Nuevo método no-invasivo para la detección de PEEP intrínseca basado en la cinetica del CO2 espirado

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Medicina, Departamento de Medicina. Fecha de lectura: 14-09-2020Presentamos un método no invasivo para la determinación del nivel de PEEP-I basado en la dilución end-tidal del capnograma volumétrico (etCO2D) utilizando un sensor de CO2 con un adaptador modificado y una fuga controlada. Una de las ramas está conectada a un ventilador capaz de mantener una presión espiratoria constante y la otra está abierta a la atmósfera. Si situamos el analizador de CO2en el extremo próximo al paciente siempre que la presión final espiratoria del paciente (PEEP-I) sea mayor que la presión proveniente del ventilador se obtendrá un capnograma completo. En cuanto la presión espiratoria del ventilador supere el nivel de PEEP-I del paciente el capnograma se diluirá con gas fresco proveniente del ventilador indicando el punto de presión de PEEP-I1. Se estudiaron 12 cerdos (25 kg) sometidos a ventilación mecánica bajo anestesia, en los que se indujo PEEP-I mediante la interposición de una resistencia en el extremo proximal del tubo endo-traqueal. Los valores de presión, flujo y CO2espirado se midieron en la vía aérea. Para la detección del nivel de PEEP-I, el nivel de presión final espiratoria del ventilador se modificó en pasos de 0,2 cmH2O. Mediante la combinación de diferentes volúmenes corrientes, frecuencias respiratorias, y relaciones I: E se obtuvieron 52 niveles diferentes de PEEP-I (rango 1,8 a 11, 7 cmH2O, Media 8,455± 0,32 cmH2O). En cada condición experimental el nivel de etCO2D obtenido se comparó con la PEEP-I medida mediante el método de referencia utilizado, de “oclusión espiratoria”. El método etCO2D fue capaz de detectar cambios en el nivel de PEEP-I de 0,2 cmH2O. La PEEP-I medida por etCO2D y la medida de referencia mostraron una buena correlación (R2 0,80, p < 0,0001). Estos resultados mostraron una buena correspondencia con el análisis residual gráfico de Bland- Altman que mostró una exactitud de -0,26 y precisión ±1,96SD (2,23; -2,74) (P<0,0001). Este método podría convertirse en una forma no invasiva y fiable de monitorizar de manera continua la PEEP-I en pacientes en ventilación mecánicaWe present a non-invasive method for determining the level of PEEP-I based on the end-tidal dilution of the volumetric capnogram (etCO2D) using a CO2sensor with a modified adapter and a controlled leak. One of the branches is connected to a ventilator able to maintain a constant expiratory pressure and the other is open to the atmosphere. If we place the CO2analyzer at the end of the endotracheal tube near the patient as long as the patient's final expiratory pressure (PEEP-I) is greater than the pressure from the ventilator, a full capnogram will be obtained. But if the expiratory pressure of the ventilator exceeds the patient's PEEP-I level, the capnogram will be diluted with fresh gas from the ventilator indicating the pressure point of PEEP-I. Twelve pigs (25 kg) were connected to mechanical ventilation under anesthesia, in which PEEP-I was induced by the interposition of a resistance at the proximal end of the endo-tracheal tube. The values of pressure, flow and exhaled CO2were measured in the airway. For the detection of the level of PEEP-I, the final expiratory pressure level of the ventilator was modified in 0.2 cmH2O steps. By combining different tidal volumes, respiratory frequencies, and I: E ratios, 52 different levels of PEEP-I were obtained (range 1.8 to 11.7 cmH2O, mean 8.455 ± 0.32 cmH2O). In each experimental condition the level of etCO2D obtained was compared with the PEEP-I measured by the reference method used, the "expiratory occlusion test". The etCO2D method was able to detect changes in the level of PEEP-I of 0.2 cmH2O. The PEEP-I measured by etCO2D and the reference measure showed a good correlation (R2 0.80, p <0.0001). These results showed a good correspondence with the residual Bland-Altman graphical analysis that showed an accuracy of -0.26 and precition of ± 1.96SD (2.23; -2.74) (P <0.0001). This method could become a non-invasive and reliable way to continuously monitor PEEP-I in patients with mechanical ventilatio

