Association between endotoxemia and enterocyte injury and clinical course in patients with gram-positive septic shock: A posthoc analysis of a prospective observational study

Effects of polymyxin B haemoperfusion on septic shock caused by Gram-positive bacteria

Polymyxin B haemoperfusion is commonly used to adsorb endotoxins in septic shock caused by Gram-negative bacterial infections. Polymyxin B haemoperfusion has been reported to improve hypotension in Gram-positive bacterial infections; however, its efficacy and mechanism in treating such cases are unclear. We hypothesised that polymyxin B haemoperfusion would be equally effective in improving haemodynamics during Gram-positive bacterial infections as in Gram-negative bacterial infections. We conducted a retrospective study that included patients with septic shock admitted to the intensive care unit. The patients were divided into two groups according to bacterial culture results: Gram-negative rod (GNR) and Gram-positive coccus (GPC). We calculated the vasoactive inotropic score (VIS) before (0 h) and 2, 6, 12 and 24 h after polymyxin B haemoperfusion therapy. Data were analysed using two-way analysis of variance and post hoc tests for the associations between infection type and treatment time. Overall, 157 patients with septic shock were enrolled in the study: 81 and 76 patients were treated or not treated with extracorporeal haemoperfusion therapy, respectively. Although there was no significant difference in the VIS in polymyxin B haemoperfusion between patients with GNR and GPC infections, there was a significant decrease in the VIS over time, even when GPC was the causative organism. In addition, the degree of reduction in the VIS was significantly different in both the GNR and GPC groups compared with that in the non-extracorporeally treated group. Thus, polymyxin B haemoperfusion for septic shock caused by GNR reduced the VIS and could be effective even in cases of GPC infection.

Anti-endotoxin antibodies consumption in cardiovascular collapse: Pathophysiological concerns

OBJECTIVE

Abnormal endotoxin activity in critically ill patients has been described in the absence of Gram-negative bacterial (GNB) infection. As disease severity seems to be crucial in the detection of this phenomenon, we decided to assess and compare endotoxin exposure in those patients representing the critical situation: septic shock and cardiogenic shock.

DESIGN

Prospective, observational non intervention study.

SETTING

Critical Care Department of a University tertiary hospital.

PATIENTS

Cardiogenic shock (CS) and septic shock (SS) patients.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Follow-up was performed for the first three days. Inflammatory biomarkers (C-reactive protein, procalcitonin and interleuquin-6) and IgM antiendotoxin-core antibodies titter (IgM EndoCAb) were daily analyzed. Sixty-two patients were included; twenty-five patients with SS and thirty-seven with CS. Microbial etiology was established in 23 SS patients (92%) and GNB were present in 13 cases (52%). Although infection was suspected and even treated in 30 CS patients (81%), any episode could be finally confirmed. EndoCAb consumption was more intense in SS patients, although twenty-two CS patients (59.5%) had IgM anti-endotoxin value below 10th percentile range for healthy people. No statistically significant difference in endotoxin exposure was detected between Gram-positive and Gram-negative infections in the SS group. Endotoxin exposure ability to distinguish between SS and CS was moderate (AUC 0.7892, 95% IC: 0.6564-0.9218).

CONCLUSIONS

In the severely ill patient some mechanisms take place allowing endotoxin incursion and therefore blurring the limits of diseases pathophysiology. Our work representatively shows how exposure to endotoxin was not fully capable of distinguishing between CS and SS.

Endothelial glycocalyx damage in patients with severe COVID-19 on mechanical ventilation - a prospective observational pilot study

BACKGROUND

Coronavirus disease (COVID-19) associated endotheliopathy and microvascular dysfunction are of concern.

OBJECTIVE

The objective of the present single-center observational pilot study was to compare endothelial glycocalyx (EG) damage and endotheliopathy in patients with severe COVID-19 (COVID-19 group) with patients with bacterial pneumonia with septic shock (non-COVID group).

METHODS

Biomarkers of EG damage (syndecan-1), endothelial cells (EC) damage (thrombomodulin), and activation (P-selectin) were measured in blood on three consecutive days from admission to the intensive care unit (ICU). The sublingual microcirculation was studied by Side-stream Dark Field (SDF) imaging with automatic assessment.

RESULTS

We enrolled 13 patients in the non-COVID group (mean age 70 years, 6 women), and 15 in the COVID-19 group (64 years old, 3 women). The plasma concentrations of syndecan-1 were significantly higher in the COVID-19 group during all three days. Differences regarding other biomarkers were not statistically significant. The assessment of the sublingual microcirculation showed improvement on Day 2 in the COVID-19 group. Plasma levels of C-reactive protein (CRP) were significantly higher on the first two days in the COVID-19 group. Plasma syndecan-1 and CRP were higher in patients suffering from severe COVID-19 pneumonia compared to bacterial pneumonia patients.

CONCLUSIONS

These findings support the role of EG injury in the microvascular dysfunction in COVID-19 patients who require ICU.