Respiratory Pathophysiology of Mechanically Ventilated Patients with COVID-19: A Cohort Study.
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ABSTRACT:
SUBMITTER: Ziehr DR
PROVIDER: S-EPMC7301734 | biostudies-literature | 2020 Jun
REPOSITORIES: biostudies-literature
Publications
Respiratory Pathophysiology of Mechanically Ventilated Patients with COVID-19: A Cohort Study.
Ziehr David R DR Alladina Jehan J Petri Camille R CR Maley Jason H JH Moskowitz Ari A Medoff Benjamin D BD Hibbert Kathryn A KA Thompson B Taylor BT Hardin C Corey CC
American journal of respiratory and critical care medicine 20200601 12
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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: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:BackgroundSolid data on cardiovascular derangements in critically ill COVID-19 patients remain scarce. The aim of this study is to describe hemodynamic characteristics in a cohort of COVID-19-related critically ill patients.MethodsA retrospective observational cohort study in twenty-eight consecutive mechanically ventilated COVID-19 patients. Pulse contour analysis-derived data were obtained from all patients, using the PiCCO® system.ResultsThe mean arterial pressure increased from 77 ± 10 mmHg on day 1 to 84 ± 9 mmHg on day 21 (p=0.04), in combination with the rapid tapering and cessation of norepinephrine and the gradual use of antihypertensive drugs in the vast majority of patients. The cardiac index increased significantly from 2.8 ± 0.7 L/min/m2 on day 1 to 4.0 ± 0.8 L/min/m2 on day 21 (p < 0.001). Dobutamine was administered in only two patients. Mean markers of left ventricular contractility and peripheral perfusion, as well as lactate levels, remained within the normal range. Despite a constant fluid balance, extravascular lung water index decreased significantly from 17 ± 7 mL/kg on day 1 to 11 ± 4 mL/kg on day 21 (p < 0.001). Simultaneously, intrapulmonary right-to-left shunt fraction (Q s/Q t) decreased significantly from 27 ± 10% in week 1 to 15 ± 9% in week 3 (p=0.007). PaO2/FiO2 ratio improved from 159 ± 53 mmHg to 319 ± 53 mmHg (p < 0.001), but static lung compliance remained unchanged.ConclusionsIn general, this cohort of patients with COVID-19 respiratory failure showed a marked rise in blood pressure over time, not accompanied by distinctive markers of circulatory failure. Characteristically, increased extravascular lung water, vascular permeability, and intrapulmonary shunt diminished over time, concomitant with an improvement in gas exchange.
| S-EPMC7783514 | biostudies-literature
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| S-EPMC7640579 | biostudies-literature
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| S-EPMC11363553 | biostudies-literature
Project description:BackgroundSome unanswered questions persist regarding the effectiveness of corticosteroids for severe coronavirus disease 2019 (COVID-19) patients. We aimed to assess the clinical effect of corticosteroids on intensive care unit (ICU) mortality among mechanically ventilated COVID-19-associated acute respiratory distress syndrome (ARDS) patients.MethodsThis was a retrospective study of prospectively collected data conducted in 70 ICUs (68 Spanish, one Andorran, one Irish), including mechanically ventilated COVID-19-associated ARDS patients admitted between February 6 and September 20, 2020. Individuals who received corticosteroids for refractory shock were excluded. Patients exposed to corticosteroids at admission were matched with patients without corticosteroids through propensity score matching. Primary outcome was all-cause ICU mortality. Secondary outcomes were to compare in-hospital mortality, ventilator-free days at 28 days, respiratory superinfection and length of stay between patients with corticosteroids and those without corticosteroids. We performed survival analysis accounting for competing risks and subgroup sensitivity analysis.ResultsWe included 1835 mechanically ventilated COVID-19-associated ARDS, of whom 1117 (60.9%) received corticosteroids. After propensity score matching, ICU mortality did not differ between patients treated with corticosteroids and untreated patients (33.8% vs. 30.9%; p = 0.28). In survival analysis, corticosteroid treatment at ICU admission was associated with short-term survival benefit (HR 0.53; 95% CI 0.39-0.72), although beyond the 17th day of admission, this effect switched and there was an increased ICU mortality (long-term HR 1.68; 95% CI 1.16-2.45). The sensitivity analysis reinforced the results. Subgroups of age < 60 years, severe ARDS and corticosteroids plus tocilizumab could have greatest benefit from corticosteroids as short-term decreased ICU mortality without long-term negative effects were observed. Larger length of stay was observed with corticosteroids among non-survivors both in the ICU and in hospital. There were no significant differences for the remaining secondary outcomes.ConclusionsOur results suggest that corticosteroid treatment for mechanically ventilated COVID-19-associated ARDS had a biphasic time-dependent effect on ICU mortality. Specific subgroups showed clear effect on improving survival with corticosteroid use. Therefore, further research is required to identify treatment-responsive subgroups among the mechanically ventilated COVID-19-associated ARDS patients.
