Lung abscess following ventilator-associated pneumonia during COVID-19: a retrospective multicenter cohort study.

BACKGROUND: Patients undergoing mechanical ventilation (MV) for COVID-19 exhibit an increased risk of ventilator-associated pneumonia (VAP). The occurrence of lung abscesses following VAP in these patients has been poorly studied. We aimed to describe the incidence, characteristics, risk factors and prognosis of lung abscesses complicating VAP after COVID-19. METHODS: We conducted an observational, retrospective study in three French intensive care units. Patients admitted for acute respiratory failure with a confirmed SARS-CoV-2 PCR and requiring MV for more than 48 h were included. RESULTS: Among the 507 patients included, 326 (64%) had a documented VAP. Of these, 23 (7%) developed a lung abscess. Enterobacterales (15/23, 65%) were the main documentation, followed by non-fermenting Gram-negative bacilli (10/23, 43%) and Gram-positive cocci (8/23, 35%). Lung abscesses were mainly plurimicrobial (15/23, 65%). In multivariate analysis, a plurimicrobial 1st VAP episode (OR (95% CI) 2.93 (1.16-7.51); p = 0.02) and the use of hydrocortisone (OR (95% CI) 4.86 (1.95-12.1); p = 0.001) were associated with lung abscess development. Intensive care unit (ICU) mortality of patients with lung abscesses reached 52%, but was not significantly higher than for patients with VAP but no lung abscess. Patients with lung abscesses had reduced ventilator-free days at day 60, a longer duration of MV and ICU stay than patients with VAP but no lung abscess (respectively, 0 (0-3) vs. 16 (0-42) days; p < 0.001, 49 (32-73) vs. 25 (11-41) days; p < 0.001, 52 (36-77) vs. 28 (16-47) days; p < 0.001). CONCLUSIONS: Lung abscessing pneumonia is not uncommon among COVID-19 patients developing VAP. A plurimicrobial first VAP episode and the use of hydrocortisone are independently associated with this complication. In COVID-19 patients with persistent VAP, a chest CT scan investigating the evolution toward lung abscess should be considered.

Cytomegalovirus reactivation enhances the virulence of Staphylococcus aureus pneumonia in a mouse model.

OBJECTIVES: Cytomegalovirus (CMV) reactivation in intensive care unit patients may increase mortality and favour bacterial pneumonia. We developed a murine model to compare the severity of staphylococcal pneumonia after CMV reactivation and in CMV-negative mice. METHODS: Balb/c mice were primo-infected with murine cytomegalovirus (MCMV n=90) or received saline (control n=90). After latency, all mice underwent caecal ligation and puncture to trigger MCMV reactivation in MCMV primary-infected mice. Surviving animals received an intra-nasal inoculation with methicillin-susceptible Staphylococcus aureus (MSSA) to induce pneumonia. Mortality, lung bacterial count, histology and interferon-alpha and gamma serum levels were compared in MCMV reactivated and control mice 2, 5 and 15 days after pneumonia. RESULTS: After MSSA pneumonia, MCMV mice showed a trend towards a higher mortality (9.4% versus 0%; p 0.09) and a higher weight loss (2.2 (0.6-4.1 g) versus 0.7 (-0.3 to 1.3 g); p 0.005). The lung bacterial count was higher in MCMV mice 2 days (5×103 (103 to 3×105) versus 102 (0 to 4×102) CFU/lung; p 0.007) and 5 days (2.5×104 (1.6×104 to 6.5×105) versus 15 (10-40) CFU/lung; p 0.005) after MSSA pneumonia. 8/40 (20%) MCMV mice developed lung abscesses compared to 0% in control (p 0.011). Interferon-alpha serum levels 2 days after staphylococcal pneumonia were higher in MCMV mice. CONCLUSIONS: MCMV reactivation decreased lung bacterial clearance and favoured the development of staphylococcal abscessing pneumonia. CMV reactivation may be responsible for a higher susceptibility to bacterial sepsis.

Prone positioning during veno-venous extracorporeal membrane oxygenation for severe acute respiratory distress syndrome in adults.

