Differences in Exercise Capacity, Ventilatory Efficiency, and Gas Exchange between Patients with Pulmonary Arterial Hypertension and Chronic Thromboembolic Pulmonary Hypertension Residing at High Altitude.

Background: Cardiopulmonary exercise testing (CPET) assesses exercise capacity and causes of exercise limitation in patients with pulmonary hypertension (PH). At altitude, changes occur in the ventilatory pattern and a decrease in arterial oxygen pressure in healthy; these changes are increased in patients with cardiopulmonary disease. Our objective was to compare the response to exercise and gas exchange between patients with pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) residing at the altitude of Bogotá (2640 m). Methods: All patients performed an incremental CPET with measurement of oxygen consumption ( VO 2 ), dead space (VD/VT), ventilatory equivalents (VE/ VCO 2 ), and alveolar-arterial oxygen gradient ( PA-aO 2 ). X 2 test and one-way analysis of variance were used for comparisons between PAH and CTEPH. Results: We included 53 patients, 29 with PAH, 24 with CTEPH, and 102 controls as a reference of the normal response to exercise at altitude. CTEPH patients had a higher New York Health Association (NYHA) functional class than PAH (p = 0.037). There were no differences between patients with PAH and CTEPH in hemodynamics and VO 2 % of predicted (67.8 ± 18.7 vs. 66.0 ± 19.8, p < 0.05), but those with CTEPH had higher dyspnea, VD/VT (0.36 ± 0.09 vs. 0.23 ± 0.9, p < 0.001), VE/ VCO 2 (45.8 ± 7.1 vs. 39.3 ± 5.6, p < 0.001), and PA-aO 2 (19.9 ± 7.6 vs. 13.5 ± 7.6, p < 0.001) than PAH patients. Conclusions: At altitude, patients with PH present severe alterations in gas exchange during exercise. There were no differences in exercise capacity between PAH and CTEPH, but patients with CTEPH had more dyspnea and greater alterations in gas exchange during exercise. CPET made it possible to identify alterations related to the pathophysiology of CTEPH that could explain the functional class and dyspnea in these patients.

Consensus of the Brazilian association of hematology, hemotherapy and cellular therapy on patient blood management: Anemia tolerance mechanisms.

Understanding the physiological concepts of oxygen delivery is essential to discern the mechanisms that influence its increase, reduction or maintenance in the body. This text explores the different mechanisms that help maintain oxygen delivery even in the face of reduced hemoglobin levels. Adequate oxygen delivery ensures tissue and metabolic balance, which is crucial to avoid harmful consequences such as metabolic acidosis and cellular dysoxia. The complex interaction between variables such as cardiac output, hemoglobin and heart rate (HR) plays a fundamental role in maintaining oxygen delivery, allowing the body to temporarily adjust to situations of anemia or high metabolic demand. It is important to emphasize that blood transfusions should not be based on fixed values, but rather on individual metabolic needs. Strategies to reduce myocardial consumption and monitor macro and micro hemodynamics help in making rational decisions. Individualizing treatment and considering factors such as blood viscosity in relation to the benefits of transfusion are increasingly relevant to optimize therapy and minimize risks, especially in complex clinical scenarios, such as neurocritical patients and trauma victims.

Arterial blood gas measurements are different for brachycephalic and nonbrachycephalic dogs acclimatized to an altitude of 1,535 meters.

OBJECTIVE: To define reference intervals (RIs) for arterial blood gas (aBG) measurements in healthy, nonsedated, dolichocephalic, and mesocephalic (nonbrachycephalic) dogs at approximately 1,535 m above sea level and compare these findings with healthy, nonsedated, brachycephalic dogs living at the same altitude. ANIMALS: 120 adult nonbrachycephalic dogs and 20 adult brachycephalic dogs. METHODS: Cases were prospectively enrolled from October 2021 to June 2022. Dogs were enrolled from the community or after presentation for wellness examinations or minor injuries including lacerations, nail injuries, and lameness. Physical examinations and systolic blood pressure (sBP) measurements were obtained before blood sample collection. Arterial blood was collected from the dorsal pedal artery or femoral artery. After data collection, brachycephalic dogs underwent pre- and postexercise tolerance assessments. RESULTS: The mean and RI values for arterial pH (7.442; 7.375 to 7.515), partial pressure of oxygen in arterial blood (Pao2; 78.3; 59.2 to 92.7 mm Hg), partial pressure of carbon dioxide in arterial blood (Paco2; 28.0; 21.5 to 34.4 mm Hg), saturation of arterial oxygen (Sao2; 98.4; 84.3% to 101.4%), HCO3 (18.9; 14.9 to 22.4 mmol/L), concentration of total hemoglobin (ctHb; 17.5; 13.4 to 21.1 g/dL), and sBP (133; 94 to 180 mm Hg) were established for healthy nonbrachycephalic dogs at 1,535-m altitude. All aBG measurements were statistically and clinically different from those previously reported for dogs at sea level. Brachycephalic dogs had significantly lower Pao2 and Sao2 (P = .0150 and P = .0237, respectively) and significantly higher ctHb (P = .0396) compared to nonbrachycephalic dogs acclimatized to the same altitude; the nonbrachycephalic RIs were not transferable to the brachycephalic dogs for Pao2. CLINICAL RELEVANCE: This study represents the first collation of aBG measurements for healthy nonbrachycephalic dogs acclimatized to an altitude of 1,535 m. Additionally, this study identified differences in arterial oxygenation measurements between brachycephalic and nonbrachycephalic dogs. RIs in brachycephalic dogs need to be established.

