Characteristics and risk factors associated with mortality during the first cycle of prone secondary to ARDS due to SARS-CoV-2 pneumonia / Características y factores de riesgo asociados a mortalidad durante el primer ciclo de prono por SDRA secundario a neumonía por SARS-CoV-2

Objective To analyze characteristics, changes in oxygenation, and pulmonary mechanics, in mechanically ventilated patients with ARDS due to SARS-CoV-2 treated with prone position and evaluate the response to this maneuver.Design Cohort study including patients with PaO2/FiO2 <150mmHg requiring prone position over 18 months. We classified patients according to PaO2/FiO2 changes from basal to 24h after the first prone cycle as: 1) no increase 2) increase <25%, 3) 25%–50% increase 4) increase >50%. Setting 33-bed medical-surgical Intensive Care Unit (ICU) in Argentina. Patients 273 patients. Interventions None. Main variables of interest Epidemiological characteristics, respiratory mechanics and oxygenation were compared between survivors and non-survivors. Independent factors associated with in-hospital mortality were identified. Results Baseline PaO2/FiO2 was 116 [97–135]mmHg (115 [94–136] in survivors vs. 117 [98–134] in non-survivors; p=0.50). After prone positioning, 22 patients (8%) had similar PaO2/FiO2 values; 46(16%) increased PaO2/FiO2 ≤25%; 55 (21%) increased it 25%–50%; and 150 (55%), >50%. Mortality was 86%, 87%, 72% and 50% respectively (p<0.001). Baseline PaO2/FiO2, <100mmHg did not imply that patients were refractory to prone position. Factors independently associated with mortality were age, percentage increase in PaO2/FiO2 after 24h being in prone, and number of prone cycles. Conclusions Older patients unable to improve PaO2/FiO2 after 24h in prone position and who require >1 cycle might early receive additional treatments for refractory hypoxemia. After the first 24h in the prone position, a low percentage of PaO2/FiO2 increase over baseline, beyond the initial value, was independently associated with higher mortality. (AU)

Objetivo Analizar las características, cambios en la oxigenación y mecánica pulmonar, en pacientes ventilados mecánicamente con SDRA por SARS-CoV-2 tratados con posición prona, y evaluar la respuesta a esta maniobra. Diseño Estudio de cohorte que incluyó pacientes con PaO2/FiO2 <150mmHg que requirieron posición prona durante 18 meses. Se clasificaron los pacientes según los cambios de PaO2/FiO2 desde el basal y 24horas después del primer ciclo prono como: 1) Sin aumento 2) Aumento <25%, 3) 25–50% de aumento 4) Aumento >50%. Ambito Unidad de Cuidados Intensivos (UCI) médico-quirúrgica de 33 camas en Argentina. Pacientes 273 pacientes. Intervenciones Ninguna. Principales variables de interés Se compararon características epidemiológicas, mecánica respiratoria y oxigenación entre sobrevivientes y no sobrevivientes. Se identificaron factores independientes asociados a la mortalidad hospitalaria. Resultados La PaO2/FiO2 basal fue de 116 [97–135]mmHg (115 [94–136] en sobrevivientes vs. 117 [98–134] en no sobrevivientes; p=0,50). Después de la posición prona, 22 pacientes (8%) tenían valores similares de PaO2/FiO2; 46 (16%) aumentaron PaO2/FiO2 ≤25%; 55 (21%) lo aumentaron 25%–50%; y 150 (55%), >50%. La mortalidad fue de 86%, 87%, 72% y 50% respectivamente (p<0,001). La PaO2/FiO2 basal, <100mmHg no implicó que los pacientes fueran refractarios a la posición prona. Los factores asociados independientemente con la mortalidad fueron la edad, el aumento porcentual de PaO2/FiO2 después de 24horas en prona, y el número de ciclos prono. Conclusiones Los pacientes mayores que no pueden mejorar PaO2/FiO2 después de 24 horas en posición prona y que requieren más de 1 ciclo podrían recibir tratamientos adicionales para la hipoxemia refractaria. Después de las primeras 24horas en decúbito prono, un bajo porcentaje de aumento de PaO2/FiO2 sobre el valor basal, más allá del valor inicial, se asoció de forma independiente con una mayor mortalidad. (AU)

Funciones ejecutivas en pacientes con apnea obstructiva del sueño: explorando el modelo prefrontal / Executive functions in patients with obstructive sleep apnea: exploring the prefrontal model

Introducción El modelo prefrontal propone que los individuos con apnea obstructiva del sueño (AOS) manifiestan conductas similares a un síndrome disejecutivo como resultado de las alteraciones de gases en la sangre y la fragmentación del sueño. Objetivo Comparar las funciones ejecutivas en pacientes con AOS con valores normativos y explorar su relación con las alteraciones de gases en la sangre y la fragmentación del sueño. Pacientes y métodos Se reclutó a pacientes de la comunidad general y de un hospital de tercer nivel. La puntuación obtenida en la evaluación neuropsicológica se contrastó con la t de Student para una muestra. Posteriormente, se estimó un análisis de regresión lineal múltiple mediante parámetros polisomnográficos de hipercapnia, hipoxemia y fragmentación del sueño como variables predictoras, y la puntuación de funciones ejecutivas como variable que se debe predecir. Resultados Pese a que el desempeño en la evaluación neuropsicológica del 26% de esta muestra se clasificó como alteración ejecutiva, los indicadores de fragmentación del sueño y alteraciones de gases no predijeron el desempeño ejecutivo. Conclusión Una fracción de los pacientes con AOS mostró un desempeño similar a un síndrome disejecutivo; no obstante, permanecen indefinidos los factores que subyacen y favorecen este tipo de manifestaciones cognitivas. La atención temprana de este problema de salud pública podría ser la mejor herramienta disponible en aras de mejorar la calidad de vida y prevenir riesgos a la salud. (AU)

INTRODUCTION According to the prefrontal model, individuals with obstructive sleep apnea (OSA) manifest behaviours mimicking dysexecutive syndrome as a result of blood gas abnormalities and sleep fragmentation. OBJECTIVE. To compare executive functions in OSA patients with normative values and explore their relationship with blood gas abnormalities and sleep fragmentation. PATIENTS AND METHODS Patients were recruited from the wider community and from a tertiary care hospital. The score obtained in the neuropsychological assessment was compared with Student’s t-test for a sample. A multiple linear regression analysis was subsequently estimated, using polysomnographic parameters of hypercapnia, hypoxemia and sleep fragmentation as the predictor variables, and the executive function score as the variable to be predicted. RESULTS Although the neuropsychological assessment performance of 26% of this sample was classified as executive impairment, indicators of sleep fragmentation and gas abnormalities failed to predict the performance of executive functions. CONCLUSION. A proportion of the patients with OSA presented performance similar to a dysexecutive syndrome; however, the factors underlying and fostering this type of cognitive manifestation remain unclear. Early treatment for this public health problem could be the best tool available for improving quality of life and preventing health risks. (AU)

Characteristics and risk factors associated with mortality during the first cycle of prone secondary to ARDS due to SARS-CoV-2 pneumonia.

