Arterial Blood Gases in Normal Subjects at 2240 Meters Above Sea Level: Impact of Age, Gender, and Body Mass Index

ABSTRACT Background The values of arterial blood gases (ABG) change with altitude above sea level; empirical verification is essential because ventilatory acclimatization varies with ethnicity and a population's adaptation. Objective The aim of the study was to describe ABG in a healthy population residing at 2,240 meters above sea level, to identify the mean level of alveolar ventilation (PaCO2), and to know whether a progressive increase in PaCO2 occurs with age and the impact of increasing body mass index (BMI). Methods We conducted a cross-sectional study in a referral center for respiratory diseases in Mexico City. Associations among variables with correlation coefficient and regression models of PaO2, SaO2, and P(A-a)O2 as dependent variables as a function of age, BMI, minute ventilation, or breathing frequency were explored. Results Two hundred and seventeen healthy subjects were evaluated with a mean age of 40 ± 15 years, mean of the PaO2 was 71 ± 6 mmHg, SaO2 94% ± 1.6%, PaCO2 30.2 ± 3.4 mmHg, HCO3 20 ± 2 mmol/L, BE-2.9 ± 1.9 mmol/L, and the value of pH was 7.43 ± 0.02. In a linear regression, the main results were PaO2 = 77.5-0.16*age (p < 0.0001) and with aging P(A-a)O2 tended to increase 0.12 mmHg/year. PaCO2 in women increased with age by 0.075 mmHg/year (p = 0.0012, PaCO2 =26.3 + 0.075*age). SaO2 and PaO2 decreased significantly in women with higher BMI 0.14% and 0.52 mmHg per kg/m2, (p = 0.004 and 0.002 respectively). Conclusion Mean PaCO2 was 30.7 mmHg, implying a mean alveolar ventilation of around 30% above that at sea level.

Delta de CO2 como estrategia del manejo integral del paciente con choque séptico en la UCI / CO2 delta as a strategy for the comprehensive management of patients with septic shock in the ICU / Delta CO2 como estratégia para o tratamento integral do paciente com choque séptico na UTI

Resumen: Introducción: el choque séptico es un subconjunto de sepsis en el que las anomalías circulatorias, celulares y metabólicas subyacentes son lo suficientemente profundas para aumentar de manera sustancial la mortalidad. Estos pacientes pueden ser identificados en un contexto clínico de choque séptico con hipotensión persistente. La importancia de vigilar valores de delta de pCO2 (presión parcial de dióxido de carbono) de 6 mmHg sirve como herramienta complementaria para evaluar el flujo sanguíneo adecuado hacia la demanda metabólica global. Objetivo: demostrar que el delta de pCO2 es útil en el manejo integral del paciente con choque séptico en la unidad de cuidados intensivos para dirigir el tratamiento de acuerdo con este biomarcador, que se registró al ingreso y a las 24 horas, se relacionaron al pronóstico y a la mortalidad en choque séptico. Material y métodos: estudio descriptivo, ambispectivo, longitudinal y analítico. El universo se compuso de los pacientes que ingresaron a la Unidad de Cuidados Intensivos del Hospital General «La Villa¼ y del Hospital General «Dr. Rubén Leñero¼. Diseño de la maniobra: se tomaron gasometrías arterial y venosa de los pacientes que ingresaron a la UCI, se calculó el delta de pCO2 para ver si los valores de este biomarcador estaban por arriba o debajo de 6 mmHg, ya que un delta de pCO2 se relaciona con mortalidad; sin embargo, el delta de pCO2 se comparó contra el lactato para correlacionar niveles mayores de lactato de 2 mmol/L con la mortalidad. y finalmente observar cuál de los dos biomarcadores es más útil. Se utilizó estadística descriptica para los resultados. Conclusión: de acuerdo a los resultados encontrados en este estudio, se puede decir que el delta de pCO2 y el lactato predijeron el fallecimiento de 15%, lo cual tiene una significancia positiva débil (p = 0.245).

