Noninvasive Ventilation in Acute Cardiogenic Pulmonary Edema

Background
Noninvasive ventilation (continuous positive airway pressure [CPAP] or noninvasive
intermittent positive-pressure ventilation [NIPPV]) appears to be of benefit in the
immediat e t reat ment of pat ient s wit h acut e cardiogenic pulmonar y edema and may reduce mort alit y. We conducted a st udy to determine whet her noninvasive ventilation reduces mortality and whether there are important differences in outcome associated with the method of treatment (CPAP or NIPPV).
Methods In a multicenter, open, prospect ive, randomized, cont rolled t r ial, pat ient s were assigned to standard oxygen therapy, CPAP (5 to 15 cm of water), or NIPPV (inspiratory pressure, 8 to 20 cm of water; expiratory pressure, 4 to 10 cm of water). The primary end point for the comparison between noninvasive ventilation and standard oxygen therapy was death within 7 days after the initiation of treatment, and the primary end point for the comparison between NIPPV and CPAP was death or intubation within 7 days.
Results
A total of 1069 patients (mean [±SD] age, 77.7±9.7 years; female sex, 56.9%) were assigned to standard oxygen therapy (367 patients), CPAP (346 patients), or NIPPV (356 patients). There was no significant difference in 7-day mortality between patients receiving standard oxygen therapy (9.8%) and those undergoing noninvasive ventilation (9.5%, P=0.87). There was no significant difference in the combined end point of death or intubation within 7 days between the two groups of patients undergoing noninvasive vent ilat ion (11.7% for CPAP and 11.1% for NIPPV, P=0.81). As compared with standard oxygen therapy, noninvasive ventilation was associated with greater mean improvements at 1 hour after the beginning of treatment in patient-reported dyspnea (t reat ment dif ference, 0.7 on a visual-analogue scale ranging from 1 to 10; 95% conf idence inter val [CI], 0.2 to 1.3; P=0.008), heart rate (t reat ment dif ference, 4 beats per minute; 95% CI, 1 to 6; P=0.004), acidosis (treatment difference, pH 0.03;
95% CI, 0.02 to 0.04; P<0.001), and hypercapnia (treatment difference, 0.7 kPa
[5.2 mm Hg]; 95% CI, 0.4 to 0.9; P<0.001). There were no treatment-related adverse events.
Conclusions
In patients with acute cardiogenic pulmonary edema, noninvasive ventilation induces a more rapid improvement in respiratory distress and metabolic disturbance than does standard oxygen therapy but has no effect on short-term mortality.