Noninvasive Mechanical Ventilation in Patients with Viral Pneumonia-Associated Acute Respiratory Distress Syndrome: An Observational Retrospective Study.

Objectives: Appropriate mechanical ventilation may change the prognosis of patients with viral pneumonia-associated acute respiratory distress syndrome (ARDS). This study aimed to identify the factors associated with the success of noninvasive ventilation in the management of patients with ARDS secondary to respiratory viral infection. Methods: In this retrospective cohort study, all patients with viral pneumonia-associated ARDS were divided into the noninvasive mechanical ventilation (NIV) success group and the NIV failure group. The demographic and clinical data of all patients were collected. The factors associated with the success of noninvasive ventilation were identified by the logistic regression analysis. Results: Among this cohort, 24 patients with an average age of 57.9 ± 17.0 years received successful NIVs, and NIV failure occurred in 21 patients with an average age of 54.1 ± 14.0 years. The independent influencing factors for the success of the NIV were the acute physiology and chronic health evaluation (APACHE) II score (odds ratio (OR): 1.83, 95% confidence interval (CI): 1.10-3.03) and lactate dehydrogenase (LDH) (OR: 1.011, 95% CI: 1.00-1.02). When the oxygenation index (OI) is <95 mmHg, APACHE II > 19, and LDH > 498 U/L, the sensitivity and specificity of predicting a failed NIV were (66.6% (95% CI: 43.0%-85.4%) and 87.5% (95% CI: 67.6%-97.3%)); (85.7% (95% CI: 63.7%-97.0%) and 79.1% (95% CI: 57.8%-92.9%)); (90.4% (95% CI: 69.6%-98.8%) and 62.5% (95% CI: 40.6%-81.2%)), respectively. The areas under the receiver operating characteristic curve (AUC) of the OI, APACHE II scores, and LDH were 0.85, which was lower than the AUC of the OI combined with LDH and the APACHE II score (OLA) of 0.97 (P=0.0247). Conclusions: Overall, patients with viral pneumonia-associated ARDS receiving successful NIV have lower mortality rates than those for whom NIV failed. In patients with influenza A-associated ARDS, the OI may not be the only indicator of whether NIV can be used; a new indicator of NIV success may be the OLA.

Histopathological findings in a critically ill patient with avian influenza A (H7N9).

To date, data regarding the pulmonary histopathology of human H7N9 disease are scarce. We herein describe a patient with a severe case of avian influenza A (H7N9). A chest computerized tomography (CT) scan showed diffuse ground-glass opacities and consolidation throughout the lungs. A resection of pulmonary bullae in the right middle lobe was performed by video-assisted thoracic surgery (VATS) based on the extracorporeal membrane oxygenation (ECMO) supportive technique on the 23(rd) day after the onset of symptoms because of a right pneumothorax persistent air leak. The histopathological findings of the resected lung tissue revealed pneumocyte hyperplasia and fibroproliferative changes along with diffuse alveolar damage. Bronchoalveolar lavage fluid (BALF) specimens for influenza A (H7N9) virus were continuously positive for more than three weeks, despite oseltamivir treatment, and continuous viral replication significantly prolonged the course of the disease. The patient's clinical status continuously deteriorated, with the development of refractory hypoxemia due to progressive and rapid lung fibrosis, which was confirmed by the final histological changes observed from a limited post-mortem biopsy of lung tissue. Pre-terminally, he developed multi-organ failure and died on the 39(th) day after symptom onset, despite corticosteroid treatment.