Sublingual Microcirculatory Evaluation of Extracorporeal Hemoadsorption with CytoSorb® in Abdominal Sepsis: A Case Report

Cytokemia is associated with microcirculatory alterations often with persistent loss of coherence between the micro- and macrocirculation, linked to organ failure and poor outcome of septic patients. Addition of a hemoadsorbant filter to an extracorporeal circuit next to conventional treatment of septic shock results in the hematological clearance of cytokines, hypothetically leading to normalization of the microcirculation and thus organ perfusion. Bedside sublingual microcirculatory assessment using handheld vital microscopy allows real-time direct visualization of the microcirculation and its response to therapy. This is demonstrated in the present case report of an 83-year-old man admitted to our intensive care unit after surgical repair of a colonic perforation for fecal soiling after a low anterior resection for a rectum carcinoma, with leakage of bowel content at the resection site. The clinical course of this patient can be described as having undergone adequate surgical treatment taking away the source of the disease, followed by optimal support including antibiotic treatment in the ICU. However, during the course of his stay in the ICU, his condition deteriorated with symptoms consistent with septic shock. Our report shows that the addition of a hemoadsorbent (CytoSorb) to the continuous renal replacement therapy circuit was associated with an improvement in the condition of our severely ill patient with abdominal sepsis. Parallel to the clinical improvement of our patient, the functional parameters of the microcirculation also showed improvement suggesting that such a noninvasive real-time evaluation of the status of the microcirculation may be a sensitive diagnostic tool to monitor the effectiveness of hemoadsorbent therapy.

Evaluation of microcirculation disorders in patients with severe COVID-19 by nail bed capillaroscopy

Microcirculation disorders caused by thrombosis are the most important factor determining the pathogenesis of organ damage in severe COVID-19 including the absence of obvious macrohemodynamic instability. However, there are very few publications demonstrating the results of intravital visualization of changes in the microcirculation system in this disease.The objective: to assess the state of microcirculation in patients with viral pneumonia associated with COVID-19 using nail bed microscopy.Subjects and methods. Eleven patients with COVID-19 were examined; they were admitted to the intensive care unit due to progressing acute respiratory failure. Vital microscopy of the microcirculatory bloodstream in the fingers’ nail bed was performed by admission and over time. When assessing microcirculation, the presence of aggregates in the lumen of capillaries and avascular zones, and the linear velocity of blood flow were taken into account. The results were summarized taking with the outcome consideration (6 people recovered, 5 died). Results. Microcirculation disorders were objectively confirmed in all patients. In 100% of cases, microaggregates were detected in the capillary lumen. The values of the mean linear velocity of capillary blood flow turned out to be extremely variable. However, the values of the maximum linear velocities of capillary blood flow in the patients who subsequently died were significantly lower versus survivors (190 μm/sec (135.5; 237) and 387 μm/sec (329.3; 407.5), p = 0.018). The irregularity of blood flow in the visualized field was revealed: when the value of the maximum linear velocity in some capillaries was less than 180 µm/sec, in others, disturbances in the form of pendulum-like movement were already noted. Further slowing down of the blood flow velocity led to the development of stasis and the formation of avascular zones.Conclusion. Impaired microcirculation (decreased blood flow rate in the capillaries, the presence of microaggregates and a lower number of perfused capillaries in the form of avascular zones) develops in all patients with severe COVID-19.

Intra-vital imaging of mesenchymal stromal cell kinetics in the pulmonary vasculature during infection

Mesenchymal stem/stromal cells (MSCs) have demonstrated efficacy in pre-clinical models of inflammation and tissue injury, including in models of lung injury and infection. Rolling, adhesion and transmigration of MSCs appears to play a role during MSC kinetics in the systemic vasculature. However, a large proportion of MSCs become entrapped within the lungs after intravenous administration, while the initial kinetics and the site of arrest of MSCs in the pulmonary vasculature are unknown. We examined the kinetics of intravascularly administered MSCs in the pulmonary vasculature using a microfluidic system in vitro and intra-vital microscopy of intact mouse lung. In vitro, MSCs bound to endothelium under static conditions but not under laminar flow. VCAM-1 antibodies did not affect MSC binding. Intravital microscopy demonstrated MSC arrest at pulmonary micro-vessel bifurcations due to size obstruction. Retention of MSCs in the pulmonary microvasculature was increased in Escherichia coli-infected animals. Trapped MSCs deformed over time and appeared to release microvesicles. Labelled MSCs retained therapeutic efficacy against pneumonia. Our results suggest that MSCs are physically obstructed in pulmonary vasculature and do not display properties of rolling/adhesion, while retention of MSCs in the infected lung may require receptor interaction.