Utility of non-invasive synchronized intermittent mandatory ventilation in acute cardiogenic pulmonary edema

Acute cardiogenic pulmonary edema (ACPE), one of the outcomes of acute heart failure (AHF), is a common reason in a critical condition with respiratory distress. Non-invasive synchronized intermittent mandatory ventilation(nSIMV) mode, which includes inspiratory pressure in addition to positive end expiratory pressure with/without pressure support provided in the non-invasive continuous positive airway pressure plus/pressure support(nCPAP/PS) mode can be effective in hypercarbia and the associated changes in consciousness. This study aimed to demonstrate the efficacy of nSIMV in ACPE.

Patients who presented with clinical acute respiratory failure and were admitted to the critical care unit of the emergency department with the diagnosis of ACPE were included. Patients were placed on non-invasive mechanical ventilators with an oronasal mask under the nCPAP/PS and nSIMV modes. Pulse and respiratory rate, systolic and diastolic blood pressure and Glasgow Coma Scores(GCS), HACOR(heart rate, acidosis, consciousness, oxygenation and respiratory rate) scores, pH, PaCO2, PaO2/FiO2 and lactate at the time of admission and at 30 and 60 min were evaluated.

Twenty-two patients were recruited, nCPAP/PS mode was 10 and nSIMV mode was 12. Although there was no statistically significant difference between the two groups in terms of the change in the relevant parameters from admission to 60 min, the decreases in PaCO2 and lactate levels (31.4% vs. 21.2%, p = 0.383; 68.8% vs. 47.1%, p = 0.224; respectively) and the increase in PaO2 and PaO2/FiO2 values (34% vs. 14.2%, p = 0.710 and 132.1% vs. 52.7%, p = 0.073; respectively) were higher in the nSIMV group.

The nSIMV mode is as effective as the nCPAP/PS mode in the treatment of patients with ACPE. We believe that the nSIMV mode can be preferable, particularly in patients with hypercarbia who have relatively lower GCS and oxygenation.