Sistemática para el manejo del equilibrio ácido-base en pacientes graves / Systemization for the management of acid-base balance in seriously ill patients

Introducción: Las alteraciones del equilibrio ácido-base pueden ser de carácter primario. En la mayoría de los casos dependen de la complicación de una enfermedad preexistente. La frecuencia de estos trastornos es elevada, especialmente, en enfermos hospitalizados en las unidades de atención al paciente grave. Su aparición conlleva implicaciones pronósticas significativas. Objetivo: Sistematizar sobre el estado actual del manejo del equilibrio ácido-base. Método: Se realizó una revisión bibliográfica en la que se utilizaron las herramientas del método científico. Se examinó toda la bibliografía disponible publicada en los últimos cinco años y así, elaborar una síntesis crítica, acorde al criterio y las competencias de los autores sobre la temática. Resultados: Se expone la importancia de la evaluación clínica, que unida a los niveles de PCO2, y de exceso o déficit de bases en una gasometría arterial, permiten identificar el trastorno ácido base existente. Igualmente, se destaca que el CO2 tiene una función clave en el control de la ventilación, así como las modificaciones que produce al flujo sanguíneo cerebral, el pH y el tono adrenérgico. Otro aspecto importante fue la reciente práctica clínica de la "hipercapnia permisiva" para reducir el metabolismo tisular y de esta manera, mejorar la función del surfactante e impedir la nitración de las proteínas. Conclusiones: El manejo de los desequilibrios ácido-base debe ser del dominio de todos los profesionales vinculados a la asistencia médica, pues el retraso de su diagnóstico puede empeorar la evolución y el pronóstico de los pacientes graves(AU)

Introduction: Acid-base balance alterations can be of a primary nature. In most cases, they depend on the complication of a pre-existing disease. The frequency of these disorders is high, especially in patients hospitalized in critical care units. Its appearance carries significant prognostic implications. Objective: To systematize the current state of acid-base balance management. Method: A bibliographic review was carried out, for which the tools of the scientific method were used. All the available bibliography, published in the last five years, was examined; thus, a critical synthesis was prepared, according to the criteria and competences of the authors regarding the subject. Results: The importance of the clinical evaluation is exposed, which, together with PCO2 levels as well as excess or deficit of bases in an arterial blood gas, allow to identify the existing acid-base disorder. Likewise, it is highlighted that CO2 has a key function in ventilation control, together with the modifications it produces on cerebral blood flow, pH and adrenergic tone. Another important aspect was the recent clinical practice of "permissive hypercapnia" to reduce tissue metabolism and thus improve surfactant function and prevent protein nitration. Conclusions: The management of acid-base imbalances should be mastered by all professionals associated to medical care, since any delay in its diagnosis can worsen the evolution and prognosis of seriously ill patients(AU)

Alterações hidroeletrolíticas em pessoas com cirrose / Hydroelectrolytic alterations in cirrhotic patients

O objetivo deste estudo foi evidenciar e discutir as principais alterações hidroeletrolíticas em pessoas com cirrose. Trata-se de uma revisão integrativa, de natureza qualitativa. Os artigos foram selecionados por meio da plataforma Medical Literature Analysis and Retrievel System Online. Os principais achados identificados a partir dos artigos selecionados foram a ocorrência de hiponatremia, o mau prognóstico diante da presença de distúrbios hidroeletrolíticos em relação à sobrevida em pessoas com cirrose e a importância da albumina. Indivíduos com cirrose são suscetíveis ao desenvolvimento de distúrbios hidroeletrolíticos devido às mudanças fisiopatológicas da doença e às condições clínicas apresentadas. A hiponatremia e a hipocalemia são os mais recorrentes, destacando, porém, a necessidade de atenção aos demais distúrbios. (AU)

The objective of this study was to show and discuss the main hydroelectrolytic alterations in cirrhotic patients. This is an integrative review, a qualitative study, in which articles were selected at the Medical literature Analysis and Retrieval System Online. The main findings identified in the articles selected were the occurrence of hyponatremia, the poor prognostic, due to the presence of hydroelectrolytic disorders, regarding cirrhotic individuals survival and the importance of albumin. Individuals with cirrhosis are susceptible to the development of hydroelectrolytic disorders due to the pathophysiological alterations of the disease and because of the clinical status presented. Hyponatremia and hypokalemia are the most recurrent, but attention shall be given to the other disorders too. (AU)

Assessment of Fluoride and pH Levels in a Range of Ready-to-Drink Children’s Beverages Marketed in Malaysia