Abstract: Introduction: septic shock is a subset of sepsis in which underlying circulatory, cellular, and metabolic abnormalities are profound enough to substantially increase mortality. These patients can be identified in a clinical setting of septic shock with persistent hypotension. The importance of monitoring delta pCO2 values of 6 mmHg serves as a complementary tool to assess adequate blood flow towards global metabolic demand. Objective: to demonstrate that the pCO2 delta is useful in the comprehensive management of patients with septic shock in the Intensive Care Unit to direct the treatment according to this biomarker (pCO2 delta) that was recorded at admission and at 24 hours, were related to prognosis and mortality in septic shock. Material and methods: descriptive, ambispective, longitudinal and analytical study. The universe was made up of patients admitted to the ICU of the La Villa and Rubén Leñero General Hospitals. Maneuver design: arterial and venous blood gases were taken from the patients admitted to the ICU, the pCO2 delta was calculated to see if the values of this biomarker were above or below 6 mmHg, since a pCO2 delta is related to with mortality; however, delta pCO2 was compared against Lactate to correlate lactate levels greater than two with mortality and finally see which of the two biomarkers is more useful. Descriptive statistics were used for the results. Conclusion: according to the results found in this study, it can be said that delta pCO2 and lactate predicted the death of 15%, which has a weak positive significance (p = 0.245).

Resumo: Introdução: choque séptico é um subconjunto de sepse em que anormalidades circulatórias, celulares e metabólicas subjacentes são profundas o suficiente para aumentar substancialmente a mortalidade, esses pacientes podem ser identificados em um cenário clínico de choque séptico com hipotensão persistente. A importância do monitoramento de valores Delta de pCO2 de 6 mmHg serve como ferramenta complementar para avaliar o fluxo sanguíneo adequado à demanda metabólica global. Objetivo: demonstrar que o Delta pCO2 é útil no manejo integral de pacientes com choque séptico na Unidade de Terapia Intensiva para direcionar o tratamento de acordo com este biomarcador (Delta pCO2) que foi registrado na admissão e em 24 horas, relacionado ao prognóstico e mortalidade no choque séptico. Material e métodos: estudo descritivo, ambispectivo, longitudinal e analítico. O universo foi constituído pelos pacientes internados na UTI dos Hospitais Gerais La Villa e Rubén Leñero. Desenho da estratégia: foram coletadas gasometrias arteriais e venosas dos pacientes internados na UTI, o Delta pCO2 foi calculado para ver se os valores desse biomarcador estavam acima ou abaixo de 6 mmHg, pois um Delta pCO2 está relacionado com mortalidade; entretanto, Delta pCO2 foi comparado com Lactato para correlacionar níveis de lactato maiores que 2 com mortalidade e finalmente observar qual dos dois biomarcadores é mais útil. Foram usadas estatísticas descritivas para os resultados. Conclusão: de acordo com os resultados encontrados neste estudo, pode-se dizer que Delta pCO2 e Lactato predizem óbito em 15%, o que tem uma fraca significância positiva (p = 0.245).

Alteraciones del estado ácido básico en pacientes adultos con insuficiencia renal crónica / Acid-base status alterations in adult patients with chronic renal failure

RESUMEN Introducción: el portador de insuficiencia renal crónica puede presentar diversas alteraciones del estado ácido básico, siendo la acidosis metabólica la más frecuente. Objetivos: describir las características demográficas y clínicas y las alteraciones del estado ácido básico de pacientes adultos que ingresan con insuficiencia renal crónica en dos centros hospitalarios del Paraguay. Metodología: se aplicó un diseño observacional, descriptivo, transversal. Se incluyó a sujetos adultos de ambos sexos, portadores de insuficiencia renal crónica, que acudieron al Hospital Nacional (Itauguá) y Hospital Militar (Asunción) entre abril y noviembre del 2021. Se midieron variables antropométricas, clínicas y laboratoriales al ingreso. Los datos se sometieron a estadística descriptiva con el programa Epi Info 7™. El estudio contó con la aprobación del Comité de Ética de la Universidad Privada del Este, Paraguay. Resultados: se incluyó a 148 sujetos, siendo 78 (52,7 %) varones con edad media 58 ± 16 años y 70 (47,3 %) mujeres con edad media 54 ± 17 años. Las etiologías más frecuentes de la insuficiencia renal crónica fueron la diabetes mellitus e hipertensión arterial (44,5 %). Se detectó 12 sujetos (8,1 %) con gasometría normal. La alteración del estado ácido básico más frecuente fue la acidosis metabólica (87,2 %), predominando en este grupo los casos con brecha aniónica normal. Conclusiones: las alteraciones del estado ácido básico predominantes en pacientes con insuficiencia renal crónica fue la acidosis metabólica con brecha aniónica normal. Se sugiere aplicar los cálculos de los mecanismos compensadores para llegar al diagnóstico certero de estas alteraciones metabólicas.

