Mechanical Ventilation Strategies Research Articles

Risk Factors for Prolonged Mechanical Ventilation After Pulmonary Endarterectomy: 7 Years' Experience From an Experienced Hospital in China.

Background: Prolonged mechanical ventilation (PMV) is common after cardiothoracic surgery, whereas the mechanical ventilation strategy after pulmonary endarterectomy (PEA) has not yet been reported. We aim to identify the incidence and risk factors for PMV and the relationship between PMV and short-term outcomes.Methods: We studied a retrospective cohort of 171 who undergoing PEA surgery from 2014 to 2020. Cox regression with restricted cubic splines was performed to identify the cutoff value for PMV. The Least absolute shrinkage and selection operator regression and logistic regressions were applied to identify risk factors for PMV. The impacts of PMV on the short-term outcomes were evaluated.Results: PMV was defined as the duration of mechanical ventilation exceeding 48 h. Independent risk factors for PMV included female sex (OR 2.911; 95% CI 1.303–6.501; P = 0.009), prolonged deep hypothermic circulatory arrest (DHCA) time (OR 1.027; 95% CI 1.002–1.053; P = 0.036), increased postoperative blood product use (OR 3.542; 95% CI 1.203–10.423; P = 0.022), elevated postoperative total bilirubin levels (OR 1.021; 95% CI 1.007–1.034; P = 0.002), increased preoperative pulmonary artery pressure (PAP) (OR 1.031; 95% CI 1.014–1.048; P < 0.001) and elongated postoperative right ventricular anteroposterior dimension (RVAD) (OR 1.119; 95% CI 1.026–1.221; P = 0.011). Patients with PMV had longer intensive care unit stays, higher incidences of postoperative complications, and higher in-hospital medical expenses.Conclusions: Female sex, prolonged DHCA time, increased postoperative blood product use, elevated postoperative total bilirubin levels, increased preoperative PAP, and elongated postoperative RVAD were independent risk factors for PMV. Identification of risk factors associated with PMV in patients undergoing PEA may facilitate timely diagnosis and re-intervention for some of these modifiable factors to decrease ventilation time and improve patient outcomes.

Protective ventilation and outcomes of critically ill patients with COVID-19: a cohort study

BackgroundApproximately 5% of COVID-19 patients develop respiratory failure and need ventilatory support, yet little is known about the impact of mechanical ventilation strategy in COVID-19. Our objective was to describe baseline characteristics, ventilatory parameters, and outcomes of critically ill patients in the largest referral center for COVID-19 in Sao Paulo, Brazil, during the first surge of the pandemic.MethodsThis cohort included COVID-19 patients admitted to the intensive care units (ICUs) of an academic hospital with 94 ICU beds, a number expanded to 300 during the pandemic as part of a state preparedness plan. Data included demographics, advanced life support therapies, and ventilator parameters. The main outcome was 28-day survival. We used a multivariate Cox model to test the association between protective ventilation and survival, adjusting for PF ratio, pH, compliance, and PEEP.ResultsWe included 1503 patients from March 30 to June 30, 2020. The mean age was 60 ± 15 years, and 59% were male. During 28-day follow-up, 1180 (79%) patients needed invasive ventilation and 666 (44%) died. For the 984 patients who were receiving mechanical ventilation in the first 24 h of ICU stay, mean tidal volume was 6.5 ± 1.3 mL/kg of ideal body weight, plateau pressure was 24 ± 5 cmH2O, respiratory system compliance was 31.9 (24.4–40.9) mL/cmH2O, and 82% of patients were ventilated with protective ventilation. Noninvasive ventilation was used in 21% of patients, and prone, in 36%. Compliance was associated with survival and did not show a bimodal pattern that would support the presence of two phenotypes. In the multivariable model, protective ventilation (aHR 0.73 [95%CI 0.57–0.94]), adjusted for PF ratio, compliance, PEEP, and arterial pH, was independently associated with survival.ConclusionsDuring the peak of the epidemic in Sao Paulo, critically ill patients with COVID-19 often required mechanical ventilation and mortality was high. Our findings revealed an association between mechanical ventilation strategy and mortality, highlighting the importance of protective ventilation for patients with COVID-19.

