Elsevier

The Lancet

Volume 356, Issue 9248, 23–30 December 2000, Pages 2126-2132
The Lancet

Articles
Non-invasive pressure support ventilation versus conventional oxygen therapy in acute cardiogenic pulmonary oedema: a randomised trial

https://doi.org/10.1016/S0140-6736(00)03492-9Get rights and content

Summary

Background

Non-invasive pressure support ventilation (NIPSV) is an effective treatment for acute respiratory failure in patients with chronic obstructive pulmonary disease. We assessed the efficacy of this therapy in acute cardiogenic pulmonary oedema in a randomised comparison with conventional oxygen therapy.

Methods

40 patients were randomly assigned conventional oxygen therapy or NIPSV supplied by a standard ventilator through a face mask, with adjustment of tidal volume and pressure support in addition to a positive end-expiratory pressure of 5 cm water. Physiological measurements were obtained in the first 2 h and at 3 h, 4 h, and 10 h. The main endpoints were intubation rate and resolution time. Analyses were by intention to treat.

Findings

Three patients were withdrawn on the basis of clinical and chest radiography results. Endotracheal intubation was required in one (5%) of 19 patients assigned NIPSV and in six (33%) of 18 assigned conventional oxygen therapy (p=0·037). Resolution time (defined as a clinical improvement with oxygen saturation of 96% or more and respiratory rate less than 30 breaths/min) was significantly shorter in the NIPSV group (median 30 [IQR 15-53] vs 105 [50-230] min, p=0·002). NIPSV led to a rapid improvement in oxygenation in the first 2 h. There were no differences in hospital length of stay or mortality.

Interpretation

In this study of acute cardiogenic pulmonary oedema, NIPSV was superior to conventional oxygen therapy. Further studies should compare NIPSV with continuous positive airway pressure.

Introduction

Acute cardiogenic pulmonary oedema is a common cause of acute respiratory failure. During the past decade, several studies have shown that continuous positive airway pressure (CPAP) is effective in this setting, through improvement in gas exchange and decrease in the need for intubation.1, 2, 3 CPAP is usually obtained with a hermetic nasal or face mask that has an expiratory valve to maintain a positive pressure at the end of expiration. With this modality, patients do not receive any assistance with respiration. Non-invasive pressure support ventilation (NIPSV) is a new mode of mechanical ventilation without intubation, in which a certain volume of air is delivered by a ventilator during the inspiratory cycle, by means of a preset pressure and through a nasal or face mask. Addition of positive end-expiratory pressure to NIPSV results in a CPAP mode with an assisted inspiration (also called bilevel positive airway pressure). This assistance can improve ventilation indices and vital signs4, 5 more rapidly than CPAP alone and also seems to reduce the work of breathing more effectively in intubated6 and nonintubated patients.7 In chronic obstructive pulmonary disease, NIPSV reduces the need for endotracheal intubation, the length of stay in the intensive-care unit, and mortality compared with conventional oxygen therapy.8, 9, 10 In patients with acute respiratory failure from other causes, the effect of NIPSV is less conclusive.11, 12, 13 However, good results have been reported,14 especially in hypercapnic patients.15 No study has tested the efficacy of NIPSV over conventional oxygen therapy in acute cardiogenic pulmonary oedema,16 and the available data come from one prematurely stopped trial of bilevel positive airway pressure versus CPAP4 and from uncontrolled studies.17, 18 Therefore, we undertook a controlled prospective randomised study to investigate whether the use of NIPSV would decrease the need for intubation and shorten time to recovery as compared with conventional oxygen therapy in patients with acute cardiogenic pulmonary oedema.

Section snippets

Patients

Our institutional ethics committee approved the study design, and all patients or their next of kin gave written informed consent. We enrolled patients with acute respiratory failure. Inclusion criteria were: dyspnoea of sudden onset with physical findings consistent with pulmonary oedema (widespread rales with or without third heart sound) and typical findings of congestion on a chest radiograph (to initiate treatment as soon as possible, patients could be assigned randomised treatment on

Results

Between April, 1996, and December, 1998, 40 patients were enrolled in the study (figure 1). 102 other patients seen during this period were not included because they did not meet entry criteria. Three patients enrolled were later excluded because they were judged not to have had cardiogenic pulmonary oedema; two were thought to have had pneumonia/bronchopneumonia and one chronic obstuctive pulmonary disease with pulmonary fibrosis. Thus, 19 patients in the NIPSV group and 18 in the control

Discussion

In this study, NIPSV shortened the resolution time of acute cardiogenic pulmonary oedema in comparison with conventional oxygen therapy. This effect could be achieved by several mechanisms: more rapid improvement in oxygenation; more rapid lowering of the respiratory rate, probably as a result of a decrease in the work of breathing; and faster reversal of acidosis (essentially by decreasing hypercapnia). These results are consistent with previous uncontrolled studies of NIPSV in acute

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