ABSTRACT@#This study aimed to determine the fluoride and pH levels of beverages likely to be consumed by children in Malaysia and to estimate daily fluoride intake from consumption of these beverages. A convenience sampling of 120 ready-to-drink beverages were purchased and categorised into 11 groups (UHT recombined milk, fresh milk [pasteurised], cultured milk [probiotic], yogurt beverages, fresh fruit juices, fruit flavoured beverages, soy-based beverages, malt-based beverages, tea, carbonated beverages and bottled waters). Fluoride concentration was measured using a fluoride ion-selective electrode while the pH level was measured using a pH meter. The fluoride concentration in the beverages ranged from 0.02±0.00 mg/L to 2.77±0.06 mg/L. Tea was found to have the highest fluoride concentration. The intake of fluoride from consumption of other types of beverages is below the lowest-observed-adverse-effect level (except tea). The pH of the beverages included in the study ranged from 2.20±0.01 to 7.76±0.00. Carbonated beverages (mean pH: 2.98±0.50) were found to be extremely acidic followed by fresh fruit juices (mean pH: 3.38±0.34) and fruit flavoured beverages (mean pH: 3.90±0.92). The correlation between fluoride and pH levels was weak, τ = 0.058 and not statistically significant (p < 0.35). The majority of the beverages had a low fluoride level and their consumption is unlikely to cause fluorosis except for tea. Almost half of the beverages had a low pH level with carbonated beverages being the most acidic.

Acid-base imbalance: a review with proposed unified diagnostic algorithm / Desequilibrio ácido-base: una revisión con el algoritmo de diagnóstico unificado propuesto

Abstract Introduction: Alterations in the acid-base balance are studied in all medical specialties. Although most cases derive from a preexisting pathology, they can also manifest themselves in a primary context. The proper identification of the acid-base disorder allows the pathological process to be characterized. The correct interpretation of the blood gasometry as a technique for monitoring the ventilatory status, oxygenation and acid-base balance of a patient requires the integration of various physicochemical approaches in order to specify a diagnosis, quantify a therapeutic response, and monitor the severity or the progression of a pathological process. Methodology: A literature review was conducted in the PubMed, Scopus and Science Direct databases. The articles were selected according to the title and the abstract and sorted by topics relevant by pathophysiology, divergences, clinical approach, diagnosis, and management. Results: A guide the clinical correlation of the critical patient with the blood gasometry parameters to characterize the acid-base disorder through the proposition of a diagnostic algorithm. Conclusion: The incorporation of the three theories in a diagnostic algorithm facilitates a greater understanding of the pathophysiological mechanisms and allows us to identify a more precise therapeutic objective to correct the underlying disorder in the different clinical contexts of the patient.

Resumen Introducción: las alteraciones del equilibrio ácido-base se estudian en todas las especialidades médicas. Aunque la mayoría de los casos derivan de una patología preexistente, también pueden manifestarse en un contexto primario, por lo que la identificación adecuada del trastorno ácido-base permite caracterizar su proceso patológico. La correcta interpretación de la gasometría sanguínea como técnica para monitorizar el estado ventilatorio, la oxigenación y el equilibrio ácido-base de un paciente requiere la integración de varios enfoques fisicoquímicos para precisar un diagnóstico, cuantificar una respuesta terapéutica y monitorizar la gravedad o la progresión de un proceso patológico. Materiales y métodos: se realizó una revisión de la literatura en las bases de datos PubMed, Scopus y ScienceDirect. Los artículos fueron seleccionados según el título y el resumen, y ordenados por tópicos relevantes por fisiopatología, divergencias, abordaje clínico, diagnóstico y manejo. Resultados: en la literatura consultada se evidenció que el uso de un enfoque lógico y sistemático es necesario para interpretar adecuadamente los parámetros de la gasometría sanguínea e identificar oportunamente el trastorno ácido-base. Conclusión: la incorporación de las tres teorías en un algoritmo diagnóstico facilita una mayor comprensión de los mecanismos fisiopatológicos y permite identificar un objetivo terapéutico más preciso para corregir el trastorno de base en los diferentes contextos clínicos del paciente.

Caracterização dos distúrbios da regulação ácido-base: uma abordagem didática e intuitiva / Characterization of acid-base regulation disorders: a didactic and intuitive approach

Em humanos, o pH sanguíneo é mantido em uma faixa estreita, entre 7,35 e 7,45. Diferentes mecanismos bioquímicos, de forma harmônica, atuam para a manutenção do pH fisiológico. Múltiplos processos patológicos podem promover alterações no pH e nos gases sanguíneos, caracterizando acidose (pH <7,35) ou alcalose (pH >7,45). A ruptura da homeostasia do pH é identificada pela medição do pH, pressão parcial de dióxido de carbono (pCO2), concentração do bicarbonato (HCO3-) e, adicionalmente, com a pressão de oxigênio (pO2) em sangue arterial, processo descrito como gasometria arterial. Este artigo revisa os principais elementos associados a compreensão das alterações e tem como objetivo central apresentar uma abordagem didática e intuitiva para a caracterização destes distúrbios; e também comenta sobre ferramentais digitais destinadas a interpretações das alterações da gasometria arterial que também são abordados, como programas para computadores em ambiente web e aplicativos para telefonia móvel.

