目的 Volume-targeted noninvasive ventilation(VT-NIV),a hybrid mode that delivers a preset target tidal volume(VT)through theautomated adjustment of pressure support,could guarantee a relatively constant target VT over pressure-limited noninvasiveventilation(PL-NIV)with fixed-level pressure support.Whether VT-NIV is more effective in improving ventilatory status insubjects with acute hypercapnic respiratory failure(AHRF)remains unclear.Our aim was to verify whether,in comparison with PLNIV,VT-NIV would be more effective in correcting hypercapnia,hence reducing the need for intubation and improving survival insubjects with AHRF.