Dataset Information

Associations between changes in oxygenation, dead space and driving pressure induced by the first prone position session and mortality in patients with acute respiratory distress syndrome.

ABSTRACT:

Background

Outcome prediction in acute respiratory distress syndrome (ARDS) is challenging, especially in patients with severe hypoxemia. The aim of the current study was to determine the prognostic capacity of changes in PaO₂/FiO₂, dead space fraction (V_D/V_T) and respiratory system driving pressure (ΔP_RS) induced by the first prone position (PP) session in patients with ARDS.

Methods

This was a post hoc analysis of the conveniently-sized 'Molecular Diagnosis and Risk Stratification of Sepsis' study (MARS). The current analysis included ARDS patients who were placed in the PP. The primary endpoint was the prognostic capacity of the PP-induced changes in PaO₂/FiO₂, V_D/V_T, and ΔP_RS for 28-day mortality. PaO₂/FiO₂, V_D/V_T, and ΔP_RS was calculated using variables obtained in the supine position before and after completion of the first PP session. Receiving operator characteristic curves (ROC) were constructed, and sensitivity, specificity positive and negative predictive value were calculated based on the best cutoffs.

Results

Ninety patients were included; 28-day mortality was 46%. PP-induced changes in PaO₂/FiO₂ and V_D/V_T were similar between survivors vs. non-survivors [+83 (+24 to +137) vs. +58 (+21 to +113) mmHg, and -0.06 (-0.17 to +0.05) vs. -0.08 (-0.16 to +0.08), respectively]. PP-induced changes in ΔP_RS were different between survivors vs. non-survivors [-3 (-7 to 2) vs. 0 (-3 to +3) cmH₂O; P=0.03]. The area under the ROC of PP-induced changes in ΔP_RS for mortality, however, was low [0.63 (95% confidence interval (CI), 0.50 to 0.75]; PP-induced changes in ΔP_RS had a sensitivity and specificity of 76% and 56%, and a positive and negative predictive value of 60% and 73%.

Conclusions

Changes in PaO₂/FiO₂, V_D/V_T, and ΔP_RS induced by the first PP session have poor prognostic capacities for 28-day mortality in ARDS patients.

SUBMITTER: van Meenen DM

PROVIDER: S-EPMC6987992 | biostudies-literature | 2019 Dec

REPOSITORIES: biostudies-literature

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Publications

Associations between changes in oxygenation, dead space and driving pressure induced by the first prone position session and mortality in patients with acute respiratory distress syndrome.

van Meenen David M DM Roozeman Jan-Paul JP Serpa Neto Ary A Pelosi Paolo P Gama de Abreu Marcelo M Horn Janneke J Cremer Olaf L OL Paulus Frederique F Schultz Marcus J MJ

Journal of thoracic disease 20191201 12

<h4>Background</h4>Outcome prediction in acute respiratory distress syndrome (ARDS) is challenging, especially in patients with severe hypoxemia. The aim of the current study was to determine the prognostic capacity of changes in PaO<sub>2</sub>/FiO<sub>2</sub>, dead space fraction (V<sub>D</sub>/V<sub>T</sub>) and respiratory system driving pressure (ΔP<sub>RS</sub>) induced by the first prone position (PP) session in patients with ARDS.<h4>Methods</h4>This was a post hoc analysis of the conven ...[more]

PMID: 32030216

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Project description: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, ΔPaO2/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 ΔP 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.

Project description:BackgroundThe application of prone position (PP) in acute respiratory distress syndrome (ARDS) supported by venovenous extracorporeal membrane oxygenation (VV-ECMO) is controversial.ObjectivesTo evaluate the safety and efficacy of application of PP during VV-ECMO in patients with ARDS.MethodsThis was a single-center, retrospective study of patients who met the Berlin definition of ARDS, and were supported with VV-ECMO. We divided the patients into two groups. The prone group included patients who were supported by VV-ECMO, and experienced at least one period of PP, while those without PP during VV-ECMO were defined as the supine group. Propensity score matching (PSM) at a ratio of 1:1 was introduced to minimize potential confounders. The primary outcomes were the complications of PP and the change of arterial oxygen pressure/fraction of the inspiration (PaO2/FiO2) ratio after PP. The secondary outcomes were hospital survival, ICU survival, and ECMO weaning rate.ResultsFrom April 2013 to October 2020, a total of 91 patients met the diagnostic criteria of ARDS who were supported with ECMO. 38 patients (41.8%) received at least one period of PP during ECMO, while 53 patients (58.2%) were maintained in supine position during ECMO. 22 minor complications were reported in the prone group and major complications were not found. The other ECMO-related complications were similar between two groups. The PaO2/FiO2 ratio significantly improved after PP compared with before (174.50 (132.40-228.25) mmHg vs. 158.00 (122.93-210.33) mmHg, p < 0.001). PSM selected 25 pairs of patients with similar characteristics. Hospital survival or ICU survival did not differ between the two groups (40% vs. 28%, p = 0.370; 40% vs. 32%, p = 0.556). Significant difference of ECMO weaning rate between two groups was not found (56% vs. 32%, p = 0.087).ConclusionsPP during VV-ECMO was safe and could improve oxygenation. A large-scale and well-designed RCT is needed in the future.

