Disseminated intravascular coagulation (DIC) is a severe complication of septic shock. Polymorphonuclear neutrophils (PMNs) may play a key role in septic shock-induced DIC via the release of ...neutrophils extracellular traps (NETs). NETs capture invading pathogens, but also act as a pro-coagulant surface at the interface between immunity and thrombosis. During septic shock-induced DIC, neutrophil activation may result in excessive NET formation. Herein, we originally report the presence of circulating NETs in human blood during septic shock-induced DIC.
To investigate NET formation during shock-induced DIC neutrophils were isolated from patients in septic shock associated with (n = 3) or without (n = 3) DIC. Neutrophils from healthy donors (n = 3) were stimulated in vitro with ionomycin as NET formation positive controls. PMNs smears were stained with mouse anti-human FITC anti-myeloperoxidase antibody and the blue-fluorescent DAPI nucleic acid stain. NETs were identified as elongated extracellular DNA fibers associated to myeloperoxidase detected by immunofluorescence.
NETs were unambiguously observed in PMNs from septic shock patients with DIC but not from patients without DIC. NETs features in DIC+ patients were undistinguishable from those observed in ionomycin-induced PMNs from healthy donors. Fluorescence images of NETs were associated to extracellular cytoplasmic expansions.
Our data report for the first time the direct visualization of circulating NETs in patients with septic shock-induced DIC. The in vivo relevance of previously reported indirect markers of NETosis (neutrophil side fluorescence) is confirmed.
•Netosis features can be detected in blood PMNs using simple fluorescence microscopy.•PMNs purified from patients with DIC-induced septic shock display NETosis features.•Morphological analysis of PMNs can distinguish septic shock patients with DIC.
Cardiogenic shock is usually defined as primary cardiac dysfunction with low cardiac output leading to critical organ hypoperfusion, and tissue hypoxia, resulting in high mortality rate between 40% ...and 50% despite recent advances. Many studies have now evidenced that cardiogenic shock not only involves systemic macrocirculation, such as blood pressure, left ventricular ejection fraction, or cardiac output, but also involves significant systemic microcirculatory abnormalities which seem strongly associated with the outcome. Although microcirculation has been widely studied in the context of septic shock showing heterogeneous alterations with clear evidence of macro and microcirculation uncoupling, there is now a growing body of literature focusing on cardiogenic shock states. Even if there is currently no consensus regarding the treatment of microcirculatory disturbances in cardiogenic shock, some treatments seem to show a benefit. Furthermore, a better understanding of the underlying pathophysiology may provide hypotheses for future studies aiming to improve cardiogenic shock prognosis.
Graphical Abstract
Highlights
Most reviews about cardiogenic shock still focus mainly on systemic macrocirculation parameters, such as blood pressure, left ventricular ejection fraction, or cardiac index to explain the pathophysiology.
However, mortality and outcomes in cardiogenic shock are also strongly associated with microcirculation disorders that are not necessarily correlated with those of the macrocirculation.
Although microcirculation has been widely studied in the context of septic shock, there is now a growing body of literature focusing on cardiogenic shock.
Activation of platelets and neutrophils in septic shock results in the formation of microvascular clots containing an intricate scaffold of fibrin with neutrophil extracellular traps (NETs) DNA. NETs ...contain multiple components that might impact endogenous fibrinolysis, resulting in failure to lyse clots in the microcirculation and residual systemic microthrombosis. We propose herein that the reservoir of human neutrophil elastase (HNE) on NETs may directly interfere with the fibrinolytic mechanism via a plasminogen proteolytic pathway. To investigate this mechanism, we constructed fibrin‐NETs matrices by seeding and activating neutrophils onto a fibrin surface and monitored plasminogen activation or degradation. We demonstrate that the elastase activity of HNE‐DNA complexes is protected from inhibition by plasma antiproteases and sustains its ability to degrade plasminogen. Using mass spectrometry proteomic analysis, we identified plasminogen fragments composed of kringle (K) domains (K1+2+3, k1+2+3+4) and the serine protease (SP) region (K5‐SP). We further demonstrate that patients with septic shock with disseminated intravascular coagulation have circulating HNE‐DNA complexes, HNE‐derived plasminogen fragments, a low plasminogen concentration, and a reduced capacity to generate plasmin onto fibrin. In conclusion, we show that NETs bearing active HNE‐DNA complexes reduce plasminogen into fragments, thus impairing fibrinolysis by decreasing the local plasminogen concentration, plasminogen binding to fibrin, and localized plasmin formation.—Barbosa da Cruz, D., Helms, J., Aquino, L. R., Stiel, L., Cougourdan, L., Broussard, C., Chafey, P., Riès‐Kautt, M., Meziani, F., Toti, F., Gaussem, P., Anglés‐Cano, E. DNA‐bound elastase of neutrophil extracellular traps degrades plasminogen, reduces plasmin formation, and decreases fibrinolysis: proof of concept in septic shock plasma. FASEB J. 33, 14270‐14280 (2019). www.fasebj.org
Purpose
Guidelines for shock recommend mean arterial pressure (MAP) targets for vasopressor therapy of at least 65 mmHg and, until recently, suggested that patients with underlying chronic ...hypertension and atherosclerosis may benefit from higher targets. We conducted an individual patient-data meta-analysis of recent trials to determine if patient variables modify the effect of different MAP targets.
