Significance of Lung Ultrasound in Patients with Suspected COVID-19 Infection at Hospital Admission.

With a lung ultrasound (LUS) the typical findings are interstitial pneumonia. COVID-19 pneumonia is often manifested in sub-pleural areas, which is preferably detected by sonography. An RT-PCR test cannot always ensure a safe differentiation of COVID-19- and non-diseased cases. Clinically challenging is that a reliable and time efficient decision regarding COVID-19 suspects requiring isolation. Therefore, this study was aimed at evaluating the significance of LUS in symptomatic patients with COVID-19 suspicion at hospital admission. A total of 101 patients admitted to a suspect ward with COVID-19-typical symptoms were assessed. All patients received prospectively a standardized LUS at admission. Patients were classified as LUS-positive and -negative cases based on a specific LUS score. The RT-PCR test in combination with the clinical findings served as a reference. Correctly classified were 14/15 COVID-19 diseased suspects as LUS-positive (sensitivity: 93.3%). Twenty-seven out of 61 non-positive cases were classified as false positive with LUS (specificity: 55.7%). In 34/35 patients who were assessed as LUS negative, no COVID-19 disease was detected during the hospitalization. The PPV and NPV of the LUS were 34.1% and 97.1%. LUS is a valuable tool in symptomatic patients for the assessment of COVID-19-disease. The high negative predictive value of LUS is helpful to rule out the disease.

A simulation study of the HIFU ablation process on lung tumours, showing consequences of atypical acoustic properties in flooded lung.

Recent work has shown that One Lung Flooding (OLF) enables acoustic access to central lung tumours which can be used for non-invasive ablation using therapeutic ultrasound (HIFU). Therefore acoustic properties of flooded lung as a saline-tissue compound was determined in earlier work, which revealed that atypical acoustical condition in lung exists. Their influence on the HIFU ablation process under aspects of clinical requirements has to be investigated before clinical introduction. For this study a MATLAB based ultrasound simulation tool and a customized bioheat solver were used to determine the temporal course of HIFU induced heating with the corresponding ablation zones. This work revealed that due to the low attenuation in flooded lung the heat induction and therefore the lesion size in lung tumours is enhanced. However, HIFU raster ablation schemes should only be used for benign tumours and the volumetric ablation scheme for malignancies. A minimum power density of 0.1Wcm-3 is required during volumetric ablation to radical ablate lung tumours. The simulations indicate that up to 3 T1 (∅ 3cm) tumours with a sufficient margin (>3mm) can be ablated during one flooding session. The ablation margin is dependent upon perfusion, intra-lobular temperature, as well as ablation temperature, and can be adjusted within range of 2-6mm depending on nodule size. The acoustic conditions in flooded lung are beneficial for thermal HIFU ablation in lung but require an individualized HIFU treatment planning.

An ex vivo human lung model for ultrasound-guided high-intensity focused ultrasound therapy using lung flooding.

The usability of an ex vivo human lung model for ablation of lung cancer tissue with high-intensity focused ultrasound (HIFU) is described. Lung lobes were flooded with saline, with no gas remaining after complete atelectasis. The tumor was delineated sono-morphologically. Speed of sound, tissue density and ultrasound attenuation were measured for flooded lung and different pulmonary cancer tissues. The acoustic impedance of lung cancer tissue (1.6-1.9 mega-Rayleighs) was higher than that of water, as was its attenuation coefficient (0.31-0.44 dB/cm/MHz) compared with that of the flooded lung (0.12 dB/cm/MHz). After application of HIFU, the temperature in centrally located lung cancer surrounded by the flooded lung increased as high as 80°C, which is sufficient for treatment. On the basis of these preliminary results, ultrasound-guided HIFU ablation of lung cancer, by lung flooding with saline, appears feasible and should be explored in future clinical studies.

Sealing of pulmonary arteries with LigaSure: in vivo and ex vivo examinations.