ABSTRACT Introduction: the carrier of chronic renal failure can present various alterations of the basic acid state, being the metabolic acidosis the most frequent. Objectives: to describe the demographic and clinical characteristics and alterations in the acid-base status of adult patients admitted with chronic renal failure in two hospitals in Paraguay. Methodology: an observational, descriptive, cross-sectional design was applied. Adult subjects of both sexes, carriers of chronic renal failure, who attended the National Hospital (Itauguá) and the Military Hospital (Asunción) between April and November 2021 were included. Anthropometric, clinical and laboratory variables were measured at admission. The data was submitted to descriptive statistics with the Epi Info 7™ program. The study was approved by the Ethics Committee of the Universidad Privada del Este, Paraguay. Results: 148 subjects were included, being 78 (52.7 %) men with a mean age of 58 ± 16 years and 70 (47.3 %) women with a mean age of 54 ± 17 years. The most frequent etiologies of chronic renal failure were diabetes mellitus and arterial hypertension (44.5 %). 12 subjects (8.1 %) with normal blood gases were detected. The most frequent alteration of the acid-base status was metabolic acidosis (87.2 %), with cases with normal anion gap predominating in this group. Conclusions: the predominant acid-base status alterations in patients with chronic renal failure was metabolic acidosis with normal anion gap. It is suggested to apply the calculations of the compensatory mechanisms to arrive at the accurate diagnosis of these metabolic alterations.

Aclaramiento de lactato y déficit de base estándar como pronóstico de mortalidad en choque séptico / Lactate clearance and standard base deficit as a prognosis of mortality in septic shock / Depuração de lactato e deficiência de base padrão como prognóstico de mortalidade no choque séptico

Resumen: Introducción: la asociación del nivel de lactato con la mortalidad en pacientes con sospecha de infección y sepsis está bien establecida. La sensibilidad es entre 66 y 83%, con especificidad de 80 y 85%. Sin embargo, el lactato no es sensible ni lo suficientemente específico para detectar o descartar el diagnóstico por sí solo, ya que el lactato sérico es un biomarcador importante de la hipoxia y disfunción tisular, pero no es una medida directa de la perfusión tisular. El lactato y la base estándar medidos al ingreso a la Unidad de Cuidados Intensivos (UCI) son de utilidad pronóstica en los pacientes críticamente enfermos, pues sus niveles séricos predicen mortalidad a través de la puntuación en sí misma. Pero la importancia real va más allá de un valor absoluto, pues es mejor medir su aclaramiento a través de un tiempo determinado. Objetivo: demostrar que el aclaramiento de lactato y déficit de base estándar registrados al ingreso y a las 24 h se relacionan con mejor pronóstico y disminución de mortalidad en choque séptico. Material y métodos: se utilizó estadística descriptiva (medidas de tendencia central y dispersión; así como frecuencias y porcentajes). Asimismo, se ocupó estadística inferencial con la prueba t de Student, χ2, curva ROC, área bajo la curva e índice de Youden, con un intervalo de confianza de 95%. Resultados: la asociación estadística con la mortalidad se presentó en el aclaramiento de déficit de base estándar y en aclaramiento de lactato. Conclusión: se demostró que el aclaramiento de lactato y déficit de base estándar registrados al ingreso y a las 24 h se relacionaron con mejor pronóstico y disminución de mortalidad en pacientes con choque séptico.

Abstract: Introduction: the association of lactate level with mortality in patients with suspected infection and sepsis is well established. Sensitivity is between 66 and 83%, with specificity between 80 and 85%. However, lactate is neither sensitive nor specific enough to detect or rule out the diagnosis on its own as serum lactate is an important biomarker of tissue hypoxia and dysfunction but is not a direct measure of tissue perfusion. Lactate and standard base measured on admission to the Intensive Care Unit (ICU) are useful for prognosis in critically ill patients since their serum levels predict mortality through the score itself. But the real importance goes beyond an absolute value, since it is better to measure its clearance over a given time. Objective: to demonstrate that lactate clearance and standard base deficit recorded at admission and at 24 hours are related to a better prognosis and decreased mortality in septic shock. Material and methods: descriptive statistics were used (measures of central tendency and dispersion, as well as frequencies and percentages). Likewise, inferential statistics were used with the Student's t test, χ2, ROC curve, area under the curve and Youden index, with a confidence interval of 95%. Results: the statistical association with mortality was presented in the clearance of standard base deficit and in lactate clearance. Conclusion: it was shown that lactate clearance and standard base deficit recorded at admission and at 24 hours were related to a better prognosis and decreased mortality in patients with septic shock.