Clinical consensus recommendations regarding non-invasive respiratory support in the adult patient with acute respiratory failure secondary to SARS-CoV-2 infection

La enfermedad por coronavirus 2019 (COVID-19) es una infección del tracto respiratorio causada por un nuevo coronavirus emergente que se reconoció por primera vez en Wuhan, China, en diciembre de 2019. Actualmente la Organización Mundial de la Salud (OMS) ha definido la infección como pandemia y existe una situación de emergencia sanitaria y social para el manejo de esta nueva infección. Mientras que la mayoría de las personas con COVID-19 desarrollan solo una enfermedad leve o no complicada, aproximadamente el 14% desarrollan una enfermedad grave que requiere hospitalización y oxígeno, y el 5% pueden requerir ingreso en una unidad de cuidados intensivos. En casos severos, COVID-19 puede complicarse por el síndrome de dificultad respiratoria aguda (SDRA), sepsis y shock séptico y fracaso multiorgánico. Este documento de consenso se ha preparado sobre directrices basadas en evidencia desarrolladas por un panel multidisciplinario de profesionales médicos de cuatro sociedades científicas españolas (Sociedad Española de Medicina Intensiva y Unidades Coronarias [SEMICYUC], Sociedad Española de Neumología y Cirugía Torácica [SEPAR], Sociedad Española de Urgencias y Emergencias [SEMES], Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor [SEDAR]) con experiencia en el manejo clínico de pacientes con COVID-19 y otras infecciones virales, incluido el SARS, así como en sepsis y SDRA. El documento proporciona recomendaciones clínicas para el soporte respiratorio no invasivo (ventilación no invasiva, oxigenoterapia de alto flujo con cánula nasal) en cualquier paciente con presentación sospechada o confirmada de COVID-19 con insuficiencia respiratoria aguda. Esta guía de consenso debe servir como base para una atención optimizada y garantizar la mejor posibilidad de supervivencia, así como permitir una comparación fiable de las futuras intervenciones terapéuticas de investigación que formen parte de futuros estudios observacionales o de ensayos clínicos.Coronavirus disease 2019 (COVID-19) is a respiratory tract infection caused by a newly emergent coronavirus, that was first recognized in Wuhan, China, in December 2019. Currently, the World Health Organization (WHO) has defined the infection as a global pandemic and there is a health and social emergency for the management of this new infection. While most people with COVID-19 develop only mild or uncomplicated illness, approximately 14% develop severe disease that requires hospitalization and oxygen support, and 5% require admission to an intensive care unit. In severe cases, COVID-19 can be complicated by the acute respiratory distress syndrome (ARDS), sepsis and septic shock, and multiorgan failure. This consensus document has been prepared on evidence-informed guidelines developed by a multidisciplinary panel of health care providers from four Spanish scientific societies (Spanish Society of Intensive Care Medicine [SEMICYUC], Spanish Society of Pulmonologists [SEPAR], Spanish Society of Emergency [SEMES], Spanish Society of Anesthesiology, Reanimation, and Pain [SEDAR]) with experience in the clinical management of patients with COVID-19 and other viral infections, including SARS, as well as sepsis and ARDS. The document provides clinical recommendations for the noninvasive respiratory support (noninvasive ventilation, high flow oxygen therapy with nasal cannula) in any patient with suspected or confirmed presentation of COVID-19 with acute respiratory failure. This consensus guidance should serve as a foundation for optimized supportive care to ensure the best possible chance for survival and to allow for reliable comparison of investigational therapeutic interventions as part of randomized controlled trials

Main Procedures in the Intermediate Respiratory Care Units

Respiratory intermediate care units (RICU) are a structure that in terms of complexity is between that of a hospitalization ward and the intensive care unit. However, given that its cost efficiency increases with complexity, the procedures that are carried out in it have also been increasing with it over time. We present the most frequent ones

