Mechanics of Breathing and Gas Exchange in Mechanically Ventilated Patients with COVID-19-associated Respiratory Failure.
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ABSTRACT:
SUBMITTER: Haouzi P
PROVIDER: S-EPMC7427403 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The association of respiratory mechanics, particularly respiratory system static compliance (CRS), with severity of hypoxaemia in patients with COVID-19-related acute respiratory distress syndrome (ARDS) has been widely debated, with some studies reporting distinct ARDS phenotypes based on CRS. Ascertaining whether such phenotypes exist is important, because they might indicate the need for ventilation strategies that differ from those used in patients with ARDS due to other causes. In a systematic review and meta-analysis of studies published between Dec 1, 2019, and March 14, 2022, we evaluated respiratory system mechanics, ventilator parameters, gas exchange parameters, and clinical outcomes in patients with COVID-19-related ARDS. Among 11 356 patients in 37 studies, mean reported CRS, measured close to the time of endotracheal intubation, was 35·8 mL/cm H2O (95% CI 33·9-37·8; I2=96·9%, τ2=32·6). Pooled mean CRS was normally distributed. Increasing ARDS severity (assessed by PaO2/FiO2 ratio as mild, moderate, or severe) was associated with decreasing CRS. We found no evidence for distinct CRS-based clinical phenotypes in patients with COVID-19-related ARDS, and we therefore conclude that no change in conventional lung-protective ventilation strategies is warranted. Future studies should explore the personalisation of mechanical ventilation strategies according to factors including respiratory system mechanics and haemodynamic status in patients with ARDS.
| S-EPMC9708089 | biostudies-literature
Project description:PurposeThe outcomes of patients requiring invasive mechanical ventilation for COVID-19 remain poorly defined. We sought to determine clinical characteristics and outcomes of patients with COVID-19 managed with invasive mechanical ventilation in an appropriately resourced US health care system.MethodsOutcomes of COVID-19 infected patients requiring mechanical ventilation treated within the Inova Health System between March 5, 2020 and April 26, 2020 were evaluated through an electronic medical record review.Results1023 COVID-19 positive patients were admitted to the Inova Health System during the study period. Of these, 164 (16.0%) were managed with invasive mechanical ventilation. All patients were followed to definitive disposition. 70/164 patients (42.7%) had died and 94/164 (57.3%) were still alive. Deceased patients were older (median age of 66 vs. 55, p <0.0001) and had a higher initial d-dimer (2.22 vs. 1.31, p = 0.005) and peak ferritin levels (2998 vs. 2077, p = 0.016) compared to survivors. 84.3% of patients over 70 years old died in the hospital. Conversely, 67.4% of patients age 70 or younger survived to hospital discharge. Younger age, non-Caucasian race and treatment at a tertiary care center were all associated with survivor status.ConclusionMortality of patients with COVID-19 requiring invasive mechanical ventilation is high, with particularly daunting mortality seen in patients of advanced age, even in a well-resourced health care system. A substantial proportion of patients requiring invasive mechanical ventilation were not of advanced age, and this group had a reasonable chance for recovery.
| S-EPMC7682899 | biostudies-literature
Project description:BackgroundAcute hypoxic respiratory failure (AHRF) is a hallmark of severe COVID-19 pneumonia and often requires supplementary oxygen therapy. Critically ill COVID-19 patients may require invasive mechanical ventilation, which carries significant morbidity and mortality. Understanding of the relationship between dynamic changes in blood oxygen indices and clinical variables is lacking. We evaluated the changes in blood oxygen indices-PaO2, PaO2/FiO2 ratio, oxygen content (CaO2) and oxygen extraction ratio (O2ER) in COVID-19 patients through the first 30-days of intensive care unit admission and explored relationships with clinical outcomes.Methods and findingsWe performed a retrospective observational cohort study of all adult COVID-19 patients in a single institution requiring invasive mechanical ventilation between March 2020 and March 2021. We collected baseline characteristics, clinical outcomes and blood oxygen indices. 36,383 blood gas data points were analysed from 184 patients over 30-days. Median participant age was 59.5 (IQR 51.0, 67.0), BMI 30.0 (IQR 25.2, 35.5) and the majority were men (62.5%) of white ethnicity (70.1%). Median duration of mechanical ventilation was 15-days (IQR 8, 25). Hospital survival at 30-days was 72.3%. Non-survivors exhibited significantly lower PaO2 throughout intensive care unit admission: day one to day 30 averaged mean difference -0.52 kPa (95% CI: -0.59 to -0.46, p<0.01). Non-survivors exhibited a significantly lower PaO2/FiO2 ratio with an increased separation over time: day one to day 30 averaged mean difference -5.64 (95% CI: -5.85 to -5.43, p<0.01). While all patients had sub-physiological CaO2, non-survivors exhibited significantly higher values. Non-survivors also exhibited significantly lower oxygen extraction ratio with an averaged mean difference of -0.08 (95% CI: -0.09 to -0.07, p<0.01) across day one to day 30.ConclusionsAs a novel cause of acute hypoxic respiratory failure, COVID-19 offers a unique opportunity to study a homogenous cohort of patients with hypoxaemia. In mechanically ventilated adult COVID-19 patients, blood oxygen indices are abnormal with substantial divergence in PaO2/FiO2 ratio and oxygen extraction ratio between survivors and non-survivors. Despite having higher CaO2 values, non-survivors appear to extract less oxygen implying impaired oxygen utilisation. Further exploratory studies are warranted to evaluate and improve oxygen extraction which may help to improve outcomes in severe hypoxaemic mechanically ventilated COVID-19 patients.