OBJECTIVE: To analyze characteristics, changes in oxygenation, and pulmonary mechanics, in mechanically ventilated patients with ARDS due to SARS-CoV-2 treated with prone position and evaluate the response to this maneuver. DESIGN: Cohort study including patients with PaO2/FiO2 <150mmHg requiring prone position over 18 months. We classified patients according to PaO2/FiO2 changes from basal to 24h after the first prone cycle as: 1) no increase 2) increase <25%, 3) 25%-50% increase 4) increase >50%. SETTING: 33-bed medical-surgical Intensive Care Unit (ICU) in Argentina. PATIENTS: 273 patients. INTERVENTIONS: None. MAIN VARIABLES OF INTEREST: Epidemiological characteristics, respiratory mechanics and oxygenation were compared between survivors and non-survivors. Independent factors associated with in-hospital mortality were identified. RESULTS: Baseline PaO2/FiO2 was 116 [97-135]mmHg (115 [94-136] in survivors vs. 117 [98-134] in non-survivors; p=0.50). After prone positioning, 22 patients (8%) had similar PaO2/FiO2 values; 46(16%) increased PaO2/FiO2 ≤25%; 55 (21%) increased it 25%-50%; and 150 (55%), >50%. Mortality was 86%, 87%, 72% and 50% respectively (p<0.001). Baseline PaO2/FiO2, <100mmHg did not imply that patients were refractory to prone position. Factors independently associated with mortality were age, percentage increase in PaO2/FiO2 after 24h being in prone, and number of prone cycles. CONCLUSIONS: Older patients unable to improve PaO2/FiO2 after 24h in prone position and who require >1 cycle might early receive additional treatments for refractory hypoxemia. After the first 24h in the prone position, a low percentage of PaO2/FiO2 increase over baseline, beyond the initial value, was independently associated with higher mortality.

Atropine does not prevent hypoxemia and bradycardia in tracheal intubation in the pediatric emergency department: observational study / O uso da atropina não previne hipoxemia e bradicardia na intubação traqueal no departamento de emergência pediátrica: estudo observacional

ABSTRACT Objective: The benefit of atropine in pediatric tracheal intubation is not well established. The objective of this study was to evaluate the effect of atropine on the incidence of hypoxemia and bradycardia during tracheal intubations in the pediatric emergency department. Methods: This is a single-center observational study in a tertiary pediatric emergency department. Data were collected on all tracheal intubations in patients from 31 days to incomplete 20 years old, performed between January 2016 and September 2020. Procedures were divided into two groups according to the use or not of atropine as a premedication during intubation. Records with missing data, patients with cardiorespiratory arrest, cyanotic congenital heart diseases, and those with chronic lung diseases with baseline hypoxemia were excluded. The primary outcome was hypoxemia (peripheral oxygen saturation ≤88%), while the secondary outcomes were bradycardia (decrease in heart rate >20% between the maximum and minimum values) and critical bradycardia (heart rate <60 bpm) during intubation procedure. Results: A total of 151 tracheal intubations were identified during the study period, of which 126 were eligible. Of those, 77% had complex, chronic underlying diseases. Atropine was administered to 43 (34.1%) patients and was associated with greater odds of hypoxemia in univariable analysis (OR: 2.62; 95%CI 1.15-6.16; p=0.027) but not in multivariable analysis (OR: 2.07; 95%CI 0.42-10.32; p=0.37). Critical bradycardia occurred in only three patients, being two in the atropine group (p=0.26). Bradycardia was analyzed in only 42 procedures. Atropine use was associated with higher odds of bradycardia in multivariable analysis (OR: 11.00; 95%CI 1.3-92.8; p=0.028). Conclusions: Atropine as a premedication in tracheal intubation did not prevent the occurrence of hypoxemia or bradycardia during intubation procedures in pediatric emergency.

RESUMO Objetivo: Avaliar o efeito da atropina na incidência de hipoxemia e bradicardia durante a intubação orotraqueal no departamento de emergência pediátrica. Métodos: Estudo observacional, realizado em departamento de emergência pediátrica terciário em que foram analisados os registros de intubações orotraqueais de pacientes com 31 dias a 20 anos incompletos, entre janeiro de 2016 e setembro de 2020. Os procedimentos foram divididos em dois grupos de acordo com o uso ou não da atropina como pré-medicação durante a intubação. Foram excluídos os procedimentos com falhas no preenchimento dos dados, pacientes com parada cardiorrespiratória, cardiopatias congênitas cianóticas, e aqueles com pneumopatias crônicas com hipoxemia basal. O desfecho primário foi hipoxemia (saturação periférica de oxigênio ≤88%), enquanto os desfechos secundários foram bradicardia (queda >20% entre a frequência cardíaca máxima e mínima) e bradicardia crítica (frequência cardíaca <60 bpm) durante o procedimento de intubação Resultados: Foram identificados 151 procedimentos de intubação orotraqueal, sendo 126 elegíveis para o estudo. Desses, 77% tinham doenças subjacentes complexas e crônicas. A atropina foi administrada em 43 (34,1%) pacientes e foi associada a maiores chances de hipoxemia na análise univariada (OR: 2,62; IC95% 1,15-6,16; p=0,027), porém, não na análise multivariada (OR: 2,073; IC95% 0,416-10,32; p=0,373). A bradicardia crítica ocorreu em apenas três pacientes, sendo dois no grupo atropina (p=0,268). A bradicardia foi analisada em apenas 42 procedimentos. O uso de atropina foi associado a maior probabilidade de bradicardia (OR: 11,00; IC95% 1,3-92,8; p=0,028) na análise multivariável. Conclusões: Atropina como pré-medicação na intubação orotraqueal não evitou a ocorrência de hipoxemia ou bradicardia durante os procedimentos de intubação na emergência pediátrica.