Lactate and base excess (BE) as markers of hypoperfusion and mortality in traumatic hemorrhagic shock in patients undergoing Damage Control: a historical cohort / Lactato e excesso de base (BE) como marcadores de hipoperfusão e mortalidade no choque hemorrágico traumático em pacientes submetidos à estratégia de controle de danos - Uma coorte histórica

ABSTRACT Introduction: hemorrhagic shock is a significant cause of trauma-related deaths in Brazil and worldwide. This study aims to compare BE and lactate values at ICU admission and twenty-four hours after in identifying tissue hypoperfusion and mortality. Methods: examines a historical cohort of trauma patients over eitheen years old submittet to damage control resuscitation approch upon hospital admission and were then admitted to the ICU. We collected and analyzed ISS, mechanism and type of trauma, need for renal replacement therapy, massive transfusion. BE, lactate, pH, bicarbonate at ICU admission and twenty-four hours later, and mortality data. The patients were grouped based on their BE values (≥-6 and <-6mmol/L), which were previously identified in the literature as predictors of severity. They were subsequently redivided using the most accurate values found in this sample. In addition to performing multivariate binary logistic regression. The data were compared using several statistical tests due to diversity and according to the indication for each variable. Results: there were significant changes in perfusion upon admission to the Intensive Care Unit. BE is a statistically significant value for predicting mortality, as determined by using values from previous literature and from this study. Conclusion: the results demonstrate the importance of monitoring BE levels in the prediction of ICU mortality. BE proves to be a valuable bedside marker with quick results and wide availability.

RESUMO Introdução: o choque hemorrágico é a principal causa reversível de morte no trauma no Brasil e no mundo. Objetivo: comparar o valor de BE ao do lactato na admissão da UTI e vinte e quatro horas após o internamento na identificação de hipoperfusão tecidual e predição de mortalidade Método: coorte histórica de pacientes traumatizados, maiores de dezoito anos, submetidos à estratégia de controle de danos na admissão hospitalar, seguido de internamento em UTI. Foram coletados e analisados ISS, mecanismo e tipo de trauma, necessidade de terapia de substituição renal e transfusão maciça; BE, lactato, pH e bicarbonato coletados na admissão da UTI e vinte e quatro horas após, e a mortalidade. Os pacientes foram divididos em grupos conforme valores de BE (≥-6 e <-6mmol/L) já descritos na literatura como preditores de gravidade, e após redivididos de acordo com os valores de melhor acurácia encontrados nesta amostra, além de realização de regressão logística binária multivariada. Os dados foram comparados através de diversos testes estatísticos devido a diversidade e conforme a indicação para cada variável. Resultados: houve alterações perfusionais impactantes já na admissão da UTI. BE manteve-se com valor estatisticamente significativo para predição de mortalidade tanto quando utilizado os valores já conhecidos da literatura como quando aplicados os valores neste estudo identificados. Conclusão: valores de BE e de lactato foram capazes de predizer hipoperfusão tecidual e mortalidade nos dois momentos estudados, quando comparados, o BE tem boa performance como preditor de mortalidade, com rápido resultado e ampla disponibilidade.

Consensus of the Brazilian association of hematology, hemotherapy and cellular therapy on patient blood management: Anemia tolerance mechanisms

Abstract Understanding the physiological concepts of oxygen delivery is essential to discern the mechanisms that influence its increase, reduction or maintenance in the body. This text explores the different mechanisms that help maintain oxygen delivery even in the face of reduced hemoglobin levels. Adequate oxygen delivery ensures tissue and metabolic balance, which is crucial to avoid harmful consequences such as metabolic acidosis and cellular dysoxia. The complex interaction between variables such as cardiac output, hemoglobin and heart rate (HR) plays a fundamental role in maintaining oxygen delivery, allowing the body to temporarily adjust to situations of anemia or high metabolic demand. It is important to emphasize that blood transfusions should not be based on fixed values, but rather on individual metabolic needs. Strategies to reduce myocardial consumption and monitor macro and micro hemodynamics help in making rational decisions. Individualizing treatment and considering factors such as blood viscosity in relation to the benefits of transfusion are increasingly relevant to optimize therapy and minimize risks, especially in complex clinical scenarios, such as neurocritical patients and trauma victims.

Analysis of Different Tidal Volumes on Ventilatory Mechanics and Arterial Blood Gas Variables in Patients Undergoing Cardiac Surgery.