Individualized Mechanical power-based ventilation strategy for acute respiratory failure formalized by finite mixture modeling and dynamic treatment regimen.

BackgroundMechanical ventilation (MV) is the key to the successful treatment of acute respiratory failure (ARF) in the intensive care unit (ICU). The study aims to formalize the concept of individualized MV strategy with finite mixture modeling (FMM) and dynamic treatment regime (DTR).MethodsARF patients requiring MV for over 48 h from 2008 to 2019 were included. FMM was conducted to identify classes of ARF. Static and dynamic mechanical power (MP_static and MP_dynamic) and relevant clinical variables were calculated/collected from hours 0 to 48 at an interval of 8 h. was calculated as the difference between actual and optimal MP.FindingsA total of 8768 patients were included for analysis with a mortality rate of 27%. FFM identified three classes of ARF, namely, the class 1 (baseline), class 2 (critical) and class 3 (refractory respiratory failure). The effect size of MP_static on mortality is the smallest in class 1 (HR for every 5 Joules/min increase: 1.29; 95% CI: 1.15 to 1.45; p < 0.001) and the largest in class 3 (HR for every 5 Joules/min increase: 1.83; 95% CI: 1.52 to 2.20; p < 0.001).InterpretationMP has differing therapeutic effects for subtypes of ARF. Optimal MP estimated by DTR model may help to improve survival outcome.FundingThe study was funded by Health Science and Technology Plan of Zhejiang Province (2021KY745), Key Research & Development project of Zhejiang Province (2021C03071) and Yilu "Gexin" - Fluid Therapy Research Fund Project (YLGX-ZZ-2,020,005).

Physiological and inflammatory consequences of high and low respiratory rate in acute respiratory distress syndrome.

Using protective mechanical ventilation strategies with low tidal volume is usually accompanied by an increment of respiratory rate to maintain adequate alveolar ventilation. However, there is no robust data that support the safety of a high respiratory rate concerning ventilator-induced lung injury. Several experimental animal studies have explored the effects of respiratory rate over lung physiology, using a wide range of frequencies and different models. Clinical evidence is scarce and restricted to the physiological impact of increased respiratory rate. Undoubtedly, the respiratory rate can influence respiratory mechanics in various ways as a factor of multiplication of the power of ventilation, and gas exchange, and also on alveolar dynamics. In this narrative review, we present our point of view over the main experimental and clinical evidence available regarding the effect of respiratory rate on ventilator-induced lung injury development.

Critically Ill COVID-19 Patient with Chronic Liver Disease - Insights into a Comprehensive Liver Intensive Care.

The novel coronavirus-related coronavirus disease 2019 (COVID-19) pandemic has been relentless in disrupting and overwhelming healthcare the world over. Clinical outcomes of COVID-19 in patients with chronic comorbidities, especially in those with metabolic syndrome, are well documented. Chronic liver disease and cirrhosis patients are a special sub-group, among whom the management of COVID-19 is challenging. Understanding the pathophysiology of COVID-19 in patients with cirrhosis and portal hypertension improves our identification of at-risk patients for disease progression that will further help compartmentalize generalized and specialized treatment options in this special patient group. In this exhaustive review, we critically review the impact of COVID-19 on the liver and in chronic liver disease and cirrhosis patients. We further discuss common features associated with the pathophysiology of COVID-19 and cirrhosis, based on the renin-angiotensin system and deliberate current literature on guidelines for the treatment of COVID-19 and extrapolate the same to the cirrhosis population to provide a concise and stepwise, evidence-based management for cirrhosis patients with severe and critical COVID-19. There are no specific management guidelines for cirrhosis patients with COVID-19 and current recommendations for treatment are as per guidelines for general population. Nevertheless, specific issues like avoiding corticosteroids in decompensated patients with variceal bleeding, suspected sepsis, high grade hepatic encephalopathy and acute kidney injury, use of early mechanical ventilation strategies in those with severe ascites and hepatopulmonary syndrome, avoidance of remdesivir in advanced liver disease, and application of liver-specific severity scores for prognostication and identification of futility need to be highlighted.

