W) correspondientes a los umbrales ventilatorio (UV) y de lactato (UL), respectivamente. La intensidad correspondiente a la menor glucemia ([gluc]) se consideró umbral glucémico individual (UGI). El UAn también fue determinado por ajuste polinomial de las razones VE/Watts (UV VE/W) y [lac]/Watts (UL[lac]/W), las que identificaron intensidades por encima de las cuales ocurriera un aumento desproporcionado en la VE y [lac]. Resultados: No se observaron diferencias entre UL, UV, UG, UL[lac]/W y UV VE/W en diabéticos (85,0±32,1; 88,0±31,7; 86,0±33,8; 82,0±20,9 y 90,2±22,2W) y no diabéticos (139,0±39,0; 133,0±42,7; 140,8±36,4; 122,7±44,3 y 133,0±39,1W). Sin embargo, los valores de UAn difirieron significativamente entre los grupos (p<0.001). La técnica de Bland-Altman confirmó una concordancia entre los protocolos. En las intensidades sobre los umbrales se observaron reducciones significativas en el pH y pCO2 paralelamente a un aumento en la [lac], pO2 y VE. Conclusión: Los protocolos presentaron, para ambos grupos estudiados, concordancia en la identificación del UAn, que se mostró como una intensidad de ejercicio, por encima de la cual ocurre pérdida de equilibrio ácido-base.

Effects of acid-base imbalance on vascular reactivity

Acid-base homeostasis maintains systemic arterial pH within a narrow range. Whereas the normal range of pH for clinical laboratories is 7.35-7.45, in vivo pH is maintained within a much narrower range. In clinical and experimental settings, blood pH can vary in response to respiratory or renal impairment. This altered pH promotes changes in vascular smooth muscle tone with impact on circulation and blood pressure control. Changes in pH can be divided into those occurring in the extracellular space (pHo) and those occurring within the intracellular space (pHi), although, extracellular and intracellular compartments influence each other. Consistent with the multiple events involved in the changes in tone produced by altered pHo, including type of vascular bed, several factors and mechanisms, in addition to hydrogen ion concentration, have been suggested to be involved. The scientific literature has many reports concerning acid-base balance and endothelium function, but these concepts are not clear about acid-base disorders and their relations with the three known mechanisms of endothelium-dependent vascular reactivity: nitric oxide (NO/cGMP-dependent), prostacyclin (PGI2/cAMP-dependent) and hyperpolarization. During the last decades, many studies have been published and have given rise to confronting data on acid-base disorder and endothelial function. Therefore, the main proposal of this review is to provide a critical analysis of the state of art and incentivate researchers to develop more studies about these issues.

Blood-gas and electrolyte values for Amazon parrots (Amazona aestiva)

The aim was to provide reference data for blood gas/acid-base status and electrolytes for non-anesthetized Amazon parrots (Amazona aestiva). Thirty-five adult parrots from Tietê ecologic park were utilized. Arterial blood (0.3ml) samples were anaerobically collected from the superficial ulnar artery in heparinized (sodium heparin) 1-ml plastic syringes. The samples were immediately analyzed through a portable analyzer (i-STAT*, Abbot, Illinois, USA) with cartridges (EG7+). These data were grouped in such a way as to present both mean and standard deviation: body weight (360±37g), respiratory rate (82±33 b/m), temperature (41.8±0.6ºC), hydrogen potential (7.452±0.048), carbon dioxide partial pressure (22.1±4.0mmHg), oxygen partial pressure (98.1±7.6mmHg), base excess (-7.9±3.1), plasma concentration of bicarbonate ions (14.8±2.8mmol/L), oxygen saturation (96.2±1.1 percent), plasma concentration of sodium (147.4±2.2mmol/L), plasma concentration of potassium (3.5±0.53mmol/L), plasma concentration of calcium (0.8±0.28mmol/L), hematocrit (38.7±6.2 percent) and concentration of hemoglobin (13.2±2.1g/dl). This study led us to conclude that, although the results obtained showed hypocapnia and low values of bicarbonate and base excess, when compared to other avian species, these data are very similar. Besides, in spite of the equipment being approved only for human beings, it was considered simple and very useful in the analysis of avian blood samples. By using this equipment we were able to provide references data for non-anaesthetized Amazon parrots.

