Dataset Information

Effects of early versus delayed application of prone position on ventilation-perfusion mismatch in patients with acute respiratory distress syndrome: a prospective observational study.

ABSTRACT:

Background

Prone position has been shown to improve oxygenation and survival in patients with early acute respiratory distress syndrome (ARDS). These beneficial effects are partly mediated by improved ventilation/perfusion (V/Q) distribution. Few studies have investigated the impact of early versus delayed proning on V/Q distribution in patients with ARDS. The aim of this study was to assess the regional ventilation and perfusion distribution in early versus persistent ARDS after prone position.

Methods

This is a prospective, observational study from June 30, 2021, to October 1, 2022 at the medical ICU in Zhongda Hospital, Southeast University. Fifty-seven consecutive adult patients with moderate-to-severe ARDS ventilated in supine and prone position. Electrical impedance tomography was used to study V/Q distribution in the supine position and 12 h after a prone session.

Results

Of the 57 patients, 33 were early ARDS (≤ 7 days) and 24 were persistent ARDS (> 7 days). Oxygenation significantly improved after proning in early ARDS (157 [121, 191] vs. 190 [164, 245] mm Hg, p < 0.001), whereas no significant change was found in persistent ARDS patients (168 [136, 232] vs.177 [155, 232] mm Hg, p = 0.10). Compared to supine position, prone reduced V/Q mismatch in early ARDS (28.7 [24.6, 35.4] vs. 22.8 [20.0, 26.8] %, p < 0.001), but increased V/Q mismatch in persistent ARDS (23.8 [19.8, 28.6] vs. 30.3 [24.5, 33.3] %, p = 0.006). In early ARDS, proning significantly reduced shunt in the dorsal region and dead space in the ventral region. In persistent ARDS, proning increased global shunt. A significant correlation was found between duration of ARDS onset to proning and the change in V/Q distribution (r = 0.54, p < 0.001).

Conclusions

Prone position significantly reduced V/Q mismatch in patients with early ARDS, while it increased V/Q mismatch in persistent ARDS patients. Trial registration ClinicalTrials.gov (NCT05207267, principal investigator Ling Liu, date of registration 2021.08.20).

SUBMITTER: Yuan X

PROVIDER: S-EPMC10683149 | biostudies-literature | 2023 Nov

REPOSITORIES: biostudies-literature

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Publications

Effects of early versus delayed application of prone position on ventilation-perfusion mismatch in patients with acute respiratory distress syndrome: a prospective observational study.

Yuan Xueyan X Zhao Zhanqi Z Chao Yali Y Chen Dongyu D Chen Hui H Zhang Rui R Liu Songqiao S Xie Jianfeng J Yang Yi Y Qiu Haibo H Heunks Leo L Liu Ling L

Critical care (London, England) 20231127 1

<h4>Background</h4>Prone position has been shown to improve oxygenation and survival in patients with early acute respiratory distress syndrome (ARDS). These beneficial effects are partly mediated by improved ventilation/perfusion (V/Q) distribution. Few studies have investigated the impact of early versus delayed proning on V/Q distribution in patients with ARDS. The aim of this study was to assess the regional ventilation and perfusion distribution in early versus persistent ARDS after prone p ...[more]

PMID: 38012731

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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:ObjectivesProne positioning allows to improve oxygenation and decrease mortality rate in COVID-19-associated acute respiratory distress syndrome (C-ARDS). However, the mechanisms leading to these effects are not fully understood. The aim of this study is to assess the physiologic effects of pronation by the means of CT scan and electrical impedance tomography (EIT).DesignExperimental, physiologic study.SettingPatients were enrolled from October 2020 to March 2021 in an Italian dedicated COVID-19 ICU.PatientsTwenty-one intubated patients with moderate or severe C-ARDS.InterventionsFirst, patients were transported to the CT scan facility, and image acquisition was performed in prone, then supine position. Back to the ICU, gas exchange, respiratory mechanics, and ventilation and perfusion EIT-based analysis were provided toward the end of two 30 minutes steps (e.g., in supine, then prone position).Measurements and main resultsProne position induced recruitment in the dorsal part of the lungs (12.5% ± 8.0%; p < 0.001 from baseline) and derecruitment in the ventral regions (-6.9% ± 5.2%; p < 0.001). These changes led to a global increase in recruitment (6.0% ± 6.7%; p < 0.001). Respiratory system compliance did not change with prone position (45 ± 15 vs 45 ± 18 mL/cm H2O in supine and prone position, respectively; p = 0.957) suggesting a decrease in atelectrauma. This hypothesis was supported by the decrease of a time-impedance curve concavity index designed as a surrogate for atelectrauma (1.41 ± 0.16 vs 1.30 ± 0.16; p = 0.001). Dead space measured by EIT was reduced in the ventral regions of the lungs, and the dead-space/shunt ratio decreased significantly (5.1 [2.3-23.4] vs 4.3 [0.7-6.8]; p = 0.035), showing an improvement in ventilation-perfusion matching.ConclusionsSeveral changes are associated with prone position in C-ARDS: increased lung recruitment, decreased atelectrauma, and improved ventilation-perfusion matching. These physiologic effects may be associated with more protective ventilation.

