Estimating arterial blood gases with the EABC® System ("Earlobe Arterialized Blood Collector") in critically ill patients. A validation study

The Earlobe Arterialized Blood Collector® is a minimally invasive system able to perform arterialized capillary blood gas analysis from the earlobe (EL). A prospective validation study was performed in 55 critical ill patients. Sampling failure rate was high (53.6%). Risk factors were age > 65 years, diabetes, vasoactive drug therapy and noradrenaline (NA) doses above 0.22 μg / kg / min. Multivariate analysis showed age > 65 years was the only factor independently associated with failure. Concordance analysis with arterial blood gases and Bland-Altman agreement evaluation were insufficient for validating the new system for all gasometrical variables.El Earlobe Arterialized Blood Collector® és un sistema mínimament invasiu capaç d'analitzar geomètricament sang capil·lar arterialitzada del lòbul de l'orella (EL). Un estudi prospectiu de validació es va realitzar en 55 pacients crítics. La taxa de fracàs fou alta i els següents foren factors de risc: edat> 65, diabetis, drogues vasoactives i tractament amb noradrenalina a dosis > 0,22 mg / kg / min. L'anàlisi multivariat mostrà l'edat > 65 com l'únic factor independent. L'anàlisi de concordança amb els valors de sang arterial i l'avaluació pel mètode de Bland-Altman no van ser suficients per validar el nou sistema

The HADES mission concept - astrobiological survey of Jupiter's icy moon Europa

The HADES Europa mission concept aims to provide a framework for an astrobiological in-depth investigation of the Jupiter moon Europa, relying on existing technologies and feasibility. This mission study proposes a system consisting of an orbiter, lander and cryobot as a platform for detailed exploration of Europa. While the orbiter will investigate the presence of a liquid ocean and characterize Europa's internal structure, the lander will survey local dynamics of the ice layer and the surface environment. The lander releases a cryobot, that melts into the ice, will sample the pristine subsurface and is expected to provide data on organic and gaseous content and putative bio-signatures. In summary, we present the scientific objectives for an astrobiological investigation of Europa, resulting in a mission concept with a detailed evaluation of scientific instrumentation, mission sequences, basic design of the spacecraft, technology needs and cost estimation

The HADES mission concept – Astrobiological survey of Jupiter's icy moon Europa

The HADES Europa mission concept aims to provide a framework for an astrobiological in-depth investigation of the Jupiter moon Europa, relying on existing technologies and feasibility. This mission study proposes a system consisting of an orbiter, lander and cryobot as a platform for detailed exploration of Europa. While the orbiter will investigate the presence of a liquid ocean and characterize Europa's internal structure, the lander will survey local dynamics of the ice layer and the surface environment. The lander releases a cryobot, that melts into the ice, will sample the pristine subsurface and is expected to provide data on organic and gaseous content and putative bio-signatures. In summary, we present the scientific objectives for an astrobiological investigation of Europa, resulting in a mission concept with a detailed evaluation of scientific instrumentation, mission sequences, basic design of the spacecraft, technology needs and cost estimations

Evaluation of femoral dP/dt max as a marker of cardiac function in critically ill patients