O objetivo deste trabalho foi estabelecer dados de referência do equilíbrio ácido-básico e eletrólitos de papagaios (Amazonas aestiva) não anestesiados. Foram utilizados trinta e cinco papagaios oriundos do Parque ecológico do Tietê. Amostras de sangue (0,3ml) da artéria superficial ulnar foram coletadas em seringas plásticas (1ml) heparinizadas. As amostras foram analisadas imediatamente, usando um analisador portátil (i-stat*, Abbott, Illinois, USA) com cartuchos (i-stat EG7+). Os resultados foram demonstrados em média e desvio padrão: peso corpóreo (360±37g), freqüência respiratória (82±33mpm), temperatura (41,8±0,6ºC), potencial hidrogeniônico (7,452±0,05), pressão parcial de dióxido de carbono (22,1±4,0mmHg), pressão parcial de oxigênio (98,1±7,6mmHg), excesso de base (-7,45±3,1), saturação da hemoglobina (96,2±1,1 por cento), concentração plasmática de sódio (147,4±2,2mmol/L), concentração plasmática de potássio (3,5±0,53mmol/L), concentração plasmática de cálcio (0,8±0,28mmol/L), hematócrito (38,7±6,2 por cento) e concentração de hemoglobina (13,2±2,1g/dl). Este estudo nos levou a concluir que embora os animais apresentassem hipocapnia e valores baixos de bicarbonato e excesso de bases, quando comparamos aos das outras espécies aviárias, os dados são similares. Embora o equipamento seja aprovado somente para espécie humana, foi considerado prático e útil na análise do sangue de aves. Utilizando este equipamento, fomos capazes de estabelecer dados de referência do status ácido-básico e eletrólitos de papagaios não anestesiados.

Distúrbios do equilíbrio ácido-básico na prática clínica / Disorders of basic acid balance in clinical practice

Na prática médica, o distúrbio do equilíbrio ácido-básico possui grande relevância. Muitas funções metabólicas e fisiológicas dependem do pH. Alterações no pH em geral, decorrem de patologias concomitantes (EX: sepse, insuficiência renal, pneumonia, etc...) e, dependendo do grau de alteração, representam um risco eminente de vida ao paciente,O equilíbrio ácido – básico é um assunto de importância para todas as especialidades. Porém, seu entendimento prático é revestido de diversos graus de dificuldade.

Diagnosis and management of metabolic alkalosis.

Elevated pH and elevated plasma bicarbonate level above normal characterise metabolic alkalosis. When bicarbonate is elevated pCO2 must also be elevated to maintain pH to its normal range. Therefore with metabolic alkalosis, the compensation is to decrease alveolar ventilation, and increase pCO2. The causes of metabolic alkalosis are gastro-intestinal hydrogen and chloride loss and due to renal cause. For metabolic alkalosis to continue both generation and maintenance of high levels of bicarbonate are necessary. The diagnosis of metabolic alkalosis is established by noting pH, serum bicarbonate (elevated) and pCO2 (compensatory) elevation. To establish the causes it is necessary to determine intravascular volume, supine and standing blood pressure and renin angiotension alolosterone axis. In chloride responsive alkalosis in which the conditions are extracellular volume depletion, hypokalaemia and hypochloraemia correction of intravascular volume with sodium chloride is needed. In severe metabolic alkalosis of any cause dilute hydrochloric acid (0.1 N HCl) may be infused intravenously but haemolysis may be a complication. In emergency situation with severe hypokalaemia dialysis with higher K+, Cl- and low HCO3- bath will be appropriate.

