Objective  To investigate the clinical treatment and outcomes of severe community-acquired pneumonia (CAP) complicated with mediastinal emphysema after renal transplantation.

  Methods  Clinical data of9 patients with severe CAP complicated with mediastinal emphysema after renal transplantation were retrospectively analyzed. The acute physiology and chronic health evaluationⅡ(APACHEⅡ) and oxygenation index were recorded when the patients were admitted to the intensive care unit (ICU). The complications of mediastinal emphysema and corresponding treatment were observed. The treatment course during the ICU, mortality rate in ICU, ICU stay time and hospital stay time were recorded. All patients underwent pathogenic examinations.

  Results  The APACHEⅡ score of9 patients with severe CAP complicated with mediastinal emphysema after renal transplantation was 14 (8-21) scores and the oxygenation index was 150 (133-189) mmHg. Among 9 patients, 3 cases were infected by bacteria alone, 3 cases were infected by bacterial infection combined with viral infection, 1 case was infected by mycobacterium tuberculosis complicated with other bacterial infection and 1 case was viral infection. No pathogenic evidence was detected in the remaining 1 patient. Mediastinal emphysema complicated with subcutaneous emphysema occurred in 7 cases and pneumothorax occurred in 6 cases. Treatment methods included anti-infection, modified immunosuppressive program, mediastinal drainage, thoracic closed drainage, subcutaneous incision and extracorporeal membrane oxygenation (ECMO) treatment. Six patients received invasive mechanical ventilation (IMV), 2 received non-invasive positive pressure ventilation (NIV) and 1 received high-flow nasal oxygen cannula (HFNC). Among 9 patients, the mortality rate in ICU was 6/9, the remaining 3 patients were recovered and discharged, the ICU stay time was 26 (17-40) d, and the total hospital stay time was 27-61 d.

  Conclusions  Mediastinal emphysema is a serious complication of patients presenting with severe CAP after renal transplantation with a high mortality rate. For these patients, imaging evaluation, timely drainage and full sedation should be strengthened, and ECMO treatment should be delivered when necessary.