Limitations of the ARDS criteria during high-flow oxygen or non-invasive ventilation: evidence from critically ill COVID-19 patients (original) (raw)
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Introduction Acute respiratory distress syndrome (ARDS) due to Coronavirus Disease 2019 (COVID-19) causes high mortality. The objective of this study is to determine whether the arterial pressure of oxygen/inspiratory fraction of oxygen (PaO2/FiO2) 24 h after invasive mechanical ventilation (IMV) and the difference between PaO2/FiO2 at 24 h after IMV and PaO2/FiO2 before admission to IMV (ΔPaO2/FiO2 24 h) are predictors of survival in patients with ARDS due to COVID-19. Methods A retrospective cohort study was conducted that included patients with ARDS due to COVID-19 in IMV admitted to the intensive care unit (ICU) of a hospital in southern Peru from April 2020 to April 2021. The ROC curves and the Youden index were used to establish the cut-off point for PaO2/FiO2 at 24 h of IMV and ΔPaO2/FiO2 at 24 h associated with mortality. The association with mortality was determined by Cox regression, calculating the crude (cHR) and adjusted (aHR) risk ratios, with their respective 95% conf...
BMJ open, 2015
A recent update of the definition of acute respiratory distress syndrome (ARDS) proposed an empirical classification based on ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (PaO2/FiO2) at ARDS onset. Since the proposal did not mandate PaO2/FiO2 calculation under standardised ventilator settings (SVS), we hypothesised that a stratification based on baseline PaO2/FiO2 would not provide accurate assessment of lung injury severity. A prospective, multicentre, observational study. A network of teaching hospitals. 478 patients with eligible criteria for moderate (100<PaO2/FiO2≤200) and severe (PaO2/FiO2≤100) ARDS and followed until hospital discharge. We examined physiological and ventilator parameters in association with the PaO2/FiO2 at ARDS onset, after 24 h of usual care and at 24 h under a SVS. At 24 h, patients were reclassified as severe, moderate, mild (200<PaO2/FiO2≤300) ARDS and non-ARDS (PaO2/FiO2>300). Group severity and hospital mortality...
Cochrane Database of Systematic Reviews, 2020
Background Supplemental oxygen is frequently administered to patients with acute respiratory distress syndrome (ARDS), including ARDS secondary to viral illness such as coronavirus disease 19 (COVID-19). An up-to-date understanding of how best to target this therapy (e.g. arterial partial pressure of oxygen (PaO 2) or peripheral oxygen saturation (SpO 2) aim) in these patients is urgently required. Objectives To address how oxygen therapy should be targeted in adults with ARDS (particularly ARDS secondary to COVID-19 or other respiratory viruses) and requiring mechanical ventilation in an intensive care unit, and the impact oxygen therapy has on mortality, days ventilated, days of catecholamine use, requirement for renal replacement therapy, and quality of life. Search methods We searched the Cochrane COVID-19 Study Register, CENTRAL, MEDLINE, and Embase from inception to 15 May 2020 for ongoing or completed randomized controlled trials (RCTs). Selection criteria Two review authors independently assessed all records in accordance with standard Cochrane methodology for study selection. We included RCTs comparing supplemental oxygen administration (i.e. different target PaO 2 or SpO 2 ranges) in adults with ARDS and receiving mechanical ventilation in an intensive care setting. We excluded studies exploring oxygen administration in patients with different underlying diagnoses or those receiving non-invasive ventilation, high-flow nasal oxygen, or oxygen via facemask. Data collection and analysis One review author performed data extraction, which a second review author checked. We assessed risk of bias in included studies using the Cochrane 'Risk of bias' tool. We used the GRADE approach to judge the certainty of the evidence for the following outcomes; mortality at longest follow-up, days ventilated, days of catecholamine use, and requirement for renal replacement therapy. Main results We identified one completed RCT evaluating oxygen targets in patients with ARDS receiving mechanical ventilation in an intensive care setting. The study randomized 205 mechanically ventilated patients with ARDS to either conservative (PaO 2 55 to 70 mmHg, or SpO 2 88% to 92%) or liberal (PaO 2 90 to 105 mmHg, or SpO 2 ≥ 96%) oxygen therapy for seven days. Overall risk of bias was high (due to lack of blinding, small numbers of participants, and the trial stopping prematurely), and we assessed the certainty of the evidence as very low. The available data suggested that mortality at 90 days may be higher in those participants receiving a lower oxygen target (odds ratio (OR) 1.83, 95% confidence interval (CI) 1.03 to 3.27). There was no evidence of a difference between the lower and higher target groups in mean number of days ventilated (14.0, 95% CI 10.0 to 18.0 versus 14.5, 95% CI 11.8 to 17.1); number of days of catecholamine use (8.0, 95% CI 5.5 to 10.5 versus 7.2, 95% CI 5.9 to 8.4); or participants receiving renal replacement therapy (13.7%, 95% CI 5.8% to 21.6% versus 12.0%, 95% CI 5.0% to 19.1%). Quality of life was not reported.