Evolutive standard base excess and serum lactate level in severe sepsis and septic shock patients resuscitated with early goal-directed therapy: still outcome markers?

OBJETIVO: Comparar a evolução do "standard base excess" e o nível de lactato sérico entre pacientes sobreviventes e não sobreviventes com sepse grave ou choque séptico reanimados com o "early goal directed therapy". MÉTODOS: Estudo retrospectivo em uma unidade de terapia intensiva de um hospital escola onde sessenta e cinco pacientes com sepse grave e choque séptico foram observados sem intervenções. RESULTADOS: Em nosso estudo, a mortalidade na sepse grave e choque séptico foi de 38%. A saturação venosa central de oxigênio nos dois grupos foi maior que 70% depois da reanimação, exceto no segundo dia no grupo dos pacientes não sobreviventes (69,8%). Depois do segundo dia, a saturação venosa central foi significantemente maior no grupo dos sobreviventes (p<0.001). O "standard base excess" foi inicialmente baixo em ambos os grupos, mas a partir do segundo dia a recuperação do "standard base excess" foi significantemente mais importante e linear no grupo dos sobreviventes (p<0.001). Os níveis de lactato foram similares na evolução dos dois grupos. DISCUSSÃO: O "standard base excess" e o lactato são ainda considerados como marcadores prognósticos em pacientes com sepse grave ou choque séptico reanimados de acordo com o "early goal directed therapy". Outros estudos devem ser realizados com a intenção de demonstrar se intervenções hemodinâmicas baseadas no "standard base excess" e nos níveis de lactato podem ser úteis em melhorar desfechos clínicos em pacientes com sepse grave ou choque séptico.

Validation of an electrometric blood cholinesterase measurement in goats

A modified electrometric method was described and validated for measurement of plasma and erythrocyte cholinesterase activities in 6~18 months old goats. The enzymatic reaction mixture contained 3 ml distilled water, 3 ml barbital-phosphate buffer (pH 8.1), 0.2 ml plasma or erythrocytes and 0.1 ml acetylthiocholine iodide (7.5%) as a substrate. The mixture was incubated at 37 degrees C for 40 minutes. The pH of the reaction mixture was determined by a pH meter before and after the incubation. The initial pH was measured before the substrate addition. The enzyme activity was expressed as deltapH/40 min. The coefficients of variation of the described method in measuring plasma and erythrocyte cholinesterase activities were 4 and 2%, respectively. Preliminary reference values (n = 14) of the mean cholinesterase activity (deltapH/40 min) and 95% confidence interval in the plasma were 0.194 and 0.184~ 0.204, respectively, and those of the erythrocytes were 0.416 and 0.396~0.436, respectively. The pseudocholinesterase activity of the plasma cholinesterase was 63.5% as determined by quinidine sulfate inhibition. The organophosphorus insecticides dichlorvos and diazinon at 0.5~4 micrometer and the carbamate insecticide carbaryl at 5~20 micrometer in the reaction mixture significantly inhibited plasma (13.7~85.5%) and erythrocyte (16.4~71.9%) cholinesterases in vitro in a concentration-dependent manner. The results suggest that the described electrometric method is simple, precise and efficient in measuring blood cholinesterase activity in goats.

Hydration in soccer: a review

Hydration should be considered before, during and after the exercise. This review intends to approach the main points of hydration process in soccer. The replacement of fluids during exercise is proportional to some factors, such as: exercise intensity; climatic conditions; the athlete's acclimatization; the athlete's physical conditioning; physiologic individual characteristics and the player's biomechanics. Performance is improved when players ingest not only water but also carbohydrate. The rates that carbohydrate and water are absorbed by the organism are limited by the rates of gastric emptying and intestinal absorption. The composition of drinks offered to the players should be influenced by the relative importance of the need of supplying carbohydrates or water; it should be remembered that the depletion of carbohydrate can result in fatigue and decrease of performance, but it is not usually a life-threatening condition. The addition of carbohydrate in these drinks increases the concentrations of blood glucose, increases the use of external fuel through the increase of the glucose oxidation in the muscles and it spares muscle glycogen. So, the ingestion of carbohydrate before and during the exercise can delay the emergence of fatigue and increase the players' performance. Several tactics can be used to avoid dehydration, like hyperhydration before exercise and player's acclimatization. The ideal situation to restore the player's fluid losses is between the sessions of exercises. Since soccer is a sport with quite peculiar characteristics related to hydration, the players should be concerned and educated about the importance of fluid ingestion before, during and after the exercise

