The open lung approach is a mechanical ventilation strategy involving lung recruitment and a decremental positive end-expiratory pressure trial. We compared the Acute Respiratory Distress Syndrome network protocol using low levels of positive end-expiratory pressure with open lung approach resulting in moderate to high levels of positive end-expiratory pressure for the management of established moderate/severe acute respiratory distress syndrome.
A prospective, multicenter, pilot, randomized controlled trial.
A network of 20 multidisciplinary ICUs.
Patients meeting the American-European Consensus Conference definition for acute respiratory distress syndrome were considered for the study.
At 12-36 hours after acute respiratory distress syndrome onset, patients were assessed under standardized ventilator settings (FIO2≥0.5, positive end-expiratory pressure ≥10 cm H2O). If Pao2/FIO2 ratio remained less than or equal to 200 mm Hg, patients were randomized to open lung approach or Acute Respiratory Distress Syndrome network protocol. All patients were ventilated with a tidal volume of 4 to 8 ml/kg predicted body weight.
From 1,874 screened patients with acute respiratory distress syndrome, 200 were randomized: 99 to open lung approach and 101 to Acute Respiratory Distress Syndrome network protocol. Main outcome measures were 60-day and ICU mortalities, and ventilator-free days. Mortality at day-60 (29% open lung approach vs. 33% Acute Respiratory Distress Syndrome Network protocol, p = 0.18, log rank test), ICU mortality (25% open lung approach vs. 30% Acute Respiratory Distress Syndrome network protocol, p = 0.53 Fisher’s exact test), and ventilator-free days (8 [0-20] open lung approach vs. 7 [0-20] d Acute Respiratory Distress Syndrome network protocol, p = 0.53 Wilcoxon rank test) were not significantly different. Airway driving pressure (plateau pressure - positive end-expiratory pressure) and PaO2/FIO2 improved significantly at 24, 48 and 72 hours in patients in open lung approach compared with patients in Acute Respiratory Distress Syndrome network protocol. Barotrauma rate was similar in both groups.
In patients with established acute respiratory distress syndrome, open lung approach improved oxygenation and driving pressure, without detrimental effects on mortality, ventilator-free days, or barotrauma. This pilot study supports the need for a large, multicenter trial using recruitment maneuvers and a decremental positive end-expiratory pressure trial in persistent acute respiratory distress syndrome.
1Department of Respiratory Care, Massachusetts General Hospital, Boston, MA.
2Department of Anesthesia, Critical Care and Pain Medicine, Harvard Medical School, Boston, MA.
3CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain.
4Multidisciplinary Organ Dysfunction Evaluation Research Network, Research Unit, Hospital Universitario Dr. Negrin, Las Palmas de Gran Canaria, Spain.
5Intensive Care Unit, Hospital Universitario NS de Candelaria, Santa Cruz de Tenerife, Spain.
6Department of Anesthesiology, Hospital Clinico de Valencia, Valencia, Spain.
7Intensive Care Unit, Hospital Universitario Río Hortega, Valladolid, Spain.
8Department of Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.
9Intensive Care Unit, Hospital Universitario Morales Meseguer, Murcia, Spain.
10Intensive Care Unit, Hospital Universitario Virgen de la Arrixaca, Murcia, Spain.
11Intensive Care Unit, Hospital Universitario de Txagorritxu, Vitoria, Spain.
12Respiratory ICU, Hospital das Clínicas, University of São Paulo, São Paulo, Brazil.
13Intensive Care Unit, Hospital Universitario Fundacion Jiménez Díaz, Madrid, Spain.
14Intensive Care Unit, Hospital Virgen de La Luz, Cuenca, Spain.
*See also p. 237.
Drs. Amato and Suárez-Sipmann contributed equally as senior authors.
The complete list of investigators of the Open Lung Approach Network is provided in Appendix 1.
Registered at ClinicalTrials.gov NCT00431158.
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Dr. Kacmarek is a consultant for Covidien and Orange Med, has received research grants from Covidien and Venner Medical, and had airfare and expenses to study meetings paid by the Research Unit, Hospital Dr. Negrin Las Palmas de Gran Canaria, Spain. Dr. Villar received funding from Maquet (grant for partially supporting the study), from the Instituto de Salud Carlos III, Spain (PI07/0113), and received support from Asociación Científica Pulmón y Ventilación Mecánica (Spain) for supporting traveling expenses and for coordinating study-related activities among Spanish centers. Dr. Amato received support for article research from São Paulo, State Research Foundation and Brazilian Council for Scientific and Technological Development (Brazil). He received support for travel from Maquet, consulted for Covidien (mechanical ventilation), and received grant support from Dixtal LTDA (electrical impedance tomography). Dr. Suarez-Sipmann consulted for Maquet Critical Care. The remaining authors have disclosed that they do not have any potential conflicts of interest.
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