32 research outputs found
Lung Imaging and Artificial Intelligence in ARDS
Get PDFArtificial intelligence (AI) can make intelligent decisions in a manner akin to that of the human mind. AI has the potential to improve clinical workflow, diagnosis, and prognosis, especially in radiology. Acute respiratory distress syndrome (ARDS) is a very diverse illness that is characterized by interstitial opacities, mostly in the dependent areas, decreased lung aeration with alveolar collapse, and inflammatory lung edema resulting in elevated lung weight. As a result, lung imaging is a crucial tool for evaluating the mechanical and morphological traits of ARDS patients. Compared to traditional chest radiography, sensitivity and specificity of lung computed tomography (CT) and ultrasound are higher. The state of the art in the application of AI is summarized in this narrative review which focuses on CT and ultrasound techniques in patients with ARDS. A total of eighteen items were retrieved. The primary goals of using AI for lung imaging were to evaluate the risk of developing ARDS, the measurement of alveolar recruitment, potential alternative diagnoses, and outcome. While the physician must still be present to guarantee a high standard of examination, AI could help the clinical team provide the best care possible
Assessment of recruitment from CT to the bedside: challenges and future directions
No full textAbstract Assessing and quantifying recruitability are important for characterizing ARDS severity and for reducing or preventing the atelectrauma caused by the cyclic opening and closing of pulmonary units. Over the years, several methods for recruitment assessment have been developed, grouped into three main approaches: 1) Quantitative CT Scanning: This method accurately measures the amount of atelectatic lung tissue that regains aeration; 2) Regional Gas Volume Measurement: Based on anatomical markers, this approach assesses gas volume within a specified lung region; 3) Compliance-Based Gas Volume Measurement: This technique compares actual gas volume at a given pressure to expected values, assuming respiratory system compliance is constant within the explored pressure range. Additional methods, such as lung ultrasonography and electrical impedance variation, have also been explored. This paper details the distribution of opening and closing pressures throughout the lung parenchyma, which underpin the concept of recruitability. The distribution of recruitable regions corresponds to atelectasis distribution, with the pressure needed for recruitment varying according to whether the atelectasis is “loose” or “sticky.” We also discuss the effects of different PEEP levels on preventing atelectrauma, the importance of keeping some lung areas closed throughout the respiratory cycle, and briefly cover the roles of sigh ventilation, prone positioning, and the closed lung approach.Open-Access-Publikationsfonds 202
Clinical Performance of Spo 2/Fio 2 and Pao 2/Fio 2 Ratio in Mechanically Ventilated Acute Respiratory Distress Syndrome Patients: A Retrospective Study
Get PDFObjectives: The present study aims to evaluate the severity classification of acute respiratory distress syndrome (ARDS) in mechanically ventilated patients according to peripheral oxygen saturation by pulse oximetry (Spo2)/Fio2 ratio compared with Pao2/Fio2 ratio and the relationship between Spo2/Fio2 ratio and venous admixture. Design: Retrospective observational study. Setting: Medical-surgical ICU. Patients: A cohort of 258 mechanically ventilated patients with ARDS already enrolled in previous studies. Interventions: None. Measurements and Main Results: Gas exchange, Spo2, and respiratory mechanics were measured on ICU admission and during the positive end-expiratory pressure (PEEP) trial. Radiological data from CTs were used to compute lung recruitability and to assess different lung compartments. A nonlinear association was found between Spo2/Fio2 and Pao2/Fio2. Considering the possible confounding factors of the pulse oximeter on the relationship between Spo2/Fio2 and Pao2/Fio2 ratio, arterial pH, and Paco2 had no effect. Spo2/Fio2 and Pao2/Fio2 ratio demonstrated a moderate agreement in classifying ARDS severity (intraclass correlation coefficient = 0.63). Between the correspondent classes according to Spo2/Fio2 vs. Pao2/Fio2 ratio-derived severity classifications, there was no difference in terms of respiratory mechanics, gas exchange, lung radiological characteristics and mortality in ICU, and within two levels of PEEP. A Spo2/Fio2 ratio less than 235 was able to detect 89% of patients with a venous admixture greater than 20%, similarly to a Pao2/Fio2 ratio less than 200. Conclusions: Spo2/Fio2 ratio can detect oxygenation impairment and classify ARDS severity similarly to Pao2/Fio2 ratio in a more rapid and handy way, even during a PEEP trial. However, our results may not be applicable to different patient populations; in fact, the pulse oximeter is merely a monitoring device and the information should be personalized by the physician on the patient's characteristics and conditions
In-vitro effect of heat stress on bovine monocytes lifespan and polarization
