Related Experiment Video
Updated: Apr 17, 2026
Surfactant Depletion Combined with Injurious Ventilation Results in a Reproducible Model of the Acute Respiratory Distress Syndrome ARDS
Published on: April 7, 2021
Driving pressure and survival in the acute respiratory distress syndrome
Marcelo B P Amato1, Maureen O Meade, Arthur S Slutsky
1From the Cardio-Pulmonary Department, Pulmonary Division, Heart Institute (Incor), University of São Paulo (M.B.P.A., E.L.V.C., C.R.R.C.), and the Research and Education Institute, Hospital Sirio-Libanês (E.L.V.C.) - both in São Paulo; the Departments of Clinical Epidemiology and Biostatistics and Medicine, McMaster University, Hamilton, ON (M.O.M., T.E.S., M.B.), and the Keenan Research Centre for Biomedical Science, St. Michael's Hospital (A.S.S., L.B.), and the Interdepartmental Division of Critical Care Medicine and Department of Medicine, University of Toronto (A.S.S., L.B.), Toronto - all in Canada; the Massachusetts General Hospital Biostatistics Center, Harvard Medical School (D.A.S.), and Department of Anesthesia, Critical Care, and Pain Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School (D.T.) - both in Boston; the Basel Institute for Clinical Epidemiology and Biostatistics, University Hospital Basel, Basel, Switzerland (M.B.); the Department of Intensive Care and Hyperbaric Medicine, Angers University Hospital, Angers (A.M.), the Emergency Department, General Hospital of Annecy, Annecy (J.-C.M.R.), and INSERM UMR 955, Creteil (J.-C.M.R.) - all in France; and the Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore (R.G.B.).
Background:
Mechanical-ventilation strategies that use lower end-inspiratory (plateau) airway pressures, lower tidal volumes (VT), and higher positive end-expiratory pressures (PEEPs) can improve survival in patients with the acute respiratory distress syndrome (ARDS), but the relative importance of each of these components is uncertain. Because respiratory-system compliance (CRS) is strongly related to the volume of aerated remaining functional lung during disease (termed functional lung size), we hypothesized that driving pressure (ΔP=VT/CRS), in which VT is intrinsically normalized to functional lung size (instead of predicted lung size in healthy persons), would be an index more strongly associated with survival than VT or PEEP in patients who are not actively breathing.
Methods:
Using a statistical tool known as multilevel mediation analysis to analyze individual data from 3562 patients with ARDS enrolled in nine previously reported randomized trials, we examined ΔP as an independent variable associated with survival. In the mediation analysis, we estimated the isolated effects of changes in ΔP resulting from randomized ventilator settings while minimizing confounding due to the baseline severity of lung disease.
Results:
Among ventilation variables, ΔP was most strongly associated with survival. A 1-SD increment in ΔP (approximately 7 cm of water) was associated with increased mortality (relative risk, 1.41; 95% confidence interval [CI], 1.31 to 1.51; P<0.001), even in patients receiving "protective" plateau pressures and VT (relative risk, 1.36; 95% CI, 1.17 to 1.58; P<0.001). Individual changes in VT or PEEP after randomization were not independently associated with survival; they were associated only if they were among the changes that led to reductions in ΔP (mediation effects of ΔP, P=0.004 and P=0.001, respectively).
Conclusions:
We found that ΔP was the ventilation variable that best stratified risk. Decreases in ΔP owing to changes in ventilator settings were strongly associated with increased survival. (Funded by Fundação de Amparo e Pesquisa do Estado de São Paulo and others.).
More Related Videos
09:36Halogenated Agent Delivery in Porcine Model of Acute Respiratory Distress Syndrome via an Intensive Care Unit Type Device
Published on: September 24, 2020
07:20Lavage-induced Surfactant Depletion in Pigs As a Model of the Acute Respiratory Distress Syndrome ARDS
Published on: September 7, 2016
Related Concept Videos
01:29Acute Respiratory Failure-V
Ensure that patients are monitored continuously for their response to therapy, including changes in...
01:23Acute Respiratory Failure-IV
01:30Acute Respiratory Failure-III
01:21Acute Respiratory Failure-II
The underlying physiological abnormalities that contribute to hypoxemic respiratory failure include:
01:21Acute Respiratory Failure-I
Definition: It is defined by specific criteria based on blood gas measurements. Hypoxemia happens when the partial pressure of oxygen (PaO2) falls below 60 mmHg. At the same time,...
01:24Pressure Relationships in Thoracic Cavity
Breathing Mechanisms
Both intra-alveolar and intrapleural pressures rely on specific lung properties. The ability to breathe—allowing air to enter the lungs...