Resumo: Introdução: a associação do nível de lactato com mortalidade em pacientes com suspeita de infecção e sepse está bem estabelecida. A sensibilidade está entre 66 e 83%, com especificidade de 80 e 85%. No entanto, o lactato não é sensível nem específico o suficiente para detectar ou descartar o diagnóstico por si só, uma vez que o lactato sérico é um importante biomarcador de hipóxia e disfunção tecidual, mas não é uma medida direta da perfusão tecidual. O lactato e a base padrão medidos na admissão na UTI são de utilidade prognóstica em pacientes críticos, uma vez que seus níveis séricos predizem a mortalidade pelo próprio escore. Mas a real importância vai além de um valor absoluto, pois é melhor medir sua depuração em um determinado tempo. Objetivo: demonstrar que a depuração de lactato e o déficit de base padrão registrados na admissão e em 24 horas estão relacionados a um melhor prognóstico e diminuição da mortalidade no choque séptico. Material e métodos: foi utilizada estatística descritiva (medidas de tendência central e dispersão, bem como frequências e percentagens). Da mesma forma, foi utilizada estatística inferencial com teste t de Student, χ2, curva ROC, área sob a curva e índice de Youden, com intervalo de confiança de 95%. Resultados: a associação estatística com a mortalidade foi apresentada na depuração do déficit de base padrão e na eliminação do lactato. Conclusão: foi demonstrado que a depuração de lactato e o déficit de base padrão registrados na admissão e em 24 horas foram relacionados a um melhor prognóstico e diminuição da mortalidade em pacientes com choque séptico.

Valores de la gasometría arterial en pacientes embarazadas con preeclampsia severa / Arterial blood gas parameters in pregnant patients with severe preeclampsia

Resumen OBJETIVO: Determinar e interpretar los valores de la gasometría arterial en pacientes embarazadas con preeclampsia severa. MATERIALES Y MÉTODOS: Estudio observacional, transversal, retrospectivo y descriptivo llevado a cabo en pacientes con más o menos 20 semanas de embarazo y diagnóstico establecido de preeclampsia severa atendidas en la unidad de cuidados intensivos entre el 1 de julio y el 31 de diciembre del 2019. Los datos generales, la condición obstétrica, los estudios de laboratorio clínico y los valores de la gasometría arterial se documentaron conforme a lo registrado en los expedientes clínicos. Se utilizó estadística descriptiva y los datos se procesaron en el programa SPSS versión 20. RESULTADOS: Se estudiaron 30 pacientes con media de edad de 31.6 ± 6.85 años, mediana de paridad 1, todas con feto único de 33.89 ± 3.43 semanas y residencia en la Ciudad de México. Los valores de la gasometría arterial fueron: pH 7.41 ± 0.08, presión parcial de dióxido de carbono 25.51 ± 6.12 mmHg, presión parcial de oxígeno 85.24 ± 41.81 mmHg, hematocrito 33.86 ± 7.51%, ión carbonato 16.95 ± 5.13 mmol/L, patrón de bicarbonato estandarizado 19.04 ± 2.50 mmol/L, gases de efecto invernadero 16.94 ± 2.51 mmHg, exceso de base del fluido extracelular -7.72 ± 5.60 mmol/L, BE (B) -7.36 ± 3.07 mmol/L, porcentaje de saturación de oxígeno 93 ± 8.29, hemoglobina total en la gasometría arterial 10.64 ± 2.36 g/dL, gradiente alvéolo-arterial de oxígeno 49.43 ± 10.98 mmHg, presión parcial de oxígeno 140.43 ± 106.93 mmHg, concentraciones de dióxido de carbono 0.79 ± 0.28 mmHg e Índice respiratorio 0.95 ± 2.57. CONCLUSIONES: Los resultados corresponden a un patrón gasométrico de acidosis metabólica compensada.

