1,721,135 research outputs found
Acute Respiratory Distress Syndrome (ARDS) : Pathophysiological Insights and Lung Imaging
No full textAcute respiratory distress syndrome (ARDS) is in the center of the scientific debate both for its complex pathophysiology and for the discussion about the remedies that could contribute to its healing. The intricate interplay of different body systems that characterizes ARDS is mirrored by two main research threads, one centered on the pathophysiological mechanisms of the disease and the other on the new approaches to lung imaging. In this Special Issue of the Journal of Clinical Medicine are presented studies using imaging technologies based on electrical impedance tomography, synchrotron radiation computed tomography and intravital probe-based confocal laser endomicroscopy. The studies on the pathophysiological mechanisms pertain to the evaluation of the biomarkers of the disease and the platelet disfunction during extracorporeal membrane oxygenation. These contributions witness the intensity of ARDS research as many of the key problems of the disease are only in part resolved
Respiratorisches Versagen: Innovationen zur Diagnostik und Therapie
No full textZusammenfassungDie akute oder chronische respiratorische Insuffizienz hat eine große Bedeutung sowohl in der präklinischen als auch innerklinischen Versorgung. Sie zählt zu den häufigsten Gründen für stationäre Aufnahmen. Dieser Beitrag fasst aktuelle Entwicklungen in der Diagnostik und Therapie des Krankheitsbildes zusammen. Darüber hinaus gibt er einen Ausblick, wie sich die Behandlung in den kommenden Jahren weiterentwickeln könnte.</jats:p
Spontaneous breathing with airway pressure release ventilation favors ventilation in dependent lung regions and counters cyclic alveolar collapse in oleic-acid-induced lung injury: a randomized controlled computed tomography trial
No full textIntroduction Experimental and clinical studies have shown a reduction in intrapulmonary shunt with spontaneous breathing during airway pressure release ventilation (APRV) in acute lung injury. This reduction was related to reduced atelectasis and increased aeration. We hypothesized that spontaneous breathing will result in better ventilation and aeration of dependent lung areas and in less cyclic collapse during the tidal breath. Methods In this randomized controlled experimental trial, 22 pigs with oleic-acid-induced lung injury were randomly assigned to receive APRV with or without spontaneous breathing at comparable airway pressures. Four hours after randomization, dynamic computed tomography scans of the lung were obtained in an apical slice and in a juxtadiaphragmatic transverse slice. Analyses of regional attenuation were performed separately in nondependent and dependent halves of the lungs on end-expiratory scans and end-inspiratory scans. Tidal changes were assessed as differences between inspiration and expiration of the mechanical breaths. Results Whereas no differences were observed in the apical slices, spontaneous breathing resulted in improved tidal ventilation of dependent lung regions ( P < 0.05) and less cyclic collapse ( P < 0.05) in the juxtadiaphragmatic slices. In addition, with spontaneous breathing, the end-expiratory aeration increased and nonaerated tissue decreased in dependent lung regions close to the diaphragm ( P < 0.05 for the interaction ventilator mode and lung region). Conclusion Spontaneous breathing during APRV redistributes ventilation and aeration to dependent, usually well-perfused, lung regions close to the diaphragm, and may thereby contribute to improved arterial oxygenation. Spontaneous breathing also counters cyclic collapse, which is a risk factor for ventilation-associated lung injury
Effects of a single-lung recruitment maneuver on the systemic release of inflammatory mediators
No full textObjective: To study the hypothesis, that systemic levels of proinflammatory and anti-inflammatory cytokines may be affected by a single recruitment maneuver in mechanically ventilated patients. Design: Prospective, interventional clinical trial. Setting: Intensive care unit of a university hospital. Patients: Sixteen mechanically ventilated patients with clinical and radiological signs of atelectasis. Interventions: A single recruitment maneuver (RM) was performed by elevating the airway pressure to 40 cmH(2)O for 7 s. Measurements and main results: Plasmatic concentrations of interleukin (IL)-1 beta, IL-6, IL-8, IL-10, IL-12p70 and tumor necrosis factor (TNF-alpha), arterial blood gases and hemodynamic parameters were measured immediately before and 5-360 min after the RM. The RM caused a minor, nevertheless significant improvement of oxygenation (p = 0.02) and carbon dioxide elimination (p = 0.006) as well as a moderate drop of the mean arterial pressure (p = 0.025). In contrast, plasma concentrations remained unaffected by the RM in all six mediators measured. Conclusion: A single inflation with an airway pressure of 40 cmH(2)O for 7s improved gas exchange only slightly and did not modify systemic levels of inflammatory mediators in mechanically ventilated patients with radiological evidence of atelectasis
