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Microcirculatory Perfusion-Based Approach to the Critically Ill Patient: Bringing a Research Tool Technology to the Bedside
Get PDFMonitorare il microcircolo nel paziente critico offre un approccio più fisiologico alla loro gestione: un microcircolo alterato, quale causa primaria di ipoperfusione tissutale e disfunzione d’organo dovrebbe rappresentare il target dei trattamenti, specialmente quando il ripristino delle variabili emodinamiche standard sembra essere insufficiente a migliorare l’outcome. Nonostante questo enorme potenziale, esso resta ancora solamente uno strumento di ricerca.
Questo lavoro, una raccolta di alcuni articoli di ricerca, è stato condotto nel tentativo di avvicinare la ricerca alla pratica clinica.
Lo studio di validazione della tecnologia di terza generazione per l’imaging del microcircolo, l’Incident Dark Field illumination (IDF), fornisce il confronto con il gold standard. È stata poi posta l’attenzione sulle difficoltà tecniche di acquisizione di imaging adeguato del microcircolo e sull’ impatto sull’interpretazione dei dati, con particolare riguardo all’esperienza dell’operatore e alla collaborazione del paziente.
Il core del progetto è rappresentato dal MicroDAIMON, uno studio prospettico osservazionale sul monitoraggio giornaliero del microcircolo nel paziente critico che fornisce uno dei più ampi database esistenti e che ha mostrato l’associazione tra alterazioni del microcircolo al baseline e outcome. Il monitoraggio è stato eseguito anche con Near InfraRed Spectroscopy su muscolo scheletrico con test di occlusione vascolare, per valutare la reattività dinamica del microcircolo ad un insulto ischemico e la sua capacità di riserva. Un’analisi di sottogruppo ha incentrato l’attenzione sul paziente politraumatizzato, mostrando che la persistenza di un microcircolo alterato in presenza di variabili macro-emodinamiche ottimizzate può predire un aumentato rischio di disfunzione d’organo. Infine, con uno studio open label, è stato valutato l’effetto della ketanserina sul microcircolo, cercando di fornire un approccio farmacologico alle alterazioni microcircolatorie.Focusing microcirculation in critically ill patients offers a physiologic approach to their management: an impaired microcirculation, as the “motor” of tissues hypoperfusion and organ dysfunction, should represent the target of interventions, especially when the restoring of the standard macrohemodynamic variables appears to be insufficient to improve the patient outcome. Despite this huge potential, microcirculatory monitoring still remains a research tool.
The present work, a collection of diverse research articles, was conducted trying to build a bridge between the research setting and the clinical practice.
It includes the validation study of the third-generation technology for microcirculatory imaging, the Incident Dark Field illumination (IDF), providing a comparison with the gold standard. Moreover, it gives a deep insight on the technical issues in collecting appropriate imaging and on their impact on the data interpretation, focusing the attention on the operator experience and patient’s cooperation.
The core of the project is represented by the MicroDAIMON, a prospective observational study with one of the largest databases of microcirculatory data in critically ill patients to date: it shows the association between microcirculatory abnormalities at the baseline and mortality. Daily monitoring was also performed with Near InfraRed Spectroscopy of skeletal muscle associated to a vascular occlusion test in order to evaluate the dynamic response and reserve capacity of the microcirculation to an ischemic disturbance. A subgroup analysis, focuses the attention on trauma patients, showing that the persistence of microcirculatory abnormalities in presence of normalized macro-hemodynamic variables could predict a major risk of development of organ dysfunction. Finally, with an open label pilot study, the effect of ketanserin in recruiting a dysfunctional microcirculation was investigate, trying to propose a pharmacologic approach to microcirculatory abnormalities
Evaluation of the Microcirculation in Critically Ill Patients
No full textAbstract: The first goal of therapies in critically ill patients is to improve tissue perfusion and oxygenation. Hemodynamic monitoring has long been limited to measure-ments of cardiac output and global oxygen delivery. The clinical introduction of hand-held vital microscopes in the late 1990s enabled the real-time, non-invasive, bedside ob-servation of blood flow in the microcirculation (vessels with diameter <100 μm), i.e. the real site of oxygen and nutrient exchange between blood and cells. Microcirculatory alter-ations have been described during sepsis and shock states and were associated with mor-tality. These can occur independently of systemic hemodynamic alterations. Sublingual videomicroscopy allowed evaluating the microvascular response to resuscitation proce-dures, including oxygen therapy, fluids, blood transfusions, vasopressors. Future re-search directions should be aimed to integrate microcirculatory monitoring with standard hemodynamic measurements and verify the utility of microcirculation as a therapeutic tar-get. Continuous technological developments are imperative to facilitate the introduction of sublingual videomicroscopy in the clinical practice
Comment on "Respiratory mechanics and gas exchanges in the early course of COVID-19 ARDS: a hypothesis-generating study"
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Comment on "Effects of short-term hyperoxia on sytemic hemodynamics, oxygen transport, and microcirculation: An observational study in patients with septic shock and healthy volunteers"
No full textMicrocirculation-guided resuscitation in sepsis: the next frontier?
Get PDFMicrocirculatory dysfunction plays a key role in the pathogenesis of tissue dysoxia and organ failure in sepsis. Sublingual videomicroscopy techniques enable the real-time non-invasive assessment of microvascular blood flow. Alterations in sublingual microvascular perfusion were detected during sepsis and are associated with poor outcome. More importantly, sublingual videomicroscopy allowed to explore the effects of commonly applied resuscitative treatments in septic shock, such as fluids, vasopressors and inotropes, and showed that the optimization of macro-hemodynamic parameters may not be accompanied by an improvement in microvascular perfusion. This loss of "hemodynamic coherence," i.e., the concordance between the response of the macrocirculation and the microcirculation, advocates for the integration of microvascular monitoring in the management of septic patients. Nonetheless, important barriers remain for a widespread use of sublingual videomicroscopy in the clinical practice. In this review, we discuss the actual limitations of this technique and future developments that may allow an easier and faster evaluation of the microcirculation at the bedside, and propose a role for sublingual microvascular monitoring in guiding and titrating resuscitative therapies in sepsis
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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