Inclusion Criteria:
The criteria for the diagnosis of SCAP included:
- Blood systolic pressure lower than 90 mmHg or blood diastolic pressure lower than 60 mmHg
- RR higher than 30 breaths per minute
- PaO2/FiO2 lower than 250 while breathing through a Venturi mask with a 50% inspired oxygen fraction (FiO2)
- Bilateral or multiple lobar infiltrations evidenced by thorax X-ray, and
- Use of vasopressor drugs
Exclusion Criteria:
Exclusion criteria included:
- COPD
- Asthma
- Acute cardiogenic pulmonary edema
- Severe haemodynamic instability (arterial systolic pressure lower than 70 mmHg) or requirements of vasoactive drugs
- Glasgow score equal to or lower than 9 or requiring OTI for airway protection or for recent pulmonary resucitation
- Antecedents of respiratory failure resulting from neuromuscular pathology
- Failure of two or more organs
- Facial deformities; and
- Recent facial, aesophagic and gastric surgeries