Introduction: Cardiovascular diseases have been increasing gradually each year, and their incidence has reached 80%. Mechanical ventilation (MV) is essential in the postoperative period of cardiac surgery (CS) due to anesthetic induction. The tidal volume (TV) is a parameter that depends on the conditions of the respiratory system mechanics, aiming at the reduction of dynamic hyperinflation. Objective: Analyze the effect of different TVs on blood gas analysis variables and respiratory mechanics in patients submitted to CS. Materials and methods: This was an uncontrolled randomized clinical trial. Patients were randomized by lottery into the following two groups: One group was ventilated with a TV of 6 mL/kg; while the other received a TV of 8 mL/kg. After 30 minutes of admission with the VT, blood gas analysis data were evaluated, such as pH, oxygen arterial pressure (PaO2), arterial pressure of carbon dioxide (PaCO2), and peripheral oxygen saturation (SpO2). The evaluation of respiratory mechanics was composed of static and dynamic compliance, airway resistance, and driving pressure. Results: A total of 78 patients were included, 58% of whom were males with a mean age of 55 ± 13 years. It was observed that there were no significant differences regarding respiratory mechanics, only the driving pressure presented statistical significance, the group 6 mL/kg was 8.3 ± 2.5 in the group 8 mL/kg 10.4 ± 2.1 presenting a value of (p < 0.001). Conclusion: Based on the findings of the present study, we conclude that different TVs do not significantly alter the blood gas variables and do not influence the respiratory mechanics of patients undergoing CS. How to cite this article: Cordeiro A, Souza A, de Brito Lima CR, Araújo J, Mascarenhas H, Guimarães A. Analysis of Different Tidal Volumes on Ventilatory Mechanics and Arterial Blood Gas Variables in Patients Undergoing Cardiac Surgery. Indian J Crit Care Med 2023;27(12):930-933.

[COVID-19: Association of gasometric parameters at admission with in-hospital mortality]. / COVID-19: Parámetros gasométricos al ingreso y su asociación con mortalidad hospitalaria.

INTRODUCTION: At the beginning of the SARS-CoV-2 pandemic, acute respiratory failure has been the most important cause of hospitalization in patients with COVID-19, being more severe in patients with comorbidities and risk factors. In these scenarios hypoxemia has been associated with increased mortality. Our objective was to identify parameters obtained from arterial blood gases (ABG) associated with mortality in patients with COVID-19 at hospital admission. METHODS: GSA samples obtained by breathing room air (FiO2 21%) processed in the clinical laboratory were retrospectively studied in an ABL90 flex analyzer (Radiometer). RESULTS: Acute respiratory alkalosis was the predominant acid-base disturbance. Considering those patients with respiratory failure (paO2 < 60 mmHg), "silent" hypoxemia was observed in 11/176 (6%) of studied patients. In a multivariate analysis, three gasometric parameters at admission showed a positive association with hospital mortality: paO2 (p=0.053), paO2/pO2e index (which expresses the paO2 adjusted to the paO2 expected for age) (p=0.047) and fractional saturation of hemoglobin (OxiHb%) (p=0.028). DISCUSSION: GSA generate a key contribution in understanding the pathophysiology of the COVID-19 patient: in the initial evaluation, monitoring and prognosis of this disease.

Introducción: En los inicios de la pandemia por SARSCoV-2 la insuficiencia respiratoria aguda ha sido la causa más importante de hospitalización inmediata en los pacientes con COVID-19 que acudían a los servicios de urgencias, siendo mayor la gravedad en pacientes con comorbilidades y factores de riesgo preexistentes; en estos escenarios la hipoxemia ha sido asociada a mortalidad. Nuestro objetivo fue identificar parámetros obtenidos de los gases en sangre arterial (GSA) asociados a mortalidad en pacientes con COVID-19 al ingreso hospitalario. Métodos: Se estudiaron retrospectivamente muestras de GSA obtenidos respirando aire ambiente (FiO2 21%) procesadas en el laboratorio clínico en un analizador ABL90 flex (Radiometer). Resultados: La alcalosis respiratoria aguda fue el disturbio ácido base predominante. Considerando aquellos pacientes con insuficiencia respiratoria (paO2 < 60 mmHg) se observó hipoxemia "silenciosa" en 11/176 (6%) de los pacientes estudiados. En un análisis multivariado tres parámetros gasométricos al ingreso mostraron asociación positiva a mortalidad hospitalaria: paO2 (p = 0.053), índice paO2/pO2e (que expresa la paO2 ajustada a la paO2 esperada para la edad) (p = 0.047) y saturación fraccional de hemoglobina (OxiHb%) (p = 0.028). Discusión: Los GSA generan un aporte clave en la comprensión de la fisiopatología del paciente COVID-19; en la evaluación inicial, seguimiento y pronóstico de esta enfermedad.

