Objective: To analyze the characteristic of changes in extravascular lung water index (EVLWI) of H7N9 avian influenza patients who complicated with acute respiratory distress syndrome (ARDS), and to approach the relevance between EVLWI and severity, pulmonary oxygenation in patients with lung injury.
Methods: Four H7N9 avian influenza patients administered from April to June in 2013 in First Affiliated Hospital of Nanchang University were studied. The patients who suffered from severe ARDS were administered with low tide volume ventilation plus positive end-expiratory pressure (PEEP), namely protected ventilation strategy, with monitoring hemodynamic parameters and EVLWI through pulse-indicated continuous cardiac output (PiCCO) catheter. During ventilation, patients' parameters, such as PEEP, fraction of inspired oxygen (FiO2), arterial partial pressure of oxygen (PaO2), oxygenation index (PaO2/FiO2), cardiac index (CI), systemic vascular resistance index (SVRI), pulmonary vascular resistance index (PVRI), EVLWI, and central venous pressure (CVP) were collected.
Results: All 4 H7N9 avian influenza patients were complicated with ARDS, 2 patients were classified to severe ARDS and administered with comprehensive therapies, specially protected ventilation strategy; ventilation duration was 9 days and 30 days respectively, and PiCCO monitoring was 9 days and 21 days respectively. EVLWI of 2 patients on the 1st, 2nd, 3rd day was 10.0±3.2 ml/kg, 12.0±2.9 ml/kg, 14.0±4.2 ml/kg, and 24.0±6.7 ml/kg, 24.0±6.1 ml/kg, 23.0±5.8 ml/kg, respectively. As their conditions became better, patients' EVLWI decreased to 5.5±2.7 ml/kg and 7.0±3.0 ml/kg, respectively at weaning. PEEP and FiO2 of 2 patients were down-regulated, PaO2/FiO2 increased to 334±64 mm Hg and 142±53 mm Hg at weaning. However, no significant changes in CI, SVRI, PVRI and CVP in the 2 patients were observed.
Conclusions: EVLWI increases when H7N9 avian influenza patients are complicated with severe ARDS. As the conditions get better, EVLWI returns to normal value gradually. There is relevance between the motive changes in EVLWI and severity of ARDS and pulmonary oxygenation.