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Randomized Trial of Bilevel versus Continuous Positive Airway Pressure for Acute Pulmonary Edema

https://doi.org/10.1016/j.jemermed.2013.08.015Get rights and content

Abstract

Background

Studies have shown different clinical outcomes of noninvasive positive pressure ventilation (NPPV) from those of continuous positive airway pressure (CPAP).

Objective

We evaluated whether bilevel positive airway pressure (BPAP) more rapidly improves dyspnea, ventilation, and acidemia without increasing the myocardial infarction (MI) rate compared to continuous positive pressure ventilation (CPAP) in patients with acute cardiogenic pulmonary edema (APE).

Methods

Patients with APE were randomized to either BPAP or CPAP. Vital signs and dyspnea scores were recorded at baseline, 30 min, 1 h, and 3 h. Blood gases were obtained at baseline, 30 min, and 1 h. Patients were monitored for MI, endotracheal intubation (ETI), lengths of stay (LOS), and hospital mortality.

Results

Fourteen patients received CPAP and 13 received BPAP. The two groups were similar at baseline (ejection fraction, dyspnea, vital signs, acidemia/oxygenation) and received similar medical treatment. At 30 min, PaO2:FIO2 was improved in the BPAP group compared to baseline (283 vs. 132, p < 0.05) and the CPAP group (283 vs. 189, p < 0.05). Thirty-minute dyspnea scores were lower in the BPAP group compared to the CPAP group (p = 0.05). Fewer BPAP patients required intensive care unit (ICU) admission (38% vs. 92%, p < 0.05). There were no differences between groups in MI or ETI rate, LOS, or mortality.

Conclusions

Compared to CPAP to treat APE, BPAP more rapidly improves oxygenation and dyspnea scores, and reduces the need for ICU admission. Further, BPAP does not increase MI rate compared to CPAP.

Section snippets

Introductions

Multiple randomized controlled studies and meta-analyses have demonstrated the efficacy of either continuous positive airway pressure (CPAP) or noninvasive positive pressure ventilation (NPPV) (i.e., the combination of positive end expiratory pressure and pressure support administered via a face mask) to treat acute cardiogenic pulmonary edema (APE) 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18. When compared with standard oxygen and medical therapy, these modalities more

Methods

The study was approved by Rhode Island Hospital’s institutional review board. Written informed consent was obtained from either the patient or the proxy prior to study enrollment and randomization.

Results

From a total of 150 screened patients with a presumed diagnosis of APE, 36 were enrolled. Nineteen patients were randomized to CPAP and 17 patients were randomized to BPAP. Of the remaining 114 patients, 42 patients had a diagnosis other than APE (chronic obstructive pulmonary disease exacerbation [n = 25], pneumonia [n = 7], asthma exacerbation [n = 7], pulmonary embolism [n = 1], idiopathic pulmonary fibrosis [n = 1], and obstructive sleep apnea [n = 1]); 26 had a respiratory rate ≤24; 15

Discussion

Our findings indicate that, contrary to our previous study, patients with APE treated with BPAP do not have higher MI rates than those treated with CPAP (19). Furthermore, BPAP more rapidly improves oxygenation and dyspnea scores in these patients, compared to CPAP therapy. Perhaps related to these more rapid improvements, fewer BPAP than CPAP patients required ICU admission.

Although both CPAP and BPAP have demonstrated improved outcomes in APE patients when compared to oxygen therapy alone,

Conclusions

In this follow-up study to the Mehta study on APE that found a strong trend for increased MI rate in a BPAP compared to a CPAP group, we found no indication that MI rate was increased in either group (19). This contrary finding is most likely related to better randomization, improved methods to detect and exclude patients with MIs upon ED presentation, and advances in BPAP device technology. BPAP manifested early advantages over CPAP with regard to resolution of dyspnea and better oxygenation,

Acknowledgments

The authors are very grateful for the assistance of the Department of Respiratory Care at Rhode Island Hospital, who were very helpful in identifying possible candidates for the study and collecting data.

Oronasal masks connected to BPAP were donated by Respironics, Inc.

Nicholas S. Hill, MD, received a research grant from Breathe Technologies.

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