Efficacy of non-invasive positive pressure ventilation in acute cardiogenic pulmonary oedema

摘要

Non-invasive positive pressure ventilation (NIPPV), administered via a nasal or full-face mask, is now a well-documented modality of ventilatory assistance to avoid endotracheal intubation in selected patients with acute respiratory failure (ARF) . Preservation of airway defence mechanisms and speech, complete avoidance of trauma to oropharynx, larynx, and trachea, reduction in ventilator-associated pneumonia (VAP) , and reduction in length of stay (LOS) are the main advantages over conventional invasive ventilation. However NIPPV has potential limitations, including the lack of direct access to the airway for removal of secretions, facial trauma related to a mask, and need for patient co-operation. NIPPV using bilevel positive airway pressure (BiPAP), via nasal or full-face mask, has been shown to improve arterial blood gas (ABG), decrease intensive care unit (ICU) LOS and complication rates, and improve patient survival. In majority of trials with BiPAP, the major patient group enrolled was ARF due to exacerbation of chronic obstructive pulmonary disease (COPD). Many researchers, such as Meduri et al. Kramer et al., and Popnick et al. have included a few patients with acute cardiogenic pulmonary edema (ACPE) presenting as ARF in their studies, and have reported improvement in clinical and ABG status of this subset of patients. Although a few studies on the utility of continuous positive airway pressure (CPAP) in ACPE have been performed in the past, very few studies have been published on the efficacy of BiPAP in ACPE . Mehta et al. compared BiPAP and CPAP in their trial, and concluded that BiPAP improves ventilation and vital signs more rapidly than CPAP in patients with ACPE. One of the largest studies is by Hoffman and Welte from Germany. In an open, prospective, uncontrolled trial in patients with ACPE in ARF, they reported successful avoidance of intubation in 28 of 29 patients, with significant improvement in PCO_2, pH, and oxygen saturation.