Project description:ObjectivesProne position is used in acute respiratory distress syndrome and in coronavirus disease 2019 acute respiratory distress syndrome. However, it is unclear how responders may be identified and whether an oxygenation response improves outcome. The objective of this study was to quantify the response to prone position, describe the differences between coronavirus disease 2019 acute respiratory distress syndrome and acute respiratory distress syndrome, and explore variables associated with survival.DesignRetrospective, observational, multicenter, international cohort study.SettingSeven ICUs in Italy, United Kingdom, and France.PatientsThree hundred seventy-six adults (220 coronavirus disease 2019 acute respiratory distress syndrome and 156 acute respiratory distress syndrome).InterventionNone.Measurements and main resultsPreproning, a greater proportion of coronavirus disease 2019 acute respiratory distress syndrome patients had severe disease (53% vs 40%), worse Pao2/Fio2 (13.0 kPa [interquartile range, 10.5-15.5 kPa] vs 14.1 kPa [interquartile range, 10.5-18.6 kPa]; p = 0.017) but greater compliance (38 mL/cm H2O [interquartile range, 27-53 mL/cm H2O] vs 31 mL/cm H2O [interquartile range, 21-37 mL/cm H2O]; p < 0.001). Patients with coronavirus disease 2019 acute respiratory distress syndrome had a longer median time from intubation to prone position (2.0 d [interquartile range, 0.7-5.0 d] vs 1.0 d [interquartile range, 0.5-2.9 d]; p = 0.03). The proportion of responders, defined by an increase in Pao2/Fio2 greater than or equal to 2.67 kPa (20 mm Hg), upon proning, was similar between acute respiratory distress syndrome and coronavirus disease 2019 acute respiratory distress syndrome (79% vs 76%; p = 0.5). Responders had earlier prone position (1.4 d [interquartile range, 0.7-4.2 d] vs 2.5 d [interquartile range, 0.8-6.2 d]; p = 0.06)]. Prone position less than 24 hours from intubation achieved greater improvement in oxygenation (11 kPa [interquartile range, 4-21 kPa] vs 7 kPa [interquartile range, 2-13 kPa]; p = 0.002). The variables independently associated with the "responder" category were Pao2/Fio2 preproning (odds ratio, 0.89 kPa-1 [95% CI, 0.85-0.93 kPa-1]; p < 0.001) and interval between intubation and proning (odds ratio, 0.94 d-1 [95% CI, 0.89-0.99 d-1]; p = 0.019). The overall mortality was 45%, with no significant difference observed between acute respiratory distress syndrome and coronavirus disease 2019 acute respiratory distress syndrome. Variables independently associated with mortality included age (odds ratio, 1.03 yr-1 [95% CI, 1.01-1.05 yr-1]; p < 0.001); interval between hospital admission and proning (odds ratio, 1.04 d-1 [95% CI, 1.002-1.084 d-1]; p = 0.047); and change in Pao2/Fio2 on proning (odds ratio, 0.97 kPa-1 [95% CI, 0.95-0.99 kPa-1]; p = 0.002).ConclusionsProne position, particularly when delivered early, achieved a significant oxygenation response in ~80% of coronavirus disease 2019 acute respiratory distress syndrome, similar to acute respiratory distress syndrome. This response was independently associated with improved survival.

Project description:BackgroundPatients with moderate to severe acute respiratory distress syndrome (ARDS) have been recommended to receive prone position ventilation (PPV). However, the dynamic changes in respiratory mechanics during PPV and their relationship with the prognosis have not been sufficiently evaluated. In addition, the impact of using neuromuscular blocking agents (NMBAs) during PPV on respiratory mechanics is not clear enough. Thus, the study aims to investigate the above-mentioned issues.MethodsA prospective cohort study was conducted on 22 patients with moderate to severe ARDS who received PPV in the intensive care unit (ICU) of the First Affiliated Hospital of Guangzhou Medical University. A multifunctional gastric tube was used to measure the patients' respiratory mechanics during supine position ventilation (SPV), early PPV (PPV within 4 h of initiation), and middle/late PPV (more than 6 h after the initiation of PPV). Longitudinal data were analyzed with generalized estimating equations (GEE).ResultsCompared with SPV, the esophageal pressure swings (ΔPes) measured during the PPV was significantly higher (SPV 7.46 vs. early PPV 8.00 vs. middle/late PPV 8.30 cmH2O respectively; PSPV vs. middle/late PPV =0.025<0.05). A stratified analysis by patients' outcome showed that the peak airway pressure (Ppeak), ΔPes and respiration rate (RR) in the death group were significantly higher than survival group. On the contrary, the tidal volume (Vt), diaphragmatic electromyogram (EMGdi) and PaO2/FiO2 ratio (PFR) in the death group were significantly lower than survival group. Notably, the ΔPes and transpulmonary driving pressure (DPL) were significantly lower in the patients treated with NMBAs (7.08 vs. 8.76 cmH2O ΔPes; P<0.01), (14.82 vs. 18.08 cmH2O DPL; P<0.001).ConclusionsDuring the transition from SPV to early PPV and then to middle/late PPV, the ΔPes in the PPV were greater than SPV and it fluctuated within a normal range while oxygenation improved significantly in all patients. The Ppeak, ΔPes and RR in the death group were significantly higher than survival group. When NMBAs were used, the ΔPes, inspiratory transpulmonary pressure (PLei), driving pressure (DP) and DPL were significantly decreased, suggesting that the rational combination of NMBAs and PPV may exert a synergistic protective effect on the lungs.