Abstract OBJECTIVE: To determine and interpret arterial blood gas values in pregnant patients with severe preeclampsia. MATERIALS AND METHODS: study carry out in a series of 30 patients with a pregnancy ≥ 20 weeks and an established diagnosis of SP admitted to the Intensive Care Unit from July 1 to December 31, 2019, in whom arterial blood gases are part of the routine studies upon admission to the ICU. Patients with recurrence of preeclampsia, eclampsia and HELLP syndrome or with metabolic, respiratory, cardiological and renal morbidities affecting arterial blood gas values were excluded. The general data, obstetric condition, clinical laboratory and arterial blood gas values were documented from the clinical records. Statistical analysis: descriptive statistics were used with the statistical package SPSS version 20. RESULTS: Thirty patients were studied, with a mean age of mean age 31.6 ± 6.85 years, median parity 1, all with a single product of 33.89±3.43 weeks and residence in Mexico City 31.37 ± 7 years. Arterial blood gas values were: pH 7.41 ± 0.08, PCO2 25.51 ± 6.12 mmHg, PO2 85.24 ± 41.81 mmHg, Hct 33.86 ± 7.51%, HCO3- 16.95 ± 5.13 mmol/L, HCO3- std 19.04 ± 2.50 mmol/L, TCO2 16.94 ± 2.51 mmHg, BE ecf -7.72 ± 5.60 mmol/L, BE (B) -7.36 ± 3.07 mmol/L, SO2c% 93 ± 8.29%, THbc 10.64 ± 2.36 g/dL, Aa DO2 49.43 ± 10.98 mmHg, pAO2 140.43 ± 106.93 mmHg, PaO2/PAO2 0.79 ± 0.28 mmHg and Respiratory Index 0.95 ± 2.57. CONCLUSIONS: The results correspond to a gasometric pattern of compensated metabolic acidosis.

Gasometría arterial en embarazo a muy alta altitud / Arterial blood gas analysis during pregnancy at a very high altitude

La gasometría arterial es fundamental en el diagnóstico y manejo del medio interno. El objetivo es caracterizar los valores de gasometría arterial en gestantes sanas con embarazo normoevolutivo residentes a 4 150 metros sobre el nivel del mar. Serie de casos llevada a cabo durante la gestión 2019, la cual incluye pacientes sin clínica ni antecedentes de enfermedades cardiopulmonares o hematológicas, así como ausencia de tabaquismo y residencia de al menos los últimos 6 meses. Se incluye 30 pacientes, media de edad 25.23 años (desvío estándar 3.69), con edad gestacional media de 26 semanas (desvío estándar 5.5). El valor de pH tiende a ser más alto, así como los valores de PaO2, PaCO2, HCO3 y SatpO2% son más bajos, incluso en comparación con adultos sanos residentes de la misma altitud. Existe cierta tendencia positiva hacia el incremento progresivo del pH mientras la edad gestacional avanza. La gasometría arterial en la altura, debe ser interpretada con suma precaución en relación a las condiciones barométricas, proporcionándose así, valiosa información con aplicación a la obstetricia crítica a muy alta altitud.

Arterial blood gases analysis is essential in the diagnosis and management of pathologies. The objective is to characterize arterial blood gases values in healthy pregnant residents at 4150 meters above sea level. Series case performed during 2019, including patients without a clinical features or antecedents of cardiopulmonary or hematological diseases as well as absence of smoking and residence for at least the last 6 months. Thirty patients are included, mean age 25.23 years (standard deviation 3.69), with average gestational age of 26 weeks (standard deviation 5.5). The pH tends to be higher, as well as the values of PaO2, PaCO2, HCO3 and SatpO2% are lower, even compared to healthy adults living at the same altitude. There is some positive trend towards progressive pH is higher such as gestational age progresses. Arterial gas blood analysis at altitude, should be interpreted with extreme caution in relation to barometric conditions, thus providing, valuable information to critical care obstetrics at very high altitude

Can Venous blood gas be a reliable substitute for Arterial blood gas in modern clinical practice?

