The effect of matrix metalloproteinase-3 deficiency on pulmonary surfactant in a mouse model of acute lung injury.

The acute respiratory distress syndrome (ARDS) is characterized by arterial hypoxemia accompanied by severe inflammation and alterations to the pulmonary surfactant system. Published data has demonstrated a protective effect of matrix metalloproteinase-3 (Mmp3) deficiency against the inflammatory response associated with ARDS; however, the effect of Mmp3 on physiologic parameters and alterations to surfactant have not been previously studied. It was hypothesized that Mmp3 deficient (Mmp3(-/-)) mice would be protected against lung dysfunction associated with ARDS and maintain a functional pulmonary surfactant system. Wild type (WT) and Mmp3(-/-) mice were subjected to acid-aspiration followed by mechanical ventilation. Mmp3(-/-) mice maintained higher arterial oxygenation compared with WT mice at the completion of ventilation. Significant increase in functional large aggregate surfactant forms were observed in Mmp3(-/-) mice compared with WT mice. These findings further support a role of Mmp3 as an attractive therapeutic target for drug development in the setting of ARDS.

[Place of biomarkers in the renutrition of patients with serious Covid-19 infection: discussion around a clinical case]. / Place des biomarqueurs dans la renutrition des patients ayant une infection grave à Covid-19 : discussion autour d'un cas clinique.

Covid-19 infection is a potentially serious disease. Overweight, obesity, and diabetes are comorbidities frequently found in the severe form of the disease. Appropriate nutritional management of the patient is an integral part of care. We will discuss the renutrition of a 76-year-old, obese (BMI = 35kg/m2), malnourished patient, according to the 2021 Haute Autorité de santé criteria, with Covid-19 infection, admitted to the intensive care unit at the Bordeaux University Hospital for an acute respiratory distress syndrome. Adaptation of nutritional intakes was achieved by clinical and biological monitoring. A refeeding syndrome was treated on the first day of hospitalization in the intensive care unit. After thiamine supplementation and when kalemia and phosphatemia have been normalized, renutrition was started. Parenteral nutrition as a complement to oral nutrition was used. Parenteral nutrition was well tolerated; recommended caloric and protein intakes were achieved by the fourth day of hospitalization. The clinical evolution was favorable. In conclusion, patients with Covid-19 infection should be considered malnourished when admitted to the intensive care unit. Macro and micronutrient intakes adapted to metabolically stressed patients are essential. Biological monitoring including monitoring of ionogram, phosphate, uremia, creatinine, liver function tests and blood glucose is essential in the nutritional management of patients with serious Covid-19 infection.

[Severe pneumonia and acute respiratory distress syndrome: Implication of unconventional T cells]. / Pneumonies sévères et syndrome de détresse respiratoire aiguë : implication des lymphocytes T non conventionnels.

Pneumonia is frequently complicated by occurrence of acute respiratory distress syndrome (ARDS), consequently to dysregulated inflammatory response. However, mechanisms driving this dysregulation are poorly understood. To address this, "unconventional T-cells (UTC)" -γδT, NKT and MAIT cells- appear to be relevant targets due to their key role in orchestrating anti-microbial immune response in the lung. Thus, using an experimental and translational approach, we test the hypothesis that a tight regulation of UTC is mandatory to fine-tune host response, and, subsequently to prevent emergence of an aberrant response leading to excessive tissue damages, and eventually, ARDS.

[Extracorporeal life support in thoracic surgery: What are the indications and the pertinence?] / Support extracorporel en chirurgie thoracique : quelles indications et quels intérêts ?

INTRODUCTION: In thoracic surgery, extracorporeal life support (ECLS) technologies are used in cases of severe and refractory respiratory failure or as intraoperative cardiorespiratory support. The objectives of this review are to describe the rationale of ECLS techniques, to review the pulmonary diseases potentially treated by ECLS, and finally to demonstrate the efficacy of ECLS, using recently published data from the literature, in order to practice evidence based medicine. STATE OF THE ART: ECLS technologies should only be undertaken in expert centers. ECLS allows a protective ventilatory strategy in severe ARDS. In the field of lung transplantation, ECLS may be used successfully as a bridge to transplantation, as intraoperative cardiorespiratory support or as a bridge to recovery in cases of severe primary graft dysfunction. In general thoracic surgery, ECLS technology seems to be safe and efficient as intraoperative respiratory support for tracheobronchial surgery or for severe respiratory insufficiency, without significant increase in perioperative risk. PERSPECTIVE: The indications for ECLS are going to increase. Future improvements both in scientific knowledge and bioengineering will improve the prognosis of patients treated with ECLS for respiratory failure. Multicenter randomized controlled trials will refine the indications for ECLS and improve the global care strategies for these patients. CONCLUSION: ECLS is an efficient therapeutic strategy that will improve the prognosis of patients suffering from, or exposed to, the risks of severe respiratory failure.

Extracorporeal circuit for Panton-Valentine leukocidin-producing Staphylococcus aureus necrotizing pneumonia.

