This randomized controlled trial is primarily aimed at assessing the rate of acute myocardial infarction with the two noninvasive ventilatory techniques, non-invasive intermittent positive pressure ventilation and non-invasive continuous positive airway pressure.

Objective: To determine whether the application of non-invasive intermittent positive pressure ventilation (n-IPPV) increases the incidence of acute myocardial infarction (AMI) in patients with acute respiratory failure (ARF) secondary to acute cardiogenic pulmonary edema (ACPE), as opposed to non-invasive continuous positive airway pressure (n-CPAP).

Background Both n-CPAP or n-IPPV are used to treat ACPE complicated by ARF. Two previous studies, however, report an increased rate of AMI associated with the use of n-IPPV.

Methods: Fifty-two patients with severe ARF consequent to ACPE were randomized to receive n-CPAP (n=27) or n-IPPV (n=25), both associated with standard medical therapy. Cardiac markers, electrocardiogram and clinical-physiological parameters were monitored at study entry, after 30 and 60 minutes, and every 6 hours for the first two days.

Inclusion Criteria:

• rapid onset of the symptoms
• severe dyspnoea at rest
• respiratory rate > 30 breaths per minute
• use of accessory respiratory muscles
• oxygen saturation (SpO2) inferior to 90% with an inspiratory oxygen fraction of 60% via a Venturi mask
• radiological findings of ACPE

Exclusion Criteria:

• acute ischemic heart disease (myocardial infarction, chest pain, ST elevation)
• hemodynamic instability (i.e. systolic blood pressure < 90 with dopamine or dobutamine infusion ≥ 5 mcgr/Kg/min) or life-threatening arrhythmias
• need for immediate endotracheal intubation (respiratory arrest, bradypnea or gasping)
• inability to protect the airways
• impaired sensorium (i.e. unconsciousness or agitation)
• inability to clear secretions
• respiratory tract infection
• recent oesophageal/gastric surgery
• gastrointestinal bleeding
• facial deformities
• hematological malignancy or cancer with an Eastern Cooperative Oncology Group performance status ≥ 2
• chronic respiratory failure necessitating long-term oxygen therapy
• diagnosis of myocardial infarction, pulmonary embolism, pneumonia, exacerbation of chronic obstructive pulmonary disease, pneumothorax in the previous 3 months
• denial or refusal of intubation
• claustrophobia
• inclusion in other research protocols