Impact of Recruitment on Static and Dynamic Lung Strain in Acute Respiratory Distress Syndrome

2016 ◽  
Vol 124 (2) ◽  
pp. 443-452 ◽  
Author(s):  
Emilio García-Prieto ◽  
Josefina López-Aguilar ◽  
Diego Parra-Ruiz ◽  
Laura Amado-Rodríguez ◽  
Inés López-Alonso ◽  
...  

Abstract Background Lung strain, defined as the ratio between end-inspiratory volume and functional residual capacity, is a marker of the mechanical load during ventilation. However, changes in lung volumes in response to pressures may occur in injured lungs and modify strain values. The objective of this study was to clarify the role of recruitment in strain measurements. Methods Six oleic acid–injured pigs were ventilated at positive end-expiratory pressure (PEEP) 0 and 10 cm H2O before and after a recruitment maneuver (PEEP = 20 cm H2O). Lung volumes were measured by helium dilution and inductance plethysmography. In addition, six patients with moderate-to-severe acute respiratory distress syndrome were ventilated with three strategies (peak inspiratory pressure/PEEP: 20/8, 32/8, and 32/20 cm H2O). Lung volumes were measured in computed tomography slices acquired at end-expiration and end-inspiration. From both series, recruited volume and lung strain (total, dynamic, and static) were computed. Results In the animal model, recruitment caused a significant decrease in dynamic strain (from [mean ± SD] 0.4 ± 0.12 to 0.25 ± 0.07, P < 0.01), while increasing the static component. In patients, total strain remained constant for the three ventilatory settings (0.35 ± 0.1, 0.37 ± 0.11, and 0.32 ± 0.1, respectively). Increases in tidal volume had no significant effects. Increasing PEEP constantly decreased dynamic strain (0.35 ± 0.1, 0.32 ± 0.1, and 0.04+0.03, P < 0.05) and increased static strain (0, 0.06 ± 0.06, and 0.28 ± 0.11, P < 0.05). The changes in dynamic and total strain among patients were correlated to the amount of recruited volume. An analysis restricted to the changes in normally aerated lung yielded similar results. Conclusion Recruitment causes a shift from dynamic to static strain in early acute respiratory distress syndrome.

2019 ◽  
Vol 130 (2) ◽  
pp. 263-283 ◽  
Author(s):  
Tài Pham ◽  
Ary Serpa Neto ◽  
Paolo Pelosi ◽  
John Gerard Laffey ◽  
Candelaria De Haro ◽  
...  

Abstract Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New Background Patients with initial mild acute respiratory distress syndrome are often underrecognized and mistakenly considered to have low disease severity and favorable outcomes. They represent a relatively poorly characterized population that was only classified as having acute respiratory distress syndrome in the most recent definition. Our primary objective was to describe the natural course and the factors associated with worsening and mortality in this population. Methods This study analyzed patients from the international prospective Large Observational Study to Understand the Global Impact of Severe Acute Respiratory Failure (LUNG SAFE) who had initial mild acute respiratory distress syndrome in the first day of inclusion. This study defined three groups based on the evolution of severity in the first week: “worsening” if moderate or severe acute respiratory distress syndrome criteria were met, “persisting” if mild acute respiratory distress syndrome criteria were the most severe category, and “improving” if patients did not fulfill acute respiratory distress syndrome criteria any more from day 2. Results Among 580 patients with initial mild acute respiratory distress syndrome, 18% (103 of 580) continuously improved, 36% (210 of 580) had persisting mild acute respiratory distress syndrome, and 46% (267 of 580) worsened in the first week after acute respiratory distress syndrome onset. Global in-hospital mortality was 30% (172 of 576; specifically 10% [10 of 101], 30% [63 of 210], and 37% [99 of 265] for patients with improving, persisting, and worsening acute respiratory distress syndrome, respectively), and the median (interquartile range) duration of mechanical ventilation was 7 (4, 14) days (specifically 3 [2, 5], 7 [4, 14], and 11 [6, 18] days for patients with improving, persisting, and worsening acute respiratory distress syndrome, respectively). Admissions for trauma or pneumonia, higher nonpulmonary sequential organ failure assessment score, lower partial pressure of alveolar oxygen/fraction of inspired oxygen, and higher peak inspiratory pressure were independently associated with worsening. Conclusions Most patients with initial mild acute respiratory distress syndrome continue to fulfill acute respiratory distress syndrome criteria in the first week, and nearly half worsen in severity. Their mortality is high, particularly in patients with worsening acute respiratory distress syndrome, emphasizing the need for close attention to this patient population.