Alteraciones del equilibrio ácido-base / Alterations of the balance cido-basis

Es un trastorno del medio interno dependiente de la predominanacia de ACIDOS o BASE en el organismo.El resultado final viene expresado por el pH,cuyo valor en condiciones normales o de equilibrio se siyua entre 7,35 y 7,45.(au)

Anion gap estimation in the diagnosis and prognosis of pregnancy-induced hypertension

To identify the role of the anion gap estimation in the diagnosis and prognosis of pregnancy-induced hypertension. This Cohort study included 224 pregnant women that have attented the antenatal clinic. These comprise 101 women who had developed pregnancy-induced hypertension and 123 healthy pregnant women. Serum electrolytes including sodium, potassium and chloride, blood gases including bicarbonate level, serum albumin and 24 hour-proteins in urine were estimated. Anion gap was then calculated and consequently correlated to the clinical and laboratory data in both groups. Anion gap was significantly decreased in the hypertensive pregnant women than the healthy ones [P < 0.001]. This observation was more severe in the proteinuric hypertensive women than the non-proteinuric women [P< 0.01]. The value of the anion gap was negatively correlated to the severity of the disease. Anion gap depression was significantly increased with the development of placental abruption, intrauterine growth restriction, intrauterine fetal death as well as prematurity [P < 0.05] but this correlation was not observed on the cases of fetal distress. Anion gap estimation could be a reliable test as a diagnostic adjunct in women with pregnancy-induced hypertension as well as a good prognostic test for the development of the complications

Alteraçöes hemodinâmicas, do equilíbrio ácido básico e enzimáticas no exercício exaustivo com pesos / Changing in hemodynemics, basic acid equilibium and enzymatics in the exhaustive exercise with weights

O trabalho muscular exaustivo resulta em alteraçöes metabólicas adaptativas de conseqüências fisiológicas ou mesmo patológicas, características das situaçöes de estresse. Os processos envolvidos incluem ácidos e hemoconcentrraçäo. No presente trabalho utilizou-se um protocolo de exaustäo física, com pesos, para estudo de variáveis sangüíneas indicativas do estresse metabólico. Para tanto, foram selecionados 7 homens, atletas de musculaçäo, voluntários, em bom estado de saúde e nutricional. Todos foram submetidos ao protocolo de exaustäo referente ao teste de peso máximo (1RM) em 5 exercícios, em aparelhos envolvendo grupamentos musculares do peito, braço e coxa, com duraçäo total próxima de 15 minutos. Amostras de sangue venoso foram colhidas antes (MO) e imediatamente após teste (M1) de exaustäo. Essas amostras foram utilizadas para atividade enzimática, indicadores de hemoconcentraçäo, hemogasimétricos amônia e glicemia. A análise estatística mostrou que o teste de exaustäo resultou em acidose metabólica com elevaçäo da PO amônia e LD (maior produçäo de lactato) e reduçäo de HCO e seu precursor PCO. Adicionalmente, observou-se hemoconcentraçäo (aumento da albumina, osmolaridade e hematócrito), assim como, indicativos de alteraçöes na permeabilidade de membranas celulares, com elevaçöes nas concentraçöes séricas das enzimas AST, CK e LD. Os resultados apontam o exercício exaustivo como bom modelo de estudo para estresse metabólico.(au)