| S-EPMC9187096 | biostudies-literature
Project description:PurposeMeasure the effect of inhaled pulmonary vasodilators on gas exchange in mechanically ventilated patients with COVID-19.MethodsA retrospective observational cohort study at three New York University Hospitals was performed including eighty-four mechanically ventilated SARS Cov-2 nasopharyngeal PCR positive patients, sixty nine treated with inhaled nitric oxide (iNO) and fifteen with inhaled epoprostenol (iEPO). The primary outcomes were change in PAO2:FIO2 ratio, oxygenation Index (OI), and ventilatory ratio (VR) after initiation of inhaled pulmonary vasodilators.ResultsThere was no significant change in PAO2:FIO2ratio after initiation of iNO (mean - 4.1, 95% CI -17.3-9.0, P = 0.54) or iEPO (mean - 3.4, 95% CI -19.7-12.9, P = 0.66), in OI after initiation of iNO (mean 2.1, 95% CI-0.04-4.2, P = 0.054) or iEPO (mean - 3.4, 95% CI -19.7-12.9, P = 0.75), or in VR after initiation of iNO (mean 0.17, 95% CI -0.03-0.36, P = 0.25) or iEPO (mean 0.33, 95% CI -0.0847-0.74, P = 0.11). PAO2:FIO2, OI and VR did not significantly change over a five day period starting the day prior to drug initiation in patients who received either iNO or iEPO assessed with a fixed effects model.ConclusionInhaled pulmonary vasodilators were not associated with significant improvement in gas exchange in mechanically ventilated patients with COVID-19.
| S-EPMC8847100 | biostudies-literature
Project description: Not available
| S-EPMC7301734 | biostudies-literature
Project description:BackgroundPatients with COVID-19 receiving mechanical ventilation may become aggravated with a secondary respiratory infection. The aim of this study was to describe secondary respiratory infections, their predictive factors, and outcomes in patients with COVID-19 requiring mechanical ventilation.MethodsA cohort study was carried out in a single tertiary hospital in Santiago, Chile, from 1st June to 31st July 2020. All patients with COVID-19 admitted to the intensive care unit that required mechanical ventilation were included.ResultsA total of 175 patients were enrolled, of which 71 (40.6%) developed at least one secondary respiratory infection during follow-up. Early and late secondary infections were diagnosed in 1.7% and 31.4% respectively. Within late secondary infections, 88% were bacterial, 10% were fungal, and 2% were of viral origin. One-third of isolated bacteria were multidrug-resistant. Bivariate analysis showed that the history of corticosteroids used before admission and the use of dexamethasone during hospitalization were associated with a higher risk of secondary infections (p = 0.041 and p = 0.019 respectively). Multivariate analysis showed that for each additional day of mechanical ventilation, the risk of secondary infection increases 1.1 times (adOR = 1.07; 95% CI 1.02-1.13, p = 0.008) CONCLUSIONS: Patients with COVID-19 admitted to the intensive care unit and requiring mechanical ventilation had a high rate of secondary infections during their hospital stay. The number of days on MV was a risk factor for acquiring secondary respiratory infections.