OBJECTIVE: To describe two cases of Panton-Valentine leukocidin-producing Staphylococcus aureus (PVL-SA) necrotizing pneumonia treated with ECMO, and complete pulmonary evaluation at six months. METHODS: Retrospective analysis of two patients presenting with severe PVL-SA pneumonia who both underwent complete respiratory function testing and chest CT scan six months after hospital discharge. RESULTS: Indications for ECMO were refractory hypoxia and left ventricular dysfunction associated with right ventricular dilatation. Patients were weaned off ECMO after 52 and 5 days. No ECMO-related hemorrhagic complication was observed. Pulmonary function tests performed at six months were normal and the CT scan showed complete regression of pulmonary injuries. CONCLUSION: PVL-SA pneumonia is characterized by extensive parenchymal injuries, including necrotic and hemorrhagic complications. ECMO may be used as a salvage treatment without any associated hemorrhagic complication, provided anticoagulant therapy is carefully monitored, and may lead to complete pulmonary recovery at six months.

[Pneumomediastinum: an aspect of pulmonary barotrauma during mechanical ventilation of acute respiratory distress syndrome]. / Le pneumomédiastin : un aspect du barotraumatisme pulmonaire au cours de la ventilation mécanique du syndrome de détresse respiratoire aiguë

Mechanical ventilation is a fundamental treatment of acute respiratory distress syndrome (ARDS). Despite compliance with the recommendations of protective mechanical ventilation, it can results in serious complications including the pulmonary barotrauma. This is often manifested by a pneumothorax. This observation describes an unusual aspect of barotrauma which is pneumomediastinum. The authors also point out the role of chest imaging in the management of mechanical ventilation during ARDS.

[The acute pulmonary renal syndrome: An unusual presentation of granulomatosis with polyangiitis]. / Le syndrome pneumo-rénal aigu : un mode de révélation rare de la granulomatose avec polyangéite.

INTRODUCTION: We report a case of acute pulmonary renal syndrome mimicking septic shock, which led to the diagnosis of granulomatosis with polyangiitis. CASE REPORT: A 70-year-old man was hospitalized because of acute kidney injury and acute respiratory distress syndrome with diffuse alveolar hemorrhage associated with a serum procalcitonin level of 18 µg/L. Initially, septic shock was suspected and antibiotic therapy was started. The absence of microbiological isolates and the patient's rapid clinical deterioration prompted laboratory testing for autoimmune disease, which confirmed the diagnosis of granulomatosis with polyangiitis. Immunosuppressive therapy was promptly initiated with corticosteroids, cyclophosphamide and several plasma exchanges, which resulted in a rapid clinical improvement and ICU discharge. CONCLUSIONS: Granulomatosis with polyangiitis is a systemic necrotizing vasculitis with antineutrophil cytoplasmic antibodies, which can present with acute pulmonary renal syndrome, combining acute respiratory distress syndrome and acute kidney injury. This misleading presentation must prompt an autoimmune disease testing in order to yield an early diagnosis of a vasculitis, allowing for timely initiation of immunosuppressive treatment. Serum procalcitonin levels can be markedly elevated and this must not override the possibility of a vasculitis where the patient shows a compatible symptomatology.

[Acute respiratory distress syndrome complicating an acute chest syndrome: potential benefit of early combination of exchange transfusion and prone positioning]. / Syndrome de défaillance respiratoire aiguë sévère au cours d'un syndrome thoracique aigu chez une enfant drépanocytaire de 8ans : bénéfice potentiel de l'association précoce échange transfusionnel et décubitus ventral.

We report the case of an 8-year-old sickle cell anemia child admitted for acute respiratory failure complicating acute chest syndrome. Because of threatening respiratory failure, tracheal intubation was performed immediately after ICU admission. The patient met the criteria for ARDS with a PaO2/FiO2 ratio of 94mmHg. An exchange transfusion was performed immediately after admission. HbS fraction failed from 69 % to 30 %. Fluid resuscitation with crystalloids and continuous norepinephrine infusion was needed because of arterial hypotension. Due to persistent severe hypoxemia with PaO2/FiO2 ratio below 100, the patient was placed in prone positioning 16hours after admission, for a total duration of 14hours. A second 12-hour session of prone positioning was performed 41h after admission and PaO2/FiO2 ratio reached 300mmHg after. Treatment also included transfusion of two red-cell pack on day 1 and 2 after admission in order to maintain hemoglobin level above 8g/dL, and a daily folic acid supplementation. The control of hyperthermia was achieved by a systematic parenteral administration of paracetamol. Cefotaxime and erythromycine were continued until day 7 despite the negative results of all bacteriological samples. The outcome was favorable from day 3 and the patient met the criteria for extubation on day 5. A first attempt of extubation was performed on day 5, but re-intubation was required because of laryngeal edema. Steroids were given for 48h and the patient was successfully extubated on day 7. She was discharged from the ICU on day 8, and from the hospital on day 12. We discuss the various treatments available for the management of acute chest syndrome and their actual relevance in acute respiratory distress syndrome in the absence of strong evidence-based guidelines in pediatric ARDS.

[The acute respiratory distress syndrome in malaria: is it always the prerogative of Plasmodium falciparum?]. / Le syndrome de détresse respiratoire aiguë au cours du paludisme: est-il toujours l'apanage du Plasmodium falciparum?

Severe malaria causes nearly one million deaths annually in endemic areas and is a public health priority worldwide. Severity associated with the occurrence of acute respiratory distress syndrome (ARDS) is a well-known complication of infection with Plasmodium falciparum and can reach 25% of infected adults. However, ARDS is less often described with other Plasmodium species. We report the case of a young Moroccan soldier who died in an array of ARDS related to malaria of Plasmodium ovale 7 months after his return from an endemic country.