In humans, blood pH is kept in a narrow range, between 7.35 to 7.45. Different biochemical mechanisms, in a harmonic way, act to maintain the physiological pH. Multiple pathological processes can promote changes in pH and blood gases, characterizing acidosis (pH <7.35) or alkalosis (pH> 7.45). The rupture of pH homeostasis is identified by measuring pH, partial pressure of carbon dioxide (pCO2), bicarbonate concentration (HCO3 - and, in addition, with the pressure of oxygen (pO2) in arterial blood, a process described as gasometry arterial. This article reviews the main elements associated with the understanding of acid-base changes and aims to present a didactic and intuitive approach to the characterization of these disorders; and also comments on digital tools for the interpretation of alterations in arterial blood gases are also covered, such as programs for computers in a web environment and applications for mobile phone.

Distúrbios ácido-base nas doenças hepáticas / Acid-base disorders in liver diseases

O objetivo deste artigo foi abordar as controvérsias científicas acerca dos distúrbios ácido-base nas doenças hepáticas. Nos estágios avançados da doença hepática, os distúrbios ácido-base atuam de forma complexa, comprometendo a qualidade de vida do paciente e desafiando o manejo clínico. A literatura apresenta a alcalose respiratória como uma das principais alterações, porém há uma longa discussão sobre o mecanismo fisiopatológico; em especial, citam-se a hipóxia, a hipocapnia e o nível de progesterona. Nas desordens metabólicas, com destaque para a acidose, os estudos apontam principalmente o lactato, os unmeasured ions ou íons não medidos e as alterações hidroeletrolíticas, mas cada componente desse sobressai-se dependendo da fase da doença estudada, compensada ou descompensada. As controvérsias dos distúrbios ácido-base nas doenças hepáticas devem-se ora à complexidade da fisiopatologia da própria doença, ora à necessidade de mais estudos esclarecedores.

The aim of this study is to address the scientific controversy about acid-base disorders in liver diseases. In the end stage of liver diseases, the acid-base disorder has a complex performance, impairing the patient's quality of life and challenging the clinic management. Although the literature shows respiratory alkalosis as one of the main alterations, there is a long discussion about the pathophysiological mechanism, specially regarding hypoxia, hypocapnia, and progesterone level. In metabolic disorders, especially acidosis, the studies mainly indicate the lactate, unmeasured ions, and hydroelectrolytic alterations, but, depending on the disease phase, either compensated or decompensated, each element has a particular action. The controversy about acid-base disorders in liver diseases is associated with the complexity of this condition, as well as with the necessity of more specialized research.

Identifying hydric, electrolytic and acid-base imbalances through traditional and quantitative approaches in dogs with hemorrhagic gastroenteritis / Identificação de desequilíbrios hídricos, eletrolíticos e ácido-base pelas abordagens tradicional e quantitativa em cães com gastroenterite hemorrágica

Vomiting and diarrhea are two important clinical signs that can cause significant electrolytic and acid-base imbalances. The purposes of this study were to characterize hydric, electrolytic and acid-base disorders presented by puppies with hemorrhagic gastroenteritis and to compare the traditional and quantitative approaches to acid-base status interpretation. Sixty-one animals with a history of vomiting and/or diarrhea were used in this study and the following tests were performed: complete blood count, total plasma protein concentration and hemogasometry. Mean, standard deviation and Kappa values were calculated. The imbalances characterized by both approaches were: 42 (69%) animals without imbalance, 17 (28%) with metabolic alkalosis and 2 (3%) with metabolic acidosis by the traditional approach and 17 (28%) dogs without imbalance, 26 (43%) with metabolic alkalosis and 18 (29%) with metabolic acidosis by the quantitative approach. The agreement calculated between two approaches coincide in 28 cases, with a moderate Kappa value equivalent to 0.459. The most found imbalances were metabolic alkalosis, hypokalemia, and mild dehydration. Most of acid-base disturbances were not identified by the traditional approach, whereas by the quantitative approach, they were easily determined. Thus quantitative approach proved to be superior in identification of possible acid-base imbalances.(AU)

