High flow nasal cannula (HFNC) vs. non-invasive ventilation in OHS with severe pneumonia patients: A prospective study

Objective:To compare the clinical outcomes of HFNC with non-invasive ventilation(NIV) with auto-titrating EPAP for severe pneumonia patients with OHS(obesity hypoventilation syndrome). Methods:It was a prospective, randomized and controlled study. 60 severe pneumonia patients with OHS (27.3±8.9 yrs,BMI:40±8.9 kg/m2) were included, who had no a history of immunosuppressant therapy. Main criteria: 100＜PO2/FiO2＜300 mmHg; APACHE-Ⅱ:20-30. All subjects were randomly divided (1:1:1) into three groups: HFNC-group(Flow:50-60L/min,FiO2:40-60%); AVAPS- group (NIV with AVAPS mode, EPAP=8 cmH2O) and AVAPS-AE (average volume assured pressure support auto-titrating EPAP)group: AVAPS-AE mode, maximum EPAP=14cmH2O,minimum EPAP=4cmH2O. Results:Higher occurrence of ventilator-induced lung injury(VILI) and patient-ventilator asynchrony were observed in AVAPS-group than in other groups (pl0.001) .28-day mortality rates of 20.0%(n=4) in HFNC–group was significantly lower than in 45% (n=9) in “AVAPS-group and 30% (n=6) in AVAPS- AE group(pl0.05). There were no significant differences in changes of PO2/FiO2 between AVAPS-AE and AVAPS group(pg0.05). Degree of the comfortable during NIV in AVAPS-AE group were higher than in AVAPS group(pl0.05). Conclusions:Young OHS patients with severe pneumonia maybe could not benefit from noninvasive ventilation, either AVAPS or AVAPS-AE mode, and there were high mortality rate in both groups. HFNC seems to be superior to NIV in increasing VILI and 28-day mortality rate. AVAPS-AE mode could improve the patient’s comfort by auto-titrating EPAP level.