Decúbito prono en el tercer trimestre del embarazo durante la era COVID-19: un abordaje transdisciplinar / Prone position in the third trimester of pregnancy during the COVID-19 era: A transdisciplinary approach

Existe evidencia muy limitada respecto del uso de la ventilación en decúbito prono como parte del tratamiento de un síndrome de distrés respiratorio agudo severo para pacientes en periodo de gestación. Actualmente las recomendaciones para el manejo ventilatorio invasivo en esta población son muy escasas y se basan en la extrapolación de las conclusiones obtenidas en estudios de pacientes no gestantes. La literatura disponible asevera que la anatomía y la fisiología de la gestante experimentan complejos cambios adaptativos que deben ser considerados durante el soporte ventilatorio invasivo y el prono. Con la ventilación en decúbito prono, los beneficios obtenidos para el binomio superan ampliamente a los eventuales riesgos. La programación adecuada del ventilador mecánico se correlaciona con un concepto claro y simple: la individualización del soporte. De todas maneras, la decisión del momento oportuno para la interrupción del embarazo debe fundamentarse con un adecuado juicio clínico multidisciplinario y además debe ser respaldado con una estricta monitorización fetal.(AU)

There is very limited evidence regarding the use of prone position as part of the treatment of severe acute respiratory distress syndrome in pregnant patients. Currently, recommendations for invasive ventilatory management in this population are very scarce and are based on the extrapolation of conclusions obtained in studies of non-pregnant patients. The available literature asserts that the anatomy and physiology of the pregnant woman undergoes complex adaptive changes that must be considered during invasive ventilatory support and prone position. With prone ventilation, the benefits obtained for the couple far outweigh the eventual risks. Adequate programming of the mechanical ventilator correlates with a clear and simple concept: individualization of support. In any case, the decision on the timing of termination of pregnancy should be based on adequate multidisciplinary clinical judgment and should be supported by strict monitoring of the product.(AU)

Métodos no invasivos de oxigenación en pacientes con COVID-19 / Non-invasive oxygenation methods in patients with COVID-19

Resumen: Desde el inicio de la pandemia por COVID-19, dentro de las complicaciones más frecuentes de esta infección se encuentran la neumonía y el síndrome de dificultad respiratoria aguda. La hipoxemia y el aumento del trabajo respiratorio son determinantes para adoptar diversas estrategias terapéuticas de oxigenación no invasiva en pacientes con COVID-19. Es importante conocer y describir las diferentes modalidades de oxigenoterapia no invasiva, con la finalidad de preservar la oxigenación y un adecuado trabajo respiratorio, las estrategias descritas en la literatura abarcan: cánulas nasales convencionales, cánulas nasales de alto flujo y ventilación mecánica no invasiva, aunado a otras medidas de soporte como posición prono, administración de esquemas con esteroide, inmunomoduladores y óxido nítrico inhalado. Las estrategias no invasivas de oxigenación por diferentes métodos son herramientas indispensables para el tratamiento de pacientes con neumonía por COVID-19 moderada-grave. Es necesario evaluar el dispositivo a emplear, ya que esta enfermedad tiene características heterogéneas de acuerdo con gravedad y el tiempo de evolución.

Abstract: Since the start of the COVID-19 pandemic, the most frequent complications of this infection include pneumonia and Acute Respiratory Distress Syndrome. Hypoxemia and increased work of breathing are determining factors in adopting various non-invasive oxygenation therapeutic strategies in patients with COVID-19. It is important to know and describe the different modalities of non-invasive oxygen therapy, in order to preserve oxygenation and adequate respiratory work, the strategies described in the literature include: conventional nasal cannulas, high-flow nasal cannulas and non-invasive mechanical ventilation coupled with other support measures such as prone position, administration of schemes with steroids, immunomodulators and inhaled nitric oxide. Non-invasive oxygenation strategies by different methods are essential tools for the treatment of patients with moderate-severe COVID-19 pneumonia. It is necessary to evaluate the device to be used, since this disease has heterogeneous characteristics according to severity and time of evolution.

Biochemical and haematological abnormalities in severe acute organophosphorus poisoning / Anomalías bioquímicas y hematológicas en la intoxicación grave por organofosforados. Estudio prospectivo en un solo centro

Background: Organophosphorus insecticides are considered one of the commonest causes of morbidity and mortality due to poisoning worldwide. Severe organophosphorus poisoning can lead to multiple sometimes lethal metabolic and haematological abnormalities. Methods: A total of 141 OP poisoning patients were admitted during the study period and their blood samples were collected on admission and analysed for the biochemical abnormalities. Results: Out of 141 patients 76 were males (53.9%) and 65 were females (46.1%). Bradycardia with Pulse rate of less than 60 was seen in in 21 patients (14.7). Hypoxemia with oxygen saturation of less than 94% was seen in 32 (22.7%). leucocytosis with TLC o 11000 or more was seen in 19 patients (13.5%).101 patients (83.5%) had low serum choline esterase levels less than 1.5kU/L. Hypokalaemia with K+ of less than 3.5 was seen in 16 patients (9.9%). Five patients died out of 141 (3.5%). Hypoxemia Spo2 of less than 90% was seen in 3 (60%) patients who died and hypoglycaemia with blood glucose of less than 70mg/dl was seen in 2 out of 5 Patients (40%). Conclusions: low choline esterase levels less than 1.5kU/L was the most common abnormality indicating severe poisoning followed by hypoxemia. Both Hypoxemia and low acetylcholine esterase levels are bad prognostic signs and result in high mortality in organophosphorus poisoning. (AU)

Introducción: De entre todos los procesos de intoxicación, el envenenamiento por organofósforados se considera una de las causas más comunes de morbilidad y mortalidad en todo el mundo. La intoxicación grave por organofósforo puede provocar múltiples anomalías metabólicas y hematológicas, a veces letales. Métodos: Un total de 141 pacientes intoxicados por organofósforados fueron ingresados durante el periodo de estudio y sus muestras e sangre fueron recogidas al ingreso y analizadas para detectar las anomalías bioquímicas. Resultados: De los 141 pacientes, 76 eran varones (53,9%) y 65 mujeres (46,1%). Se observó bradicardia con una frecuencia de pulso inferior a 60 en 21 pacientes (14,7). Se observó hipoxemia con una saturación de oxígeno inferior al 94% en 32 (22,7%). Leucocitosis con un recuento total de leucocitos de 11.000 o más en 19 pacientes (13,5%). 101 pacientes (83,5%) tenían niveles bajos de colina esterasa sérica inferiores a 1,5 kU/L. Se observó hipopotasemia con K+ inferior a 3,5 en 16 pacientes (9,9%). Cinco pacientes fallecieron de un total de 141 (3,5%). Se observó hipoxemia Spo2 inferior al 90% en 3 (60%) pacientes que fallecieron e hipoglucemia con glucemia inferior a 70 mg/dl en 2 de 5 pacientes (40%). Conclusiones: Los niveles bajos de colinesterasa inferiores a 1,5 kU/L fueron la anomalía más frecuente que indicaba intoxicación grave, seguida de hipoxemia. La hipoxemia, la hipoglucemia y los niveles bajos de acetilcolinesterasa son signos de mal pronóstico y dan lugar a una elevada mortalidad en la intoxicación por organofosforados. (AU)

Efectos cerebrales del oxígeno y el dióxido de carbono en el síndrome de dificultad respiratoria aguda