OBJECTIVE: The LigaSure device has been demonstrated to be safe for systemic vessels up to 7 mm in diameter, although its use in thoracic surgery remains understudied. We aimed to evaluate the safety of LigaSure for pulmonary artery sealing. METHODS: In 30 cases of open lung lobectomy, 15 small pulmonary arteries (diameter, 3-5 mm) and 15 thick pulmonary arteries (diameter, 6-8 mm) were divided with LigaSure. Before closure of the thoracotomy, the vessel stumps were ligated proximal to the sealing zone, resected, and preserved in formaldehyde for histopathologic examination. In a control group, a similar number and size of pulmonary arteries were suture-ligated. The burst pressure of the pulmonary arteries from the resected lung lobes was measured. RESULTS: The mean burst pressure of small pulmonary arteries was 4.3-fold less after sealing than after ligation (315 ± 213.1 mm Hg vs 1345 ± 256 mm Hg; P < .001), and 6.4-fold less than after ligation of thick pulmonary arteries (156 ± 42.5 mm Hg vs 1007 ± 141.6 mm Hg; P < .001). Sealed pulmonary arteries >5 mm in diameter have a burst pressure that is 50% less than that of smaller arteries (P < .001). In all cases after sealing, the histologic examination demonstrated only a fusion of the adventitia, whereas the intima and media were replaced and invaginated into the vessel lumen. CONCLUSIONS: LigaSure does not result in complete fusion of the wall layers of pulmonary arteries. The pulmonary artery burst pressure after sealing is significantly less compared with conventional suture ligation. It remains unclear whether these findings create a clinical risk of rupture.

Cystic medionecrosis of the carotid bifurcation as an uncommon cause of stroke.

BACKGROUND AND PURPOSE: Cystic medionecrosis is characterized by degeneration of elastic and collagenous fibers in the media and predominantly involves the thoracic aorta. This rare disease is usually manifested clinically by a dissecting aneurysm. Cystic medionecrosis as a cause of moderate stenosis of the carotid artery in a patient having a stroke has not been reported. SUMMARY OF CASE: We report a case of a man who had a cerebral infarction caused by medium-degree stenosis of the left internal carotid artery. Duplex sonography and magnetic resonance imaging revealed no typical signs of dissection. The stenosis was caused by cystic medionecrosis that involved only the carotid bifurcation with microdissection, predominantly older intramural hemorrhage, and fresh intraluminal thrombotic deposits. CONCLUSIONS: Patients with cystic medionecrosis may have a stroke due to short-track stenosis of the internal carotid artery.

Laser application enables awake thoracoscopic resection of pulmonary nodules with minimal access.

BACKGROUND: Thoracoscopic resection of indeterminate pulmonary nodules is most commonly performed through three trocars using an endoscopic stapler. We assessed the safety, feasibility, and results of laser resection via minimal access under only local anesthesia. METHODS: Between September 2009 and June 2010, excision of subpleural nodules using laser application under only local anesthesia was performed in 28 patients (Laser group). A 2-mm trocar (minigrasper) and an 11-mm trocar (operating scope) were used. Anesthesia time, surgery time, global operating room time, chest tube time, piritramid dose, and hospital stay were assessed and compared with data from a patient group (n = 28) that required nodule resection through three trocars using an endoscopic stapler under general anesthesia (Control group). RESULTS: There was no mortality or major morbidity. There was no difference in technical feasibility between the groups. Two patients in the Laser group and one patient in the Control group required conversion to thoracotomy due to severe adhesions. The mean nodule size was 0.9 ± 0.2 cm in the Laser group and 1.0 ± 0.3 cm in the Control group (P = 0.05). Comparisons of Laser group results with Control group results showed that in the Laser group, anesthesia time (3 ± 0.7 vs. 42 ± 6.3 min, P < 0.001), global operating room time (51 ± 4.8 vs. 88 ± 10.8 min, P < 0.001), piritramid dose (65.9 ± 30.5 vs. 109.1 ± 21.9 mg, P < 0.001), and hospital stay (2.3 ± 0.9 vs. 3.2 ± 0.6 days, P < 0.001) were significantly reduced. Patients' satisfaction was high. Ninety-eight percent of patients said they would undergo this surgery again. CONCLUSION: Awake thoracoscopic laser resection of subpleural pulmonary nodules proved safe and feasible. This technique may enable further reduction of invasiveness, length of hospital stay, and costs in selected patients.