Vômito e diarreia são dois sinais clínicos importantes, que podem causar desequilíbrios eletrolíticos e ácido-base importantes. Os objetivos deste trabalho foram caracterizar os desequilíbrios hídrico, eletrolítico e ácido-base apresentados por filhotes de cães com gastroenterite hemorrágica e comparar as abordagens de interpretação do equilíbrio ácido-base tradicional e quantitativa. Sessenta e um animais com histórico de vômito e/ou diarreia foram utilizados neste estudo, e os seguintes testes foram realizados: hemograma, concentração de proteína total plasmática e hemogasometria. Média, desvio-padrão e valor de Kappa foram calculados. Os desequilíbrios caracterizados pelas duas abordagens foram: 42 (69%) animais sem desequilíbrio, 17 (28%) com alcalose metabólica e dois (3%) com acidose metabólica, pela abordagem tradicional, e 17 (28%) cães sem desequilíbrio, 26 (43%) com alcalose metabólica e 18 (29%) com acidose metabólica, pela abordagem quantitativa. A concordância calculada entre as duas abordagens coincidiu em 28 casos, com um valor de Kappa moderado, equivalente a 0,459. Os desequilíbrios mais encontrados foram alcalose metabólica, hipocalemia e desidratação leve. A maioria dos distúrbios não foram identificados pela abordagem tradicional, enquanto, pela abordagem quantitativa, foram facilmente determinados. Portanto, a abordagem quantitativa provou-se superior na identificação de possíveis desequilíbrios ácido-base.(AU)

Prevalence and Clinical Outcomes of Patients with Diabetic Ketoacidosis/Hyperglycemic Hyperosmolar Syndrome and COVID-19: A Systematic Review

@#BACKGROUND AND OBJECTIVES. Several reports have shown that coexistence of diabetes mellitus and COVID-19 is one of the risk factors for poor outcome and increased mortality. Rapid metabolic deterioration with development of diabetic ketoacidosis (DKA) or hyperglycemic hyperosmolar syndrome (HHS) may result due to the acute insulin secretory capacity loss, stress condition and the cytokine storm. In this review, we aim to describe the prevalence of hyperglycemic crises(DKA/HHS) in patients with COVID-19 infection as well as their clinical outcomes. METHODS. An intensive search was done using the WebMD, PubMed, Medline and Google Scholar databases for articles published between December 2019 to October 2020 that identified the number of patients who developed DKA and/or HHS among those who were admitted for COVID-19. Their clinical outcomes were likewise described. RESULTS. This review included 4 articles in which individual quality was assessed. A total of 1282 patients were admitted for COVID-19 and the prevalence of DKA was 1.32%. HHS was not reported in any of the studies. Five (29.4%) of the patients with DKA and COVID-19 died and 12 (70.6%) recovered. CONCLUSIONS. A significant number of COVID-19 patients developed DKA and it is associated with a high mortality rate. This reimposes the need for an appropriate algorithm for the optimal management of concomitant COVID 19 and hyperglycemic crises to avoid morbidity and mortality. Additionally, there is paucity of large-scale studies describing the prevalence of DKA/HHS in patients with COVID-19.

Metabolic and volume status evaluation of hemodialysis patients with and without residual renal function in the long interdialytic interval / Avaliação metabólica e volêmica no maior intervalo interdialítico de pacientes em hemodiálise com e sem função renal residual

Abstract Introduction: It is unclear whether residual renal function (RRF) in dialysis patients can attenuate the metabolic impact of the long 68-hour interdialytic interval, in which water, acid, and electrolyte accumulation occurs. Objective: to evaluate serum electrolyte levels, water balance, and acid-base status in dialytic patients with and without RRF over the long interdialytic interval (LII). Methodology: this was a single-center, cross-sectional, and analytical study that compared patients with and without RRF, defined by diuresis above 200 mL in 24 hours. Patients were weighed and serum samples were collected for biochemical and gasometric analysis at the beginning and at the end of the LII. Results: 27 and 24 patients with and without RRF were evaluated, respectively. Patients without RRF had a higher increase in serum potassium during the LII (2.67 x 1.14 mEq/L, p < 0.001), reaching higher values at the end of the study (6.8 x 5.72 mEq/L, p < 0.001) and lower pH value at the beginning of the interval (7.40 x 7.43, p = 0.018). More patients with serum bicarbonate < 18 mEq/L (50 x 14.8%, p = 0.007) and mixed acid-base disorder (57.7 x 29.2%, p = 0.042), as well as greater interdialytic weight gain (14.67 x 8.87 mL/kg/h, p < 0.001) and lower natremia (137 x 139 mEq/L, p = 0.02) at the end of the interval. Calcemia and phosphatemia were not different between the groups. Conclusion: Patients with RRF had better control of serum potassium, sodium, acid-base status, and volemia throughout the LII.