Introducción: El síndrome de dificultad respiratoria aguda producido por la COVID-19 provoca alteraciones en el intercambio de oxígeno y la excreción de dióxido de carbono con consecuencias neurológicas. Objetivo: Describir las implicaciones del oxígeno y el dióxido de carbono sobre la dinámica cerebral durante el tratamiento ventilatorio del síndrome de dificultad respiratoria aguda en el accidente cerebrovascular. Métodos: Se realizó una búsqueda en bases referenciales como: PubMed/Medline, SciELO, Google Académico y BVS Cuba. Los términos incluidos fueron brain-lung crosstalk, ARDS, mechanical ventilation, COVID-19 related stroke, ARDS related stroke y su traducción al español. Fueron referenciados libros de neurointensivismo y ventilación mecánica artificial. El período de búsqueda incluyó los últimos 20 años. Se seleccionaron 46 bibliografías que cumplieron con los criterios de selección. Resultados: Se ha descrito que los niveles de oxígeno y dióxido de carbono participan en la neurorregulación vascular en pacientes con daño cerebral. Algunas alteraciones alusivas son la vasodilatación cerebral refleja o efectos vasoconstrictores con reducción de la presión de perfusión cerebral. Como consecuencia aumenta la presión intracraneal y aparecen afectaciones neurocognitivas, isquemia cerebral tardía o herniación del tronco encefálico. Conclusiones: El control de la oxigenación y la excreción de dióxido de carbono resultaron cruciales para mantener la homeostasis neuronal, evita la disminución de la presión de perfusión cerebral y el aumento de la presión intracraneal. Se sugiere evitar la hipoxemia e hiperoxemia, limitar o eludir la hipercapnia y usar hiperventilación hipocápnica solo en condiciones de herniación del tallo encefálico.

Introduction: The acute respiratory distress syndrome produced by COVID-19 causes alterations in the exchange of oxygen and the excretion of carbon dioxide with neurological consequences. Objective: To describe the implications of oxygen and carbon dioxide on brain dynamics during ventilatory treatment of acute respiratory distress syndrome in stroke. Methods: A search was carried out in referential bases such as PubMed/Medline, SciELO, Google Scholar and VHL Cuba. The terms included were brain-lung crosstalk, ARDS, mechanical ventilation, COVID-19 related stroke, ARDS related stroke and their translation into Spanish. Books on neurointensive care and artificial mechanical ventilation were referenced. The search period included the last 20 years. Forty six bibliographies that met the selection criteria were selected. Results: Oxygen and carbon dioxide levels have been described to participate in vascular neuroregulation in patients with brain damage. Some allusive alterations are reflex cerebral vasodilatation or vasoconstrictor effects with reduced cerebral perfusion pressure. As a consequence, intracranial pressure increases and neurocognitive impairments, delayed cerebral ischemia or brainstem herniation appear. Conclusions: The control of oxygenation and the excretion of carbon dioxide were crucial to maintain neuronal homeostasis, avoiding the decrease in cerebral perfusion pressure and the increase in intracranial pressure. It is suggested to avoid hypoxemia and hyperoxemia, limit or avoid hypercapnia, and use hypocapnic hyperventilation only in conditions of brainstem herniation.

Hipoxemia y el riesgo de hipertensión arterial en apnea obstructiva del sueño / Hypoxemia and the Hypertension Risk in Obstructive Sleep Apnea

Hay poca información sobre el rol de la hipoxemia como factor de riesgo de hipertensión arterial (HTA) en pacientes con apnea obstructiva del sueño. El objetivo de este estudio fue evaluar la hipoxemia como factor de riesgo independiente de HTA en un modelo de trabajo basado en pacientes reales examinados en una unidad de sueño. Métodos: estudio retrospectivo. Modelo predictivo mediante regresión logística múltiple para establecer la relación entre HTA y edad, sexo, índice de masa corporal (IMC), índice de apneas e hipopneas por hora de registro (IAH) y tiempo de saturación de oxígeno debajo de 90% (T90 > 3%). Resultados: incluimos 3854 pacientes (edad mediana 55 años), predominio varones (61.5%). Según el modelo, las variables asociadas con HTA fueron: edad (OR 3.27 ­ 3.29, IC95% 2.83 ­ 3.80, p < 0.0001), sexo masculino (OR 1.35, IC95% 1.17 ­ 1.56, p < 0.001), obesidad (OR 1.83, IC95% 1.59 ­ 2.11, p < 0.0001), IAH ≥ 15 eventos por hora (OR 1.22, IC95% 1.05 ­ 1.43, p < 0.01) y T90 ≥ 3% (OR 1.56 ­ 1.57, IC95% 1.32 ­ 1.84, p < 0.0001). Conclusiones: en una población clínica con sospecha de apnea obstructiva del sueño, la hipoxemia (T90 ≥ 3%) se asoció con hipertensión arterial. (AU);

There is limited information about the role of hypoxemia degree as a risk factor for hypertension (HTN) in patients with obstructive sleep apnea (OSA). The objective of this study is to assess hypoxemia as an independent risk factor for HTN in a work model based on real-life patients examined at sleep unit. Methods: this retrospective study consisted of a predictive model using multiple logistic regression to establish the relationship between HTN and age, sex, body mass index (BMI), apnea/hypopnea index (AHI) and time below SO2 ≤ 90% (T90 ≥ 3%). Results: we included 3.854 patients (median age: 55 years), mostly men (61.5%). According to the model, the variables that were significantly associated with HTN were: age (OR: 3.27 ­ 3.29, CI95% 2.83 ­ 3.80, p < 0.0001), male sex (OR 1.35, CI95% 1.17 ­ 1.56, p < 0.001), Obesity (OR 1.83, CI95% 1.59 ­ 2.11, p < 0.0001), AHI > 15 events per hour (OR 1.22, CI95% 1.05 ­ 1.43, p < 0.01) and T90 ≥ 3% (OR 1.56 ­ 1.57, CI95% 1.32 ­ 1.84, p < 0.0001). Conclusion: in a clinical population of subjects suspected of OSA, nocturnal hypoxemia measure as T90 ≥ 3% was associated with HTN. (AU);

Efeito da reabilitação cardiopulmonar e metabólica em pacientes que apresentaram dessaturação da oxihemoglobina induzida pelo exercício após alta hospitalar pela COVID-19: série de casos / Effect of cardiopulmonary and metabolic rehabilitation in patients with exercise-induced oxyhemoglobin desaturation after hospital discharge from COVID-19: case series