Effects of radiofrequency ablation on normal lung tissue in a swine model.

RATIONALE AND OBJECTIVES: To determine the effect of radiofrequency (RF) ablation on normal lung tissue in an animal model. MATERIALS AND METHODS: RF ablation of lung tissue was performed on eight swine under computed tomographic control. Group A (n = 4) received peripheral ablation (subpleural needle placement) and group B (n = 4) received central ablation (hilar needle placement). RF ablation was applied via a single 4.5-gauge internally cooled electrode with a 2-cm tip for 12 minutes. The ablation was monitored with computed tomography at 3, 7, and 12 minutes, and 10 minutes after ablation. After 3, 7, 40, and 60 days, computed tomography was performed, and the animals were sacrificed to examine the lung tissue both macroscopically and histopathologically. RESULTS: There were no deaths from RF ablation. In group A, coagulative necrosis was resorbed almost completely and transformed into a fibrotic scar after 60 days. No pneumothorax, pleural effusion, or lung abscess was observed. In group B, there was also a transformation of the necrosis into connective tissue. Neither the pulmonary vessels nor the bronchi of the hilum abutting the coagulative necrosis were damaged. After 60 days, no vascular thrombosis, bleeding, aneurysm, bronchial stenosis, or bronchopulmonary fistula was observed. CONCLUSION: RF ablation of lung tissue affects coagulation necrosis, causing scar transformation. There was no damage to either great vessels or bronchi. The application of RF ablation for tumors located in or near functional structures appears feasible without severe complications.

Popliteoperoneal in situ bypass using the small saphenous vein enables revascularization with low trauma.

In patients with diabetes, a popliteocrural vein bypass frequently must be linked to the distal peroneal artery. To reduce trauma to the ischemically damaged tissue, we used a dorsal approach to the peroneal artery. With the patient prone, a incision parallel to the posterolateral margin of the Achilles tendon is made. After the deep crural fascia and flexor hallucis longus are split, access to the peroneal artery is easily obtained. The second segment of the popliteal artery is exposed in the popliteal cavity. The small saphenous vein is left in situ and anastomosed with the arteries after proximal and distal preparation and valvulotomy.

Endothoracic sonography improves the estimation of operability in locally advanced lung cancer.

BACKGROUND: Patients with T4 non-small cell lung cancers with limited involvement of mediastinal structures can undergo resection, with acceptable long-term survival. Computed tomography has not proven to be reliable in determining the operability of locally advanced lung carcinoma. This study evaluated the ability of video-assisted thoracoscopy alone and with endothoracic sonography to determine operability. METHODS: Computed tomography showed a close contact of the tumor with mediastinal structures (T4) in 155 patients. Staging was expanded with video-assisted thoracoscopy, followed by thoracoscopic ultrasound. Lateral thoracotomy with hilar and mediastinal dissection was considered the gold standard in determining operability. RESULTS: Thoracoscopic ultrasound, compared with thoracoscopy alone and computed tomography, had the highest sensitivity (94.1% vs 75.2% vs 43.6%, p < 0.001) and specificity (98.1% vs 57.4% vs 37.0%, p < 0.001) for determining operability. Computed tomography, thoracoscopy, and thoracoscopic ultrasound were falsely negative in 57 (36.8%), 25 (16.1%), and 6 (3.9%) patients and falsely positive in 34 (21.9%), 23 (14.8%), and 1 (0.6%). False-negative results for operability by thoracoscopic ultrasound were found only in tumors involving the left atrium (3.9%). CONCLUSIONS: Estimation of operability in locally advanced lung cancer can be improved with video-assisted thoracoscopy and ultrasound. More than one-third of patients classified as inoperable by computed tomography were able to undergo complete resection.