COVID-19: parámetros gasométricos al ingreso y su asociación con mortalidad hospitalaria / COVID-19: Association of gasometric parameters at admission with in-hospital mortality

Resumen Introducción : En los inicios de la pandemia por SARS-CoV-2 la insuficiencia respiratoria aguda ha sido la causa más importante de hospitalización inmediata en los pacientes con COVID-19 que acudían a los servicios de urgencias, siendo mayor la gravedad en pacientes con comorbilidades y factores de riesgo preexistentes; en estos escenarios la hipoxemia ha sido asociada a mortalidad. Nuestro objetivo fue identificar parámetros obtenidos de los gases en sangre arterial (GSA) asocia dos a mortalidad en pacientes con COVID-19 al ingreso hospitalario. Métodos : Se estudiaron retrospectivamente muestras de GSA obtenidos respirando aire ambiente (FiO2 21%) procesadas en el laboratorio clínico en un analizador ABL90 flex (Radiometer). Resultados : La alcalosis respiratoria aguda fue el dis turbio ácido base predominante. Considerando aquellos pacientes con insuficiencia respiratoria (paO2 < 60 mmHg) se observó hipoxemia "silenciosa" en 11/176 (6%) de los pacientes estudiados. En un análisis multivariado tres parámetros gasométricos al ingreso mostraron asocia ción positiva a mortalidad hospitalaria: paO2 (p = 0.053), índice paO2/pO2e (que expresa la paO2 ajustada a la paO2 esperada para la edad) (p = 0.047) y saturación fraccional de hemoglobina (OxiHb%) (p = 0.028). Discusión : Los GSA generan un aporte clave en la comprensión de la fisiopatología del paciente COVID-19; en la evaluación inicial, seguimiento y pronóstico de esta enfermedad.

Abstract Introduction : At the beginning of the SARS-CoV-2 pandemic, acute respiratory failure has been the most important cause of hospitalization in patients with COVID-19, being more severe in patients with comorbidi ties and risk factors. In these scenarios hypoxemia has been associated with increased mortality. Our objective was to identify parameters obtained from arterial blood gases (ABG) associated with mortality in patients with COVID-19 at hospital admission. Methods : GSA samples obtained by breathing room air (FiO2 21%) processed in the clinical laboratory were retrospectively studied in an ABL90 flex analyzer (Radi ometer). Results : Acute respiratory alkalosis was the predomi nant acid-base disturbance. Considering those patients with respiratory failure (paO2 <60 mmHg), "silent" hypox emia was observed in 11/176 (6%) of studied patients. In a multivariate analysis, three gasometric parameters at admission showed a positive association with hos pital mortality: paO2 (p=0.053), paO2/pO2e index (which expresses the paO2 adjusted to the paO2 expected for age) (p=0.047) and fractional saturation of hemoglobin (OxiHb%) (p=0.028). Discussion : GSA generate a key contribution in un derstanding the pathophysiology of the COVID-19 pa tient: in the initial evaluation, monitoring and prognosis of this disease.

Arterial blood analysis of healthy residents in Huamachuco, Peru (3,164 m): a cross-sectional study.

Background: Given that arterial blood gas is affected by altitude and ethnicity, establishing reliable reference standards for these values requires analysis of arterial blood at different elevations and locations. Our objective was to measure the arterial blood gases of healthy young volunteers in Huamachuco, Peru, at 3,164 m above sea level. This is likely the first study of arterial blood gas analysis of healthy Northern Peruvians living at high altitude. Methods: Healthy residents of Huamachuco were recruited for this cross-sectional convenience sample study and arterial blood was drawn by standard procedures. People with obesity, diabetes, high levels of physical activity and a history of using selected substances were excluded. The samples were analyzed on-site in less than 15 minutes using a Stat Profile Prime CCS analyzer (Nova Biomedical). Results: Data from 46 participants (17 male, 29 female) were included in the study. The median values for arterial blood pH, oxygen, carbon dioxide, ionized calcium, glucose, lactate, hematocrit, oxygen saturation, and bicarbonate were 7.42, 9.3 kPa (70 mmHg), 4.5 kPa (33.5 mmHg), 1.04 mM, 5.19 mM, 1.8 mM, 50 %, 94 %, and 21.6 mM, respectively. We also found a lower prevalence of diabetes among highlanders compared to the Peruvian population. Conclusions: The results determined here were comparable to other results determined at different altitudes in the Americas, although arterial blood oxygen was slightly higher than predicted. These results indicate that Northern Peruvians have an Andean-style adaptation to high altitude.

Hemoglobina Denver, una causa de desaturación en oximetría de pulso. Reporte de caso en un paciente pediátrico / Hemoglobin Denver, a cause of desaturated pulse oximetry. A pediatric case report

Las hemoglobinopatías son trastornos genéticos que afectan a la molécula de hemoglobina (Hb). Las mutaciones en las cadenas a o b que alteran el tetrámero de Hb pueden modificar la capacidad de la molécula para unirse al oxígeno. Las hemoglobinopatías con baja afinidad al oxígeno pueden presentarse con cianosis y una lectura alterada de la oximetría de pulso, lo que lleva a pruebas innecesarias y, a veces, invasivas para descartar afecciones cardiovasculares y respiratorias. En el siguiente reporte de caso, presentamos a una paciente pediátrica, asintomática, que se presentó a la consulta por detección de desaturación en oximetría de pulso. Las pruebas de laboratorio iniciales mostraron una anemia normocítica, normocrómica. Las muestras de gas venoso demostraron una p50 elevada. Después de extensas herramientas de diagnóstico, se diagnosticó una variante de Hb con baja afinidad al oxígeno, Hb Denver.