INTRODUÇÃO: A dessaturação da oxihemoglobina induzida pelo exercício em pacientes pós-COVID-19 parece estar associada à redução da difusão e dos volumes pulmonares, à maior dispneia e baixa capacidade funcional, sendo relacionada à maior mortalidade e pior prognóstico. A reabilitação cardiopulmonar e metabólica (RCPM) é relevante, pois visa restaurar a funcionalidade, tolerância ao esforço e a qualidade de vida (QV). OBJETIVO: Verificar os efeitos da RCPM em pacientes que apresentaram dessaturação da oxihemoglobina induzida pelo exercício após alta hospitalar pela COVID-19 e ainda observar a diferença entre os treinamentos contínuo de moderada intensidade (TCMI) e o intervalado de alta intensidade (TIAI) na tolerância ao esforço, nos sintomas e na QV. MÉTODOS: Trata-se do relato de uma série de 4 casos que foram hospitalizados por COVID-19 e que após alta hospitalar apresentaram dessaturação da oxihemoglobina induzida pelo esforço durante o teste do degrau de 6 minutos (TD6). Os pacientes foram avaliados por meio de espirometria de repouso, mensuração da força da musculatura inspiratória, TD6, teste da caminhada de 6 minutos (TC6), teste de repetições máximas do quadríceps e bíceps braquial e responderam ao questionário SF-36 de QV. Submetidos a um protocolo de treinamento contendo treino da musculatura inspiratória e treino resistido para grandes grupos musculares, adicionalmente, 2 pacientes fizeram TCMI (com 60-80% da frequência cárdica de reserva (FCR)) e 2 TIAI (com 40% da FCR na fase off, durante 4 minutos e 80 a 100%, na fase on, durante 2 minutos) em esteira por 30 minutos e, por fim, após 3 meses foram reavaliados. RESULTADOS: Observouse aumento da tolerância ao esforço, da força muscular inspiratória e periférica, além da melhora da QV e redução dos sintomas em todos os pacientes após a RCPM, porém houve incrementos maiores nos pacientes submetidos ao TIAI comparados ao TCMI na distância percorrida em metros (caso 1- 156 (23% de incremento); caso 3 - 168 (40%)) versus (caso 2 e 4 - 60 metros, com incrementos de 9% e 14%, respectivamente) e maior número de degraus (caso 1- 28 (23% de aumento); caso 3- 37 (34%)) versus (caso 2 ­ 2 (2% incremento); caso 4 - 15 (21%)). CONCLUSÃO: A RCPM apresentou efeitos positivos, com incremento da capacidade funcional e melhora da QV, além da redução dos sintomas durante o esforço, particularmente nos pacientes submetidos ao TIAI.

INTRODUCTION: Exercise-induced oxyhemoglobin desaturation in post-COVID-19 patients appears to be associated with reduced diffusion and lung volumes, greater dyspnea and low functional capacity, being related to higher mortality and worse prognosis. Cardiopulmonary and metabolic rehabilitation (CPMR) is relevant, as it aims to restore functionality, exercise tolerance and quality of life (QoL). OBJECTIVE: To verify the effects of CPMR in patients who presented exercise-induced oxyhemoglobin desaturation after hospital discharge due to COVID-19 and also to observe the difference between moderate-intensity continuous training (MICT) and high intensity interval training (HIIT) on effort tolerance, symptoms and QoL. METHODS: This is the report of a series of 4 cases who were hospitalized for COVID-19 and who, after hospital discharge, presented exertion-induced oxyhemoglobin desaturation during the 6-minute step test (6MST). Patients were assessed using spirometry at rest, measurement of inspiratory muscle strength, 6MST, 6-minute walk test (6MWT), quadriceps and biceps brachii maximum repetitions test, and answered the SF-36 QoL questionnaire. Submitted to a training protocol containing training of the inspiratory muscles and resistance training for large muscle groups, additionally, 2 patients underwent CMIT (with 60-80% of heart rate reserve) and 2 HIIT (with 40% of HR reserve in the off, for 4 minutes and 80 to 100%, in the on phase, for 2 minutes) on a treadmill for 30 minutes, finally, after 3 months, they were reassessed. RESULTS: There was an increase in effort tolerance, inspiratory and peripheral muscle strength, in addition to an improvement in QoL and a reduction in symptoms in all patients after CPMR, but there were greater increments in patients submitted to HIIT compared to CMIT in the distance covered in meters (case 1 - 156 (23% increment); case 3 - 168 (40%)) versus (case 2 and 4 - 60 meters, with increments of 9% and 14%, respectively) and greater number of steps (case 1 - 28 (23% increase); case 3- 37 (34%)) versus (case 2 ­ 2 (2% increment); case 4 - 15 (21%)). CONCLUSION: CPMR had positive effects, with an increase in functional capacity and improvement in QoL, in addition to a reduction in symptoms during exertion, particularly in patients undergoing HIIT.

Caracteristicas del grado de hipoxemia en pacientes con SARVS COV2 internados en el centro de trauma Hospital Corazon de Jesús en la ciudad de El Alto Bolivia durante agosto de 2020 a junio del 2021 / Characteristics of the degree of hypoxemia in patients with SARVS COV2 hospitalized at the Hospital Corazón de Jesús trauma center in the city of El Alto, Bolivia, during August 2020 to June 2021

En el presente trabajo, se dan a conocer los resultados obtenidos de 35 pacientes, nativos de la ciudad de El Alto 4082 msnm, quienes ingresaron a la Unidad de Terapia Intensiva (UTI) del centro de trauma Hospital Corazón de Jesús con diagnóstico de insuficiencia respiratoria aguda secundario a COVID 19 , en grado severo a crítico 11 pacientes fueron del sexo femenino y 24 del sexo masculino con una edad promedio de 60 años, los mismos fueron divididos en 2 grupos, los que recibieron soporte respiratorio no invasivo y los que recibieron soporte respiratorio invasivo (ventilación mecánica). La metodología utilizada fue la extracción de una muestra de gases en sangre arterial que fue procesada inmediatamente en el laboratorio del Hospital a partir del cual se obtuvo la Pa02, la PaC02 y nivel lactato con los que se pudo calcular en todos los pacientes la diferencia alveolo arterial de oxígeno. A partir de los resultados se realiza un análisis del mecanismo fisiopatológico subyacente responsable de la insuficiencia respiratoria aguda, la cual consideramos que tiene implicaciones muy importantes en el manejo y tratamiento del soporte respiratorio en los pacientes con COVID severo y critico.

