Microcirculatory assessment in daily clinical practice - not yet ready but not too far!

Abstract

Shock is characterized by an alteration in tissue perfusion that may lead to tissue hypoxia. Recent guidelines recommend aggressive and early resuscitation therapy, but mortality rate is still unacceptably high. Unfortunately, traditional clinical surrogates used to guide resuscitation therapy poorly correlate with microcirculatory blood flow, a key determinant of tissue perfusion. New techniques that directly assess microcirculatory perfusion at the bedside have emerged as a complement to traditional macrohemodynamic parameters. These techniques have been supported by several studies showing microcirculatory alterations in different clinical settings. In addition, these microcirculatory alterations are related with outcome and persist regardless of arterial pressure normalization, being a better predictor of organ dysfunction and mortality than global hemodynamic and laboratory parameters. These findings allowed the concept of "microcirculatory-goal directed therapy", which is now in its preliminary phase, as the impact of many interventions still needs to be assessed. Finally, microcirculation assessment has also been explored in other medical fields such as perioperative, systemic arterial hypertension, heart failure, and hyperviscosity syndromes. In this review, we shortly present the characteristics of microcirculation and the main determinants of capillary blood flow, and we discuss advantages and limitations of some recently available techniques to evaluate microcirculation at the bedside, and how they could be useful for the general clinician in daily practice.Keywords: Shock; Resuscitation; Microcirculation/pathophysiology; Hemodynamics/physiology; Multiple organ failure/pathophysiology; Prognosis ReSUMOO choque é caracterizado por uma alteração na perfusão tecidual que pode levar à hipóxia tecidual. Diretrizes recentes recomendam uma terapia de ressuscitação hemodinâmica precoce e agressiva nos estados de choque, mas a taxa de mortalidade ainda é inaceitavelmente alta. Os parâmetros clínicos habituais usados para orientar a terapia de reanimação correlacionam-se mal com o fluxo sanguíneo capilar, um determinante essencial da perfusão tecidual. Novas técnicas que avaliam diretamente a perfusão da microcirculação à beira do leito surgem como um complemento aos parâmetros macro-hemodinâmicos tradicionais. Estas técnicas foram testadas em vários estudos que mostraram alterações microcirculatórias em diferentes situações clínicas de choque. Além disso, estas alterações microcirculatórias estão relacionadas ao prognóstico, e persistem independentemente da normalização da pressão arterial, sendo um melhor preditor de disfunção orgânica e mortalidade do que os parâmetros hemodinâmicos globais e laboratoriais. Estes achados permitiram lançar o conceito de "terapia dirigida por parâmetros microcirculatórios", atualmente em fase preliminar, uma vez que o impacto de muitas intervenções ainda precisa ser avaliado. Finalmente, a avaliação da microcirculação também foi explorada em outras áreas que não o choq...

Evaluation of Shoulder Microcirculation Abnormality Using Laser Doppler Flowmetry

“…Meanwhile, there was no obvious difference observed between the MMBF in MTrPs of the two groups. A study related to sepsis found that microcirculatory alterations can be detected in very early stages of the disease and may persist regardless of the macrohemodynamic status [ 11 , 30 , 31 ]. Those findings were consistent with our observations.…”

“…Methods to assess shoulder and neck pain include the visual analogue scale (VAS) score [ 5 ], Neck Disability Index, neck mobility, muscle strength [ 6 , 7 ], white-light spectroscopy, Laser Doppler Flowmetry (LDF) [ 8 , 9 ], and quantitative imaging biomarkers [ 10 ]. Salgado [ 11 ] discussed several techniques for evaluating microvasculature perfusion, such as LDF, intravital microscopy, and orthogonal polarization spectral imaging techniques. The capillary refill time constitutes an accessible route for probing microcirculation, which is applied during shock resuscitation [ 12 ].…”

Permissive Hypotension: What’s New in Fluid Resuscitation in the Management of Hemorrhagic Shock?

“…Early or large-volume resuscitation in severe hemorrhage has not been supported by randomized controlled trials so far [9]. Increased hemorrhage volume and markedly higher mortality may ensue following 'classical' high-volume, normotensive resuscitation in case of major vascular injury [9,10]. In a study of uncontrolled hemorrhage, infusion of only enough fluid to maintain a MAP of 40 mm Hg improved survival rates and decreased hemorrhage [11] withholding of intravenous fluids in severe shock resuscitation still needs to be studied [12].…”

Οξείες Επιδράσεις Του Παθητικού Καπνίσματος Στην Μικροκυκλοφορία Των Σκελετικών Μυών

“…Οι διαφορετικού βαθμού διαταραχές της μικροκυκλοφορίας έχουν ως αποτέλεσμα την υποάδρευση και την ανεπάρκεια των ιστών και έχουν συσχετιστεί με τη νοσηρότητα και τη θνησιμότητα σε διάφορες παθολογικές καταστάσεις όπως π.χ. στην σήψη και στον διαβήτη[76,78,84]. Η μικροκυκλοφορία μπορεί να εξεταστεί ευκολότερα στην περιφέρεια, π.χ.…”

“…Ο έλεγχος της αιματικής ροής γίνεται με τους προτριχοειδικούς σφιγκτήρες, οι οποίοι επηρεάζονται εν μέρει από συστημικούς παράγοντες, τη συμπαθητική διέγερση και διάφορα κυκλοφορούντα στοιχεία[74]. Τα κύρια είδη κυττάρων που εμπλέκονται στην μικροκυκλοφορία είναι τα ερυθρά και λευκά αιμοσφαίρια, τα αιμοπετάλια, τα κύτταρα του λείου μυϊκού ιστού και τα ενδοθηλιακά κύτταρα[77,78].6. Μέθοδοι εκτίμησης της μικροκυκλοφορίαςΗ βιντεομικροσκοπία και το σύστημα Λέιζερ Ντόπλερ (Laser Doppler)[84].…”