Fiabilidad de los sistemas de Venturi en la oxigenoterapia

Los sistemas de Venturi son unos de los productos más utilizados para la administración de la oxigenoterapia. A pesar de su extendido empleo en la práctica clínica habitual, se carece de rigurosos controles de calidad sobre su fiabilidad. En este trabajo se analizan por espectrometría de masas, según la normativa de la Unión Europea (UE), los sistemas de Venturi de distintas casas proveedoras disponibles en el mercado español. Se evalúa también la tolerancia de los sistemas ante diversas circustancias (cambios de flujo de oxígeno y aumento de resistencias en el sistema). Se ha encontrado que los sistemas fijos se adaptan bien a la normativa, mientras que ninguno de los sistemas variables cumple los requisitos que establece esta normativa, y un sistema (Oxigem variable) es incapaz de dar, para concentraciones del 24-28%, una concentración de O2 por debajo del 31%. En conclusión, en nuestro mercado las mascarillas variables no cumplen la normativa UE y una de ellas (Oxigem variable) tiene un rango de error que no permite su uso en la práctica clínica. Los más fiables en nuestro estudio fueron los sistemas fijos y, dentro de los variables, los de Airlife e Intersurgical se aproximaban a éstos

Continuous monitoring of intrinsic PEEP based on expired CO2 kinetics : an experimental validation study

Background Quantification of intrinsic PEEP (PEEPi) has important implications for patients subjected to invasive mechanical ventilation. A new non-invasive breath-by-breath method (etCO(2)D) for determination of PEEPi is evaluated. MethodsIn 12 mechanically ventilated pigs, dynamic hyperinflation was induced by interposing a resistance in the endotracheal tube. Airway pressure, flow, and exhaled CO2 were measured at the airway opening. Combining different I:E ratios, respiratory rates, and tidal volumes, 52 different levels of PEEPi (range 1.8-11.7cmH(2)O; mean 8.450.32cmH(2)O) were studied. The etCO(2)D is based on the detection of the end-tidal dilution of the capnogram. This is measured at the airway opening by means of a CO2 sensor in which a 2-mm leak is added to the sensing chamber. This allows to detect a capnogram dilution with fresh air when the pressure coming from the ventilator exceeds the PEEPi. This method was compared with the occlusion method. Results The etCO(2)D method detected PEEPi step changes of 0.2cmH(2)O. Reference and etCO(2)D PEEPi presented a good correlation (R-2 0.80, P&lt;0.0001) and good agreement, bias -0.26, and limits of agreement +/- 1.96 SD (2.23, -2.74) (P&lt;0.0001). Conclusions The etCO(2)D method is a promising accurate simple way of continuously measure and monitor PEEPi. Its clinical validity needs, however, to be confirmed in clinical studies and in conditions with heterogeneous lung diseases

Effectiveness of Intermediate Respiratory Care Units as an Alternative to Intensive Care Units during the COVID-19 Pandemic in Catalonia

Objectives: During the COVID-19 pandemic, the risk of collapse for the health system created great difficulties. We will demonstrate that intermediate respiratory care units (IRCU) provide adequate management of patients with non-invasive respiratory support, which is particularly important for patients with SARS-CoV-2 pneumonia. Methods: A prospective observational study of patients with COVID-19 admitted to the ICU of a tertiary hospital. Sociodemographic data, comorbidities, pharmacological, respiratory support, laboratory and blood gas variables were collected. The overall cost of the unit was subsequently analyzed. Results: 991 patients were admitted, 56 to the IRCU (from a of 81 admitted to the critical care unit). Mean age was 65 years (SD 12.8), Barthel index 75 (SD 8.3), Charlson comorbidity index 3.1 (SD 2.2), HTN 27%, COPD 89% and obesity 24%. A significant relationship (p < 0.05) with higher mortality was noted for the following parameters: fever greater than or equal to 39 degrees C [OR 5.6; 95% CI (1.2-2.7); p = 0.020], protocolized pharmacological treatment [OR 0.3; 95% CI (0.1-0.9); p = 0.023] and IOI [OR 3.7; 95% CI (1.1-12.3); p = 0.025]. NIMV had less of a negative impact [OR 1.8; 95% CI (0.4-8.4); p = 0.423] than IOI. The total cost of the IRCU amounted to euro66,233. The cost per day of stay in the IRCU was euro164 per patient. The total cost avoided was euro214,865. Conclusions: The pandemic has highlighted the importance of IRCUs in facilitating the management of a high patient volume. The treatment carried out in IRCUs is effective and efficient, reducing both admissions to and stays in the ICU