Vivência de fisioterapeutas com pacientes hospitalizados sob oxigenoterapia / Experience of physiotherapists with hospitalized patients under oxygen therapy

Objetivo: este estudo objetivou conhecer a vivência de fisioterapeutas com pacientes hospitalizados sob oxigenoterapia, bem como identificar os desafios vivenciados durante a sua intervenção. Métodos: trata-se de um estudo quantitativo e transversal, realizado no período de setembro de 2021 a março de 2022, com fisioterapeutas atuantes em hospitais da cidade de Fortaleza-CE. A coleta de dados foi realizada de forma presencial e virtual pela plataforma Google Forms, por meio de um questionário com perguntas objetivas sobre vivência, intervenção e desafios durante assistência ao paciente sob oxigenoterapia. Os dados coletados foram armazenados no Microsoft Excel® 2010 e analisados pelo SPSS® versão 20.0, utilizando-se de estatística descritiva. Resultados: participaram do estudo 101 fisioterapeutas, 76,2% do gênero feminino, e 45,5% dos participantes eram graduados há 5 anos. Destes, 83,2% dos fisioterapeutas afirmaram que SpO2 < 90% é indicativo de oxigenoterapia. A maioria (79,2%) discordou da utilização da máscara de Venturi para pacientes com Covid-19 e apontou a cânula nasal de alto fluxo (39,6%) e a máscara reservatório não reinalante (40,6%) como as mais utilizadas. Entre os desafios enfrentados durante a assistência, a interação com a equipe interdisciplinar (25,70%), o desmame da oxigenoterapia (21,80%) e a indisponibilidade de recursos (20,80%) foram os mais relatados. Conclusão: grande parte dos profissionais atua indicando o oxigênio suplementar em situações em que há SaO2 < 90%, realizando avaliação à beira leito da cânula nasal de alto fluxo por meio do índice ROX e indicando intervenção fisioterapêutica.

Objective: this study aimed to understand the experience of physiotherapists with patients hospitalized under oxygen therapy, as well as to identify the challenges experienced during their intervention. Methods: it was a quantitative and cross-sectional study conducted from September 2021 to March 2022, with physiotherapists working in hospitals in Fortaleza-CE. Data collection was performed in person and virtually through the Google Forms platform, through a questionnaire with objective questions about experience, intervention, and challenges during care to patients under oxygen therapy. The collected data were stored in Microsoft Excel® 2010 and analyzed by SPSS® version 20.0, using descriptive statistics. Results: the study included 101 physical therapists, 76.2% female, and 45.5% of the participants had graduated for five years. Of these, 83.2% of physical therapists stated that SpO2 < 90% is indicative of oxygen therapy. The majority (79.2%) disagreed with the use of the venturi mask for patients with Covid-19 and pointed to the high-flow nasal cannula (39.6%) and the non-reinlantreservoir mask (40.6%) as the most used. Among the challenges faced during care, interaction with the interdisciplinary team (25.70%), weaning from oxygen therapy (21.80%), and unavailability of resources (20.80%) was the most reported. Conclusion: most professionals indicate supplemental oxygen in situations where SaO2 < 90%, perform an evaluation at the bedside of the high-flow nasal cannula from the ROX index and suggest physiotherapeutic intervention.

Efecto del óxido nítrico inhalado en la mecánica ventilatoria y oxigenación de pacientes con hipoxemia grave refractaria a prono prolongado y bloqueo neuromuscular secundario a infección por SARS-CoV-2 / Effect of inhaled nitric oxide on ventilatory mechanics and oxygenation of patients with severe hypoxemia refractory to prolonged prone and neuromuscular blockade secondary to SARS-CoV-2 / Efeito do óxido nítrico inalado na mecânica ventilatória e oxigenação de pacientes com hipoxemia grave refratária a pronação prolongada e bloqueio neuromuscular secundário à infecção por SARS-CoV-2

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Abstract: Introduction: Among the patients infected with SARS-CoV-2, 14.6% were admitted to intensive care unit. this 29 to 75% required invasive mechanical ventilation with an associated mortality of 12 to 81%. Acute respiratory distress syndrome (ARDS) is the most serious form of presentation. The pathophysiology of ARDS secondary to SARS-CoV-2 differs from conventional causes. It presents dysregulation in hypoxic pulmonary vasoconstriction, secondary acute pulmonary hypertension and microthrombotic phenomena. The development of refractory severe hypoxemia (PaO2 < 60 mmHg or PaO2/FiO2 < 100 mmHg, with FiO2 80 to 100%, with PEEP > 10 to 20 cmH2O for at least 10 to 12 hours) constitutes the scenario of maximum severity with an associated mortality of 71 to 94%. The use of rescue strategies that impact on the specific pathophysiology of this entity such as the use of inhaled nitric oxide, neuromuscular blockade and prone ventilation have emerged as therapeutic targets of interest. Protective mechanical ventilation (plateau pressure [Pplat] < 27 cmH2O and driving pressure [DP] < 15 cmH2O) continues to be the cornerstone of the management. Objectives: To determine whether there is an association between the use of inhaled nitric oxide and prone ventilation with ventilatory mechanics in patients with severe refractory hypoxemia secondary to SARS-CoV-2 infection. Material and methods: A historical, retrospective, descriptive, comparative and retrolective cohort study was carried out. Data from the records of patients admitted to the Respiratory ICU of the ABC Medical Center with a diagnosis of ARDS secondary to SARS-CoV-2 infection who required iNO and mechanical ventilation in prone from April 1 to December 31, 2020 were analyzed. A univariate analysis was performed, the statistical analysis was performed in SPSS v 21, measures of trend, dispersion were analyzed as well as the analysis of risk factors with Student's t test and χ2. Results: A total of 108 patients were analyzed, of which 54 received iNO, neuromuscular blockade and prone and 54 only neuromuscular blockade and prone ventilation. 81.5% (n = 88) were men. The most common comorbidity was diabetes mellitus in 51.9% (n = 56). The increase in oxygenation (delta PaO2/FiO2) was with a median of 31.9 ± 15.2 mmHg in the iNO group and 52.9 ± 16.74 mmHg in the control group (p = 0.001). The postintervention Pplat in the iNO group was 26.3 ± 3 and 34.5 ± 1.9 cmH2O in the control group (p = 0.792). The preintervention DP in the iNO group was 17.2 ± 3.9 and 13.4 ± 2.8 cmH2O in control group vs 13.1 ± 1.29 and 12 ± 1.92 cmH2O after the intervention (p = 0.001). Conclusions: The use of iNO in patients with severe hypoxemia refractory to prone ventilation and neuromuscular blockade did not produce a statistically significant improvement in oxygenation, however it allowed to reprogram the ventilatory support to keep the patient in goals of alveolar protection.

