First real-time imaging of bronchoscopic lung volume reduction by electrical impedance tomography.

BACKGROUND: Bronchoscopic lung volume reduction (BLVR) with one-way endobronchial valves (EBV) has better outcomes when the target lobe has poor collateral ventilation, resulting in complete lobe atelectasis. High-inspired oxygen fraction (FIO2) promotes atelectasis through faster gas absorption after airway occlusion, but its application during BLVR with EBV has been poorly understood. We aimed to investigate the real-time effects of FIO2 on regional lung volumes and regional ventilation/perfusion by electrical impedance tomography (EIT) during BLVR with EBV. METHODS: Six piglets were submitted to left lower lobe occlusion by a balloon-catheter and EBV valves with FIO2 0.5 and 1.0. Regional end-expiratory lung impedances (EELI) and regional ventilation/perfusion were monitored. Local pocket pressure measurements were obtained (balloon occlusion method). One animal underwent simultaneous acquisitions of computed tomography (CT) and EIT. Regions-of-interest (ROIs) were right and left hemithoraces. RESULTS: Following balloon occlusion, a steep decrease in left ROI-EELI with FIO2 1.0 occurred, 3-fold greater than with 0.5 (p < 0.001). Higher FIO2 also enhanced the final volume reduction (ROI-EELI) achieved by each valve (p < 0.01). CT analysis confirmed the denser atelectasis and greater volume reduction achieved by higher FIO2 (1.0) during balloon occlusion or during valve placement. CT and pocket pressure data agreed well with EIT findings, indicating greater strain redistribution with higher FIO2. CONCLUSIONS: EIT demonstrated in real-time a faster and more complete volume reduction in the occluded lung regions under high FIO2 (1.0), as compared to 0.5. Immediate changes in the ventilation and perfusion of ipsilateral non-target lung regions were also detected, providing better estimates of the full impact of each valve in place. TRIAL REGISTRATION: Not applicable.

Impact of respiratory cycle during mechanical ventilation on beat-to-beat right ventricle stroke volume estimation by pulmonary artery pulse wave analysis.

BACKGROUND: The same principle behind pulse wave analysis can be applied on the pulmonary artery (PA) pressure waveform to estimate right ventricle stroke volume (RVSV). However, the PA pressure waveform might be influenced by the direct transmission of the intrathoracic pressure changes throughout the respiratory cycle caused by mechanical ventilation (MV), potentially impacting the reliability of PA pulse wave analysis (PAPWA). We assessed a new method that minimizes the direct effect of the MV on continuous PA pressure measurements and enhances the reliability of PAPWA in tracking beat-to-beat RVSV. METHODS: Continuous PA pressure and flow were simultaneously measured for 2-3 min in 5 pigs using a high-fidelity micro-tip catheter and a transonic flow sensor around the PA trunk, both pre and post an experimental ARDS model. RVSV was estimated by PAPWA indexes such as pulse pressure (SVPP), systolic area (SVSystAUC) and standard deviation (SVSD) beat-to-beat from both corrected and non-corrected PA signals. The reference RVSV was derived from the PA flow signal (SVref). RESULTS: The reliability of PAPWA in tracking RVSV on a beat-to-beat basis was enhanced after accounting for the direct impact of intrathoracic pressure changes induced by MV throughout the respiratory cycle. This was evidenced by an increase in the correlation between SVref and RVSV estimated by PAPWA under healthy conditions: rho between SVref and non-corrected SVSD - 0.111 (0.342), corrected SVSD 0.876 (0.130), non-corrected SVSystAUC 0.543 (0.141) and corrected SVSystAUC 0.923 (0.050). Following ARDS, correlations were SVref and non-corrected SVSD - 0.033 (0.262), corrected SVSD 0.839 (0.077), non-corrected SVSystAUC 0.483 (0.114) and corrected SVSystAUC 0.928 (0.026). Correction also led to reduced limits of agreement between SVref and SVSD and SVSystAUC in the two evaluated conditions. CONCLUSIONS: In our experimental model, we confirmed that correcting for mechanical ventilation induced changes during the respiratory cycle improves the performance of PAPWA for beat-to-beat estimation of RVSV compared to uncorrected measurements. This was demonstrated by a better correlation and agreement between the actual SV and the obtained from PAPWA.

Histopathological, immunohistochemical and biomolecular diagnosis of myocarditis due to Clostridium chauvoei in a bovine / Diagnóstico anatomopatológico, imuno-histoquímico e biomolecular de um caso de miocardite por Clostridium chauvoei em um bovino

The aim of this study was to report a case of clostridial myocarditis in a bovine in Brazil with emphasis on the pathological findings, isolation and molecular identification associated with the in situ localization of C. chauvoei. The animal, a male Brangus bull with nine months of age, was found dead without prior clinical signs. Multifocal and coalescent areas of necrosis were observed in the myocardium. Rod cells in the cardiac muscle fibers were positive immunostaining for C. chauvoei, while this bacterium was also isolated and identified by polymerase chain reaction (PCR).