Resumo Introdução: Não se sabe ao certo se a função renal residual (FRR) de pacientes dialíticos pode atenuar o impacto metabólico do maior intervalo interdialítico (MII) de 68 horas, no qual ocorre acúmulo de volume, ácidos e eletrólitos. Objetivo: Avaliar os níveis séricos de eletrólitos, balanço hídrico e status ácido-básico de pacientes dialíticos com e sem FRR ao longo do MII. Metodologia: Tratou-se de estudo unicêntrico, transversal e analítico, que comparou pacientes com e sem FRR, definida como diurese acima de 200 mL em 24 horas. Para tal, os pacientes foram pesados e submetidos à coleta de amostras séricas para análise bioquímica e gasométrica no início e fim do MII. Resultados: Foram avaliados 27 e 24 pacientes com e sem FRR, respectivamente. Pacientes sem FRR apresentaram maior aumento de potássio sérico durante o MII (2,67 x 1,14 mEq/L, p < 0,001) atingindo valores mais elevados no fim (6,8 x 5,72 mEq/L, p < 0,001); menor valor de pH no início do intervalo (7,40 x 7,43, p = 0,018), maior proporção de pacientes com bicarbonato sérico < 18 mEq/L (50 x 14,8 %, p = 0,007) e distúrbio ácido-básico misto (70,8 x 42,3 %, p = 0,042), além de maior ganho de peso interdialítico (14,67 x 8,87 mL/kg/h, p < 0,001) e menor natremia (137 x 139 mEq/L, p = 0,02) no fim do intervalo. A calcemia e fosfatemia não foram diferentes entre os grupos. Conclusão: Pacientes com FRR apresentaram melhor controle dos níveis séricos de potássio, sódio, status ácido-básico e da volemia ao longo do MII.

Comparison of electrolyte and acid-base balances of Dorper breed ewes between single and twin pregnancies / Comparação dos equilíbrios eletrolítico e ácido básico de ovelhas da raça Dorper entre gestação única e gemelar

During pregnancy there are modifications in the metabolic profile of sheep that may predispose to the occurrence of metabolic disorders, of which pregnancy toxaemia (PT) is highlighted. Blood gas analysis is detects changes in acid-base and electrolyte balance effectively. The objectives of this study were to study the acid-base and electrolyte balance of sheep during gestation and in the immediate peripartum (up to 48 hours postpartum), comparing single gestation with twins. Sixty healthy sheep of Dorper breed, two to five years old were raised in a semi-intensive system and were divided in two experimental groups: Group 1: 30 ewes, with ultrasonographic diagnosis of single fetus gestation; Group 2: 30 ewes, with ultrasonographic diagnosis of twin pregnancy. The experimental moments were defined as: MI-immediately after artificial insemination (control); MG30 - 30 days of gestation; MG90 - 90 days of gestation; MG120 - 120 days of gestation; MG130 - 130 days of gestation; MG140 - 140 days of gestation; MP - lambing; MPP1 - 24h postpartum; MPP2 - 48h postpartum. At all times 1mL of blood was collected per jugular vein puncture for blood gas evaluation in a portable equipament (I-Stat®). The pH, carbon dioxide pressure (PCO2), bicarbonate (HCO3-), base excess (BE), sodium (Na+), potassium (K+), chloride (Cl-), ionized calcium (Ca+2), lactate, anion gap (AG) were mensured and strong ion difference (SID) were calculed. This work showed that there were changes in acid-base and electrolyte balance in pregnant ewes, due to the decrease in BE, HCO3-, TCO2 and increase of lactate and AG during gestation, but the pH remained normal and did not present any difference among moments in both groups. Comparing the groups, single-gestation ewes presented higher alkaline expenditure at delivery than twin-gestation, evidenced by lower levels of BE and HCO3-. Lower Na+ levels were observed in prepartum; drop in K+ values with advancing gestation; hyperchloremia and hypocalcemia during gestation according to the reference standards for species; decreased iCa+2 levels in the final third of gestation in both groups. It was concluded that the ewes of this study were healthy until the last moment analyzed (48h postpartum), although have shown greater consumption of the alkaline reserve in the peripartum, being more explicit in the single gestation animals. In addition, this situation can be physiological and result in increased energy demand during gestation, more exacerbated by peripartum.(AU)