2006 ◽  
Vol 32 (10) ◽  
pp. 1623-1626 ◽  
Author(s):  
Jean-Christophe M. Richard ◽  
Salvatore Maurizio Maggiore ◽  
Jordi Mancebo ◽  
François Lemaire ◽  
Bjorn Jonson ◽  
...  

Medicina ◽  
2020 ◽  
Vol 56 (11) ◽  
pp. 570
Author(s):  
Mi Hwa Park ◽  
Ah Jin Kim ◽  
Man-Jong Lee ◽  
Young Sam Kim ◽  
Jung Soo Kim

Coronavirus disease (COVID-19) started in Wuhan (China) at the end of 2019, and then increased rapidly. In patients with severe acute respiratory distress syndrome (ARDS) caused by COVID-19, venovenous extracorporeal membrane oxygenation (VV-ECMO) is considered a rescue therapy that provides adequate gas exchange. The way in which mechanical ventilation is applied during VV-ECMO is not clear, however it is associated with prognosis. Currently, the mortality rate of COVID-19 patients that receive VV-ECMO stands at approximately 50%. Here, we report three patients that successfully recovered from COVID-19-induced ARDS after VV-ECMO and implementation of an ultra-protective ventilation. This ventilation strategy involved maintaining a peak inspiratory pressure of ≤20 cmH2O and a positive end-expiratory pressure (PEEP) of ≤ 10 cmH2O, which are lower values than have been previously reported. Thus, we suggest that this ultra-protective ventilation be considered during VV-ECMO as it minimizes the ventilator-induced lung injury.


2008 ◽  
Vol 74 (2) ◽  
pp. 117-123 ◽  
Author(s):  
David Plurad ◽  
Howard Belzberg ◽  
Ira Schulman ◽  
Donald Green ◽  
Ali Salim ◽  
...  

Transfusions are known to be associated with Acute Respiratory Distress Syndrome (ARDS). Transfusion of leukoreduced products may be associated with a decreased incidence of late posttraumatic ARDS (late ARDS). Data from ventilated and transfused trauma patients were analyzed. Key variables in the first 48 hours of admission were studied for their associations with late ARDS and examined for changes over the 6 year study period. Late ARDS developed in 244 of the 1488 patients studied (16.4%). The incidence in patients given nonleukoreduced (NLR) product was 30.4 per cent (75/247) versus 13.6 per cent (169/1241) for patients not exposed [2.77 (2.02–3.73), P < 0.001]. Exposure to NLR products (50.9% in 2000 vs 1.9% in 2005) and incidence of ARDS (26.3% in 2000 vs 6.3% in 2005) significantly decreased. Treatment variables independently associated with late ARDS were NLR product exposure, Total Parenteral Nutrition exposure, Peak Inspiratory Pressure ≥ 30 mm Hg, fluid balance ≥ 2 liters at 48 hours, and transfusion of ≥ 10 units of any product. NLR product exposure has an association with an increased incidence of late onset posttraumatic ARDS which is independent of large volume transfusions. Leukoreduction should be routinely included in an overall treatment strategy to furthermore mitigate this complication in critically ill trauma patients.


2020 ◽  
Vol 49 (10) ◽  
pp. 418-421
Author(s):  
Christopher Werlein ◽  
Peter Braubach ◽  
Vincent Schmidt ◽  
Nicolas J. Dickgreber ◽  
Bruno Märkl ◽  
...  

ZUSAMMENFASSUNGDie aktuelle COVID-19-Pandemie verzeichnet mittlerweile über 18 Millionen Erkrankte und 680 000 Todesfälle weltweit. Für die hohe Variabilität sowohl der Schweregrade des klinischen Verlaufs als auch der Organmanifestationen fanden sich zunächst keine pathophysiologisch zufriedenstellenden Erklärungen. Bei schweren Krankheitsverläufen steht in der Regel eine pulmonale Symptomatik im Vordergrund, meist unter dem Bild eines „acute respiratory distress syndrome“ (ARDS). Darüber hinaus zeigen sich jedoch in unterschiedlicher Häufigkeit Organmanifestationen in Haut, Herz, Nieren, Gehirn und anderen viszeralen Organen, die v. a. durch eine Perfusionsstörung durch direkte oder indirekte Gefäßwandschädigung zu erklären sind. Daher wird COVID-19 als vaskuläre Multisystemerkrankung aufgefasst. Vor dem Hintergrund der multiplen Organmanifestationen sind klinisch-pathologische Obduktionen eine wichtige Grundlage der Entschlüsselung der Pathomechanismen von COVID-19 und auch ein Instrument zur Generierung und Hinterfragung innovativer Therapieansätze.


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