Journal of Critical Care, 2022
PurposeTo identify determinants of oxygenation over time in patients with COVID-19 acute respiratory distress syndrome (ARDS); and to analyze their characteristics according to Berlin definition categories.Materials and methodsProspective cohort study including consecutive mechanically ventilated patients admitted between 3/20/2020–10/31/2020 with ARDS. Epidemiological and clinical data on admission; outcomes; ventilation, respiratory mechanics and oxygenation variables were registered on days 1, 3 and 7 for the entire population and for ARDS categories.Results1525 patients aged 61 ± 13, 69% male, met ARDS criteria; most frequent comorbidities were obesity, hypertension, diabetes and respiratory disease. On admission, 331(21%), 849(56%) and 345(23%) patients had mild, moderate and severe ARDS; all received lung-protective ventilation (mean tidal volumes between 6.3 and 6.7 mL/kg PBW) and intermediate PEEP levels (10–11 cmH2O). PaO2/FiO2, plateau pressure, static compliance, driving pressure, ventilation ratio, pH and D-dimer >2 mg/L remained significantly different among the ARDS categories over time. In-hospital mortality was, respectively, 55%, 58% and 70% (p < 0.000). Independent predictors of changes of PaO2/FiO2 over time were BMI; preexistent respiratory disease; D-dimer >2 mg/L; day 1-PEEP, and day 1-ventilatory ratio.ConclusionHypoxemia in patients with COVID-19-related ARDS is associated with comorbidities, deadspace and activated coagulation markers, and disease severity—reflected by the PEEP level required.
Reclassifying Acute Respiratory Distress Syndrome
American journal of respiratory and critical care medicine, 2018
The ratio of PaO2 to FiO2 (P/F) defines ARDS severity and suggests appropriate therapies. We investigated 1) whether a 150 mmHg P/F threshold within the range of moderate ARDS (100-200 mmHg) would define two, more homogeneous subgroups, 2) which criteria led the clinicians to apply ECMO in severe ARDS. Methods & Measurements: At 150 mmHg P/F threshold, moderate patients were split in mild-moderate (n=50) and moderate-severe (n=55). Severe ARDS patients (FiO2 not available in 3 patients ) were split in higher (n=63) and lower-FiO2 (n=18) at 80% FiO2 threshold. Compared to mild-moderate ARDS, patients with severe-moderate ARDS had higher peak pressures, PaCO2 and pH. They also had heavier lungs, greater inhomogeneity, more non-inflated tissue, and greater lung recruitability. Within 84 severe ARDS patients (P/F lower than 100 mmHg), 75% belonged to the higher-FiO2 subgroup. They differed from the severe ARDS patients with lower FiO2 only in PaCO2 and lung weight. Forty-one of 46 patie...
Fio2 and acute respiratory distress syndrome definition during lung protective ventilation*
Critical Care Medicine, 2009
Objective: PaO 2 /FIO 2 ratio (P/F) is the marker of hypoxemia used in the American-European Consensus Conference on lung injury. A high F I O 2 level has been reported to variably alter PaO 2 /FIO 2 . We investigated the effect of high FIO 2 levels on the course of P/F in lung protective mechanically ventilated patients with acute respiratory distress syndrome.