Hemoglobinopathies are genetic disorders that affect the hemoglobin (Hb) molecule. Mutations in the alpha or beta chains altering the Hb tetramer may modify the molecule's oxygen-binding capacity. Hemoglobinopathies with low oxygen affinity may occur with cyanosis and an altered pulse oximetry reading, leading to unnecessary and sometimes invasive tests to rule out cardiovascular and respiratory conditions. In the case report described here, we present an asymptomatic pediatric patient who consulted for desaturated pulse oximetry. Her initial laboratory tests showed normocytic, normochromic anemia. Venous blood gas samples showed an elevated p50. After using extensive diagnostic tools, a variant of Hb with low oxygen affinity was diagnosed: Hb Denver.

[Response to comment on the article "Variability of hemoglobin and hematocrit determined in blood gas equipment"]. / Response to comment on the article "Variability of hemoglobin and hematocrit determined in blood gas equipment".

Hemoglobin and hematocrit are parameters widely used. They can be obtained from an automated hematology analyzer or from an arterial blood gas analyzer. Its variability is shown in the article "Variability of hemoglobin and hematocrit determined in blood gas equipment." Clinical and statistical information requested is extended for a better understanding of the article and its conclusions. It is suggested to carry out an analysis of variability in parameters and laboratory equipment.

La hemoglobina y el hematocrito son parámetros de amplio uso. Pueden ser obtenidos de un analizador automatizado de hematología o de un analizador de gases arteriales. Su variabilidad se muestra en el artículo "Variabilidad de la hemoglobina y hematocrito determinados en equipo de gases sanguíneos". Se amplía la información clínica y estadística solicitada para la mejor comprensión del trabajo y sus conclusiones. Se sugiere hacer un análisis de variabilidad en parámetros y equipos de laboratorios.

Comparison of two sedation protocols for diagnostic radiography in dogs with hip dysplasia.

Hip dysplasia is an alteration with a high incidence in large dogs. The aim of the study was to compare the association of xylazine or dexmedetomidine with fentanyl for radiography with joint distractor for the diagnosis of hip dysplasia. Fifteen healthy dogs, German Shepherd and Belgian Shepherd, were randomly submitted to treatments 0.2 mg/kg xylazine + 2.5 µg/kg fentanyl (XF) or 2 µg/kg dexmedetomidine + 2.5 µg/kg fentanyl (DF), intravenously. HR, f, SAP, MAP, DAP and TR were evaluated at intervals of 5 min before and after the administration of treatments; pH, PaCO2, PaO2, BE, HCO3-, SaO2, Na+, K+ and Hb at 5 and 15 min after treatment administration; and the quality of sedation at intervals of 5 min after administration of treatments. Latency, duration, and recovery times were also compared. The HR values showed a significant reduction in both groups, as well as pH, PaCO2, PaO2 and SaO2. Latency, duration and recovery times, and quality of sedation did not differ statistically between groups. Xylazine and fentanyl or dexmedetomidine and fentanyl combinations provide adequate sedation and analgesia for performing diagnostic radiographic procedures for hip dysplasia. However, oxygen supplementation is recommended to increase protocol safety.

Hemoglobin Denver, a cause of desaturated pulse oximetry. A pediatric case report. / Hemoglobina Denver, una causa de desaturación en oximetría de pulso. Reporte de caso en un paciente pediátrico.

Hemoglobinopathies are genetic disorders that affect the hemoglobin (Hb) molecule. Mutations in the alpha or beta chains altering the Hb tetramer may modify the molecule's oxygen-binding capacity. Hemoglobinopathies with low oxygen affinity may occur with cyanosis and an altered pulse oximetry reading, leading to unnecessary and sometimes invasive tests to rule out cardiovascular and respiratory conditions. In the case report described here, we present an asymptomatic pediatric patient who consulted for desaturated pulse oximetry. Her initial laboratory tests showed normocytic, normochromic anemia. Venous blood gas samples showed an elevated p50. After using extensive diagnostic tools, a variant of Hb with low oxygen affinity was diagnosed: Hb Denver.

Las hemoglobinopatías son trastornos genéticos que afectan a la molécula de hemoglobina (Hb). Las mutaciones en las cadenas a o b que alteran el tetrámero de Hb pueden modificar la capacidad de la molécula para unirse al oxígeno. Las hemoglobinopatías con baja afinidad al oxígeno pueden presentarse con cianosis y una lectura alterada de la oximetría de pulso, lo que lleva a pruebas innecesarias y, a veces, invasivas para descartar afecciones cardiovasculares y respiratorias. En el siguiente reporte de caso, presentamos a una paciente pediátrica, asintomática, que se presentó a la consulta por detección de desaturación en oximetría de pulso. Las pruebas de laboratorio iniciales mostraron una anemia normocítica, normocrómica. Las muestras de gas venoso demostraron una p50 elevada. Después de extensas herramientas de diagnóstico, se diagnosticó una variante de Hb con baja afinidad al oxígeno, Hb Denver.