BACKGROUND: Veno-venous extracorporeal membrane oxygenation (VV-ECMO) is an effective rescue therapy for improving oxygenation in selected severe acute respiratory distress syndrome (ARDS). Prone position (PP) is usually considered before vvECMO and few data are available on the association of PP during VV-ECMO. Thus, we investigated the effect on oxygenation and the safety of PP during vvECMO. METHODS: During a two-year period, 15 patients with severe ARDS were turned into PP during VV-ECMO therapy for at least one of the three following conditions: severe hypoxemia (PaO2/FiO2 ratio below 70) despite maximal oxygenation, injurious ventilation parameters with plateau pressure exceeding 32 cmH2O or failure of attempt to wean ECMO after at least 10 days on ECMO support. RESULTS: PP was considered after a median of 9 days of ECMO and applied for a median of 12 hours and an average of 1.4 sessions per patient resulting in a total of 21 procedures. We found significant improvement in PaO2/FiO2 ratio at 6 hours (P=0.03) and 12 hours (P=0.007) after reversal. The improvement in oxygenation has still persisted 1hour (P=0.017) and 6 hours (P=0.013) after back to the supine position. No change in PaCO2, respiratory system (RS) compliance was observed. ECMO flow was maintained constant during the procedure. No complication related to PP was detected. CONCLUSION: PP may be considered in selected patients difficult to wean or remaining very hypoxemic despite VV-ECMO support.

Passive circulating cell sorting by deformability using a microfluidic gradual filter.

The deformability of circulating leukocytes plays an important role in the physiopathology of several diseases like sepsis or acute respiratory distress syndrome (ARDS). We present here a microfluidic method for the passive testing, sorting and separating of non-adherent cell populations by deformability. It consists of microfluidic sieves in series with pore sizes decreasing from the upstream to the downstream. The method capabilities are demonstrated with monocytic cell lines (THP-1) treated by Jasplakinolide (a stabilizer of polymerized actin), LatrunculinA (an inhibitor of actin polymerization), and with the plasma of patients suffering from ARDS. Simple sample injection with standard syringes and pumps makes the method readily adapted for experimentation in hospitals.

[Ventilator-associated viral pneumonia]. / Pneumonies virales acquises sous ventilation mécanique.

Viral infections (especially respiratory infections) are not rare in critically ill non-immunocompromised patients. Efficient and rapid virologic diagnosis tests such as polymerase chain reaction (PCR) are now widely available. Herpesviridae (herpes simplex virus and cytomegalovirus) are the most frequent viruses detected among non-immunocompromised patients admitted to the intensive care unit (ICU). However, causal relationships between detected viruses and outcomes are still debated, with a variable level of demonstration among the different viruses. The aim of this review was to assess the role of viruses in causing mechanical ventilation-acquired pneumonias in non-immunocompromised ICU adult patients. We also discuss the possible physiopathology of these viral infections, as well as the opportunity for therapeutic interventions.

Non-invasive ventilation for treatment of postoperative respiratory failure after oesophagectomy.

BACKGROUND: The aim of this case-control study was to compare the efficacy of non-invasive positive pressure ventilation (NPPV) with that of conventional treatment in patients who develop postoperative acute respiratory failure (ARF) after oesophagectomy. METHODS: Thirty-six consecutive patients with ARF treated by NPPV were matched for diagnosis, age within 5 years, sex, preoperative radiochemotherapy and Charlson co-morbidity index with 36 patients who received conventional treatment (control group). RESULTS: NPPV was associated with a lower reintubation rate (nine versus 23 patients; P = 0.008), lower frequency of acute respiratory distress syndrome (eight versus 19 patients; P = 0.015), and a reduction in intensive care stay (mean(s.d.) 14(13) versus 22(18) days; P = 0.034). Anastomotic leakage was less common in patients receiving NPPV (two versus ten; P = 0.027). These patients also showed a greater improvement in gas exchange in the first 3 days after onset of ARF (P = 0.013). CONCLUSION: The use of NPPV for the treatment of postoperative ARF may decrease the incidence of endotracheal intubation and related complications, without increasing the risk of anastomotic leakage after oesophagectomy.

[Acute respiratory distress syndrome following inhalation of barium sulfate]. / Syndrome de détresse respiratoire aiguë après inhalation de sulfate de baryum.

INTRODUCTION: Barium sulfate (BS) is chosen to explore swallowing disorders because of its reduced osmolality allowing no adverse reaction if aspirated in the bronchial tree. CASE REPORT: A 66-years old man treated for an advanced stage mesothelioma experienced a BS aspiration during an esophagography. He developed 3 days after an acute respiratory distress syndrome (ARDS) and deceased. The post-mortem examination revealed a diffuse alveolar damage (DAD). CONCLUSION: Whereas BS aspiration is generally well tolerated, serious adverse event as a DAD would exceptionally occurs. Thus, a close watch over respiratory symptoms has to be kept after BS administration, especially in debilitated and elderly patients.