Latent class analysis to predict intensive care outcomes in Acute Respiratory Distress Syndrome: a proposal of two pulmonary phenotypes

BackgroundAcute respiratory distress syndrome remains a heterogeneous syndrome for clinicians and researchers difficulting successful tailoring of interventions and trials. To this moment, phenotyping of this syndrome has been approached by means of inflammatory laboratory panels. Nevertheless, the systemic and inflammatory expression of acute respiratory distress syndrome might not reflect its respiratory mechanics and gas exchange.MethodsRetrospective analysis of a prospective cohort of two hundred thirty-eight patients consecutively admitted patients under mechanical ventilation presenting with acute respiratory distress syndrome. All patients received standardized monitoring of clinical variables, respiratory mechanics and computed tomography scans at predefined PEEP levels. Employing latent class analysis, an unsupervised structural equation modelling method, on respiratory mechanics, gas-exchange and computed tomography-derived gas- and tissue-volumes at a PEEP level of 5cmH2O, distinct pulmonary phenotypes of acute respiratory distress syndrome were identified.ResultsLatent class analysis was applied to 54 respiratory mechanics, gas-exchange and CT-derived gas- and tissue-volume variables, and a two-class model identified as best fitting. Phenotype 1 (non-recruitable) presented lower respiratory system elastance, alveolar dead space and amount of potentially recruitable lung volume than phenotype 2 (recruitable). Phenotype 2 (recruitable) responded with an increase in ventilated lung tissue, compliance and PaO2/FiO2 ratio (p < 0.001), in addition to a decrease in alveolar dead space (p < 0.001), to a standardized recruitment manoeuvre. Patients belonging to phenotype 2 (recruitable) presented a higher intensive care mortality (hazard ratio 2.9, 95% confidence interval 1.7–2.7, p = 0.001).ConclusionsThe present study identifies two ARDS phenotypes based on respiratory mechanics, gas-exchange and computed tomography-derived gas- and tissue-volumes. These phenotypes are characterized by distinctly diverse responses to a standardized recruitment manoeuvre and by a diverging mortality. Given multicentre validation, the simple and rapid identification of these pulmonary phenotypes could facilitate enrichment of future prospective clinical trials addressing mechanical ventilation strategies in ARDS.

Pneumothorax and pneumomediastinum in COVID-19 acute respiratory distress syndrome

COVID-19 has involved numerous countries across the globe and the disease burden, susceptible age group; mortality rate has been variable depending on the demographical profile, economic status, and health care infrastructure. In the current clinical environment, COVID-19 is one of the most important clinical differential diagnoses in patients presenting with respiratory symptoms. The optimal mechanical ventilation strategy for these patients has been a constant topic of discussion and very importantly so, since a great majority of these patients require invasive mechanical ventilation and often for an extended period of time. In this report we highlight our experience with a COVID-19 patient who most likely suffered barotrauma either as a result of traumatic endotracheal intubation or primarily due to COVID-19 itself. We also aim to highlight the current literature available to suggest the management strategy for these patients for a favorable outcome. The cases described are diverse in terms of age variance and other comorbidities. According to the literature, certain patients, with COVID-19 disease and spontaneous pneumothorax were noted to be managed conservatively and oxygen supplementation with nasal cannula sufficed. Decision regarding need and escalation to invasive mechanical ventilation should be taken early in the disease to avoid complications such as patient self-inflicted lung injury (P-SILI) and barotrauma sequelae such as pneumothorax and pneumomediastinum Recent systematic review further supports the fact that the use of non-invasive ventilation (NIV) in certain patients with COVID-19 pneumonia may give a false sense of security and clinical stabilization but has no overall benefit to avoid intubation. While invasive mechanical ventilation may be associated with higher rates of barotrauma, this should not mean that intubation and invasive mechanical ventilation should be delayed. This becomes an important consideration when non-intensivists or personnel with less experience provide care for this vulnerable patient population who may rely too heavily on NIV to avoid intubation and mechanical ventilation.