Effects of pre-analytical sample care and analysis methodology on measures of metabolic acidosis in hemodialysis patients.

INTRODUCTION: We evaluated the effects of pre-analytical care on total carbon dioxide (tCO2 ) in hemodialysis patients, as calculated by blood gas analysis (ctCO2 ) or measured by an enzymatic assay (mtCO2 ). METHODS: Blood samples were collected via vascular access before dialysis sessions. For blood gas analysis, eight aliquots were collected, refrigerated or non-refrigerated, and analyzed at 0, 4, 8, and 24 h after collection. A blood sample was then collected for the enzymatic method and distributed into 14 aliquots. Half of the aliquots were refrigerated. The samples analyzed at time point 0 were centrifuged immediately. The remaining aliquots of both the refrigerated and non-refrigerated clusters were centrifuged before storage. Samples were analyzed at 4, 8, and 24 h post-collection. FINDINGS: By blood gas analysis, no significant change was found in bicarbonate values over time, either in the non-refrigerated or refrigerated samples. ctCO2 values during the experiment showed a minor but statistically significant increase of questionable clinical relevance in both non-refrigerated and refrigerated aliquots. In the enzymatic assay, the reduction in mtCO2 levels during the experiment was negligible. The median absolute reductions at the end of the experiment were 1.77, 1.21, 1.04, and 1.12 mmol/L for the non-centrifuged/non-refrigerated, centrifuged/non-refrigerated, non-centrifuged/refrigerated, and centrifuged/refrigerated aliquots, respectively. DISCUSSION: Our results suggest that measured or calculated tCO2 levels of capped and cooled samples are adequate for analyzing the acid-base status of hemodialysis patients, even when such determination is not performed immediately after collection.

[Comment on article "Variability of hemoglobin and hematocrit determined in blood gas equipment"]. / Comentario al artículo "Variabilidad de la hemoglobina y hematocrito determinados en equipo de gases sanguíneos".

´The analysis of samples on different equipment may lead to variation between results; in the article "Variability of hemoglobin and hematocrit determined in blood gas equipment", the authors talk about the variability of hemoglobin and hematocrit between an automated hematology analyzer and an arterial blood gas analyzer. Information is requested on some aspects considered relevant to improve the understanding of the conclusions.

El análisis de muestras en diferentes equipos puede conllevar una variación entre los resultados; en el artículo "Variabilidad de la hemoglobina y hematocrito determinados en equipo de gases sanguíneos", sus autores hablan de la variabilidad de hemoglobina y hematocrito entre un analizador automatizado de hematología y un analizador de gases arteriales. Se solicita información sobre algunos aspectos considerados relevantes para mejorar la compresión de las conclusiones.

Pyometra in queens - changes in haemato-biochemical parameters

Background: Pyometra is a bacterial and hormone-induced reproductive disease that occurs in the post-estrus luteal phase in intact queens. Pyometra is more common in the diestrus period due to the high progesterone concentration (in queens that mated, spontaneously ovulated, or were induced to ovulate). However, it can also be seen due to the use of exogenous hormones such as progesterone for the suppression of estrus. More research is needed in cases of pyometra in queens, as well as in bitches. Because, considering that the pathogenesis and characteristics of feline pyometra is similar to bitches, studies on pyometra-affected bitches are taken as reference in studies and applications on queens. From this point of view, the aims of this study were to reveal the changes in complete blood count, blood gas, and serum biochemistry parameters in feline pyometra cases and to determine the correlation between the mentioned parameters. Materials, Methods & Results: In the study, a total of 25 female cats of different breeds were used, between the ages of 6 months and 7 years, 15 were diagnosed with pyometra, and 10 healthy. Anamnesis, clinical findings, and ultrasonographic examinations were used in the diagnosis of pyometra. Abdominal ultrasonography was performed on queens brought to the clinic with complaints such as anorexia, polydipsia, polyuria, abdominal tension, and fever. The control group (n =10) consisted of queens that were introduced to the clinic and were reproductively healthy. Before any treatment in queens with pyometra and the control group, 1 mL blood samples were taken from v. cephalica to evaluate complete blood count, blood gases and serum biochemistry parameters. In complete WBC, Lym, Mon, Gra, RBC, Hb, HCT, MCV, MCH and PLT parameters and, blood gas parameters such as pH, pCO2 , pO2 , sO2 , Na, K, Cl, lactate, glucose, HCO3 , and BE were also evaluated in taken blood samples. Biochemical parameters BUN, creatinine, ALT, AST, ALP, amylase, T.BIL, D.BIL, P, CHOL, TG, LDH, TP, CPK, ALP, Ca, GGT were measured in serum samples. After examination and laboratory analysis, ovariohysterectomy was performed on queens as a treatment. Granulocyte, WBC, HCT and MCH levels of the pyometra group were higher (P < 0.05) and Lym levels were lower (P < 0.05) compared to the control group. According to these results, pH, HCO3 , and BE were lower (P < 0.05) in queens with pyometra than those in the control group, while Na and lactate parameters were higher (P < 0.05). According to the results of biochemical analysis, it was determined that BUN, creatinine levels, GGT, and LDH enzyme activities were found to be higher in the pyometra group compared to the control group, while the Ca level was found to be low (P < 0.05). A positive correlation was observed between BUN and creatinine and LDH, WBC, granulocyte, HCT, and lactate, and a negative correlation between lymphocytes, pH, and BE in the correlation analysis performed on queens with pyometra and control group. However, a positive correlation was observed between creatinine and LDH and HCT, and a negative correlation between lymphocyte, pH and BE. Discussion: There is not enough information about pyometra in queens. As a result, it was determined that there were significant changes in complete blood count, blood gases and serum biochemical parameters in queens with pyometra in this study. These changes were generally thought to be related to dehydration and sepsis or endotoxemia. In addition, it was evaluated that prerenal azotemia occurring in pyometra affected queens may cause renal dysfunction. For this reason, it is thought that the results obtained in the presented study may contribute to the diagnosis, treatment, and prognosis of pyometra cases in queens.