Durante a gestação ocorrem modificações metabólicas nas ovelhas que podem predispor a ocorrência de transtornos metabólicos, dos quais se destaca a toxemia da prenhez (TP). A hemogasometria é um exame que detecta alterações nos equilíbrios ácido-básico e eletrolítico de forma eficaz. Os objetivos deste estudo foram estudar os equilíbrios ácido-básico e eletrolítico de ovelhas durante a gestação e no periparto imediato (até 48 horas pós-parto), comparando-se gestação única com gemelar. Foram utilizadas 60 ovelhas criadas em manejo semi-intensivo, hígidas, da raça Dorper, com dois a cinco anos de idade. Foram constituídos dois grupos experimentais: Grupo 1: 30 ovelhas, com diagnóstico ultrassonográfico de gestação de feto único; Grupo 2: 30 ovelhas, com diagnóstico ultrassonográfico de gestação gemelar. Os momentos experimentais foram definidos como: MI - imediatamente após a inseminação artificial (controle); MG30 - 30 dias de gestação; MG90 - 90 dias de gestação; MG120 - 120 dias de gestação; MG130 - 130 dias de gestação; MG140 - 140 dias de gestação; MP - dia do parto; MPP1 - 24h pós-parto; MPP2 - 48h pós-parto. Em todos os momentos foi colhido 1mL de sangue por punção da veia jugular para avaliação hemogasométrica em aparelho portátil (I-Stat®). Foram analisados os parâmetros: pH, pressão de dióxido de carbono (PCO2), bicarbonato (HCO3-), excesso de bases (EB), sódio (Na+), potássio (K+), cloreto (Cl-), cálcio ionizado (iCa+2), lactato, ânion gap (AG) e diferença de íons fortes (SID). Este trabalho mostrou que houve mudanças nos equilíbrios ácido-básico e eletrolítico nas ovelhas prenhes, pela diminuição do EB, HCO3- e aumento do lactato e AG no decorrer da gestação, porém o pH se manteve dentro da normalidade e não apresentou diferença ao longo dos momentos em ambos os grupos. Comparando os grupos, as ovelhas de gestação única apresentaram maior consumo da reserva alcalina no momento do parto do que as de gestação gemelar, evidenciado menores níveis de EB e HCO3-. Foram observados níveis mais baixos de Na+ no pré-parto; queda dos valores de K+ com o avanço da gestação; hipercloremia e hipocalcemia durante a gestação segundo os padrões de referência para espécie e diminuição dos níveis de iCa+2 no terço final da gestação nas ovelhas de ambos os grupos. Concluiu-se que as ovelhas deste estudo apresentaram-se saudáveis até o último momento analisado (48h pós-parto), embora tenham mostrado maior consumo da reserva alcalina no periparto, sendo mais evidente nos animais de gestação única. Apesar disso, essa ocorrência pode ser considerada fisiológica e consequência do aumento da demanda energética durante a gestação, mais exacerbada no periparto.(AU)

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.

Scorecard for early recognition of patients at high risk of delirium in emergency department

OBJECTIVE: This study was conducted to evaluate scorecards for early recognition of high-risk patients of delirium in the emergency department (ED). METHODS: Data from 399 consecutive patients aged 65 years or older between January 1, 2015 and December 31, 2015 were retrospectively analyzed. Delirium was identified by reviewing medical records and was confirmed by a psychiatrist. The study population was divided into a training and validation group. Predisposing factors were evaluated and validated by multivariate logistic regression analysis and a calibration plot, after which a scorecard was constructed using these factors and applying points to double odds to each regression coefficient. RESULTS: Dementia, transfer from a long-term care facility, acute acid-base imbalance, moderate pain, and stroke were independent predisposing factors for delirium in ED, with assigned scores in the scorecard of 3, 2, 2, 2, and 2, respectively. The total score of the scorecard for delirious patients was significantly higher than that for non-delirious patients in both the training and validation groups. The coefficient of determination (R²) of the calibration plot was 0.74 and 0.68 in the training and validation group, respectively. In the receiver operation characteristic curve, the cut-off point of the scorecard for delirium was 2.5 and the sensitivity, specificity, and accuracy were 75.0%, 87.8%, and 86.7% in training group, while they were 76.9%, 85.1%, and 84.2% in the validation group, respectively. CONCLUSION: The scorecard was a useful screening tool for early recognition of patients with a high-risk of developing delirium in the ED.

Situación del estado ácido-base de pacientes incidentes a la emergencia de Medicina de un hospital nacional de Lima Perú y su asociación a variables clínicas / Situation of the acid-base disorders and their association with clinical variables in incident patients at the emergency room in a national hospital in Lima, Peru

Objetivos: Determinar la frecuencia de trastornos del estado ácido-base de pacientes admitidos al Departamento de Emergencia de un hospital general de Lima-Perú y su asociación con enfermedades prevalentes. Material y métodos: Estudio transversal descriptivo y analítico cuyo tamaño de muestra calculado fue en 108 pacientes a quienes el médico tratante solicitó estudio de gasometría arterial. La muestra fue obtenida por saturación hasta alcanzar el tamaño mínimo calculado. Resultados: El disturbio ácido-base más frecuentemente hallado fue el trastorno mixto de la acidosis metabólica asociado con la alcalosis respiratoria (50% casos) coexistiendo en pacientes con disfunción renal aguda o crónica y shock, seguido del disturbio único de alcalosis respiratoria (26,2% casos) asociada a enfermedad respiratoria y gastrointestinal. Conclusiones: Los trastornos mixtos de acidosis metabólica con alcalosis respiratoria son altamente relevantes y la alcalosis respiratoria es el fenómeno puro más frecuente. (AU)