Diaphragm function in acute respiratory failure and the potential role of phrenic nerve stimulation.

The aim of this review was to describe the risk factors for developing diaphragm dysfunction, discuss the monitoring techniques for diaphragm activity and function, and introduce potential strategies to incorporate diaphragm protection into conventional lung-protective mechanical ventilation strategies. It is increasingly apparent that an approach that addresses diaphragm-protective ventilations goals is needed to optimize ventilator management and improve patient outcomes. Ventilator-induced diaphragm dysfunction (VIDD) is common and is associated with increased ICU length of stay, prolonged weaning and increased mortality. Over-assistance, under-assistance and patient-ventilator dyssynchrony may have important downstream clinical consequences related to VIDD. Numerous monitoring techniques are available to assess diaphragm function, including respiratory system pressures, oesophageal manometry, diaphragm ultrasound and electromyography. Novel techniques including phrenic nerve stimulation may facilitate the achievement of lung and diaphragm-protective goals for mechanical ventilation. Diaphragm protection is an important consideration in optimizing ventilator management in patients with acute respiratory failure. The delicate balance between lung and diaphragm-protective goals is challenging. Phrenic nerve stimulation may be uniquely situated to achieve and balance these two commonly conflicting goals.

Weaning patients with obesity from ventilatory support.

Obesity prevalence is increasing in most countries in the world. In the United States, 42% of the population is obese (body mass index (BMI) > 30) and 9.2% is obese class III (BMI > 40). One of the greatest challenges in critically ill patients with obesity is the optimization of mechanical ventilation. The goal of this review is to describe respiratory physiologic changes in patients with obesity and discuss possible mechanical ventilation strategies to improve respiratory function. Individualized mechanical ventilation based on respiratory physiology after a decremental positive end-expiratory pressure (PEEP) trial improves oxygenation and respiratory mechanics. In a recent study, mortality of patients with respiratory failure and obesity was reduced by about 50% when mechanical ventilation was associated with the use of esophageal manometry and electrical impedance tomography (EIT). Obesity greatly alters the respiratory system mechanics causing atelectasis and prolonged duration of mechanical ventilation. At present, novel strategies to ventilate patients with obesity based on individual respiratory physiology showed to be superior to those based on standard universal tables of mechanical ventilation. Esophageal manometry and EIT are essential tools to systematically assess respiratory system mechanics, safely adjust relatively high levels of PEEP, and improve chances for successful weaning.

Mechanical ventilation strategy in quadriplegic patients for the intensivist

In France, the number of spinal cord injuries is around 2000 new cases per year, often affecting young men, and thus having a real impact on public health. Seventy percent of patients with spinal cord injury upper than C5 require mechanical ventilation during their hospitalization. The need for this mechanical ventilation expose the spinal cord injury (SCI) patients to 2 risk periods: the intubation phase with a high risk of displacement and compression during the course of the procedure, and the withdrawal phase, which is particularly difficult in this context, resulting in an increase in morbidity and hospitalization times. Recently, the latest guidelines from SFAR-SFMU experts on the management of spinal cord injuries published. In this context, we report on good practices in the management of these patients, particularly in the field of ventilation.

Reinterpreting the ventilator-induced lung injury from the prospective of mechanical power

Mechanical power is the power that the ventilator transmits to the respirator for lung ventilation. In recent years, some researchers have suggested that mechanical power may be a good indicator for assessing ventilator-induced lung injury in general, which can be used for guiding the best mechanical ventilation strategy. While introducing the definition and calculation method of mechanical power, this paper focuses on the association and potential mechanism of mechanical power with ventilator-induced lung injury, which aims to provide a new perspective and research direction for clinical understanding of ventilator-induced lung injury.