Accuracy of intrapartum cardiotocography in identifying fetal acidemia by umbilical cord blood analysis in low-risk pregnancies

SUMMARY OBJECTIVE: The aim of this study was to evaluate the accuracy of intrapartum cardiotocography in identifying fetal acidemia by umbilical cord blood analysis in low-risk pregnancies. METHODS: This is a retrospective cohort study of low-risk singleton pregnancies in labor after performing intrapartum cardiotocography categories I, II, and III. The presence of fetal acidemia at birth was identified by analyzing the pH of umbilical cord arterial blood (pH<7.1). RESULTS: No significant effect of the cardiotocography category on the arterial (p=0.543) and venous (p=0.770) pH of umbilical cord blood was observed. No significant association was observed between the cardiotocography category and the presence of fetal acidemia (p=0.706), 1-min Apgar score <7 (p=0.260), hospitalization in the neonatal intensive care unit (p=0.605), newborn death within the first 48 h, need for neonatal resuscitation (p=0.637), and adverse perinatal outcomes (p=0.373). Sensitivities of 62, 31, and 6.0%; positive predictive values of 11.0, 16.0, and 10.0%; and negative predictive values of 85, 89.0, and 87.0% were observed for cardiotocography categories I, II, and III, respectively. CONCLUSION: The three categories of intrapartum cardiotocography presented low sensitivities and high negative predictive values to identify fetal acidemia at birth in low-risk pregnancies.

Accuracy of intrapartum cardiotocography in identifying acidemia at birth by umbilical cord blood gasometry in high-risk pregnancies

SUMMARY OBJECTIVE: The aim of this study was to evaluate the accuracy of intrapartum cardiotocography in identifying acidemia at birth by umbilical cord blood gasometry in high-risk pregnancies. METHODS: This was a retrospective cohort study of singleton high-risk parturients using intrapartum cardiotocography categories I, II, and III. The presence of fetal acidemia at birth was identified by the analysis of umbilical cord arterial blood pH (<7.1). Associations between variables were determined using the chi-square test and Kruskal-Wallis tests. RESULTS: We included 105 cases of cardiotocography category I, 20 cases of cardiotocography category II, and 10 cases of cardiotocography category III. cardiotocography category III had a higher prevalence of cesarean sections compared to cardiotocography category I (90.0 vs. 42.9%, p<0.006). Venous pH was higher in patients with cardiotocography category I compared to cardiotocography category III (7.32 vs. 7.23, p=0.036). Prevalence of neonatal intensive care unit (NICU) admission was lower in neonates of patients with cardiotocography category I compared to cardiotocography category III (3.8 vs. 30.0%, p=0.014). Prevalence of composite adverse outcomes was lower in neonates of patients with cardiotocography category I compared to cardiotocography category II (9.5 vs. 30.0%, p=0.022) and cardiotocography category III (9.5 vs. 60.0%, p=0.0004). cardiotocography categories II and III had low sensitivity (0.05 and 0.00, respectively) and high negative predictive value (NPV) (0.84 and 0.91, respectively) for identifying fetal acidemia at birth. The three categories of intrapartum cardiotocography showed high specificities (96.0, 99.0, and 99.0%, respectively). CONCLUSION: All three categories of intrapartum cardiotocography showed low sensitivity and high specificity for identifying acidemia at birth.

Cardiorespiratory effects of different intraabdominal pressures in sheep: An experimental study.