Background: It is clearly mentioned in the medicine books that blood gas analysis from arterial puncture is the gold standard. But in the past few years it is commonly seen that clinicians have started trusting on venous blood gas analysis as well as started advising VBG (Venous blood gas) in the initial diagnosis of critical patients in emergency setting. Keeping this fact in mind, we designed a study to determine whether VBG could be a better replacement of ABG (Arterial blood gas) in the emergency where diverse pathological conditions are encountered.Methods: This prospective cross-sectional study comprised of 50 patients of 20-60 yrs age with a variety of diagnoses admitted in the emergency department. 50 paired samples (ABG+VBG) were obtained from them under strict aseptic precautions after obtaining their verbal consent. With a minimum delay of less than 2 min blood gas analysis was performed on blood gas analyzer. Parameters (pH, PCO2, PO2, HCO3, Base Excess and O2 saturation) from ABG and VBG were recorded and compared using Student’s Unpaired ‘t’ test.Results: pH and HCO3 showed statistical significant (p value <0.05) differences between ABG and VBG, while BE showed statistical non-significant (p value >0.05) difference between them. Contrary to this, PCO2, PO2 and O2 saturation from ABG and VBG showed statistical highly significant (p value <0.0001) differences.Conclusions: VBG should not be interchangeably considered in place of ABG with regard to pH, HCO3, PCO2, PO2 and O2 saturation in conditions where actual oxygenation status of patient is required (e.g.; hypovolemic shock, respiratory disorders, mechanically ventilated patients, etc.)

Application of N-acetylcysteine inhalation in treatment of elderly patients with acute exacerbation of chronic obstructive pulmonary disease / 吉林大学学报(医学版)

Objective: To explore the curative effect of N-acetylcysteine (NAC) inhalation in the treatment of the elderly patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD), and to clarify the application value of NAC in the regular treatment of the AECOPD patients. Methods: A total of 78 elderly patients with AECOPD were enrolled and randomly divided into control group (n=38) and NAC group (n=40). The patients in two groups all received regular treatment; the patients in NAC group received additional NAC inhalation (0. 3 g, 2 times per day) while the patients in control group received normal saline inhalation. The arterial partial pressure of oxygen (PaO2), arterial partial pressure of carbon dioxide (PaCO2), forced expiratory volume in 1 second (FEV1), forced expiratory volume in FEV1 % predicted (FEVl%pred), the clinical COPD Questionnaire (CCQ) score, as well as the rates of intravenous steroid infusion, the incidence of hospital infection and the duration of hospitalization before and after treatment were recorded. Results: Compared with control group, the difference values of PaO2 of the patients in NAC group was significantly increased (P=0. 033), but there were no significant differences in the difference values of PaO2, FEV1 and FEV1% pred (P>0. 05); the CCQ score of the patients in NAC group was significantly higher than that in control group, and there was significant difference in the difference values (P 0.05). Conclusion: NAC inhalation could apparently improve the PaO2 and the clinical symptoms in the elderly AECOPD patients, but has no significant effects on the pulmonary function, the rate of intravenous steroid infusion, the incidence of hospital infection and the duration of hospitalization.

Gasometría arterial en diferentes niveles de altitud en residentes adultos sanos en el Perú / Arterial blood gas analysis at different levels of altitude in healthy adult residents of Peru

Objetivo: Conocer los valores de la gasometría arterial, SatO2, pO2/fiO2 y lactato en los residentes sanos de la altura a dos diferentes niveles de altitud. Materiales y métodos: Reporte de casos. Muestreo por conveniencia. Se describe los valores de gases arteriales en las ciudades de Huánuco (1818 msnm) y Cerro de Pasco (4380 msnm). Resultados: En Huánuco y Cerro de Pasco se encontró: pH: 7.42 (0.02) y 7.43 (0.01), pO2: 78.19 (4.76) y 54.18 (3.12), pO2/fiO2: 372.32 (22.66) y 258.13 (14.77), saturación de oxígeno: 96.24 (0.87) y 87.02 (2.31), lactato: 1.14 (0.49) y 1.47 (0.56), pCO2: 34.63 (3.62) y 27.69 (1.88), y HCO2: 22.56 (2.19) y 18.37 (1.33), respectivamente. Conclusiones: Los valores del análisis de gasometría arterial en la altura en los residentes adultos sanos son diferentes a los planteados como normales para los residentes del nivel del mar. A mayor altitud de residencia, los cambios son más marcados.