| S-EPMC9521562 | biostudies-literature
Project description:Background: Lung mechanics during invasive mechanical ventilation (IMV) for both prognostic and therapeutic implications; however, the full trajectory lung mechanics has never been described for novel coronavirus disease 2019 (COVID-19) patients requiring IMV. The study aimed to describe the full trajectory of lung mechanics of mechanically ventilated COVID-19 patients. The clinical and ventilator setting that can influence patient-ventilator asynchrony (PVA) and compliance were explored. Post-extubation spirometry test was performed to assess the pulmonary function after COVID-19 induced ARDS. Methods: This was a retrospective study conducted in a tertiary care hospital. All patients with IMV due to COVID-19 induced ARDS were included. High-granularity ventilator waveforms were analyzed with deep learning algorithm to obtain PVAs. Asynchrony index (AI) was calculated as the number of asynchronous events divided by the number of ventilator cycles and wasted efforts. Mortality was recorded as the vital status on hospital discharge. Results: A total of 3,923,450 respiratory cycles in 2,778 h were analyzed (average: 24 cycles/min) for seven patients. Higher plateau pressure (Coefficient: -0.90; 95% CI: -1.02 to -0.78) and neuromuscular blockades (Coefficient: -6.54; 95% CI: -9.92 to -3.16) were associated with lower AI. Survivors showed increasing compliance over time, whereas non-survivors showed persistently low compliance. Recruitment maneuver was not able to improve lung compliance. Patients were on supine position in 1,422 h (51%), followed by prone positioning (499 h, 18%), left positioning (453 h, 16%), and right positioning (404 h, 15%). As compared with supine positioning, prone positioning was associated with 2.31 ml/cmH2O (95% CI: 1.75 to 2.86; p < 0.001) increase in lung compliance. Spirometry tests showed that pulmonary functions were reduced to one third of the predicted values after extubation. Conclusions: The study for the first time described full trajectory of lung mechanics of patients with COVID-19. The result showed that prone positioning was associated with improved compliance; higher plateau pressure and use of neuromuscular blockades were associated with lower risk of AI.
| S-EPMC7472529 | biostudies-literature
Project description:BackgroundData on the efficacy of non-invasive ventilation (NIV) after progression of respiratory failure in patients who have already received oxygen therapy, or CPAP outside ICU is limited. The study aimed to find predictors of NIV failure based on breathing pattern, gas exchange, and accessory respiratory muscles evaluation in patients who progressed to moderate-to-severe COVID-19 ARDS.MethodsThis was a prospective observational study in patients with moderate-to-severe COVID-19-ARDS on NIV (n = 80) admitted to COVID-ICU of Sechenov University. The combined success rate for conventional oxygen and CPAP outside ICU was 78.6% (440 of 560 patients). The primary endpoints were intubation rate and mortality. We measured respiratory rate, exhaled tidal volume (Vte), mean peak inspiratory flow (PIF), inspiratory time (Ti), PaO2, SpO2, end-tidal carbon dioxide (PETCO2), and Patrick score, and calculated ROX index, PaO2/FiO2, ventilatory ratio, and alveolar dead space (Vdalv/Vt) on Days 1, 3, 5, 7, 10, and 14. For all significant differences between NIV success and failure groups in measured data, we performed ROC analysis.ResultsNIV failure rate in ICU after deterioration of respiratory failure outside ICU was 71.3% (n = 57). Patients with the subsequent NIV failure were older at inclusion, more frail, had longer duration of disease before ICU admission, and higher rate of CPAP use outside ICU. ROC-analysis revealed that the following respiratory parameters after 48 h of NIV can serve as a predictors for NIV failure in moderate-to-severe COVID-19-associated ARDS: PaO2/FiO2 < 112 mmHg (AUROC 0.90 (0.93-0.97), p < 0.0001); PETCO2 < 19.5 mmHg (AUROC 0.84 (0.73-0.94), p < 0.0001); VDalv/VT > 0.43 (AUROC 0.78 (0.68-0.90), p < 0.0001); ROX-index < 5.02 (AUROC 0.89 (0.81-0.97), p < 0.0001); Patrick score > 2 points (AUROC 0.87 (0.78-0.96), p = 0.006).ConclusionIn patients who progressed to moderate-to-severe COVID-19-ARDS probability of NIV success rate was about 1/3. Prediction of the NIV failure can be made after 48 h based on ROX index < 5.02, PaO2/FiO2 < 112 mmHg, PETCO2 < 19.5 mmHg, and Patrick score > = 2.Trial registrationClinicalTrials.gov identifier: NCT04667923 , registered on 16/12/2020.