| S-EPMC8617372 | 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:BackgroundInformation is lacking regarding long-term survival and predictive factors for mortality in patients with acute hypoxemic respiratory failure due to coronavirus disease 2019 (COVID-19) and undergoing invasive mechanical ventilation. We aimed to estimate 180-day mortality of patients with COVID-19 requiring invasive ventilation, and to develop a predictive model for long-term mortality.MethodsRetrospective, multicentre, national cohort study between March 8 and April 30, 2020 in 16 intensive care units (ICU) in Spain. Participants were consecutive adults who received invasive mechanical ventilation for COVID-19. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection detected in positive testing of a nasopharyngeal sample and confirmed by real time reverse-transcriptase polymerase chain reaction (rt-PCR). The primary outcomes was 180-day survival after hospital admission. Secondary outcomes were length of ICU and hospital stay, and ICU and in-hospital mortality. A predictive model was developed to estimate the probability of 180-day mortality.Results868 patients were included (median age, 64 years [interquartile range [IQR], 56-71 years]; 72% male). Severity at ICU admission, estimated by SAPS3, was 56 points [IQR 50-63]. Prior to intubation, 26% received some type of noninvasive respiratory support. The unadjusted overall 180-day survival rates was 59% (95% CI 56-62%). The predictive factors measured during ICU stay, and associated with 180-day mortality were: age [Odds Ratio [OR] per 1-year increase 1.051, 95% CI 1.033-1.068)), SAPS3 (OR per 1-point increase 1.027, 95% CI 1.011-1.044), diabetes (OR 1.546, 95% CI 1.085-2.204), neutrophils to lymphocytes ratio (OR per 1-unit increase 1.008, 95% CI 1.001-1.016), failed attempt of noninvasive positive pressure ventilation prior to orotracheal intubation (OR 1.878 (95% CI 1.124-3.140), use of selective digestive decontamination strategy during ICU stay (OR 0.590 (95% CI 0.358-0.972) and administration of low dosage of corticosteroids (methylprednisolone 1 mg/kg) (OR 2.042 (95% CI 1.205-3.460).ConclusionThe long-term survival of mechanically ventilated patients with severe COVID-19 reaches more than 50% and may help to provide individualized risk stratification and potential treatments.Trial registrationClinicalTrials.gov Identifier: NCT04379258. Registered 10 April 2020 (retrospectively registered).
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Project description:The prone position (PP) is increasingly used in mechanically ventilated coronavirus disease 2019 (COVID-19) acute respiratory distress syndrome (ARDS) patients. However, studies investigating the influence of the PP are currently lacking in these patients. This is the first study to investigate the influence of the PP on the oxygenation and decarboxylation in COVID-19 patients. A prospective bicentric study design was used, and in mechanically ventilated COVID-19 patients, PP was indicated from a partial pressure of oxygen in arterial blood (PaO2)/fraction of inspired oxygen (FIO2) ratio of <200. Patients were left prone for 16 h each. Pressure levels, FIO2, were adjusted to ensure a PaO2 greater than 60 mmHg. Blood gas analyses were performed before (baseline 0.5 h), during (1/2/5.5/9.5/13 h), and after being in the PP (1 h), the circulatory/ventilation parameters were continuously monitored, and lung compliance (LC) was roughly calculated. Responders were defined compared to the baseline value (PaO2/FIO2 ratio increase of ≥15%; partial pressure of carbon dioxide (PaCO2) decrease of ≥2%). 13 patients were included and 36 PP sessions were conducted. Overall, PaO2/FIO2 increased significantly in the PP (p < 0.001). Most PaO2/FIO2 responders (29/36 PP sessions, 77%) were identified 9.5 h after turning prone (14% slow responders), while most PaCO2 responders (15/36 PP sessions, 42%) were identified 13 h after turning prone. A subgroup of patients (interval intubation to PP ≥3 days) showed less PaO2/FIO2 responders (16% vs. 77%). An increase in PaCO2 and minute ventilation in the PP showed a significant negative correlation (p < 0.001). LC (median before the PP = 38 mL/cm H2O; two patients with LC >80 mL/cm H2O) showed a significant positive correlation with the 28 day survival of patients (p = 0.01). The PP significantly improves oxygenation in COVID-19 ARDS patients. The data suggest that they also benefit most from an early PP. A decrease in minute ventilation may result in fewer PaCO2 responders. LC may be a predictive outcome parameter in COVID-19 patients. Retrospectively registered.
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