Increased intraabdominal pressure (IAP) during laparoscopy can reduce venous return, but changes in respiratory system mechanics and their effect in left cardiac function are not well documented. This study evaluated the effects of different IAPs on respiratory mechanics and cardiac function in 10 healthy nonpregnant adult Santa Ines ewes randomly submitted to a crossover study using different IAPs: 0 mm Hg (G1), 10 mm Hg (G2), 12 mmHg (G3), and 15 mmHg (G4). Animals were anesthetized and mechanically ventilated (VT  = 15 ml/kg; positive end-expiratory pressure = 3 cmH2 O; FiO2  = 1.0). Pneumoperitoneum was induced by Hasson's trocar cannula. Variables were measured at INITIAL (IAP, 0 mmHg) and FINAL time points for each IAP after 1 h. At FINAL, driving airway pressure (ΔP,RS ), and percentage fraction of dead space (Vd/Vt) were higher in G3 and G4 than G1 (p = 0.002, difference in means [MD] 4.60, 95% CI: 7.91-1.28, and p < 0.001, MD 5.4, 95% CI: 8.7-2.0; p = 0.016, MD -9.5, 95% CI: -17.9 to -1.2; and p = 0.027, MD -8.7, 95% CI: -17.1 to -0.4). The ejection fraction and fractional shortening were lower in G3 (p = 0.039, MD -11.38, 95% CI: -0.07--22.68; p = 0.015, MD -13.05, 95% CI: -1.74--24.36) and G4 (p = 0.039, MD -9.94, 95% CI: -0.07 to -19.80; p = 0.015, MD -11.43, 95%CI: -1.57 to -21.30, respectively) than G2. In G3, the maximum pulmonary flow velocity correlated negatively with ΔP,RS (r = -0.740; p = 0.018), and Vd/Vt correlated positively with ΔP,RS (r = 0.738, p = 0.046). At IAP of 12 and 15 mm Hg impaired respiratory system mechanics, reduced left cardiac function and no change in maximum pulmonary artery flow velocity were detected. Therefore, respiratory mechanics should be monitored as an interplay to reduce left cardiac function.

[Variability of hemoglobin and hematocrit determined in blood gas equipment]. / Variabilidad de la hemoglobina y hematocrito determinados en equipo de gases sanguíneos.

Background: Usually hemoglobin and hematocrit are obtained from peripheral venous blood samples processed in equipment for hematic biometry. These parameters can also be determined from arterial samples processed on blood gas equipment. Its variability when using arterial samples and this equipment is unknown, in addition, if the lack of knowledge of this variability affects clinical decisions. Objective: To know the variability of hemoglobin and hematocrit from arterial blood samples processed in blood gas equipment. Material and methods: Analytic cross design. Consecutive subjects with stable cardiopulmonary disease were blindly studied. The samples were obtained at the same time for analysis in both equipments. Variability was analyzed with Bland-Altman descriptive statistic and its magnitude with the intraclass correlation coefficient. Results: Two hundred of blood samples from 50 patients were studied, 31 (62%) women, age 62 ± 14 years old, body mass index 30.11 ± 5.69 Kg/m2. The main comparison was peripheral venous blood sample processed in laboratory equipment (SYSMEX) vs. arterial sample on blood gas equipment (GEM). The mean difference (bias) and intraclass correlation coefficient for hemoglobin were: 0.12 (-1.45, 1.23) and 0.95 (0.91, 0.97); for the hematocrit -4.4 (-0.4, 8.54), and 0.72 (0.51, 0.84). Conclusions: The mean difference and bias for hemoglobin was close to 0; the hematocrit was higher. Hemoglobin from arterial samples processed in blood gas equipment can be used to make clinical decisions.

Introducción: usualmente, la hemoglobina y el hematocrito se obtienen de sangre venosa periférica procesada en equipo convencional para biometría hemática, también pueden ser determinados de muestras arteriales procesadas en equipos para gases sanguíneos. Se desconoce su variabilidad al utilizar muestras arteriales y equipos para gases sanguíneos, además, si esta variabilidad pudiera afectar las decisiones clínicas. Objetivo: conocer la variabilidad de la hemoglobina y hematocrito de muestras sanguíneas arteriales procesadas en equipo de gases sanguíneos. Material y métodos: diseño transversal analítico. Se estudiaron de forma ciega sujetos consecutivos con enfermedad cardiopulmonar estable. Las muestras sanguíneas se adquirieron al mismo tiempo para su análisis en ambos equipos. La variabilidad se analizó con el estadístico descriptivo de Bland-Altman y su magnitud con el coeficiente de correlación intraclase. Resultados: se analizaron 200 muestras sanguíneas de 50 pacientes, 31 (62%) mujeres, edad grupal 62 ± 14 años, índice de masa corporal 30.11 ± 5.69 Kg/m2. La principal comparación: muestra sanguínea venosa periférica procesada en equipo del laboratorio (SYSMEX) frente a muestra arterial en equipo de gases sanguíneos (GEM). La diferencia media (sesgo) y el coeficiente de correlación intraclase de la hemoglobina fueron: 0.12 (-1.45, 1.23) y 0.95 (0.91, 0.97); hematocrito -4.4 (-0.4, 8.54) y 0.72 (0.51, 0.84). Conclusiones: la diferencia media y sesgo de la hemoglobina fue cercana a 0; la del hematocrito fue mayor. La hemoglobina de muestras arteriales procesadas en equipos de gases sanguíneos son útiles para tomar decisiones clínicas.