TY - JOUR
T1 - Response to ventilator adjustments for predicting acute respiratory distress syndrome mortality
T2 - Driving pressure versus oxygenation
AU - Yehya, Nadir
AU - Hodgson, Carol L.
AU - Amato, Marcelo B.P.
AU - Richard, Jean Christophe
AU - Brochard, Laurent J.
AU - Mercat, Alain
AU - Goligher, Ewan C.
N1 - Funding Information:
Supported by U.S. National Institutes of Health (NIH) grants K23-HL136688 and R01-HL148054 (N.Y.); National Health and Medical Research Council (NHMRC) Investigator Grant and Australian Heart Foundation Fellowship (C.L.H.); and an Early Career Investigator Award from Canadian Institutes of Health Research (CIHR) (E.C.G.).
Publisher Copyright:
Copyright © 2021 by the American Thoracic Society
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2021/5
Y1 - 2021/5
N2 - Rationale: Clinicians commonly use short-term physiologic markers to assess the benefit of ventilator adjustments. Improved arterial oxygen tension/pressure (PaO2)/fraction of inspired oxygen (FIO2) after ventilator adjustment in acute respiratory distress syndrome is associated with lower mortality. However, as driving pressure (ΔP) reflects lung stress and strain, changes in ΔP may more accurately reflect benefits or harms of ventilator adjustments compared with changes in oxygenation. Objectives: We aimed to compare the association between mortality and the changes in PaO2/FIO2 and ΔP following protocolized ventilator changes. Methods: We assessed associations between mortality and changes in PaO2/FIO2 (ΔPaO2/FIO2) and ΔP (ΔΔP) after postrandomization positive end-expiratory pressure (PEEP) and tidal volume adjustment in reanalyses of the ALVEOLI (Assessment of Low Tidal Volume and Elevated End-Expiratory Volume to Obviate Lung Injury) and ExPress (Expiratory Pressure) trials. We included subjects with available pre- and postintervention PaO2/FIO2 and ΔP (372 in ALVEOLI and 596 in ExPress). In each separate trial cohort, we performed multivariable Cox regression testing the association between ΔPaO2/FIO2 and ΔΔP with mortality. Results: In ALVEOLI, when analyzed as separate variables, DPaO2/ FIO2 was associated with mortality only in subjects in whom PEEP increased, whereas ΔΔP was associated with mortality irrespective of direction of PEEP change. When modeled together, improved ΔPaO2/ FIO2 was not associated with mortality, whereas ΔΔP remained associated with mortality (adjusted hazard ratio [aHR], 1.50 per 5 cm H2O increase; 95% confidence interval [95% CI], 1.21–1.85). When modeled together in ExPress, ΔΔP (aHR, 1.42; 95% CI, 1.14–1.78) was more strongly associated with mortality than ΔPaO2/FIO2 (aHR, 0.95 per 25 mm Hg increase; 95% CI, 0.90–1.00). Conclusions: Reduced DP following protocolized ventilator changes was more strongly and consistently associated with lower mortality than was increased PaO2/FIO2, making ΔΔP more informative about benefit from ventilator adjustments. Our results reinforce the primacy of ΔP, rather than oxygenation, as the key variable associated with outcome.
AB - Rationale: Clinicians commonly use short-term physiologic markers to assess the benefit of ventilator adjustments. Improved arterial oxygen tension/pressure (PaO2)/fraction of inspired oxygen (FIO2) after ventilator adjustment in acute respiratory distress syndrome is associated with lower mortality. However, as driving pressure (ΔP) reflects lung stress and strain, changes in ΔP may more accurately reflect benefits or harms of ventilator adjustments compared with changes in oxygenation. Objectives: We aimed to compare the association between mortality and the changes in PaO2/FIO2 and ΔP following protocolized ventilator changes. Methods: We assessed associations between mortality and changes in PaO2/FIO2 (ΔPaO2/FIO2) and ΔP (ΔΔP) after postrandomization positive end-expiratory pressure (PEEP) and tidal volume adjustment in reanalyses of the ALVEOLI (Assessment of Low Tidal Volume and Elevated End-Expiratory Volume to Obviate Lung Injury) and ExPress (Expiratory Pressure) trials. We included subjects with available pre- and postintervention PaO2/FIO2 and ΔP (372 in ALVEOLI and 596 in ExPress). In each separate trial cohort, we performed multivariable Cox regression testing the association between ΔPaO2/FIO2 and ΔΔP with mortality. Results: In ALVEOLI, when analyzed as separate variables, DPaO2/ FIO2 was associated with mortality only in subjects in whom PEEP increased, whereas ΔΔP was associated with mortality irrespective of direction of PEEP change. When modeled together, improved ΔPaO2/ FIO2 was not associated with mortality, whereas ΔΔP remained associated with mortality (adjusted hazard ratio [aHR], 1.50 per 5 cm H2O increase; 95% confidence interval [95% CI], 1.21–1.85). When modeled together in ExPress, ΔΔP (aHR, 1.42; 95% CI, 1.14–1.78) was more strongly associated with mortality than ΔPaO2/FIO2 (aHR, 0.95 per 25 mm Hg increase; 95% CI, 0.90–1.00). Conclusions: Reduced DP following protocolized ventilator changes was more strongly and consistently associated with lower mortality than was increased PaO2/FIO2, making ΔΔP more informative about benefit from ventilator adjustments. Our results reinforce the primacy of ΔP, rather than oxygenation, as the key variable associated with outcome.
KW - Driving pressure
KW - Oxygenation
KW - Pa/FI
KW - PEEP
KW - Positive end-expiratory pressure
UR - http://www.scopus.com/inward/record.url?scp=85105025897&partnerID=8YFLogxK
U2 - 10.1513/AnnalsATS.202007-862OC
DO - 10.1513/AnnalsATS.202007-862OC
M3 - Article
C2 - 33112644
AN - SCOPUS:85105025897
VL - 18
SP - 857
EP - 864
JO - Annals of the American Thoracic Society
JF - Annals of the American Thoracic Society
SN - 2329-6933
IS - 5
ER -