Heart failure: pulmonary oedema: CPAP reduced the need for intubation and ventilation.

Clinical bottom line (level 1b)

  1. Patients with respiratory failure from severe pulmonary oedema who had CPAP and oxygen compared with oxygen alone had higher pO 2 and lower CO 2 levels at 30 minutes.
  2. Fewer patients needed to be intubated and ventilated (NNT = 3 at 24 hours) .
  3. Patients spent less time on the intensive care unit (mean 1.5 days less).
  4. There was no clear effect on mortality or length of hospital stay.
Bersten et al: New England Journal of Medicine 1991; 325 (26): 1825-1830
Expires July 2003

The study

Unblinded concealed randomised trial with intention-to-treat
Setting: acute hospital, Australia

39 patients (aged mean 75 years, 67% female) with respiratory failure (pO2 <70 mmHg or pCO2 >45 mmHg) due to severe cardiogenic pulmonary oedema (dyspnoea of sudden onset, typical findings on a chest film and widespread crackles without a history suggesting pulmonary aspiration or infection)

Excluded if
  • diagnosis of MI with shock
  • systolic blood pressure <90 mmHg
  • severe stenotic valvular disease
  • chronic airflow obstruction with known carbon dioxide retention before current illness


    • Control Group: (n = 20, 20 analysed): oxygen alone (8 l per minute)
    Experimental Group: (n = 19, 19 analysed): oxygen plus continuous positive airway pressure delivered through a face mask
    All patients had nitroglycerin (600 µ g sublingually and topically) and furosemide (40 mg or twice patient's normal daily dose up to 500 mg iv). If pCO 2 <55 mmHg morphine could be given iv in 1 mg increments, up to 10 mg for respiratory distress.
    100% followed for ?

    The evidence

    Outcome Time to outcome CEREERRRR
    (95% CI)    		ARR
    (95% CI)    		NNT
    (95% CI)
    intubation and mechanical ventilation 24 hours 7
    (35.0%)    		 0
    (0.00%)    		 100%
    (% to %)    		 35.0%
    (14.1% to 55.9%)    		 3
    (2 to 7)
    death discharge unknown 4
    (20.0%)    		 2
    (10.5%)    		 47%
    (-155% to 89%)    		 9.47%
    (-12.8% to 31.8%)    		 11
    (NNT = 3 to infinity;
    NNH = 8 to infinity)

    Outcome Control Group
    (SD)    		 Experimental Group
    (SD)    		 Mean Difference
    (95% CI)
    respiratory rate at 30 minutes (breaths per min) 33
    (9)     		27
    (6)     		-6
    (-11 to -1)
    pO 2 at 30 minutes (mmHg) 126
    (47)     		206
    (126)     		80
    (19 to 140)
    pCO 2 at 30 minutes (mmHg) 62
    (14)     		46
    (4)     		-16
    (-23 to -9)
    stay at ICU (days) 2.7
    ()     		1.2
    (0.4)     		-1.5
    (-2.5 to -0.6)
    hospital stay (days) 7.9
    (4.1)     		8.7
    (8.3)     		0.8
    (-3.0 to 5.0)

  • No significant differences were noted in any respiratory indices between the two groups at 48 hours.
  • Mean duration of CPAP was 9.3 +/- 4.9 hours.

    • Comments

    1. Patients were enrolled in blocks of four.

    Citation

    1. Bersten AD, Holt AW, Vedig AE, et al: Treatment of severe cardiogenic pulmonary edema with continuous positive airway pressure delivered by face mask. New England Journal of Medicine 1991; 325 (26): 1825-1830
    Search Terms: CPAP in Best Evidence
    Contributor: Chris Ball and Clare Wotton, July 2000
    Reviewer:

    Clinical Question.
    Patient heart failure
    Intervention or Exposure CPAP
    Outcome mortality