Critical Care Medicine

Adult Critical Care

CPAP for acute cardiogenic pulmonary oedema from out-of-hospital to cardiac intensive care unit: a randomised multicentre study

Ducros L, on behalf of the CPAP collaborative study group (Hôpital Universitaire Lariboisiére, Paris, France; et al) Intensive Care Med 37:1501-1509, 2011^§

M. Mathru, MD

Evidence Ranking

• A

Expert Rating

• 3

Abstract

Purpose

Continuous positive airway pressure (CPAP) is a useful treatment for patients with acute cardiogenic pulmonary oedema (CPE). However, its usefulness in the out-of-hospital setting has been poorly investigated and only by small and single-centre studies. We designed a multicentre randomised study to assess the benefit of CPAP initiated out of hospital.

Methods

A total of 207 patients with CPE were randomly allocated by emergency mobile medical units to receive either standard treatment alone or standard treatment plus CPAP. CPAP was maintained after admission to the intensive care unit (ICU). Inclusion criteria were orthopnoea, respiratory rate greater than 25 breaths/min, pulse oximetry less than 90% in room air and diffuse crackles. The primary end point was assessed during the first 48 h and combined: death, presence of intubation criteria, persistence of either all inclusion criteria or circulatory failure at the second hour or their reappearance before 48 h. Absence of all criteria defined successful treatment.

Results

CPAP was used for 60 min [40, 65] (median [Q1, Q3]) in the pre-hospital setting and 120 min [60, 242] in ICU and was well tolerated in all patients. Treatment was successful in 79% of patients in the CPAP group and 63% in the control group (p = 0.01), especially for persistence of inclusion criteria after 2 h (12 vs. 26%) and for intubation criteria (4 vs. 14%). CPAP was beneficial irrespective of the initial PaCO₂ or left ventricular ejection fraction.

Conclusion

Immediate use of CPAP in out-of-hospital treatment of CPE and until CPE resolves after admission significantly improves early outcome compared with medical treatment alone (Tables 2–4).

Table 2 Physiological Parameters at Study Entry and Echocardiographic Findings

Parameters	Control Group (N = 100)	CPAP Group (N = 107)
SpO₂ in air (%)	84 [78, 88]	84 [80, 88]
pH	7.30 [7.22, 7.36]	7.30 [7.25, 7.37]
PO₂ (mmHg)	127 [86, 177]	114 [79, 183]
PCO₂ (mmHg)	49 [41, 57]	46 [39, 55]
Bicarbonates (mmol/L)	23 [20, 26]	24 [20, 26]
Respiratory rate (per min)	35 [30, 40]	36 [30, 40]
Systolic arterial blood pressure (mmHg)	170 [143, 193]	170 [150, 195]
Diastolic arterial blood pressure (mmHg)	97 [80, 103]	95 [82, 110]
Heart rate (bpm)	101 [90, 116]	102 [83, 116]
Encephalopathy	7 (7)	13 (12)
Circulatory failure	18 (18)	17 (16)
Echocardiographic findings LVEF	35 [30, 60]	45 [35, 60]
Syst. PAP (mmHg)	40 [32, 45]	38 [31, 43]
E/A ratio	0.9 [1, 1]	0.9 [1, 2]

Data are expressed as median with 25th and 75th interquartile range [Q1, Q3] or number and percentage n (%); SpO₂ pulse oximetry; arterial blood gases were sampled under O₂ mask with a reservoir at 15 L/min. LVEF left ventricular ejection fraction, Syst PAP systolic pulmonary arterial pressure (mmHg); E/A ratio flow velocity ratio across the mitral valve between early diastole and atrial contraction.

Table 3 Overall Outcome of the Study Groups: Primary End Point