No full textHeat stress (HS) has a negative impact on dairy cows' health, milk production, reproductive performance and immune defenses. Cellular and molecular responses to high temperatures in bovine polymorphonuclear cells and peripheral blood mononuclear cells (PBMCs) have been investigated so far. On the contrary, the effects of high temperatures on isolated monocytes remain almost undisclosed. The aim of this study was to unravel the in vitro effects of high temperatures, simulating a severe HS related body hyperthermia, on bovine lifespan and M1/M2 polarisation. The PBMCs were isolated from whole blood of 9 healthy dairy cattle. Monocytes were sorted by magnetic activated cell sorting and cultured over night at 39 °C (normothermia) or 41 °C (HS). Apoptotic rate and viability were assessed and mRNA abundance for heat shock proteins (HSPs), heat transcription factors (HSFs) and genes involved in monocyte/macrophage polarization (STAT1, STAT2, STAT3, STAT6, IL1β, TGF1β, IL-10, COX2) were quantified by qPCR. We found that apoptosis increased in monocytes exposed to 41 °C, as compared to control, while viability conversely decreased. HS increased the abundance of HSF1 and HSP70. The concomitant decrease of STAT1 and STAT2 and the increase of STAT6 genes abundance at 41 °C suggest, at transcriptional factors level, a polarization of monocytes from a classical activated M1 to a non-classically activated M2 monocytes. In conclusion, the exposure of bovine monocytes to high temperatures affects their lifespan as well as the abundance of genes involved in HS response and in monocyte/macrophages polarization phenotype, confirming that bovine immune response may be significantly affected by hyperthermia
Early time-course of respiratory mechanics, mechanical power and gas exchange in ARDS patients
No full textPurpose: To describe the clinical course of ARDS during the first three days of mechanical ventilation, to compare ventilatory setting, respiratory mechanics and gas exchange variables collected during the first three days of mechanical ventilation between patients who survived and died during intensive care unit (ICU) stay and to investigate the variables associated with mortality at ICU admission and throughout the first three days of mechanical ventilation. Materials and methods: Prospective observational study. Mechanically ventilated ARDS patients were studied at ICU admission and for the following three days. Univariate logistic regression models were performed for PaO2/FiO2 ratio, driving pressure and alveolar dead space fraction and for mechanical power and mechanical power ratio. Results: Mechanical power ratio was higher in non survivors at ICU admission and over time; PaO2/FiO2 ratio was higher in survivors with a similar behavior over time in the two groups while alveolar dead space fraction was similar at ICU admission and over time between groups. Mechanical power ratio was the only physiological variable which remained consistently associated with ICU mortality throughout the study. Conclusions: The alteration in oxygenation, dead space, and mechanical power ratio should be assessed not at intensive care admission, but during the first days of mechanical ventilation to better predict outcome
Mechanical power ratio threshold for ventilator-induced lung injury
No full textAbstract Rationale Mechanical power (MP) is a summary variable incorporating all causes of ventilator-induced-lung-injury (VILI). We expressed MP as the ratio between observed and normal expected values (MP ratio ). Objective To define a threshold value of MP ratio leading to the development of VILI. Methods In a population of 82 healthy pigs, a threshold of MP ratio for VILI, as assessed by histological variables and confirmed by using unsupervised cluster analysis was 4.5. The population was divided into two groups with MP ratio above or below the threshold. Measurements and main results We measured physiological variables every six hours. At the end of the experiment, we measured lung weight and wet-to-dry ratio to quantify edema. Histological samples were analyzed for alveolar ruptures, inflammation, alveolar edema, atelectasis. An MP ratio threshold of 4.5 was associated with worse injury, lung weight, wet-to-dry ratio and fluid balance (all p 4.5 MP ratio in healthy lungs subjected to 48 h of mechanical ventilation appears to be a threshold for the development of ventilator-induced lung injury, as indicated by the convergence of histological, physiological, and anatomical alterations. In humans and in lungs that are already injured, this threshold is likely to be different.Open-Access-Publikationsfonds 202
Predictors of VILI risk: driving pressure, 4DPRR and mechanical power ratio—an experimental study
No full textAbstract Background Ventilator-induced lung injury (VILI) is one of the side effects of mechanical ventilation during ARDS; a prerequisite for averting it is the quantification of its risk factors associated with a given ventilatory setting. Many clinical variables have been proposed as predictors of VILI, of which driving pressure is the most widely used. In this study, we compared the performance of driving pressure, four times the driving pressure added to respiratory rate (4DPRR) and mechanical power ratio. Results In a study population of 121 previously healthy pigs exposed to harmful ventilation, we compared the association of driving pressure, 4DPRR and mechanical power ratio to lung weight, lung wet-to-dry and total histological score. All the three variables were associated with these outcomes. Driving pressure, 4DPRR and mechanical power ratio increase linearly with the lung weight (adjusted R 2 of 0.27, 0.36 and 0.40, respectively), the lung wet-to-dry ratio (adjusted R 2 of 0.19, 0.25 and 0.37) and the total histological score (adjusted R 2 of 0.26, 0.38 and 0.26). Using a multiple linear regression model with forward analysis, starting with tidal volume and progressively adding respiratory rate and positive end-expiratory pressure, and comparing the topic with the outcome variables, we obtained R 2 values, respectively, of 0.07, 0.20, 0.42 for lung weight, 0.09, 0.19, 0.26 for lung wet-to-dry ratio and 0.07, 0.27, 0.43 for total histological score. Conclusions Driving pressure, 4DPRR and mechanical power ratio, were all associated with lung injury in healthy animals undergoing mechanical ventilation.Open-Access-Publikationsfonds 202
