The microcirculation in the first days of ICU admission in critically ill COVID-19 patients is influenced by severity of disease.

The objective of this study was to investigate the relationship between sublingual microcirculatory parameters and the severity of the disease in critically ill coronavirus disease 2019 (COVID-19) patients in the initial period of Intensive Care Unit (ICU) admission in a phase of the COVID-19 pandemic where patients were being treated with anti-inflammatory medication. In total, 35 critically ill COVID-19 patients were included. Twenty-one critically ill COVID-19 patients with a Sequential Organ Failure Assessment (SOFA) score below or equal to 7 were compared to 14 critically ill COVID-19 patients with a SOFA score exceeding 7.

Identifying a sublingual triangle as the ideal site for assessment of sublingual microcirculation.

The sublingual mucosa is a commonly used intraoral location for identifying microcirculatory alterations using handheld vital microscopes (HVMs). The anatomic description of the sublingual cave and its related training have not been adequately introduced. The aim of this study was to introduce anatomy guided sublingual microcirculatory assessment.

Microcirculatory alterations in critically ill COVID-19 patients analyzed using artificial intelligence.

Background: The sublingual microcirculation presumably exhibits disease-specific changes in function and morphology. Algorithm-based quantification of functional microcirculatory hemodynamic variables in handheld vital microscopy (HVM) has recently allowed identification of hemodynamic alterations in the microcirculation associated with COVID-19. In the present study we hypothesized that supervised deep machine learning could be used to identify previously unknown microcirculatory alterations, and combination with algorithmically quantified functional variables increases the model's performance to differentiate critically ill COVID-19 patients from healthy volunteers.

Morphologic Mapping of the Sublingual Microcirculation in Healthy Volunteers.

Purpose: Monitoring the sublingual and oral microcirculation (SM-OM) using hand-held vital microscopes (HVMs) has provided valuable insight into the (patho)physiology of diseases. However, the microvascular anatomy in a healthy population has not been adequately described yet.

Methods: Incident dark field-based HVM imaging was used to visualize the SM-OM.

Increased Hepatic Microvascular Density, Oxygenation, and VEGF in the Hypertrophic Lobe following Portal Vein Embolization in Rabbits.

Introduction: The microvascular events following portal vein embolization (PVE) are poorly understood despite the pivotal role of the microcirculation in liver regeneration and tumor progression. We aimed to assess the changes in hepatic microvascular perfusion and neo-angiogenesis after experimental PVE.

Methods: PVE of the cranial liver lobes was performed in 12 New Zealand White rabbits divided into 2 groups of permanent (P-PVE) and reversible PVE (R-PVE), respectively.

Goal-directed fluid therapy vs. low central venous pressure during major open liver resections (GALILEO): a surgeon- and patient-blinded randomized controlled trial.

Background: Low central venous pressure (low-CVP) is the clinical standard for fluid therapy during major liver surgery. Although goal-directed fluid therapy (GDFT) has been associated with reduced morbidity and mortality in major abdominal surgery, concerns remain on blood loss when applying GDFT in liver surgery. This randomized trial compared outcomes of low-CVP and GDFT during major liver resections.

Real-time observation of microcirculatory leukocytes in patients undergoing major liver resection.

Ischemia/reperfusion injury and inflammation are associated with microcirculatory dysfunction, endothelial injury and glycocalyx degradation. This study aimed to assess microcirculation in the sublingual, intestinal and the (remnant) liver in patients undergoing major liver resection, to define microcirculatory leukocyte activation and its association with glycocalyx degradation. In this prospective observational study, the microcirculation was assessed at the beginning of surgery (T0), end of surgery (T1) and 24 h after surgery (T2) using Incident Dark Field imaging.

Capillary Leukocytes, Microaggregates, and the Response to Hypoxemia in the Microcirculation of Coronavirus Disease 2019 Patients.

Objectives: In this study, we hypothesized that coronavirus disease 2019 patients exhibit sublingual microcirculatory alterations caused by inflammation, coagulopathy, and hypoxemia.

Design: Multicenter case-controlled study.

Setting: Two ICUs in The Netherlands and one in Switzerland.

Automated Algorithm Analysis of Sublingual Microcirculation in an International Multicentral Database Identifies Alterations Associated With Disease and Mechanism of Resuscitation.

Objectives: Reliable automated handheld vital microscopy image sequence analysis and the identification of disease states and effects of therapy are prerequisites for the routine use of quantitative sublingual microcirculation measurements at the point-of-care. The present study aimed to clinically validate the recently introduced MicroTools software in a large multicentral database of perioperative and critically ill patients and to use this automatic algorithm to data-mine and identify the sublingual microcirculatory variable changes in response to disease and therapy.

Design: Retrospective algorithm-based image analysis and data-mining within a large international database of sublingual capillary microscopy.

Hemodilution causes glycocalyx shedding without affecting vascular endothelial barrier permeability in rats.

Background: The consequences of acute normovolemic hemodilution (ANH) following different types of fluids on the different components of the glycocalyx and on vascular barrier permeability (VBP) remain unknown.

Aim: The aim of the study was to investigate whether the microcirculatory disruption and glycocalyx shedding induced by ANH alters VBP and whether this is affected by the composition and volume of the resuscitation fluid.

Materials And Methods: Anesthetized Wistar albino rats (n=24) underwent stepwise ANH at hematocrit levels of 35%, 25%, 20%, and 15% induced by the exchange of blood with 6% balanced hydroxyethyl starch (1:1), balanced crystalloid (1:3), and normal saline (NS) (1:3).