Resumo: Introdução: 14.6% dos pacientes infectados com SARS-CoV-2 são internados em terapia intensiva. Destes, 29 a 75% necessitam de ventilação mecânica invasiva com mortalidade associada de 12 a 81%. A síndrome do desconforto respiratório agudo (SDRA) é a forma mais grave de apresentação. A fisiopatologia da SDRA secundária ao SARS-CoV-2 difere das causas convencionais. Apresenta desregulação na vasoconstrição pulmonar hipóxica, hipertensão pulmonar aguda secundária e fenômenos microtrombóticos. O desenvolvimento de hipoxemia grave refratária (PaO2 < 60 mmHg ou PaO2/FiO2 < 100 mmHg, com FiO2 de 80 a 100%, PEEP > 10 a 20 cmH2O por pelo menos 10 a 12 horas) constitui o cenário mais grave com mortalidade associada de 71 a 94%. O uso de estratégias de resgate que impactam na fisiopatologia específica dessa entidade, como o uso de óxido nítrico inalatório (NOi), bloqueio neuromuscular e ventilação prona, surgiram como alvos terapêuticos de interesse. A ventilação mecânica protetora (Pressão de Platô [PPLAT] < 27 cmH2O e Pressão de Condução [CP] < 15 cmH2O) continua sendo a base de seu manejo. Objetivo: Determinar se existe associação entre o uso de óxido nítrico inalatório e ventilação prona prolongada com mecânica ventilatória em pacientes com hipoxemia refratária grave secundária à infecção por SARS-CoV-2. Material e métodos: Realizou-se um estudo de coorte histórico, retrospectivo, descritivo, comparativo e retroletivo. Analisaram-se dados dos prontuários de pacientes internados na UTI Respiratória do Centro Médico ABC com diagnóstico de SDRA secundária à infecção por SARS-CoV-2 que necessitaram de óxido nítrico inalatório e ventilação mecânica prona no período de 1o de abril a 31 de dezembro de 2020. Realizou-se uma análise univariada , a análise estatística foi realizada no SPSS v 21, foram analisadas as medidas de tendência e dispersão, assim como a análise dos fatores de risco com teste t de Student e χ2. Resultados: Analisaram-se 108 pacientes, dos quais 54 receberam NOi, bloqueio neuromuscular e prono e 54 apenas bloqueio neuromuscular e ventilação prona. 81.5% (n = 88) eram homens. A comorbidade mais comum foi diabetes mellitus em 51.9% (n = 56). O aumento da oxigenação (Delta PaO2/FiO2) foi com mediana de 31.9 ± 15.2 mmHg no grupo NOi e 52.9 ± 16.74 mmHg no grupo controle (p = 0.001). A PPLAT após a intervenção no grupo NOi foi de 26.3 ± 3 e 34.5 ± 1.9 cmH2O no grupo controle (p = 0.792). A PC antes da intervenção no grupo NOi foi de 17.2 ± 3.9 e 13.4 ± 2.8 cmH2O no grupo controle vs 13.1 ± 1.29 e 12 ± 1.92 cmH2O após a intervenção (p = 0.001). Conclusões: O uso de NOi em pacientes com hipoxemia grave refratária à ventilação em pronação e bloqueio neuromuscular não produziu melhora estatisticamente significativa na oxigenação, porém permitiu que o suporte ventilatório fosse reprogramado para manter as metas de proteção alveolar do paciente.

Pulsioximetría: papel en el paciente COVID-19 domiciliario / Pulse oximetry: Role in the COVID-19 patient at home

La COVID-19 se comporta como una enfermedad heterogénea. Algunos pacientes pueden presentar hipoxemia sin disnea durante su evolución (hipoxemia silente). La pulsioximetría juega un papel crucial en la detección de la hipoxemia en estos pacientes, especialmente cuando permanecen en su domicilio. Pacientes con niveles de SpO2 ≤ 92% o desaturaciónes ≥ 3% tras el ejercicio precisan de ingreso hospitalario. Los descensos progresivos de la saturación que alcancen niveles SpO2 < 96% precisan de valoración clínica estricta (estudio radiológico, analítica sanguínea) para lo que será enviado a un centro sanitario (AU)

COVID-19 behaves like a heterogeneous disease. Some patients may develop dyspnea-free hypoxemia during its evolution (silent hypoxemia). Pulse oximetry plays a crucial role in detecting hypoxemia in these patients, especially when they remain at home. Patients with SpO2 levels ≤ 92% or desaturations ≥ 3% after exercise test require hospital admission. Progressive saturation declines reaching SpO2 levels < 96% require strict clinical assessment (radiological study, blood test) for which it will be sent to a health center (AU)

Resistant hypertension and Morgagni hernia: The importance of nocturnal hypoxaemia

A 51-year-old woman consulted for resistant arterial hypertension despite adequate antihypertensive treatment. Physical examination and analytical study showed no relevant abnormalities, with pulse oximeter saturation of 95%. The study highlighted nocturnal respiratory polygraphy with data of mild intensity sleep apnoea syndrome, and severe nocturnal hypoxaemia (apnoea hypopnoea index per hours of sleep [AHI] 7.8; desaturation index per hour [ODI]: 12.6. Oxygen-medium saturation: 89%, minimum saturation: 72%. CT90: 34.2%). The chest X-ray showed elevation of the right hemidiaphragm, and the chest computed tomography (CT) revealed a Morgagni hernia with a maximum diameter of 20cm. After adjusting the antihypertensive treatment, the patient was referred to General Surgery for intervention. The onset of resistant hypertension secondary to severe nocturnal hypoxemia from a large Morgagni hernia has not been previously described in the literature.(AU)

Mujer de 51 años de edad que consultó por hipertensión arterial resistente, pese a tratamiento antihipertensivo adecuado. Presentaba una exploración y estudio analítico sin alteraciones relevantes, con saturación del 95% por pulsioximetría. En el estudio destacaba una poligrafía respiratoria nocturna con datos de síndrome de apnea del sueño de intensidad leve, e hipoxemia nocturna grave (índice de apneas hipopnea por horas de sueño [IAHH] 7,8; índice de desaturaciones por hora [IDH]: 12,6. Oxígeno-saturación media: 89%, saturación mínima: 72%. CT90: 34,2%). La radiografía de tórax mostró una elevación de hemidiafragma derecho, comprobándose en la tomografía computarizada (TC) torácica una hernia de Morgagni de 20 cm de diámetro máximo. Tras ajustar el tratamiento antihipertensivo, la paciente se derivó a cirugía general para su intervención. La aparición de hipertensión resistente secundaria a hipoxemia nocturna grave por una gran hernia de Morgagni no ha sido descrita previamente en la literatura.(AU)

[Pulse oximetry: Role in the COVID-19 patient at home]. / Pulsioximetría: papel en el paciente COVID-19 domiciliario.

COVID-19 behaves like a heterogeneous disease. Some patients may develop dyspnea-free hypoxemia during its evolution (silent hypoxemia). Pulse oximetry plays a crucial role in detecting hypoxemia in these patients, especially when they remain at home. Patients with SpO2 levels ≤ 92% or desaturations ≥ 3% after exercise test require hospital admission. Progressive saturation declines reaching SpO2 levels < 96% require strict clinical assessment (radiological study, blood test) for which it will be sent to a health center.

Resistant hypertension and Morgagni hernia: The importance of nocturnal hypoxaemia.