Mechanical ventilation strategy for pulmonary rehabilitation based on patient-ventilator interaction

Mechanical ventilation is an effective medical means in the treatment of patients with critically ill, COVID-19 and other pulmonary diseases. During the mechanical ventilation and the weaning process, the conduct of pulmonary rehabilitation is essential for the patients to improve the spontaneous breathing ability and to avoid the weakness of respiratory muscles and other pulmonary functional trauma. However, inappropriate mechanical ventilation strategies for pulmonary rehabilitation often result in weaning difficulties and other ventilator complications. In this article, the mechanical ventilation strategies for pulmonary rehabilitation are studied based on the analysis of patient-ventilator interaction. A pneumatic model of the mechanical ventilation system is established to determine the mathematical relationship among the pressure, the volumetric flow, and the tidal volume. Each ventilation cycle is divided into four phases according to the different respiratory characteristics of patients, namely, the triggering phase, the inhalation phase, the switching phase, and the exhalation phase. The control parameters of the ventilator are adjusted by analyzing the interaction between the patient and the ventilator at different phases. A novel fuzzy control method of the ventilator support pressure is proposed in the pressure support ventilation mode. According to the fuzzy rules in this research, the plateau pressure can be obtained by the trigger sensitivity and the patient’s inspiratory effort. An experiment prototype of the ventilator is established to verify the accuracy of the pneumatic model and the validity of the mechanical ventilation strategies proposed in this article. In addition, through the discussion of the patient-ventilator asynchrony, the strategies for mechanical ventilation can be adjusted accordingly. The results of this research are meaningful for the clinical operation of mechanical ventilation. Besides, these results provide a theoretical basis for the future research on the intelligent control of ventilator and the automation of weaning process.

Lung-protective ventilation and adjunctive strategies to manage respiratory failure: are they safe in the neurological patient?

The coexistence of neurological injury and respiratory failure is common in intensive care. This article provides a contemporary overview of the safety and efficacy of different strategies for mechanical ventilation and adjunctive respiratory approaches in patients with acute brain injury. Available evidence indicates that lung-protective ventilation (LPV) can be implemented safely in a range of patients with concurrent respiratory failure and brain injury of different etiologies; however, the clinical efficacy of LPV in this setting needs to be established. In patients who have severe acute respiratory distress syndrome (ARDS) and brain injury, adjunctive measures (neuromuscular blocker drug infusions, prone positioning, extracorporeal membrane oxygenation) may be considered, although the neurophysiological impact and safety of these techniques need further investigation. Intracranial pressure and other neuromonitoring techniques may be of value to ensure optimal management of mechanical ventilation and adjunctive measures in this population. Research is needed to determine the safety, feasibility, and efficacy of LPV and adjunctive approaches for managing patients with concurrent brain injury and respiratory failure.

Mechanical ventilation in septic shock

The aim of this study was to review the most recent literature on mechanical ventilation strategies in patients with septic shock. Indirect clinical trial evidence has refined the use of neuromuscular blocking agents, positive end-expiratory pressure (PEEP) and recruitment manoeuvres in septic shock patients with acute respiratory distress syndrome. Weaning strategies and devices have also been recently evaluated. The role of lung protective ventilation in patients with healthy lungs, while recognized, still needs to be further refined. The possible detrimental effects of spontaneous breathing in patients who develop acute respiratory distress syndrome is increasingly recognized, but clinical trial evidence is still lacking to confirm this hypothesis. A new concept of lung and diaphragm protective is emerging in the critical care literature, but its application will need a complex intervention implementation approach to allow adequate scrutiny of this concept and uptake by clinicians. Many advances in the management of the mechanically ventilated patient with sepsis and septic shock have occurred in recent years, but clinical trial evidence is still necessary to translate new hypotheses to the bedside and find the right balance between benefits and risks of these new strategies.

Optimal Upper Limits of Plateau Pressure for Patients With Acute Respiratory Distress Syndrome During the First Seven Days: A Meta-Regression Analysis.