Regional ventilation by electrical impedance tomography - A comparison with ventilation scintigraphy in pigs
No full textStudy objective: The validation of electrical impedance tomography (EIT) for measuring regional ventilation distribution by comparing it with single photon emission CT (SPECT) scanning. Design: Randomized, prospective animal study. Settings: Animal laboratories and nuclear medicine laboratories at a university hospital. Participants: Twelve anesthetized and mechanically ventilated pigs. Interventions: Lung injury was induced by central venous injection of oleic acid. Then pigs were randomized to pressure-controlled mechanical ventilation, airway pressure-release ventilation, or spontaneous breathing. Measurements and results: Ventilation distribution was assessed by EIT using cross-sectional electrotomographic measurements of the thorax, and simultaneously by single SPECT scanning with the inhalation of Tc-99m-labeled carbon particles. For both methods, the evaluation of ventilation distribution was performed in the same transverse slice that was approximately 4 cm in thickness. The transverse slice then was divided into 20 coronal segments (going from the sternum to the spine). We compared the percentage of ventilation in each segment, normalized to the entire ventilation in the observed slice. Our data showed an excellent linear correlation between the ventilation distribution measured by SPECT scanning and EIT according to the following equation: y = 0.82x + 0.7,(R-2 = 0.92; range, 0.86 to 0.97). Conclusion: Based on these data, EIT seems to allow, at least in comparable states of lung injury, real-time monitoring of regional ventilation distribution at the bedside
Prone positioning for acute respiratory distress syndrome in adults
No full textHafner S, Lepper PM, Muellenbach RM, et al. Bauchlagerung beim akuten Lungenversagen des Erwachsenen. Update zu den physiologischen Effekten, den Indikationen und der Durchführung. Die Anaesthesiologie. 2024;73(8):556–568.The prone position is an immediately available and easily implemented procedure that was introduced more than 50 years ago as a method for improvement of gas exchange in patients with acute respiratory distress syndrome (ARDS). In the meantime, a survival advantage could also be shown in patients with severe ARDS, which led to the recommendation of the prone position for treatment of severe ARDS by expert consensus and specialist society guidelines. The continuing coronavirus disease 2019 (COVID-19) pandemic moved the prone position to the forefront of medicine, including the widespread implementation of the prone position for awake, spontaneously breathing nonintubated patients with acute hypoxemic respiratory insufficiency. The survival advantage is possible due to a reduction of the ventilator-associated lung damage. In this article, the physiological effects, data on clinical results, practical considerations and open questions with respect to the prone position are discussed. © 2024. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature
Methodologic aspects of attenuation distributions from static and dynamic thoracic CT techniques in experimental acute lung injury
No full textBackground: In acute lung injury, thoracic CT is used to gain information about lung aeration and consolidation. This can be done either during breath-holding by, spiral CT scanning of the entire lung or dynamically by scanning lung slices without interrupting ventilation. We hypothesized that attenuation distribution is dependent on static or dynamic scanning techniques. We also studied whether a variation in the CT cut level, corresponding to the diaphragm movement over a breath, had any effect on the attenuation distribution. Methods: Twenty-two pigs with oleic acid-induced lung injury, were randomly assigned to receive pressure-controlled mechanical ventilation with or without spontaneous breathing. Transversal dynamic CT scans of the chest were performed in apical and juxtadiaphragmatic regions, and end-expiratory and end-inspiratory slices were selected. In addition, after clamping the tube at end-expiration and end-inspiration, respectively, spiral CTs were performed. Guided by morphologic structures, spiral CT slices matching the dynamic scan slice and three additional neighbored slices above the diaphragm were selected. Distributions of CT attenuation were calculated and summarized in ranges for comparison. Results: No significant difference in attenuation distributions between the two scanning methods or an interaction with the factors ventilation mode, ventilation phase, and attenuation range were found. In addition, attenuation distributions of four neighbored juxtadiaphragniatic slices, 8 mm thick, from the spiral CT did not differ statistically. Conclusion: In an animal model of oleic acid-induced lung injury, analyses of transverse thoracic slices based on dynamic or static CT scanning showed comparable distributions of attenuation. Variations on the CT cut level of 24 mm had no significant effect on the distribution of Hounsfield unit numbers. CT attenuation distributions of transversal juxtadiaphragmatic slices were not dependent on exact position
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