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We present a novel approach to computationally model the dynamics of alveolar recruitment/derecruitment (RD), which reproduces the underlying characteristics typically observed in injured lungs. The basic idea is a pressure- and time-dependent variation of the stress-free reference volume in reduced dimensional viscoelastic elements representing the acinar tissue. We choose a variable reference volume triggered by critical opening and closing pressures in a time-dependent manner from a straightforward mechanical point of view. In the case of (partially and progressively) collapsing alveolar structures, the volume available for expansion during breathing reduces and vice versa, eventually enabling consideration of alveolar collapse and reopening in our model. We further introduce a method to patient-specifically determine the underlying critical parameters of the new alveolar RD dynamics when integrated into the tissue elements, referred to as terminal units, of a spatially resolved physics-based lung model that simulates the human respiratory system in an anatomically correct manner. Relevant patient-specific parameters of the terminal units are herein determined based on medical image data and the macromechanical behavior of the lung during artificial ventilation. We test the whole modeling approach for a real-life scenario by applying it to the clinical data of a mechanically ventilated patient. The generated lung model is capable to reproduce clinical measurements such as tidal volume and pleural pressure during various ventilation maneuvers. We conclude that this new model is an important step towards personalized treatment of ARDS patients by considering potentially harmful mechanisms - such as cyclic RD and overdistension - and might help to develop relevant protective ventilation strategies to reduce ventilator-induced lung injury (VILI).

Objectives: The value of biofeedback before elective coronary computed tomography angiography (CCTA) to reduce patients’ heart rates (HR) was investigated in the current work. Methods: 60 patients who received CCTA to exclude coronary artery disease were included in our study and separated into two groups: with biofeedback (W-BF) and without biofeedback (WO-BF). The W-BF group used a biofeedback device for 15 min before CCTA. HR was determined in each patient at five measurement time points (MTP): during the pre-examination interview (MTP1), positioning on the CT patient table (MTP2), immediately before CCTA (MTP3), CCTA image acquisition (MTP4), and after completing CCTA (MTP5). If necessary, beta-blockers were administered in both groups after MTP3 until a HR of less than 65 bpm was achieved. Two board-certified radiologists subsequently assessed the image quality and analyzed the findings. Results: Overall, the need for beta-blockers was significantly lower in patients in W-BF group than in WO-BF group (p=0.032). In patients with a HR of 81-90, beta-blockers were not required in 4 of 6 cases in the W-BF group, whereas in the WO-BF group all patients needed beta-blockers (p=0.03). We found a significant decrease in HR between MTP1 and MTP2 in W-BF as compared to WO-BF. There was no significant difference between the W-BF and WO-BF groups regarding image quality (p=0.179). Conclusion: By using biofeedback prior to elective CCTA beta-blocker use can be significantly decreased due to effective reduction of HR, especially in patients with a HR above 80 bpm, without compromising CT image quality and analysis.

Purpose Recurrent stroke is considered to increase the incidence of severe disability and death. For correct risk assessment and patient management it is essential to identify the origin of stroke at an early stage. Transthoracic echocardiography (TTE) is the initial standard of care for evaluating patients in whom a cardioembolic source of stroke (CES) is suspected but its diagnostic capability is limited. Transesophageal echocardiography (TEE) is considered as gold standard; however, this approach is time consuming, semi-invasive and not always feasible. We hypothesized that adding a delayed-phase cardiac computed tomography (cCT) to initial multimodal CT might represent a valid alternative to routine clinical echocardiographic work-up. Material and Methods Patients with suspected acute cardioembolic stroke verified by initial multimodal CT and subsequently examined with cCT were included. The cCT was evaluated for presence of major CES and compared to routine clinical echocardiographic work-up. Results In all, 102 patients with suspected acute CES underwent cCT. Among them 60 patients underwent routine work-up with echocardiography (50 TTE and only 10 TEE). By cCT 10/60 (16.7%) major CES were detected but only 4 (6.7%) were identified by echocardiography. All CES observed by echocardiography were also detected by cCT. In 8 of 36 patients in whom echocardiography was not performed cCT also revealed a major CES. Conclusion These preliminary results show the potential diagnostic yield of delayed-phase cCT to detect major CES and therefore could accelerate decision-making to prevent recurrence stroke. To confirm these results larger studies with TEE as the reference standard and also compared to TTE would be necessary.

Capnocytophaga canimorsus (CC) belongs to the family Flavobacteriaceae which physiologically occurs in the natural flora of the oral mucosa of dogs and cats. In patients with a compromised immune system, CC can induce a systemic infection with a fulminant course of disease. Infections with CC are rare, and the diagnosis is often complicated and prolonged. We describe a patient with a medical history of prior splenectomy who presented with an acute sepsis and disseminated intravascular coagulation (DIC) and was initially treated on Waterhouse–Friderichsen syndrome (WFS). After the patient had died despite forced treatment in the intermediate care unit, the differential diagnosis of CC was confirmed by culture of blood smears. Later on, a retrospective third-party anamnesis revealed that the patient had contact to his neighbour’s dog a few days before disease onset. In conclusion, patients with CC infection can mimic WFS and therefore must be included in the differential diagnosis, especially in patients with a corresponding medical history of dog or cat bites, scratches, licks, or simple exposure.

Aims and objectives Methods and materials Results Conclusion Personal information References, Aims and objectives: Giant cell arteritis (GCA) is the most frequent vasculitis in Europe, a disease suffered especially by older patients. GCA is a systemic vasculitis that affects in particular extra-cerebral cranial arteries, but also extracranial vessels. The...