Efects of Noninvasive Mechanical Ventilation and Conventional Mechanical Ventilation in Patients With Severe Comunity Pneumonia

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