El màxim increment de pressió per unitat de temps (dP/dtmax) mesurat a nivell de l'arteria femoral és considerat per molts com un marcador fiable i mínimament invasiu de la contractilitat cardíaca. A diferència de la mesura del dP/dtmax al ventricle esquerre, el dP/dtmax femoral te lloc durant la fase d'ejecció ventricular del cicle cardíac i, per tant, hauria d'estar subjecte als efectes de la post-càrrega i dependre del to arterial. A demès, i de forma similar al dP/dtmax del ventricle esquerre, la mesura del dP/dtmax femoral podria estar subjecte a variacions en la pre-càrrega cardíaca a través de múltiples mecanismes. L'objectiu de la present tesi doctoral és el d'analitzar els efectes de la pre-càrrega i la post-càrrega en la mesura del dP/dtmax femoral, i avaluar la seva validesa com a marcador de contractilitat cardíaca. Es van realitzar dos estudis per respondre a les hipòtesis formulades. En el primer es van analitzar els canvis en el dP/dtmax femoral de manera prospectiva durant canvis en la contractilitat cardíaca (variacions en la dosi d'infusió de dobutamina), post-càrrega (variacions en la dosi d'infusió de noradrenalina) i en la pre-càrrega (mitjançant l'administració d'una càrrega de volum estàndard o una maniobra d'elevació de les cames) en pacients crítics. En el segon, es va realitzar un estudi retrospectiu en pacients crítics que havien rebut una càrrega de volum estàndard on es va analitzar la rellevància de la pre-càrrega dependència sobre la resposta del dP/dtmax femoral a canvis en la pre-càrrega cardíaca. Els resultats suggereixen que, tot i que pot existir una relació entre les mesures de dP/dtmax femoral i ventricular, el dP/dtmax femoral és altament susceptible a canvis en la post-carrega ventricular i el to arterial, i canvia amb els canvis de pre-càrrega en pacients en situació de pre-càrrega dependència. Addicionalment, el dP/dtmax femoral va mostrar una relació quasi directe amb la pressió de pols en tots els casos, el qué suggereix que qualsevol canvi en aquesta pot influenciar la mesura del dP/dtmax femoral. Basant-se en els resultats obtinguts, es pot concloure amb una raonable certesa que el dP/dtmax femoral no és un marcador adequat de la contractilitat cardíaca, donat que es veu influenciat pels canvis en la pre i post-càrrega ventricular, i per tant, no s'hauria d'emprar com a tal en la practica clínica habitual.El máximo incremento de presión por unidad de tiempo (dP/dtmax) medido a nivel de la arteria femoral es considerado por muchos como un marcador fiable y mínimamente invasivo de la contractilidad cardíaca. A diferencia de la medida del dP/dtmax en el ventrículo izquierdo, el dP/dtmax femoral tiene lugar durante la fase de eyección ventricular del ciclo cardíaco y, por tanto, debería estar sujeta a los efectos de la post-carga y depender del tono arterial. Además, y de forma similar al dP/dtmax del ventrículo izquierdo, la medida del dP/dtmax femoral podría estar sujeta a variaciones en la pre-carga cardíaca a través de múltiples mecanismos. El objetivo de la presente tesis doctoral es el analizar los efectos de la pre-carga y la post-carga en la medida del dP/dtmax femoral, y evaluar su validez como marcador de contractilidad cardíaca. Se realizaron dos estudios para responder a las hipótesis formuladas. En el primero se analizaron los cambios en el dP/dtmax femoral de manera prospectiva durante cambios en la contractilidad cardíaca (variaciones en la dosis de infusión de dobutamina), post-carga (variaciones en la dosis de infusión de noradrenalina) y en la pre-carga (mediante la administración de una carga de volumen estándar o una maniobra de elevación de las piernas) de pacientes críticos. En el segundo, se realizó un estudio retrospectivo en pacientes críticos que habían recibido una carga de volumen estándar donde se analizó la relevancia de la pre-carga dependencia sobre la respuesta del dP/dtmax femoral a cambios en la pre-carga cardíaca. Los resultados sugieren que, a pesar de que puede existir una relación entre las medidas de dP/dtmax femoral y ventricular, el dP/dtmax femoral es altamente susceptible a cambios en la post-carga ventricular y el tono arterial, y cambia con las variaciones de pre-carga en pacientes en situación de pre-carga dependencia. Adicionalmente, el dP/dtmax femoral mostró una relación cuasi directa con la presión de pulso en todos los casos, lo que sugiere que cualquier cambio en ésta puede influenciar la medida del dP/dtmax femoral. De acuerdo con los resultados obtenidos, se puede concluir con una certeza razonable que el dP/dtmax femoral no es un marcador adecuado de la contractilidad cardíaca, dado que se ve influenciado por los cambios en la pre y post-carga ventricular, y por tanto, no se debería utilizar como tal en la práctica clínica habitual.Femoral dP/dtmax (the maximum rise of pressure over time) has been considered by many as a minimally invasive, peripheral marker of left ventricle contractility. However, in contrast to left ventricular dP/dtmax, femoral dP/dtmax occurs during the ejection phase of the cardiac cycle and should therefore be subject to afterload and arterial load variations. Furthermore, similar to the left ventricle dP/dtmax, femoral dP/dtmax might be subject to preload variations through several potential mechanisms. The objective of the present work was to elucidate the effects of left ventricle loading conditions (preload and afterload) on the measure of femoral dP/dtmax and to assess the reliability of this marker as an estimator of cardiac contractility. Two studies were performed to address the hypothesis formulated for the present doctoral work. In the first, changes in femoral dP/dtmax were prospectively monitored during contractility (dobutamine infusion change), afterload (norepinephrine dose change) and preload (passive leg raising or volume expansion) variations in critically ill patients. In the second, a retrospective analysis of a database of critically ill patients receiving fluid infusion was analysed to evaluate the relevance of preload-dependence on the responsiveness of femoral dP/dtmax to preload variations. Results suggested that although a link between femoral dP/dtmax and left ventricle contractility variations may exists, femoral dP/dtmax is highly susceptible to changes in afterload and arterial load, and varies with preload increases in preload-dependent patients. Furthermore, femoral dP/dtmax retained an almost direct correlation with pulse pressure in all cases, suggesting that any change in the later should also influence the former. According to present results, it can therefore be concluded with reasonable certainly that femoral dP/dtmax is not an adequate marker of cardiac contractility as it is affected by left ventricular loading conditions and should not be used as such in clinical practice.Universitat Autònoma de Barcelona. Programa de Doctorat en Medicin