Development and validation of a predictive model of in-hospital mortality in COVID-19 patients.

We retrospectively evaluated 2879 hospitalized COVID-19 patients from four hospitals to evaluate the ability of demographic data, medical history, and on-admission laboratory parameters to predict in-hospital mortality. Association of previously published risk factors (age, gender, arterial hypertension, diabetes mellitus, smoking habit, obesity, renal failure, cardiovascular/ pulmonary diseases, serum ferritin, lymphocyte count, APTT, PT, fibrinogen, D-dimer, and platelet count) with death was tested by a multivariate logistic regression, and a predictive model was created, with further validation in an independent sample. A total of 2070 hospitalized COVID-19 patients were finally included in the multivariable analysis. Age 61-70 years (p80 years (p2 ULN (p = 0.003; OR: 1.79; 95%CI: 1.22 to 2.62), and prolonged PT (p<0.001; OR: 2.18; 95%CI: 1.49 to 3.18) were independently associated with increased in-hospital mortality. A predictive model performed with these parameters showed an AUC of 0.81 in the development cohort (n = 1270) [sensitivity of 95.83%, specificity of 41.46%, negative predictive value of 98.01%, and positive predictive value of 24.85%]. These results were then validated in an independent data sample (n = 800). Our predictive model of in-hospital mortality of COVID-19 patients has been developed, calibrated and validated. The model (MRS-COVID) included age, male gender, and on-admission coagulopathy markers as positively correlated factors with fatal outcome

Fluid Intake in Critically Ill Patients: The “Save Useless Fluids For Intensive Resuscitation” Multicenter Prospective Cohort Study

International audienceObjectives: Patients at risk of adverse effects related to positive fluid balance could benefit from fluid intake optimization. Less attention is paid to nonresuscitation fluids. We aim to evaluate the heterogeneity of fluid intake at the initial phase of resuscitation. Design: Prospective multicenter cohort study. Setting: Thirty ICUs across France and one in Spain. Patients: Patients requiring vasopressors and/or invasive mechanical ventilation. Interventions: None. Measurements and Main Results: All fluids administered by vascular or enteral lines were recorded over 24 hours following admission and were classified in four main groups according to their predefined indication: fluids having a well-documented homeostasis goal (resuscitation fluids, rehydration, blood products, and nutrition), drug carriers, maintenance fluids, and fluids for technical needs. Models of regression were constructed to determine fluid intake predicted by patient characteristics. Centers were classified according to tertiles of fluid intake. The cohort included 296 patients. The median total volume of fluids was 3546 mL (interquartile range, 2441–4955 mL), with fluids indisputably required for body fluid homeostasis representing 36% of this total. Saline, glucose-containing high chloride crystalloids, and balanced crystalloids represented 43%, 27%, and 16% of total volume, respectively. Whatever the class of fluids, center of inclusion was the strongest factor associated with volumes. Compared with the first tertile, the difference between the volume predicted by patient characteristics and the volume given was +1.2 ± 2.0 L in tertile 2 and +3.0 ± 2.8 L in tertile 3. Conclusions: Fluids indisputably required for body fluid homeostasis represent the minority of fluid intake during the 24 hours after ICU admission. Center effect is the strongest factor associated with the volume of fluids. Heterogeneity in practices suggests that optimal strategies for volume and goals of common fluids administration need to be developed