| S-EPMC9525938 | biostudies-literature
Project description:The impact of extrapulmonary organ dysfunction, independent from sepsis and lung injury severity, on outcomes in pediatric acute respiratory failure is unclear. We sought to determine the frequency, timing, and risk factors for extrapulmonary organ dysfunction and the independent association of multiple organ dysfunction syndrome with outcomes in pediatric acute respiratory failure.Secondary observational analysis of the Randomized Evaluation of Sedation Titration for Respiratory Failure cluster-randomized prospective clinical trial conducted between 2009 and 2013.Thirty-one academic PICUs in the United States.Two thousand four hundred forty-nine children mechanically ventilated for acute respiratory failure enrolled in Randomized Evaluation of Sedation Titration for Respiratory Failure.Organ dysfunction was defined using criteria published for pediatric sepsis. Multiple organ dysfunction syndrome was defined as respiratory dysfunction one or more extrapulmonary organ dysfunctions. We used multivariable logistic regression to identify risk factors for multiple organ dysfunction syndrome, and logistic or proportional hazards regression to compare clinical outcomes. All analyses accounted for PICU as a cluster variable. Overall, 73% exhibited extrapulmonary organ dysfunction, including 1,547 (63%) with concurrent multiple organ dysfunction syndrome defined by onset on day 0/1 and 244 (10%) with new multiple organ dysfunction syndrome with onset on day 2 or later. Most patients (93%) with indirect lung injury from sepsis presented with concurrent multiple organ dysfunction syndrome, whereas patients with direct lung injury had both concurrent (56%) and new (12%) multiple organ dysfunction syndrome. Risk factors for concurrent multiple organ dysfunction syndrome included older age, illness severity, sepsis, cancer, and moderate/severe lung injury. Risk factors for new multiple organ dysfunction syndrome were moderate/severe lung injury and neuromuscular blockade. Both concurrent and new multiple organ dysfunction syndrome were associated with 90-day in-hospital mortality (concurrent: adjusted odds ratio, 6.54; 95% CI, 3.00-14.25 and new: adjusted odds ratio, 3.21; 95% CI, 1.48-6.93) after adjusting for sepsis, moderate/severe lung injury, and other baseline characteristics.Extrapulmonary organ dysfunction was common, generally occurred concurrent with respiratory dysfunction (especially in sepsis), and was a major risk factor for mortality in pediatric acute respiratory failure.
| S-EPMC5380520 | biostudies-literature
Project description:BackgroundDuring control mechanical ventilation (CMV), the driving pressure of the respiratory system (ΔPrs) serves as a surrogate of transpulmonary driving pressure (ΔPlung). Expiratory muscle activity that decreases end-expiratory lung volume may impair the validity of ΔPrs to reflect ΔPlung. This prospective observational study in patients with acute respiratory distress syndrome (ARDS) ventilated with proportional assist ventilation (PAV+), aimed to investigate: (1) the prevalence of elevated ΔPlung, (2) the ΔPrs-ΔPlung relationship, and (3) whether dynamic transpulmonary pressure (Plungsw) and effort indices (transdiaphragmatic and respiratory muscle pressure swings) remain within safe limits.MethodsThirty-one patients instrumented with esophageal and gastric catheters (n = 22) were switched from CMV to PAV+ and respiratory variables were recorded, over a maximum of 24 h. To decrease the contribution of random breaths with irregular characteristics, a 7-breath moving average technique was applied. In each patient, measurements were also analyzed per deciles of increasing lung elastance (Elung). Patients were divided into Group A, if end-inspiratory transpulmonary pressure (PLEI) increased as Elung increased, and Group B, which showed a decrease or no change in PLEI with Elung increase.ResultsIn 44,836 occluded breaths, ΔPlung ≥ 12 cmH2O was infrequently observed [0.0% (0.0-16.9%) of measurements]. End-expiratory lung volume decrease, due to active expiration, was associated with underestimation of ΔPlung by ΔPrs, as suggested by a negative linear relationship between transpulmonary pressure at end-expiration (PLEE) and ΔPlung/ΔPrs. Group A included 17 and Group B 14 patients. As Elung increased, ΔPlung increased mainly due to PLEI increase in Group A, and PLEE decrease in Group B. Although ΔPrs had an area receiver operating characteristic curve (AUC) of 0.87 (95% confidence intervals 0.82-0.92, P < 0.001) for ΔPlung ≥ 12 cmH2O, this was due exclusively to Group A [0.91 (0.86-0.95), P < 0.001]. In Group B, ΔPrs showed no predictive capacity for detecting ΔPlung ≥ 12 cmH2O [0.65 (0.52-0.78), P > 0.05]. Most of the time Plungsw and effort indices remained within safe range.ConclusionIn patients with ARDS ventilated with PAV+, injurious tidal lung stress and effort were infrequent. In the presence of expiratory muscle activity, ΔPrs underestimated ΔPlung. This phenomenon limits the usefulness of ΔPrs as a surrogate of tidal lung stress, regardless of the mode of support.
| S-EPMC10785492 | biostudies-literature