Objectives: To determine the frequency of acid-base disorders and their association with prevalent diseases in patients admitted to the emergency department of a national hospital in Lima. Methods: Cross-sectional study with a sample size of 108 patients in whom the treating physician requested arterial blood gases determination. The sample was attained by saturation until reaching the targeted sample size. Results: The most common acid-base disorder was mixed metabolic acidosis (50%) co-existing in patients with acute or chronic renal dysfunction and shock, followed by respiratory alkalosis (26.2%) associated to respiratory and gastro-intestinal disorders. Conclusions: Mixed metabolic acidosis and respiratory alkalosis are the most frequent acid-base abnormalities observed in this setting, respiratory alkalosis is the most common single acid-base disorder found. (AU)

Effects of 37℃ Carbon Dioxide Pneumoperitoneum on Core Body Temperature, Systolic Blood Pressure, Heart Rate and Acid-Base Balance: A Randomized Double-blind Controlled Trial

PURPOSE: The purpose of this study was to compare the effects of 21℃ CO₂ and 37℃ CO₂ pneumoperitoneum on body temperature, blood pressure, heart rate, and acid-base balance. METHODS: Data were collected at a 1300-bed university hospital in Incheon, from February through September 2012. A total of 74 patients who underwent laparoscopic colectomy under general anesthesia with desflurane were randomly allocated to either a control group or an experimental group. The control group received 21℃ CO₂ pneumoperitoneum; the experimental group received 37℃ CO₂ pneumoperitoneum. The pneumoperitoneum of the two groups was under abdominal pressure 15 mmHg. Body temperature, systolic blood pressure, heart rate and acid-base balance were assessed at 30 minutes and 90 minutes after pneumoperitoneum, and again at 30 minutes after arriving at the Post Anesthesia Care Unit. RESULTS: Body temperature in the 37℃ CO2 pneumoperitoneum group was significantly higher (F=9.43, p<.001) compared to the 21℃ CO₂ group. However, there were no statistically significant differences in systolic blood pressure (p=.895), heart rate (p=.340), pH (p=.231), PaCO₂ (p=.490) and HCO3- (p=.768) between the two groups. CONCLUSION: Pneumoperitoneum of 37℃ CO₂ is effective for the increase of body temperature compared to pneumoperitonium of 21℃ CO₂, and it does not result in a decrease of blood pressure, heart rate or acid-base imbalance.

Acute but not chronic metabolic acidosis potentiates the acetylcholine-induced reduction in blood pressure: an endothelium-dependent effect

Metabolic acidosis has profound effects on vascular tone. This study investigated the in vivo effects of acute metabolic acidosis (AMA) and chronic metabolic acidosis (CMA) on hemodynamic parameters and endothelial function. CMA was induced by ad libitum intake of 1% NH4Cl for 7 days, and AMA was induced by a 3-h infusion of 6 M NH4Cl (1 mL/kg, diluted 1:10). Phenylephrine (Phe) and acetylcholine (Ach) dose-response curves were performed by venous infusion with simultaneous venous and arterial blood pressure monitoring. Plasma nitrite/nitrate (NOx) was measured by chemiluminescence. The CMA group had a blood pH of 7.15±0.03, which was associated with reduced bicarbonate (13.8±0.98 mmol/L) and no change in the partial pressure of arterial carbon dioxide (PaCO2). The AMA group had a pH of 7.20±0.01, which was associated with decreases in bicarbonate (10.8±0.54 mmol/L) and PaCO2 (47.8±2.54 to 23.2±0.74 mmHg) and accompanied by hyperventilation. Phe or ACh infusion did not affect arterial or venous blood pressure in the CMA group. However, the ACh infusion decreased the arterial blood pressure (ΔBP: -28.0±2.35 mm Hg [AMA] to -4.5±2.89 mmHg [control]) in the AMA group. Plasma NOx was normal after CMA but increased after AMA (25.3±0.88 to 31.3±0.54 μM). These results indicate that AMA, but not CMA, potentiated the Ach-induced decrease in blood pressure and led to an increase in plasma NOx, reinforcing the effect of pH imbalance on vascular tone and blood pressure control.

Can venous base excess replace arterial base excess as a marker of early shock and a predictor of survival in trauma?