Intraoperative Imaging Techniques to Visualize Hepatic (Micro)Perfusion: An Overview.

The microcirculation plays a crucial role in the distribution of perfusion to organs. Studies have shown that microcirculatory dysfunction is an independent predictor of morbidity and mortality. Hence, assessment of liver perfusion offers valuable information on the (patho)physiological state of the liver.

Interpatient heterogeneity in hepatic microvascular blood flow during vascular inflow occlusion (Pringle manoeuvre).

Background: Vascular inflow occlusion (VIO) during liver resections (Pringle manoeuvre) can be applied to reduce blood loss, however may at the same time, give rise to ischemia-reperfusion injury (IRI). The aim of this study was to assess the characteristics of hepatic microvascular perfusion during VIO in patients undergoing major liver resection.

Methods: Assessment of hepatic microcirculation was performed using a handheld vital microscope (HVM) at the beginning of surgery, end of VIO (20 minutes) and during reperfusion after the termination of VIO.

Poor perfusion of the microvasculature in peritoneal metastases of ovarian cancer.

Most women with epithelial ovarian cancer (EOC) suffer from peritoneal carcinomatosis upon first clinical presentation. Extensive peritoneal carcinomatosis has a poor prognosis and its pathophysiology is not well understood. Although treatment with systemic intravenous chemotherapy is often initially successful, peritoneal recurrences occur regularly.

Leukocyte-Endothelium Interaction in the Sublingual Microcirculation of Coronary Artery Bypass Grafting Patients.

Objective: The aim of this study was to apply an innovative methodology to incident dark-field (IDF) imaging in coronary artery bypass grafting (CABG) patients for the identification and quantification of rolling leukocytes along the sublingual microcirculatory endothelium.

Methods: This study was a post hoc analysis of a prospective study that evaluated the perioperative course of the sublingual microcirculation in CABG patients. Video images were captured using IDF imaging following the induction of anesthesia (T0) and cardiopulmonary bypass (CPB) (T1) in 10 patients.

Quantitative assessment of liver function using hepatobiliary scintigraphy: the effect of microcirculatory alterations after portal vein embolization.

Objectives: Hepatobiliary scintigraphy using technetium-99m mebrofenin has been validated as a quantitative liver function test. Preoperative portal vein embolization (PVE) is performed in patients to increase future remnant liver function and volume. Changes in hepatic microcirculation after PVE remain largely unknown and may influence the uptake of mebrofenin.

Glycocalyx Degradation Is Independent of Vascular Barrier Permeability Increase in Nontraumatic Hemorrhagic Shock in Rats.

Background: Glycocalyx shedding after traumatic hemorrhagic or septic shock, as well as different resuscitation fluids, has been causally linked to increased vascular barrier permeability (VBP) resulting in tissue edema. In nontraumatic hemorrhagic shock (NTHS), it remains questionable whether glycocalyx degradation in itself results in an alteration of VBP. The composition of fluids can also have a modulatory effect on glycocalyx shedding and VBP.

Recruitment of sublingual microcirculation using handheld incident dark field imaging as a routine measurement tool during the postoperative de-escalation phase-a pilot study in post ICU cardiac surgery patients.

Background: Management of tissue perfusion following cardiac surgery is a challenging task where common clinical parameters do not reflect microcirculatory dysfunction. Heterogeneity in blood flow perfusion and abnormalities in capillary density characterize microcirculatory dysfunction. The restoration of a normal microcirculation may become a novel target for therapy in the future in addition to macrocirculatory parameters.

Assessment of hepatic microvascular flow and density in patients undergoing preoperative portal vein embolization.

Background: The microvascular effects occurring after unilateral preoperative portal vein embolization (PVE) are poorly understood. The aim of this study was to assess the microvascular changes in the embolized and the non-embolized lobes after right PVE.

Methods: Videos of the hepatic microcirculation in patients undergoing right hemihepatectomy following PVE were recorded using a handheld vital microscope (Cytocam) based on incident dark field imaging.

Intraoperative Incident Dark Field Imaging of the Human Peritoneal Microcirculation.

Background/aims: This study describes the peritoneal microcirculation, compares quantitative parameters and angioarchitecture to the standard of sublingual microcirculatory assessment, and determines the practical feasibility of this method.

Methods: Incident dark field imaging was performed of the peritoneum and sublingually to determine angioarchitecture, total and perfused vessel density (TVD and PVD), the proportion of perfused vessels (PPV), the microvascular flow index (MFI) and image acquisition time.

Results: Peritoneal angioarchitecture was characterized by a quadrangular network of longitudinally oriented capillaries, often flanked by fat cells.

Identification and quantification of human microcirculatory leukocytes using handheld video microscopes at the bedside.

Leukocyte recruitment and adhesion to the endothelium are hallmarks of systemic inflammation that manifest in a wide range of diseases. At present, no method is available to directly measure leukocyte kinetics at the bedside. In this study, we validate a new method to identify and quantify microcirculatory leukocytes observed by handheld vital microscopy (HVM) using space-time diagram (STD) analysis.

Circulating microaggregates during cardiac surgery precedes postoperative stroke.

Postoperative stroke and encephalopathy are potentially serious complications associated with coronary artery bypass grafting. In this case report a 78-year-old male patient receiving routine elective cardiac surgery presented with microaggregations in the sublingual microcirculation while on cardiopulmonary bypass that was undetected by routine intraoperative anticoagulation assessment. Microaggregates identified using video microscopy on his sublingual microcirculation during the procedure preceded a stroke postoperatively.