Objective: To know the values of arterial blood gases, SatO2, pO2/fiO2 and lactate in healthy high-altitude residents at two different levels of altitude. Materials and methods: Case report. Convenience sampling. Description of the values of arterial blood gases in the cities of Huánuco (1,818 masl) and Cerro de Pasco (4,380 masl). Results: In Huánuco and Cerro de Pasco we found the following values: pH: 7.42 (0.02) and 7.43 (0.01), pO2: 78.19 (4.76) and 54.18 (3.12), pO2/fiO2: 372.32 (22.66) and 258.13 (4.77), oxygen saturation: 96.24 (0.87) and 87.02 (2.31), lactate: 1.14 (0.49) and 1.47 (0.56), pCO2: 34.63 (3.62) and 27.69 (1.88), and HCO2: 22.56 (2.19) and 18.37 (1.33), respectively. Conclusions: The values of the arterial blood gas analysis in healthy high-altitude adult residents are different from the normal values in sea-level residents. The higher the altitude of residence, the more pronounced the changes.

Punción de la arteria radial guiada por ultrasonido para obtención de gases arteriales / Puncture of the radial artery guided by ultrasound for the obtaining of arterial blood gases

Introducción: La punción de la arteria radial es utilizada para tomar muestras de sangre arterial y realizar exàmentes gasométricos. Es un procedimiento que se realiza de manera frecuente en el área de emergencias, sin embargo, no está exento de complicaciones, por lo que es necesario evaluar técnicas accesorias que permitan reducir los riesgos para el paciente. El objetivo del estudio fue comparar la técnica de punción arterial convencional guiada por palpación con la punción arterial guiada por ultrasonido. Materiales y métodos: Estudio prospectivo en pacientes que ingresaron al Servicio de Emergencia del Hospital Carlos Andrade Marín a quienes se les solicitó gasometría arterial. Para obtener la muestra de sangre arterial se asignó en forma aleatoria a cada paciente a uno de los dos grupos de estudio, el primero en el que se utilizó el método convencional, guiados por palpación y el segundo, guiados por ultrasonido. Los participantes fueron pacientes adultos a quienes se les solicitó gasometría arterial, excluyendo aquellos que tenían alguna contraindicación para el procedimiento. El enrolamiento tuvo lugar en un período de 2 meses. El desenlace primario fue la punción arterial exitosa en el primer intento. Se consideró fracaso, cuando los pacientes requirieron 2 o más punciones para obtener la muestra. Resultados: Noventa y ocho pacientes, fueron enrolados. Cincuenta asignados al grupo guiado por ultrasonido y 48 al grupo control. La punción arterial fue exitosa al primer intento en el 92% del grupo guiado por ultrasonido y 9.6% en el grupo control. El tiempo requerido para obtener la muestra fue similar en los dos grupos (p=0.91). Discusión: La punción arterial guiada por ultrasonido no fue más efectiva que la técnica convencional.

Introduction: Arterial blood gas (ABG) sampling by direct vascular puncture guided by pulse palpation is a common procedure performed in the emergency setting. Reducing the number of attempts to draw arterial blood samples was one of our main goals. The other goal was comparing the standard technique with the ultrasound-guided arterial puncture. Methods: Prospective study in patients admitted to the Emergency Department at Carlos Andrade Marín Hospital, who needed arterial blood gas exams. Patients allocation to draw arterial blood by palpation or guided by ultrasound was chosen at random. Participants were adult patients who needed ABG analysis and excluded patients with any contraindication. The enrollment period lasted two months. The primary endpoint was the successful arterial blood gas sample obtained at first attempt. Failure was taken when patients required more than two punctures to obtain the blood sample. Surrogate endpoint was the amount of time employed in the procedure. Statistical analysis, including Fisher's exact test for categorical variables and independent t-test for quantitative variables, was performed. Results: Ninety-eight patients were enrolled. Fifty were assigned to the ultrasound-guided group and 48 to the control group. The proportion of successful first attempts was 92% in the ultrasound group, and 91.6% in the control group . The amount of time required to draw the blood sample was similar in both groups (p= 0.91). Discusion: Arterial puncture guided by ultrasound was not more effective than the conventional technique to draw arterial blood sample by pulse palpation.