Project description:BackgroundImprovements in oxygenation and lung mechanics with prone position (PP) in patients with acute respiratory distress syndrome (ARDS) are inconstant. The objectives of the study were (i) to identify baseline variables, including the recruitment-to-inflation ratio (R/I), associated with a positive response to PP in terms of oxygenation (improvement of the ratio of arterial oxygen partial pressure over the inspired oxygen fraction (PaO2/FiO2) ≥ 20 mmHg) and lung mechanics; (ii) to evaluate whether the response to the previous PP session is associated with the response to the next session.MethodsIn this prospective, observational, single-center study in patients who underwent PP for ARDS due to COVID-19, respiratory variables were assessed just before PP and at the end of the session. Respiratory variables included mechanical ventilation settings and respiratory mechanics variables, including R/I, an estimate of the potential for lung recruitment compared to lung overinflation.ResultsIn 50 patients, 201 PP sessions lasting 19 ± 3 h were evaluated. Neuromuscular blockades were used in 116 (58%) sessions. The PaO2/FiO2 ratio increased from 109 ± 31 mmHg to 165 ± 65 mmHg, with an increase ≥ 20 mmHg in 142 (71%) sessions. In a mixed effect logistic regression, only pre-PP PaO2/FiO2 (OR 1.12 (95% CI [1.01-1.24])/every decrease of 10 mmHg, p = 0.034) in a first model and improvement in oxygenation at the previous PP session (OR 3.69 (95% CI [1.27-10.72]), p = 0.017) in a second model were associated with an improvement in oxygenation with PP. The R/I ratio (n = 156 sessions) was 0.53 (0.30-0.76), separating lower- and higher-recruiters. Whereas PaO2/FiO2 improved to the same level in both subgroups, driving pressure and respiratory system compliance improved only in higher-recruiters (from 14 ± 4 to 12 ± 4 cmH2O, p = 0.027, and from 34 ± 11 to 38 ± 13 mL/cmH2O, respectively, p = 0.014).ConclusionsA lower PaO2/FiO2 at baseline and a positive O2-response at the previous PP session are associated with a PP-induced improvement in oxygenation. In higher-recruiters, lung mechanics improved along with oxygenation. Benefits of PP could thus be greater in these patients.

Project description:BackgroundA combination of prone positioning (PP) and venovenous extracorporeal membrane oxygenation (VV-ECMO) is safe, feasible, and associated with potentially improved survival for severe acute respiratory distress syndrome (ARDS). However, whether ARDS patients, especially non-COVID-19 patients, placed in PP before VV-ECMO should continue PP after a VV-ECMO connection is unknown. This study aimed to test the hypothesis that early use of PP during VV-ECMO could increase the proportion of patients successfully weaned from ECMO support in severe ARDS patients who received PP before ECMO.MethodsIn this prospective observational study, patients with severe ARDS who were treated with VV-ECMO were divided into two groups: the prone group and the supine group, based on whether early PP was combined with VV-ECMO. The proportion of patients successfully weaned from VV-ECMO and 60-day mortality were analyzed before and after propensity score matching.ResultsA total of 165 patients were enrolled, 50 in the prone and 115 in the supine group. Thirty-two (64%) and 61 (53%) patients were successfully weaned from ECMO in the prone and the supine groups, respectively. The proportion of patients successfully weaned from VV-ECMO in the prone group tended to be higher, albeit not statistically significant. During PP, there was a significant increase in partial pressure of arterial oxygen (PaO2) without a change in ventilator or ECMO settings. Tidal impedance shifted significantly to the dorsal region, and lung ultrasound scores significantly decreased in the anterior and posterior regions. Forty-five propensity score-matched patients were included in each group. In this matched sample, the prone group had a higher proportion of patients successfully weaned from VV-ECMO (64.4% vs. 42.2%; P = 0.035) and lower 60-day mortality (37.8% vs. 60.0%; P = 0.035).ConclusionsPatients with severe ARDS placed in PP before VV-ECMO should continue PP after VV-ECMO support. This approach could increase the probability of successful weaning from VV-ECMO.Trial registrationClinicalTrials.Gov: NCT04139733. Registered 23 October 2019.

Dataset Information

Effects of early versus delayed application of prone position on ventilation-perfusion mismatch in patients with acute respiratory distress syndrome: a prospective observational study.

Background

Methods

Results

Conclusions

Publications

Effects of early versus delayed application of prone position on ventilation-perfusion mismatch in patients with acute respiratory distress syndrome: a prospective observational study.

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