Estimating arterial blood gases with the EABC® System (“Earlobe Arterialized Blood Collector”) in critically ill patients. A validation study.

The Earlobe Arterialized Blood Collector® is a minimally invasive system able to perform arterialized capillary blood gas analysis from the earlobe (EL). A prospective validation study was performed in 55 critical ill patients. Sampling failure rate was high (53.6%). Risk factors were age > 65 years, diabetes, vasoactive drug therapy and noradrenaline (NA) doses above 0.22 μg / kg / min. Multivariate analysis showed age > 65 years was the only factor independently associated with failure. Concordance analysis with arterial blood gases and Bland-Altman agreement evaluation were insufficient for validating the new system for all gasometrical variables.El Earlobe Arterialized Blood Collector® és un sistema mínimament invasiu capaç d’analitzar geomètricament sang capil•lar arterialitzada del lòbul de l'orella (EL). Un estudi prospectiu de validació es va realitzar en 55 pacients crítics. La taxa de fracàs fou alta i els següents foren factors de risc: edat> 65, diabetis, drogues vasoactives i tractament amb noradrenalina a dosis > 0,22 mg / kg / min. L'anàlisi multivariat mostrà l'edat > 65 com l’únic factor independent. L’anàlisi de concordança amb els valors de sang arterial i l’avaluació pel mètode de Bland-Altman no van ser suficients per validar el nou sistema

Earlobe arterialized capillary blood gas analysis in the intensive care unit:a pilot study

BACKGROUND: Earlobe arterialized capillary blood gas analysis can be used to estimate arterial gas content and may be suitable for diagnosis and management of critically ill patients. However, its utility and applicability in the ICU setting remains unexplored. METHODS: A prospective observational validation study was designed to evaluate this technique in a cohort of mechanically ventilated adult critically ill patients admitted to a polyvalent ICU. Precision and agreement between capillary gas measures and arterial references was examined. Acute Respiratory Distress Syndrome (ARDS) diagnosis capabilities with the proposed technique were also evaluated. Finally, factors associated with sampling failure were explored. RESULTS: Fifty-five patients were included into this study. Precision of capillary samples was high (Coefficient of Variation PO(2) = 9.8%, PCO(2) = 7.7%, pH = 0.3%). PO(2) measures showed insufficient agreement levels (Concordance Correlation Coefficient = 0.45; bias = 12 mmHg; percentage of error = 19.3%), whereas better agreement was observed for PCO(2) and pH (Concordance Correlation Coefficient = 0.94 and 0.93 respectively; depreciable bias; percentage of error 11.4% and 0.5% respectively). The sensitivity and specificity for diagnosing ARDS were 100% and 92.3% using capillary gasometric measures. Sampling was unsuccessful in 43.6% of cases due to insufficient blood flow. Age > 65 years was independently associated with failure (odds ratio = 1.6), however hemodynamic failure and norepinephrine treatment were also influencing factors. CONCLUSIONS: Earlobe capillary blood gas analysis is precise and can be useful for detecting extreme gasometrical values. Diagnosis of ARDS can be done accurately using capillary measurements. Although this technique may be insufficient for precise management of patients in the ICU, it has the potential for important benefits in the acute phase of various critical conditions and in other critical care arenas, such as in emergency medicine, advanced medical transport and pre-hospital critical care