Experiencia clínica con el bloqueador bronquial de ARNDT en pacientes pediátricos / Clinical experience with Arndt bronchial blocker in pediatric patients

Describir la experiencia con el bloqueador bronquial de Arndt (BBA) y determinar los efectos de la ventilación monopulmonar (VMP) en el intercambio gaseoso en pacientes pediátricos. Método: El BBA se utilizó en 11 pacientes que requirieron VMP. Cuando el diámetro del tubo traqueal impedía el uso del BBA como originalmente estaba descrito, éste fue colocado en la tráquea previo a la intubación traqueal quedando por fuera del tubo traqueal. El BBA fue posicionado con ayuda de un fibrobroncoscopio introducido a través del adaptador del bloqueador. Se estandarizaron la modalidad deventilación y las maniobras destinadas a restablecer la oxigenación en caso de desaturación. Se controlaron gases arteriales, presión de vía aérea y CO2 de fin de espiración (EtCO2) ventilando ambos pulmones y en VMP. Resultados: El BBA fue correctamente posicionado en todos los pacientes, obteniéndose un pulmón desinflado en todos ellos. La relación pO2 /FiO2 promedio en decúbito lateral ventilando ambos pulmones y en VMP fue 287 (rango 100-424) y 199 (rango 62-332), p = 0,0108. La diferencia pCO2-EtCO2 mostró un comportamiento variable, aumentando en algunos e incluso haciéndose negativa en otros. Conclusión: El BBA permitió realizar VMP en todos los pacientes. La relación paO2/FiO2 disminuyó en todos los pacientes pero la saturación arterial de oxígeno pudo ser mantenida en niveles seguros. La capnografía mostró ser un indicador poco confiable de la efectividad de la ventilación durante VMP...

Single lung ventilation (SLV) and knowledge of its effects in pediatric patients has been limited by the lack of suitable double lumen tubes (DLT). The bronchial blocker (BB) described by Arndt allows SLV without a DLT, even in small children. Objective: Describe the experience with the Arndt’s BB, and the effects of SLV on gas exchange in children. Design: Observational study. Setting and patients: Eleven children requiring SLV using a BB were studied at a University Hospital. Interventions: A BB was used for SLV. When the internal diameter of the ET didn’t allow the use of the BB as originally described, it was inserted into the trachea before tracheal intubation, leaving the BB next to the ET. A FOB inserted through the multi-portal adapter of the BB guided it to the desired position. Ventilatory pattern and maneuvers to restore arterial oxygen saturation (SatO2) were standardized. Main outcome measures: Arterial blood gases, airway pressure, and EtCO2 were obtained in lateral decubitus position while both lungs were ventilated and during SLV. Results: Ages were between seven months and four years. In 10 patients, the BB was inserted alongside the tracheal tube. In all cases the lung was quiet and deflated. In 2 patients, surgical manipulation dislodged the BB. In one it could not be replaced and thoracotomy was required. Arterial pO2decreased in all patients, but SatO2was maintained above 90%. No significant changes in pCO2 and airway pressure were observed, and pCO2 -EtCO2 relationship was unpredictable. Conclusion: Arndt’s BB allowed SLV in all patients. Even though arterial pO2 decreased in all children, SatO2 could be maintained at an acceptable level...

Clinical Study of the Changes in Arterial Blood Gas and End Tidal CO2 after Release of Tourniquet / 대한마취과학회지

The tourniquet is not only used for facilitation of microaurgery by the bloodless surgical field on the extremities but prepared for the intravenous regional anesthesia and isolation arm test estimated the degree of the neuromuscular transmission in the anesthetic field. On the contrary, there are various complications, such as nerve paralysis and tissue damage from compression, and metabolic and hemodynamic changes from ischemia after application of the tourniquet. Since a sudden increase in PaCO2 immediately following tourniquet deflation is one of the important factors in the hemodynamic changes, we have observed the ehanges of PaCO2 and PCO2, after release of the tourniquet on the upper and the lower extremity under the general anesthesia with enflurane, N2O and respiratory control maintaining PaCO2 level (35 mmHg). The results obtained were as follows; PETCO2, PaCO2 and HCO2- were significantly elevated to peak level within 1 minutue after tourniquet release on the upper and the lawer extremity, except HCO2 on the upper extremity, and there were more severe changes on the lower extremity. pH and base excess were reduced to significantly lowest level 1 minutue and 5 minutes after tourniquet release respectively, and their changes were more reduction on the lower extremity. There were no statistically significant variations in PaO2 on the extremities. In the relationship between tourniquet time and P, it was statistically significant linear on the lower extremity (p<0.05) only. Conlusively, since the sudden changes of PaCO2, pH and base excess after release of tourniquet are closely related with PaCO2, on time and degree, noninvasive monitoring of PaCO2 has rapid interpre- tation to change in PaCO2 after release of tourniquet.