<p><b>INTRODUCTION</b>Arterial base excess is an established marker of shock and predictor of survival in trauma patients. However, venous blood is more quickly and easily obtained. This study aimed to determine if venous base excess could replace arterial base excess as a marker in trauma patients at presentation and if venous base excess is predictive of survival at 24 hours and one week.</p><p><b>METHODS</b>This was a prospective study of 394 trauma patients presenting to the emergency department of a tertiary hospital over a 17-month period. Data on base excess at presentation, vital signs, shock index (SI), injury severity score (ISS), and mortality at 24 hours and one week was collected and analysed.</p><p><b>RESULTS</b>Arterial and venous blood gas tests were performed on 260 and 134 patients, respectively. Patients were stratified into groups based on their SI and ISS for analysis. There was no statistical difference between mean venous blood gas and arterial blood gas levels at presentation when SI > 0.7, regardless of ISS (p > 0.05). The mortality rate was 4.57%. Both venous and arterial base excess was lower in nonsurvivors compared to survivors (p < 0.05). However, at 24 hours and one week, the difference in base excess values at presentation between survivors and nonsurvivors was greater when using venous base excess compared to arterial base excess (11.53 vs. 4.28 and 11.41 vs. 2.66, respectively).</p><p><b>CONCLUSION</b>In conclusion, venous base excess can replace arterial base excess in trauma patients as a means of identifying and prognosticating early shock.</p>

Confronting Practical Problems for Initiation of On-line Hemodiafiltration Therapy

Conventional hemodialysis, which is based on the diffusive transport of solutes, is the most widely used renal replacement therapy. It effectively removes small solutes such as urea and corrects fluid, electrolyte and acid-base imbalance. However, solute diffusion coefficients decreased rapidly as molecular size increased. Because of this, middle and large molecules are not removed effectively and clinical problem such as dialysis amyloidosis might occur. Online hemodiafiltration which is combined by diffusive and convective therapies can overcome such problems by removing effectively middle and large solutes. Online hemodiafiltration is safe, very effective, economically affordable, improving session tolerance and may improve the mortality superior to high flux hemodialysis. However, there might be some potential limitations for setting up online hemodiafiltaration. In this article, we review the uremic toxins associated with dialysis, definition of hemodiafiltration, indication and prescription of hemodiafiltration and the limitations of setting up hemodiafiltration.

Efeito alcalinizante da solução de Ringer com lactato em ovelhas sadias e acidóticas / Alkalinizing effect of lactated Ringer's solution in healthy and acidotic sheep

O estudo teve o objetivo de testar a hipótese de que o efeito alcalinizante da solução de Ringer com lactato (SRL) pode ser maior nos animais portadores de acidose metabólica do que nos sadios, como consequência da necessidade de retorno ao equilíbrio. Seis ovelhas receberam a SRL em volume correspondente a 10% do peso corporal, administrada por infusão contínua intravenosa, durante quatro horas, em duas condições definidas: enquanto eram saudáveis e após a indução experimental de acidose láctica ruminal aguda (ALRA). Amostras de sangue venoso e de urina foram colhidas em quatro momentos: antes do início da infusão, na metade do volume infundido, ao término da infusão e duas horas após. Foram determinados valores de pH sanguíneo e urinário, de pCO2, HCO3 - e BE no sangue, de Na+, K+, Cl-, SID, AG, PPT, Atot e lactato L no plasma, e das excreções fracionadas urinárias de Na+, K+, Cl- e lactato L. A SRL provocou hemodiluição, mas não interferiu nos equilíbrios eletrolítico e acidobase das ovelhas sadias. Apesar de eficaz para reverter a desidratação, não foi capaz de corrigir a acidose metabólica presente após a indução da ALRA.

The aim of this study was to investigate if the alkalinizing effect of lactated Ringer's solution (LRS) is greater in animals with metabolic acidosis than in healthy ones, as a result of the need to restore acid-base balance. LRS was intravenously infused in a volume corresponding to 10% of body weight, continously during four hours, in two definite conditions in the same six ewes: when they were healthy and after experimentally induced acute rumen lactic acidosis (ARLA). Venous blood and urine samples were taken in four moments: before the beginning, in the middle, at the end of the infusion and two hours after. Blood and urine pH, blood pCO2, HCO3 - and BE, and plasma Na+, K+, Cl-, TP and L lactate were measured. Na+, K+, Cl- and L lactate fractional clearance and plasma SID, AG, and Atot were calculated. LRS caused hemodilution but didn't change electrolyte and acid-base balances in healthy ewes. When ewes were affected by ARLA, the infusion of this solution was effective for dehydration reversion but was unable to correct metabolic acidosis.