BackgroundThe effects of plateau pressure during the initial days of mechanical ventilation on outcomes for patients with acute respiratory distress syndrome have not been fully examined. We conducted meta-regression analysis of plateau pressure during the first 7 days using randomized control trials to investigate the optimal upper limits of plateau pressure on different days of mechanical ventilation.MethodsRandomized controlled trials comparing two mechanical ventilation strategies with lower and higher plateau pressures in patients with acute respiratory distress syndrome were included. Meta-regression analysis was performed to determine the association of plateau pressure with mortality on days 1, 3, and 7 of mechanical ventilation.ResultsAfter evaluation of 2,975 citations from a comprehensive search across electronic databases, 14 studies were included in the final qualitative analysis. A total of 4,984 patients were included in the quantitative analysis. As a result of the pairwise comparison, overall short-term mortality was significantly higher for patients with plateau pressures over 32 cm H2O during the first 3 days after intensive care unit (ICU) admission (day 1: relative risk (RR), 0.77; 95% confidence interval (CI), 0.66 - 0.89; I2 = 0%; day 3: RR, 0.76; 95% CI, 0.64 - 0.90; I2 = 0%), but not on day 7 (RR, 0.82; 95% CI, 0.65 - 1.04; I2 = 16%). Plateau pressures below 27 cm H2O and 30 cm H2O were not associated with an absolute risk reduction of short-term mortality. According to univariable meta-regression analysis, mortality was significantly associated with plateau pressure on day 1 (β = 0.01 (95% CI, 0.002 - 0.024), P = 0.02). On days 3 and 7, however, no significant difference was detected. When the cutoffs were set at 27, 30 and 32 cm H2O on day 1, which showed a significant difference, plateau pressure tended to be associated with increased mortality at pressures above the cut-off values, and there were no significant differences at pressures below the cut-off values, regardless of the cutoff used.ConclusionsThis study suggests that the optimal cut-off value for plateau pressure may be 27 cm H2O especially during the initial period of mechanical ventilation, although this association may not continue during the latter period of mechanical ventilation.

Management of COVID-19 in the Intensive Care Unit.

A novel coronavirus was identified in the last days of 2019, which caused a cluster of pneumonia cases in Wuhan, China. Since Coronavirus Disease 2019 (COVID-19) was identified and caused a pandemic, morbidity and mortality caused by acute respiratory distress syndrome (ARDS) and other disease-related complications are being struggled against in intensive care units (ICUs). In this chapter, clinical features, epidemiological properties, and management of critically ill COVID-19 patients aree discussed with the support of recent literature. Since there isn't a definitively proven treatment for the disease, the management of critical illness is adequate supportive medical care based upon the basic principles of critically ill patient management. Supportive oxygen therapy modalities and mechanical ventilation strategies are most challenging issues during the course of the diseasein ICUs. Additionally, using combinations of investigational drugs is beneficial for the management of the disease. Because the disease is highly contagious, infection control measures to stop the disease's nosocomial spread are crucial. The basis of management in critically ill COVID-19 patients is providing adequate ICU care. Additionally, a combination of promising treatment strategies specific to the disease may be beneficial and should be monitored carefully.

Synopsis of Clinical Acute Respiratory Distress Syndrome (ARDS).

The entity of acute respiratory distress syndrome (ARDS) is an acute inflammatory lung condition associated with lung damage and increased vascular permeability. In the ICU, ARDS was reported to be the cause of 10.4% of admissions. The syndrome is associated with conditions such as sepsis, burns, trauma, and many others. The Berlin Definition which is the most up-to-date definition defines ARDS as an early onset of severe and refractory hypoxemia, PaO2/FiO2 ratio less than 300mmHg, bilateral infiltrates on chest x-ray, and alveolar edema not explained by a cardiogenic cause or fluid overload.The entity of ARDS and its treatment have been studied for many years to better understand it and help find therapies. However, the mainstay of medical management is supportive with specific strategies for mechanical ventilation. No specific drug therapy is available at present.In this chapter, the history, clinical picture, and therapeutic approaches to ARDS will be discussed. We include lung-protective ventilation, prone positioning, use of neuromuscular blockade, corticosteroids, as well as discussion of studies done on this important clinical and morbid condition. We emphasize that there are ongoing trials and research being done to better identify patients earlier in their clinical course so that supportive care with lung-protective ventilation and a conservative fluid approach can be implemented. We also mention promising therapies such as cell-based therapies which would help in decreasing lung inflammation.

