[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.

Alveolar fibroblasts in acute lung injury: biological behaviour and clinical relevance.

Although fibroblasts are key cells in the lung repair/fibrosis process, their characteristics are poorly studied in acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). The aims of our study were to: 1) determine the biological behaviour of alveolar fibroblasts during ALI; and 2) to evaluate the clinical relevance of positive alveolar fibroblast culture from patients with ALI/ARDS. Cells were cultured from bronchoalveolar lavage (BAL) obtained from 68 critically ill, ventilated patients: ALI n = 17; ARDS n = 31; and ventilated controls n = 20. Patients were followed for 28 days and clinical data was recorded. We studied proliferation, migration and collagen-1 synthesis capacities of fibroblasts. Cells expressing fibroblast markers were cultured from BAL obtained in six (35%) ALI patients and six (19%) ARDS patients, but never from ventilated controls. Alveolar fibroblasts exhibited a persistent activated phenotype with enhanced migratory and collagen-1 production capacities, with hyporesponsiveness to prostaglandin E(2) compared to normal lung fibroblasts (p< or =0.04). Positive fibroblast culture was associated with both an increased collagen-1 concentration and monocyte/macrophage percentage in BAL fluid (p< or =0.01), and with a reduced duration of mechanical ventilation (p<0.001). We conclude that activated alveolar fibroblasts can be cultured either in ALI or ARDS and that their presence might reflect the initiation of the organising phase of ALI.

Incidence and risk factors of early thromboembolic events after mechanical heart valve replacement in patients treated with intravenous unfractionated heparin.

OBJECTIVE: To evaluate the incidence and risk factors, including timing and intensity of anticoagulation, of early thromboembolic events (TE) after mechanical heart valve replacement (MHVR) in patients treated by intravenous unfractionated heparin (IVUH). DESIGN: Prospective observational study, conducted between December 2005 and May 2007. SETTING: Haemostasis laboratory, surgical intensive care unit and ward in a university hospital. PATIENTS: Three hundred consecutive patients undergoing MHVR. Mitral or double MHVR was performed in 149 patients, and aortic MHVR in 151 patients. Postoperative anticoagulation was achieved with continuous IVUH according to a standardised protocol. The timing of efficient anticoagulation was recorded for each patient. MAIN OUTCOME MEASURES: The end point was the occurrence of any arterial TE from day 1 to day 30. Transoesophageal echocardiography was systematically performed after mitral MHVR. RESULTS: Early TE occurred in 22 patients (14.8%; 95% CI 9% to 20%) after a mitral or double MHVR and in two patients (1.3%; 95% CI 0% to 3%) after an aortic MHVR (p = 0.005). After adjustment for diabetes mellitus (adjusted OR (aOR) = 3.3; 95% CI 1.0 to 10.9, p = 0.049), and for the presence of predisposing factors (heparin-induced thrombocytopenia or bradycardia requiring definitive pacemaker implantation) (aOR = 12.8; 95% CI 3.1 to 53.3, p<0.001), effective anticoagulation on day 3 was a protective factor (aOR = 0.28; 95% CI 0.1 to 0.8, p = 0.018) for early TE after mitral MHVR. CONCLUSIONS: Despite the use of IVUH, the rate of early TE after mitral MHVR remained elevated. These results suggest that early effective anticoagulation is required after mitral MHVR, since inappropriate anticoagulation on day 3 was significantly associated with early TE.

[Early diagnostic for vasospasm after aneurysmal subarachnoid haemorrhage]. / Comment faire le diagnostic précoce d'un vasospasme?

Vasospasm is the leading cause of sequelae or deaths after aneurysmal subarachnoid haemorrhage. Vasospasm occurs 2-10 days after haemorrhage and that justifies close monitoring during this period. Because clinical signs appear often to late to reverse ischaemia, paraclinic tools have been developed. Arteriography is the historical gold standard for diagnosis but no clear validated rules exist to measure vessel sections. Diagnosis of vasospasm is, thus, relatively subjective and only reflects one moment of arteries status. Transcranial doppler is a non-invasive and easily repeatable method but sensibility and specificity for vasospasm diagnosis are low compared to arteriography. However, day-to-day changes of arterial blood cells velocities can help to determine vasospasm risk and/or indicate time for arteriography. CT-scanner, PET-scan or IRM can help to evaluate ratio between perfusion and metabolism. Nevertheless, as arteriography, it is only a one-time measurement without control of treatment effects. Waiting for improvement of diagnosis techniques, arteriography stays the gold standard. To choose the right moment for invasive methods, intensivists need to use clinical and transcranial doppler data and start treatment as early as possible to be efficacious.

[Activated proteine C]. / La protéine C activée.

Recombinant human activated protein C (APC) might be the first pharmacological intervention which decreases mortality in the course of severe sepsis. Surviving Sepsis Campaign guidelines have recommended the use of APC with grade B level of proof. During sepsis, the APC pathway serves as a major system for controlling thrombosis inhibiting thrombin formation, limiting inflammatory responses, and potentially decreasing endothelial cell apoptosis. APC use was assessed in the course of severe sepsis 24 microg/kg/h for 96 hours with the aim of inhibiting coagulopathy and inflammation. The PROWESS trial included 1,690 patients and demonstrated a significantly decreased mortality in the treated group. Additional publications have clarified the characteristics of the included patients and tried to outline the potential benefits of APC. The results of ENHANCE, a multicenter open trial, have confirmed the trends reported in the PROWESS trial. Evidence supporting the efficacy of APC in the management of severe sepsis is clearly assessed. However, several issues remain unsolved and require to be addressed as the appropriate use of the drug and its place with other adjunctive therapies directed the sepsis process.