Methods
We searched the MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials for randomized controlled trials of higher versus lower blood pressure targets for vasopressor therapy in adult patients in shock (until November 2017). After obtaining individual patient data from both eligible trials, we used a modified version of the Cochrane Collaboration’s instrument to assess the risk of bias of included trials. The primary outcome was 28-day mortality.
Results
Included trials enrolled 894 patients. Controlling for trial and site, the OR for 28-day mortality for the higher versus lower MAP targets was 1.15 (95% CI 0.87–1.52). Treatment effect varied by duration of vasopressors before randomization (interaction
p
= 0.017), but not by chronic hypertension, congestive heart failure or age. Risk of death increased in higher MAP groups among patients on vasopressors > 6 h before randomization (OR 3.00, 95% CI 1.33–6.74).
Conclusions
Targeting higher blood pressure targets may increase mortality in patients who have been treated with vasopressors for more than 6 h. Lower blood pressure targets were not associated with patient-important adverse events in any subgroup, including chronically hypertensive patients.
Neutrophils serve as the frontline defenders in the host's response to infections. However, the available methods for assessing the activated status of neutrophils are still limited. The immature ...cells that appear during sepsis are large with complex cytoplasmic components and rich nucleic acids, making them diagnosable by cell population data analysis using the automated cell counter. The changes are expressed as increased forward scattered light, side fluorescence light, and side fluorescence distribution width. Additionally, changes in side fluorescence light may indicate the neutrophil extracellular trap formation and can be useful for the diagnosis of sepsis-associated disseminated intravascular coagulation.
Neutrophils extracellular traps (NETs) have recently emerged as a new potential link between inflammation, immunity, and thrombosis and could play a key role in septic shock-induced disseminated ...intravascular coagulation (DIC) pathogenesis. The objective of our study was to investigate a potential link between NETosis and septic shock-induced DIC.
Twenty patients with septic shock (10 without and 10 with DIC according to JAAM 2006 score) were prospectively included in our study. Vascular cell activation was assessed by microparticle (MP) measurement. NETosis was investigated at days 1, 3, and 7 using two different approaches: probing and measurement of neutrophil DNA decompaction by neutrophil-side fluorescence light (NEUT-SFL) as recorded by an automated blood cell cytometer and the assessment of nucleosomes and NETs (DNA-bound myeloperoxidase, DNA-MPO).
Endothelial-derived CD105-MPs, leucocyte-derived CD11a-MPs/leucocyte, and neutrophil-derived CD66b-MPs/neutrophil count ratios significantly increased in DIC compared with non-DIC patients, indicating on-going cell activation (P <0.05). NEUT-SFL, indicating DNA decompaction, was significantly higher in DIC patients. Circulating nucleosomes and DNA-MPO were increased in DIC patients (P <0.05). There were significant correlations between: nucleosomes and NETs (r = 0.397, P = 0.004), NEUT-SFL and nucleosomes (r = 0.243, P = 0.032), NEUT-SFL and DNA-MPO (r = 0.266, P = 0.024).
NEUT-SFL, NETs, and elevated nucleosome concentrations were all correlated to DIC (P <0.05). We have shown that NETosis is significantly correlated to septic shock-induced DIC.
Background
Thromboprophylaxis of COVID-19 patients is a highly debated issue. We aimed to compare the occurrence of thrombotic/ischemic events in COVID-19 patients with acute respiratory distress ...syndrome (ARDS) treated with either prophylactic or therapeutic dosage of heparin. All patients referred for COVID-19 ARDS in two intensive care units (ICUs) from two centers of a French tertiary hospital were included in our cohort study. Patients were compared according to their anticoagulant treatment to evaluate the risk/benefit of prophylactic anticoagulation versus therapeutic anticoagulation. Medical history, symptoms, biological data and imaging were prospectively collected.
Results
One hundred and seventy-nine patients (73% men) were analyzed: 108 in prophylactic group and 71 in therapeutic group. Median age and SAPS II were 62 IQR 51; 70 years and 47 IQR 37; 63 points. ICU mortality rate was 17.3%. Fifty-seven patients developed clinically relevant thrombotic complications during their ICU stay, less frequently in therapeutic group (adjusted OR 0.38 0.14–0.94, p = 0.04). The occurrences of pulmonary embolism (PE), deep vein thrombosis (DVT) and ischemic stroke were significantly lower in the therapeutic group (respective adjusted OR for PE: 0.19 0.03–0.81; DVT: 0.13 0.01–0.89, stroke: 0.06 0–0.68, all p < 0.05). The occurrence of bleeding complications was not significantly different between groups, neither were ICU length of stay or mortality rate. D-dimer levels were significantly lower during ICU stay, and aPTT ratio was more prolonged in the therapeutic group (p < 0.05).