Impact of different mechanical ventilation strategies for night purging on indoor air quality in public buildings

Night-time ventilation has been used in non-residential buildings to enhance indoor air quality before occupied periods. However, many hypotheses exist on how this ventilation should be used. A typical choice has been to shut down the ventilation after occupancy and restart the ventilation again 2 hours before occupancy. Another option has been to ventilate the buildings continuously. In this study, the shut-down, continuous, and intermittent ventilation strategies were compared by evaluating indoor air quality. The daily occupied-hour ventilation was kept as usual. Each test case lasted for 2 weeks. Indoor air quality was assessed by measuring TVOC concentrations. Also, the thermal conditions, carbon dioxide, and pressure differences over the building envelope and over the air distribution devices were measured. The results show that the averaged TVOC concentrations were at the same level in the mornings with all those ventilation strategies. The evening concentrations reached a minimum level after a 2-hour purging period. TVOC concentrations were higher during the day than at night. This reveals that space usage had the largest effect on TVOC concentrations. The results indicate that a 2-hour purging is enough to cleanse indoor air before occupancy, and therefore the continuous night-time ventilation is not necessary.

Severe coronavirus disease 2019: Is it acute respiratory distress syndrome?

The outbreak of coronavirus disease 2019 (COVID-19) poses a major global threat. Although we have learned a lot about COVID-19 from clinical studies and autopsy findings, there is still a lot of confusion. One of the biggest controversies is whether severe COVID-19 can be diagnosed as acute respiratory distress syndrome (ARDS). Severe COVID-19 may meet ARDS Berlin criteria, but it differs from ARDS caused by other etiologies and is characterized by later onset time, relatively normal lung compliance in some cases, significant hypercapnia, lung CT findings, and significant coagulation activation in lungs. Some reports classify COVID-19-related ARDS into different phenotypes, but most of them are based on observational studies, with high bias. To date, we have not fully understood the pathophysiology of COVID-19-related ARDS. Premature phenotyping may mislead mechanical ventilation strategies. We expect evidence from large clinical studies. © 2021, Peking Union Medical College Hospital. All rights reserved.

National incidence rate and related mortality for acute respiratory distress syndrome in France

IntroductionDespite many efforts to improve mechanical ventilation strategies and the use of rescue strategies, ARDS-related mortality remains high. The primary objective of this study was to determine the incidence and 90-day mortality of ARDS patients admitted to all French ICUs following the introduction of the Berlin definition of ARDS. Patients and methodsThe data source for this nationwide cohort study was the French national hospital database (Programme de Médicalisation des Systèmes d’Information (PMSI)), which systematically collects administrative and medical information related to all patients hospitalised and hospital stays. Patient-level data were obtained from the PMSI database for all patients admitted to an ICU from the 1st of January 2017, through the 31st of December 2017. The inclusion criteria were as follows: ICU patients ≥ 18 years old with at least one International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10) diagnosis code of J80 (ARDS), either as a primary diagnosis or a secondary diagnosis, during their ICU stay. ResultsA total of 12,846 ICU adult patients with ARDS were included. The crude incidence of ARDS was 24.6 per 100,000 person-years, varying with age from 6.7 per 100,000 person-years for those 18 through 40 years of age to 51.9 per 100,000 person-years for those 68 through 76 years of age. The in-hospital mortality rate was 51.1%. Day-90 mortality (day-1 being the ICU admission) was 51.2% and increased with age from 29.0% for patients 18 through 40 years of age to 69.3% for patients 77 years of age or older (p < 0.001). Only 53.9% of the survivors were transferred home directly after hospital discharge. ConclusionsThe incidence and mortality of ARDS in adults in France are higher than that generally reported in other countries.