Project description:BackgroundIn patients with severe acute respiratory distress syndrome (ARDS), prolonged and inappropriate use of prone position ventilation (PPV) is a known risk factor for mortality. Hence, it is critical to monitor patients' response to PPV and accurately differentiate responders from non-responders at an early stage. The study aimed to investigate the relationship between oxygenation improvement after three rounds of PPV and survival rate in patients with pulmonary ARDS. Additionally, we sought to identify the earliest turning point for escalation from PPV to extracorporeal membrane oxygenation.MethodsWe performed a retrospective observational study from 2015 to 2023. We included adult patients who received invasive mechanical ventilation, underwent at least three periods of at least 6 h of PPV after admission to the Intensive Care Unit, and meet the ARDS criteria. The study collected data on each PPV session, including changes in PaCO2, PaO2, pH, FiO2, PaO2:FiO2 ratio, and clinical outcomes.ResultsA total of 104 patients were enrolled in the study. The change in PaCO2 from baseline to the third PPV session (P3) had the highest area under the receiver operating characteristic curve (AUC) of 0.70 (95% CI 0.60-0.80; p < 0.001) for predicting hospital mortality, with an optimal cut-off point of 3.15 (sensitivity 75.9%, specificity 56.0%). The percentage change in PaO2:FiO2 ratio from baseline to P3 also had significant AUC of 0.71 (95% CI 0.61-0.81; p < 0.001) for predicting hospital mortality, with an optimal cut-off value of 99.465 (sensitivity 79.6%, specificity 62.0%). PaCO2 responders were defined as those with an increase in PaCO2 of ≤ 3.15% from baseline to P3, while PaO2:FiO2 responders were defined as those with an increase in PaO2:FiO2 ratio of ≥ 99.465% from baseline to P3. In the multivariable Cox analysis, PaO2:FiO2 responders had a significantly lower 60-day mortality risk (hazard ratio 0.369; 95% CI 0.171-0.798; p = 0.011).ConclusionsThe percentage change in PaO2:FiO2 ratio from baseline to P3 was a significant predictor of outcomes. The model fit and prediction accuracy were improved by including the variable of PaCO2 responders.

Project description:ObjectivesPhysiologic dead space is associated with mortality in acute respiratory distress syndrome, but its measurement is cumbersome. Alveolar dead space fraction relies on the difference between arterial and end-tidal carbon dioxide (alveolar dead space fraction = (PaCO2 - PetCO2) / PaCO2). We aimed to assess the relationship between alveolar dead space fraction and mortality in a cohort of children meeting criteria for acute respiratory distress syndrome (both the Berlin 2012 and the American-European Consensus Conference 1994 acute lung injury) and pediatric acute respiratory distress syndrome (as defined by the Pediatric Acute Lung Injury Consensus Conference in 2015).DesignSecondary analysis of a prospective, observational cohort.SettingTertiary care, university affiliated PICU.PatientsInvasively ventilated children with pediatric acute respiratory distress syndrome.InterventionsNone.Measurements and main resultsOf the 283 children with pediatric acute respiratory distress syndrome, 266 had available PetCO2. Alveolar dead space fraction was lower in survivors (median 0.13; interquartile range, 0.06-0.23) than nonsurvivors (0.31; 0.19-0.42; p < 0.001) at pediatric acute respiratory distress syndrome onset, but not 24 hours after (survivors 0.12 [0.06-0.18], nonsurvivors 0.14 [0.06-0.25], p = 0.430). Alveolar dead space fraction at pediatric acute respiratory distress syndrome onset discriminated mortality with an area under receiver operating characteristic curve of 0.76 (95% CI, 0.66-0.85; p < 0.001), better than either initial oxygenation index or PaO2/FIO2. In multivariate analysis, alveolar dead space fraction at pediatric acute respiratory distress syndrome onset was independently associated with mortality, after adjustment for severity of illness, immunocompromised status, and organ failures.ConclusionsAlveolar dead space fraction at pediatric acute respiratory distress syndrome onset discriminates mortality and is independently associated with nonsurvival. Alveolar dead space fraction represents a single, useful, readily obtained clinical biomarker reflective of pulmonary and nonpulmonary variables associated with mortality.

Dataset Information

Associations between changes in oxygenation, dead space and driving pressure induced by the first prone position session and mortality in patients with acute respiratory distress syndrome.

Background

Methods

Results

Conclusions

Publications

Associations between changes in oxygenation, dead space and driving pressure induced by the first prone position session and mortality in patients with acute respiratory distress syndrome.

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