[Pneumomediastinum in Severe COVID-19-disease: a Case Series of Eight Patients]. / Pneumomediastinum bei schwerer COVID-19-Erkrankung: eine Fallserie von acht Patienten.

The most common cause of pneumomediastinum is trauma. However, in the context of COVID-19 pneumonia, this clinical picture is more often found in patients without underlying exogenous injury. Pathophysiologically, a cause analogous to the Macklin effect is suspected here, in which tears at the alveolar level lead to emphysema along the tracheobronchial tree with concentrating in the mediastinum. Here we present a case series of eight patients who were treated in our intensive care unit. In all patients, mediastinal emphysema could already be seen in the chest X-ray. Five patients also received a computed tomography scan of the thorax. Six patients had invasive ventilation. All patients received corticosteroids, anticoagulation and antibiotics. Pleural drainage was applied only in patients with an additional pneumothorax (n = 5). Bronchoscopy was performed only if there was a suspicion of iatrogenic injury to the tracheobronchial tree in relation to the appearance of the pneumomediastinum (n = 2). Three patients died during intensive care as part of the COVID-19 disease. A prognostic relationship between the occurrence of a pneumomediastinum and a fatal course of the disease is discussed.

[Management of Rib Fractures]. / Management der Rippenfraktur.

The therapy of rib fractures is controversially discussed. Neither does an osteosynthesis have to be performed for each individual rib fracture, nor is the internal splinting by ventilation or respiratory therapy sufficient for each patient. Rib fractures are common in polytrauma patients after car and motorcycle accidents or falls from great heights. However, rib fractures are also increasingly occurring in older patients with falls from low heights. Anamnesis and clinical examination are groundbreaking for the diagnosis and therapy decision of rib fractures. In radiological diagnostics, projection radiography comes first, followed by sonography and CT. Computed tomography should be required for planning an operation. Accompanying injuries must be taken into account when deciding on therapy. We see a complicated organ injury, dislocated rib serial fractures, flail chest and respiratory insufficiency as indications for rib stabilization. As a relative indication for rib stabilization, we see a high suffering pressure due to pain and an intrathoracic volume restriction due to dislocated rib serial fractures. New osteosynthesis material and minimally invasive techniques standardize the procedure and minimize surgical trauma. In any case, adequate pain and respiratory therapy are always crucial for successful treatment.

Is it Necessary to Stabilize Every Fracture in Patients with Serial Rib Fractures in Blunt Force Trauma?

Introduction: Management of traumatic rib fractures is subject of controversial discussions. Rib fractures are common, especially after traffic accidents and falls. There is no consensus on whether and how many rib fractures need reconstruction. Not every rib fracture needs to be stabilized, but conservative treatment by internal splinting and analgesia is not effective for all patients. Deformities of the chest wall with reduced thoracic volume and restrictive ventilation disorders must be avoided. Intraoperative assessment of fractures and chest stability plays a central role. Material and methods: From 07/2016 to 07/2021, a total of 121 chest wall stabilizations were performed (m:f = 2:1, age 65 ± 14.5 a). Indications for surgery were the following criteria: (1) palpatory instability of the chest wall, (2) dislocated fracture endings, (3) concomitant injuries, (4) uncontrollable pain symptoms. In all patients, a computed tomography scan of the thorax was performed before the osteosynthetic treatment to assess dislocation of the fracture endings and possible concomitant injuries of intrathoracic organs. Results: Video-assisted thoracoscopy was performed in all patients. Hemothorax and concomitant injuries of the lung, diaphragm and mediastinum could be assessed. This was followed by an intraoperative assessment of the rib fractures, in particular penetration of fracture endings and resulting instability and deformity. Relevant fractures could be identified and subsequent incisions for rib osteosynthesis precisely defined. 6.3 (±2.7) rib fractures were detected, but 2.4 (±1.2) ribs treated osteosynthetically. Bilateral rib fractures were present in 26 patients (21.5%). Post-operative bleeding occurred in seven patients (5.8%), a breakage of the osteosynthetic material in two patients (1.7%). Discussion: Intraoperative assessment of relevant fractures and dislocation is the decisive criterium for osteosynthesis. Thoracoscopy is mandatory for this purpose - also to identify accompanying injuries. Not every fracture has to be approached osteosynthetically. Even with serial rib fractures or multiple fractures in a single rib, the thoracic contour can be restored by stabilizing only relevant fractures. Intraoperative palpation can adequately assess the stability and thus the result of the osteosynthesis. Even after surgical treatment of thoracic trauma, adequate analgesia and respiratory therapy are important to the healing process.

Histaminergic and dopaminergic traits in the human carotid body.

Carotid body (CB) chemoreceptors are the main sensors detecting systemic hypoxia. Studies in animals revealed that dopamine and histamine may serve as transmitters between the chemoreceptor cells and the afferent nerve. To gain insight whether histamine and dopamine could play a role in the human CB and thus be important for the understanding of breathing disorders, we have investigated the chemosensory traits in human CBs from nine subjects of different ages obtained at autopsy. Immunohistochemistry revealed expression of histidine decarboxylase, vesicular monoamine transporter 2, histamine receptors 1 and 3 in virtually all chemosensory cells within the glomeruli of different ages. By contrast, catecholaminergic traits (tyrosine hydroxylase and vesicular monoamine transporter 1) were only detected in a subset of CB chemosensory cells at each age group while dopamine D2 receptors were expressed in the great majority of them. Our data suggest that histamine along with catecholamines may serve as transmitters between chemoreceptor cells and the afferent nerve in humans as well.

Expression of histamine receptors and effect of histamine in the rat carotid body chemoafferent pathway.

Chemosensory information from peripheral arterial oxygen sensors in the carotid body is relayed by petrosal ganglion neurons to the respiratory networks in the medulla oblongata. Biogenic amines, including histamine, released from glomus (type I) cells of the carotid body are considered to be primary transmitters in hypoxic chemosensitivity. Immunocytochemistry at light-and electron-microscopical levels, and RT-PCR, revealed the expression of histamine receptors 1 and 3 as well as histidine decarboxylase in the rat carotid body glomus cells and petrosal ganglion neurons. Histamine receptors 1 and 3, but not histidine decarboxylase, were also observed in the ventrolateral, intermediate and commissural subnuclei of the nucleus tractus solitarii in the medulla oblongata. In order to examine the possible role of histamine in the afferent branch of the respiratory system, we applied histamine receptor 1 and 3 agonists to the carotid body, which caused a mildly increased phrenic nerve activity in a working heart-brainstem preparation. Moreover, microinjection of antagonists of histamine receptors 1 and 3 into the nucleus tractus solitarii caused significant changes in the inspiratory timing and the chemoreceptor response. Our data show that histamine acting via histamine receptors 1 and 3 plays an important neuromodulatory role in the afferent control of chemosensitivity.