A 51-year-old woman consulted for resistant arterial hypertension despite adequate antihypertensive treatment. Physical examination and analytical study showed no relevant abnormalities, with pulse oximeter saturation of 95%. The study highlighted nocturnal respiratory polygraphy with data of mild intensity sleep apnoea syndrome, and severe nocturnal hypoxaemia (apnoea hypopnoea index per hours of sleep [AHI] 7.8; desaturation index per hour [ODI]: 12.6. Oxygen-medium saturation: 89%, minimum saturation: 72%. CT90: 34.2%). The chest X-ray showed elevation of the right hemidiaphragm, and the chest computed tomography (CT) revealed a Morgagni hernia with a maximum diameter of 20cm. After adjusting the antihypertensive treatment, the patient was referred to General Surgery for intervention. The onset of resistant hypertension secondary to severe nocturnal hypoxemia from a large Morgagni hernia has not been previously described in the literature.

Predictores de fracaso con cánula nasal de alto flujo de oxígeno en pacientes COVID-19 / Predictors of failure with high-flow nasal cannula oxygen in COVID-19 patients

Introducción: El COVID-19 ha generado retos por la alta demanda de servicios, haciendo necesario buscar alternativas de soporte ventilatorio que permitan responder a las necesidades de la población. Es importante disponer de herramientas que permitan detectar precozmente el fracaso de estrategias ventilatorias no invasivas e identificar tempranamente la necesidad de intubación. Objetivo: identificar las variables asociadas a fracaso en el tratamiento con cánula de alto flujo (CNAF) en pacientes con COVID-19. Materiales y Métodos: estudio observacional analítico, corte transversal con 68 pacientes de la unidad de cuidados intensivos con COVID-19, que recibieron tratamiento con CNAF. Las variables de estudio se evaluaron en tres momentos, a las 24, 48 y 72 horas, llevando a cabo un análisis bivariado y multivariado entre los que fracasaron y los que tuvieron éxito. Resultados: en el análisis bivariado las variables que presentaron una relación estadísticamente significativa a las 24h fueron el no presentar un aumento del trabajo respiratorio (Wresp) (p=0.000) y saturación de oxígeno (SatO2) normal (p=0.006). A las 48h: no aumento en Wresp (p=0.014), SatO2 normal (p=0.005), presión arterial de oxígeno/fracción inspirada de oxígeno (PAFI) leve o moderado (p=0.039). A las 72h fracasaron: PAFI severa (p=0.000), aumento de Wresp (p=0.001) y el índice de ROX menor a 4.88 (p=0.023). De acuerdo con el análisis multivariado las variables predictoras de fracaso a las 24h fueron: FIO2, SatO2, Wresp y a las 48h FIO2 y SatO2. Conclusiones: el aumento de FIO2>70 %, presentar incremento del Wresp y SpO2 menor de 88 % son variables asociadas a fracaso de la CNAF y facilitan tomar decisiones clínicas sobre avanzar o no hacia un soporte ventilatorio invasivo.

Introduction: COVID-19 has generated challenges due to the high demand for health care services, making it necessary to seek ventilatory support alternatives that allow us to fulfill the needs of the population. It is important to have tools that allow to detect the failure of non-invasive ventilatory strategies early and to identify the need for intubation on time. Objective: Identify the variables associated with failure of high-flow nasal cannula treatment (HFNC) on COVID-19 patients. Materials and Methods: Analytical observational, cross-sectional study of 68 patients in the intensive care unit with COVID-19, who received treatment with HFNC. The variables of the study were evaluated at three time points, at 24, 48 and 72 hours. A bivariate and multivariate analysis was performed between those who failed and those who were successful. Results: In the bivariate analysis, the variables that presented a statistically significant relationship at 24h were: No increase in work of breathing (WOB) (p=0.000), normal oxygen saturation (SatO2) (p=0.006). At 48h: No increase in WOB (p=0.014), normal SatO2 (p=0.005), mild to moderate partial pressure arterial oxygen/fraction inspired oxygen ratio (P/F ratio) (p=0.039). At 72h failed: severe P/F ratio (p=0.000), Increased WOB (p=0.001) and ROX index less than 4.88 (p=0.023). According to multivariate analysis the predictive variables for the therapeutic failure at 24h were: FIO2, SatO2, WOB; at 48h: FIO2 and SatO2. Conclusions: Increased FIO2>70%, increased WOB and SpO2 less than 88% are variables associated with failure of HFNC, and facilitate clinical decisions on whether or not to progress with invasive ventilatory support.

Fisiología respiratoria hipoxemia / Hypoxemia

La hipoxemia ocurre producto de una inadecuada captación de oxígeno a nivel pulmonar y se manifiesta como presión arterial de oxígeno menor a 60 mmHg o saturación arterial de oxígeno menor de 90%. Los mecanismos fisiopatológicos por los cuales se puede producir hipoxemia son hipoventilación, alteración del equilibrio ventilación perfusión, shunt cardiaco, alteración de la difusión y disminución de la presión inspirada de oxígeno. La comprensión de estos mecanismos es fundamental para entender su presentación clínica en distintas enfermedades.

Hypoxemia is the name given to inadequate uptake in the lung and is defined as an arterial oxygen pressure less than 60 mmHg or arterial oxygen saturation less than 90%. The pathophysiological mechanisms that can produce hypoxemia are: hypoventilation, ventilation perfusion mismatch, cardiac shunt, diffusion impairment and decreased inspired oxygen pressure. Full comprehension of these mechanism facilitates the understanding of hypoxemia among different diseases.

Taquipnea persistente de la infancia: hiperplasia de células neuroendocrinas, una revisión / Persistent tachypnea of infancy: neuroendocrine cell hyperplasia, a review

La hiperplasia de células neuroendocrinas de la infancia (HCNEI) constituye una de las enfermedades intersticiales más frecuentes en pediatría. Tanto su etiología como los mecanismos fisiopatológicos involucrados son inciertos. Suele presentarse en pacientes por lo demás sanos, durante los primeros meses de vida con taquipnea, retracciones costales, rales e hipoxemia. En la tomografía axial computada de tórax de alta resolución (TACAR) presenta imágenes características en vidrio esmerilado de distribución central y zonas de atrapamiento aéreo. Para el diagnóstico, además de la clínica y la TACAR, podemos recurrir a la biopsia en casos atípicos. Los hallazgos histológicos reflejan una arquitectura pulmonar normal y un aumento en el número de células neuroendocrinas. El manejo global es con medidas de sostén, ya que no se cuenta con un tratamiento específico. La sintomatología suele mejorar con la edad y el pronóstico es favorable.

Neuroendocrine cell hyperplasia of infancy (NEHI) is one of the most common interstitial lung diseases of childhood. The etiology and pathophysiological mechanisms involved are uncertain. It usually presents in otherwise healthy patients during the first months of life with tachypnea, rib retractions, crackles, and hypoxemia. High-resolution chest computed tomography (HRCT) shows ground-glass opacities of central distribution and areas of air trapping. For diagnosis purposes, in addition to clinical and HRCT features, a lung biopsy is indicated for atypical cases. Histological findings reflect normal architecture and an increased number of neuroendocrine cells. The management consists of supportive and preventive care, since there is no specific treatment. Symptoms usually improve with age and the prognosis is favorable.