Noninvasive ventilation for acute respiratory failure: state of the art (II part)

Abstract

Background: In the last years Non-Invasive Ventilation (NIV) has been playing an important role in the treatment of Acute Respiratory Failure (ARF). Prospective randomised controlled trials have shown improvements in clinical features (respiratory rate, neurological score), pH and arterial blood gases and in particular clinical conditions (Acute Cardiogenic Pulmonary Edema, ACPE, and acute exacerbation of Chronic Obstructive Pulmonary Disease, COPD) systematic reviews and metha-analysis confirm a reduction in the need for intubation and in-hospital mortality compared to standard medical treatment. Methods: The most important techniques of ventilation in spontaneous breathing are: Continuous Positive Airway Pression (CPAP), usually performed with Venturi-like flow generators, and bi-level positive pressure ventilation (an high inspiratory pressure and a low expiratory pressure), performed with ventilators. Facial mask rather than nasal mask is used in ARF: the helmet is useful for prolonged treatments. Results: NIV’s success seems to be determined by early application, correct selection of patients and staff training. Controindications to NIV are: cardiac or respiratory arrest, a respiratory rate < 12 per minute, upper airway obstruction, hemodynamic instability or unstable cardiac arrhythmia, encephalopathy (Kelly score > 3), facial surgery trauma or deformity, inability to cooperate or protect the airway, high risk of aspiration and an inability to clear respiratory secretions. Conclusions: Bi-level ventilation for ARF due to COPD and CPAP or bi-level bentilation for ARF due to ACPE are feasible, safe and effective also in a General Medical ward if the selection of patients, the staff’s training and the monitoring are appropriate: they improve clinical parameters, arterial blood gases, prevent ETI, decrease mortality and hospitalisation. This should encourage the diffusion of NIV in this specific setting.