Randomized, prospective trial of bilevel versus continuous positive airway pressure in acute pulmonary edema.

OBJECTIVE To evaluate whether bilevel positive airway pressure, by actively assisting inhalation, more rapidly improves ventilation, acidemia, and dyspnea than continuous positive airway pressure (CPAP) in patients with acute pulmonary edema. DESIGN Randomized, controlled, double-blind trial. SETTING Emergency department in a university hospital. PATIENTS Twenty-seven patients, presenting with acute pulmonary edema, characterized by dyspnea, tachypnea, tachycardia, accessory muscle use, bilateral rales, and typical findings of congestion on a chest radiograph. INTERVENTIONS In addition to standard therapy, 13 patients were randomized to receive nasal CPAP (10 cm H2O), and 14 patients were randomized to receive nasal bilevel positive airway pressure (inspiratory and expiratory positive airway pressures of 15 and 5 cm H2O, respectively) in the spontaneous/timed mode that combines patient flow-triggering and backup time-triggering. MEASUREMENTS AND MAIN RESULTS After 30 mins, significant reductions in breathing frequency (32 +/- 4 to 26 +/- 5 breaths/min), heart rate (110 +/- 21 to 97 +/- 20 beats/min), blood pressure (mean 117 +/- 28 to 92 +/- 18 mm Hg), and Paco2 (56 +/- 15 to 43 +/- 9 torr [7.5 +/- 2 to 5.7 +/- 1.2 kPa]) were observed in the bilevel positive airway pressure group, as were significant improvements in arterial pH and dyspnea scores (p < .05 for all of these parameters). Only breathing frequency improved significantly in the CPAP group (32 +/- 4 to 28 +/- 5 breaths/min, p < .05). At 30 mins; the bilevel positive airway pressure group had greater reductions in Paco2 (p = .057), systolic blood pressure (p = .005), and mean arterial pressure (p = .03) than the CPAP group. The myocardial infarction rate was higher in the bilevel positive airway pressure group (71%) compared with both the CPAP group (31%) and historically matched controls (38%) (p = .05). Duration of ventilator use, intensive care unit and hospital stays, and intubation and mortality rates were similar between the two groups. CONCLUSIONS Bilevel positive airway pressure improves ventilation and vital signs more rapidly than CPAP in patients with acute pulmonary edema. The higher rate of myocardial infarctions associated with the use of bilevel positive airway pressure highlights the need for further studies to clarify its effects on hemodynamics and infarction rates, and to determine optimal pressure settings.

[1]  A. Sacchetti,et al.  Bi-level positive airway pressure support system use in acute congestive heart failure: preliminary case series. , 1995, Academic emergency medicine : official journal of the Society for Academic Emergency Medicine.

[2]  N. Hill,et al.  Randomized, prospective trial of noninvasive positive pressure ventilation in acute respiratory failure. , 1995, American journal of respiratory and critical care medicine.

[3]  J. Floras,et al.  Effect of continuous positive airway pressure on intrathoracic and left ventricular transmural pressures in patients with congestive heart failure. , 1995, Circulation.

[4]  E. Greene,et al.  Hemodynamic effects of nasal and face mask continuous positive airway pressure. , 1994, American journal of respiratory and critical care medicine.

[5]  A. Dimarco,et al.  Respiratory muscle rest using nasal BiPAP ventilation in patients with stable severe COPD. , 1994, Chest.

[6]  H. Fessler,et al.  Effects of systolic and diastolic positive pleural pressure pulses with altered cardiac contractility. , 1992, Journal of applied physiology.

[7]  P. McLaughlin,et al.  Cardiac output response to continuous positive airway pressure in congestive heart failure. , 1992, The American review of respiratory disease.

[8]  A D Bersten,et al.  Treatment of severe cardiogenic pulmonary edema with continuous positive airway pressure delivered by face mask. , 1991, The New England journal of medicine.

[9]  R. Wunderink,et al.  Noninvasive face mask mechanical ventilation in patients with acute hypercapnic respiratory failure. , 1991, Chest.

[10]  M. Lin,et al.  The efficacy of early continuous positive airway pressure therapy in patients with acute cardiogenic pulmonary edema. , 1991, Journal of the Formosan Medical Association = Taiwan yi zhi.

[11]  R. Shadmehr,et al.  Efficacy of positive vs negative pressure ventilation in unloading the respiratory muscles. , 1990, Chest.

[12]  W P Santamore,et al.  Mechanism of reduced cardiac output during positive end-expiratory pressure in the dog. , 1989, The American review of respiratory disease.

[13]  S K Pingleton,et al.  Complications of acute respiratory failure. , 1988, The Medical clinics of North America.

[14]  J. Katz,et al.  Inspiratory Work with and without Continuous Positive Airway‐Pressure in Patients with Acute Respiratory Failure , 1985, Anesthesiology.

[15]  W. Knaus,et al.  APACHE II: a severity of disease classification system. , 1985 .

[16]  M Klain,et al.  Determinants of cardiac augmentation by elevations in intrathoracic pressure. , 1985, Journal of applied physiology.

[17]  J. Heikkilä,et al.  Acute myocardial infarction complicated by left ventricular dysfunction and respiratory failure. The effects of continuous positive airway pressure. , 1985, Chest.

[18]  J. Heikkilä,et al.  Continuous positive airway pressure by face mask in acute cardiogenic pulmonary edema. , 1985, The American journal of cardiology.

[19]  J. Luce The cardiovascular effects of mechanical ventilation and positive end-expiratory pressure. , 1984, JAMA.

[20]  M R Pinsky,et al.  Augmentation of cardiac function by elevation of intrathoracic pressure. , 1983, Journal of applied physiology: respiratory, environmental and exercise physiology.

[21]  J F Murray,et al.  Continuous Positive‐Pressure Ventilation Decreases Right and Left Ventricular End‐Diastolic Volumes in the Dog , 1980, Circulation research.

[22]  M. Confalonieri,et al.  Severe exacerbations of chronic obstructive pulmonary disease treated with BiPAP by nasal mask. , 1994, Respiration; international review of thoracic diseases.

[23]  S. Gottfried,et al.  Ventilatory muscle support in respiratory failure with nasal positive pressure ventilation. , 1990, Chest.