Conclusion
Increasing the anticoagulation of severe COVID-19 patients to a therapeutic level might decrease thrombotic complications without increasing their bleeding risk.
There is insufficient research into the use of mechanical ventilation with increased inspiratory oxygen concentration (FiO
) and fluid resuscitation with hypertonic saline solution in patients with ...septic shock. We tested whether these interventions are associated with reduced mortality.
This two-by-two factorial, multicentre, randomised, clinical trial (HYPERS2S) recruited patients aged 18 years and older with septic shock who were on mechanical ventilation from 22 centres in France. Patients were randomly assigned 1:1:1:1 to four groups by a computer generated randomisation list stratified by site and presence or absence of acute respiratory distress syndrome by use of permuted blocks of random sizes. Patients received, in an open-labelled manner, mechanical ventilation either with FiO
at 1·0 (hyperoxia) or FiO
set to target an arterial haemoglobin oxygen saturation of 88-95% (normoxia) during the first 24 h; patients also received, in a double-blind manner, either 280 mL boluses of 3·0% (hypertonic) saline or 0·9% (isotonic) saline for fluid resuscitation during the first 72 h. The primary endpoint was mortality at day 28 after randomisation in the intention-to-treat population. This study was registered with ClinicalTrials.gov, number NCT01722422.
Between Nov 3, 2012, and June 13, 2014, 442 patients were recruited and assigned to a treatment group (normoxia n=223 or hyperoxia n=219; isotonic n=224 or hypertonic n=218). The trial was stopped prematurely for safety reasons. 28 day mortality was recorded for 434 patients; 93 (43%) of 217 patients had died in the hyperoxia group versus 77 (35%) of 217 patients in the normoxia group (hazard ratio HR 1·27, 95% CI 0·94-1·72; p=0·12). 89 (42%) of 214 patients had died in the hypertonic group versus 81 (37%) of 220 patients in the isotonic group (HR 1·19, 0·88-1·61; p=0·25). We found a significant difference in the overall incidence of serious adverse events between the hyperoxia (185 85%) and normoxia groups (165 76%; p=0·02), with a clinically relevant doubling in the hyperoxia group of the number of patients with intensive care unit-acquired weakness (24 11% vs 13 6%; p=0·06) and atelectasis (26 12% vs 13 6%; p=0·04) compared with the normoxia group. We found no statistical difference for serious adverse events between the two saline groups (p=0·23).
In patients with septic shock, setting FiO
to 1·0 to induce arterial hyperoxia might increase the risk of mortality. Hypertonic (3%) saline did not improve survival.
The French Ministry of Health.
Abstract
Background
Differences in physiology of ARDS have been described between COVID-19 and non-COVID-19 patients. This study aimed to compare initial values and longitudinal changes in ...respiratory system compliance (
C
RS
), oxygenation parameters and ventilatory ratio (VR) in patients with COVID-19 and non-COVID-19 pulmonary ARDS matched on oxygenation.
Methods
135 patients with COVID-19 ARDS from two centers were included in a physiological study; 767 non-COVID-19 ARDS from a clinical trial were used for the purpose of at least 1:2 matching. A propensity-matching was based on age, severity score, oxygenation, positive end-expiratory pressure (PEEP) and pulmonary cause of ARDS and allowed to include 112 COVID-19 and 198 non-COVID pulmonary ARDS.
Results
The two groups were similar on initial oxygenation. COVID-19 patients had a higher body mass index, higher
C
RS
at day 1 (median IQR, 35 28–44 vs 32 26–38 ml cmH
2
O
−1
,
p
= 0.037). At day 1,
C
RS
was correlated with oxygenation only in non-COVID-19 patients; 61.6% and 68.2% of COVID-19 and non-COVID-19 pulmonary ARDS were still ventilated at day 7 (
p
= 0.241). Oxygenation became lower in COVID-19 than in non-COVID-19 patients at days 3 and 7, while
C
RS
became similar. VR was lower at day 1 in COVID-19 than in non-COVID-19 patients but increased from day 1 to 7 only in COVID-19 patients. VR was higher at days 1, 3 and 7 in the COVID-19 patients ventilated using heat and moisture exchangers compared to heated humidifiers. After adjustment on PaO
2
/FiO
2
, PEEP and humidification device,
C
RS
and VR were found not different between COVID-19 and non-COVID-19 patients at day 7. Day-28 mortality did not differ between COVID-19 and non-COVID-19 patients (25.9% and 23.7%, respectively,
p
= 0.666).
Conclusions
For a similar initial oxygenation, COVID-19 ARDS initially differs from classical ARDS by a higher
C
RS
, dissociated from oxygenation.
C
RS
become similar for patients remaining on mechanical ventilation during the first week of evolution, but oxygenation becomes lower in COVID-19 patients.
Trial registration
: clinicaltrials.gov NCT04385004
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