O objetivo deste estudo foi relatar um caso de miocardite clostridial em um bovino no Brasil, com ênfase nos achados patológicos, isolamento e identificação molecular do agente e visualização in situ de C. chauvoei. O animal, um macho da raça Brangus com nove meses de idade, foi encontrado morto sem sinais clínicos prévios. Foram observadas áreas de necrose multifocal e coalescente no miocárdio, com a presença de bastonetes imunomarcados para C. chauvoei nas fibras musculares cardíacas. Uma estirpe de C. chauvoei foi isolada do tecido e sua identidade foi confirmada por reação em cadeia da polimeras (PCR).

Fuzzy modeling of electrical impedance tomography images of the lungs

OBJECTIVES: Aiming to improve the anatomical resolution of electrical impedance tomography images, we developed a fuzzy model based on electrical impedance tomography's high temporal resolution and on the functional pulmonary signals of perfusion and ventilation. INTRODUCTION: Electrical impedance tomography images carry information about both ventilation and perfusion. However, these images are difficult to interpret because of insufficient anatomical resolution, such that it becomes almost impossible to distinguish the heart from the lungs. METHODS: Electrical impedance tomography data from an experimental animal model were collected during normal ventilation and apnea while an injection of hypertonic saline was administered. The fuzzy model was elaborated in three parts: a modeling of the heart, the pulmonary ventilation map and the pulmonary perfusion map. Image segmentation was performed using a threshold method, and a ventilation/perfusion map was generated. RESULTS: Electrical impedance tomography images treated by the fuzzy model were compared with the hypertonic saline injection method and computed tomography scan images, presenting good results. The average accuracy index was 0.80 when comparing the fuzzy modeled lung maps and the computed tomography scan lung mask. The average ROC curve area comparing a saline injection image and a fuzzy modeled pulmonary perfusion image was 0.77. DISCUSSION: The innovative aspects of our work are the use of temporal information for the delineation of the heart structure and the use of two pulmonary functions for lung structure delineation. However, robustness of the method should be tested for the imaging of abnormal lung conditions. CONCLUSIONS: These results showed the adequacy of the fuzzy approach in treating the anatomical resolution uncertainties in electrical impedance tomography images.

Indução da atividade cíclica ovariana pós-parto em vacas de corte submetidas à interrupção temporária do aleitamento associada ou não ao tratamento com norgestomet-estradiol / Ovarian ciclicity induction in beef cows submited to temporary weaning associated or not with norgestomet-estradiol

Este experimento teve como objetivo comparar os efeitos do desmame temporário (DT) por 72 horas associado ou näo ao uso de Norgestomet (NOR) e estradiol na fertilidade do estro induzido e no período reprodutivo de vacas de corte acíclicas no pós-parto. O grupo DT (n= 38) era constituído por vacas que tiveram os terneiros separados por 72 horas. O grupo NOR (n= 29) foi constituído por vacas que receberam (dia 0) um implante subcutâneo de Norgestomet e uma aplicaçäo de Valerato de estradiol (5mg) e Norgestomet (3mg), intramuscular. No momento da retirada dos implantes (dia 9), os terneiros foram separados por 72 horas. O intervalo desmame-estro foi significativamente mais curto (P<0,05) no grupo NOR em relaçäo ao grupo DT (50,1 e 86,4 horas, respectivamente). A taxa de induçäo de estros foi significativamente maior (P<0,05) no grupo NOR (75,8 por cento x 26,3 por cento), mas as taxas de ovulaçäo (63 por cento x 60 por cento), de prenhez no primeiro estro (36 por cento x 20 por cento) bem como na temporada de reproduçäo (51,7 por cento x 44,7 por cento) näo diferiram (P>0,05) entre os grupos. O grupo NOR apresentou uma menor incidência (P<0,05) de períodos curtos de atividade lútea (27,2 por cento) em relaçäo as vacas näo tratadas (40 por cento). Os resultados demostraram que o tratamento de vacas de corte acíclicas com Norgestomet e estradiol determina um aumento na manifestaçäo de estros após o desmame temporário por 72 horas, sem interferir nas taxas de prenhez do primeiro estro e da estaçäo reprodutiva

Incidência de fungos anemófilos em Alfenas, Minas Gerais / Airbone fungi incidence in Alfenas, Minas Gerais

Foi realizado um estudo sobre a incidência de fungos anemófilos em Alfenas, Minas Gerais, expondo-se 80 placas de Petri ao ar, em diversos locais, por um período de 20 minutos, durante os meses de setembro a novembro de 1984. A identificaçäo foi feita segundo a técnica de Riddell e auxiliada por chaves taxonômicas (Barnett & Hunter). 10 gêneros distintos de fungos foram isolados sendo os mais frequentes Cladosporium (35,8 por cento), Penicillium (16,7 por cento), Alternaria (9,1 por cento), Aspergillus (7,8 por cento), Cospora (5,4 por cento) e Geotrichum (2,7 por cento). A frequência dos fungos isolados foi correlacionada com as áreas pesquisadas e com os resultados obtidos por outros autores brasileiros