Systematic review and meta-analysis of complications and mortality of veno-venous extracorporeal membrane oxygenation for refractory acute respiratory distress syndrome

Abstract Veno-venous extracorporeal membrane oxygenation (ECMO) for refractory acute respiratory distress syndrome (ARDS) is a rapidly expanding technique. We performed a systematic review and meta-analysis of the most recent literature to analyse complications and hospital mortality associated with this technique. Using the PRISMA guidelines for systematic reviews and meta-analysis, MEDLINE and EMBASE were systematically searched for studies reporting complications and hospital mortality of adult patients receiving veno-venous ECMO for severe and refractory ARDS. Studies were screened for low bias risk and assessed for study size effect. Meta-analytic pooled estimation of study variables was performed using a weighted random effects model for study size. Models with potential moderators were explored using random effects meta-regression. Twelve studies fulfilled inclusion criteria, representing a population of 1042 patients with refractory ARDS. Pooled mortality at hospital discharge was 37.7% (CI 95% = 31.8–44.1; I 2 = 74.2%). Adjusted mortality including one imputable missing study was 39.3% (CI 95% = 33.1–45.9). Meta-regression model combining patient age, year of study realization, mechanical ventilation (MV) days and prone positioning before veno-venous ECMO was associated with hospital mortality (p < 0.001; R 2 = 0.80). Patient age (b = 0.053; p = 0.01) and maximum cannula size during treatment (b = −0.075; p = 0.008) were also independently associated with mortality. Studies reporting H1N1 patients presented inferior hospital mortality (24.8 vs 40.6%; p = 0.027). Complication rate was 40.2% (CI 95% = 25.8–56.5), being bleeding the most frequent 29.3% (CI 95% = 20.8–39.6). Mortality due to complications was 6.9% (CI 95% = 4.1–11.2). Mechanical complications were present in 10.9% of cases (CI 95% = 4.7–23.5), being oxygenator failure the most prevalent (12.8%; CI 95% = 7.1–21.7). Despite initial severity, significant portion of patients treated with veno-venous ECMO survive hospital discharge. Patient age, H1N1-ARDS and cannula size are independently associated with hospital mortality. Combined effect of patient age, year of study realization, MV days and prone positioning before veno-venous ECMO influence patient outcome, and although medical complications are frequent, their impact on mortality is limited

Active transmembrane drug transport in microgravity: A validation study using an ABC transporter model

Microgravity has been shown to influence the expression of ABC (ATP-Binding Cassette) transporters in bacteria, fungi and mammals, but also to modify the activity of certain cellular components with structural and functional similarities to ABC transporters. Changes in activity of ABC transporters could lead to important metabolic disorders and undesired pharmacological effects during spaceflights. However, no current means exist to study the functionality of these transporters in microgravity. To this end, a Vesicular Transport Assay® (Solvo Biotechnology, Hungary) was adapted to evaluate multi-drug resistance-associated protein 2 (MRP2) trans-membrane estradiol-17-ß-glucuronide (E17ßG) transport activity, when activated by adenosine-tri-phosphate (ATP) during parabolic flights. Simple diffusion, ATP-independent transport and benzbromarone inhibition were also evaluated. A high accuracy engineering system was designed to perform, monitor and synchronize all procedures. Samples were analysed using a validated high sensitivity drug detection protocol. Experiments were performed in microgravity during parabolic flights, and compared to 1g on ground results using identical equipment and procedures in all cases. Our results revealed that sufficient equipment accuracy and analytical sensitivity were reached to detect transport activity in both gravitational conditions. Additionally, transport activity levels of on ground samples were within commercial transport standards, proving the validity of the methods and equipment used. MRP2 net transport activity was significantly reduced in microgravity, so was signal detected in simple diffusion samples. Ultra-structural changes induced by gravitational stress upon vesicle membranes or transporters could explain the current results, although alternative explanations are possible. Further research is needed to provide a conclusive answer in this regard. Nevertheless, the present validated technology opens new and interesting research lines in biology and human physiology with the potential for significant benefits for both space and terrestrial medicine

MOESM1 of Systematic review and meta-analysis of complications and mortality of veno-venous extracorporeal membrane oxygenation for refractory acute respiratory distress syndrome

Additional file 1. Study Databas