Investigation on the nasal airflow characteristics of anterior nasal cavity stenosis

We used a computational fluid dynamics (CFD) model to study the inspiratory airflow profiles of patients with anterior nasal cavity stenosis who underwent curative surgery, by comparing pre- and postoperative airflow characteristics. Twenty patients with severe anterior nasal cavity stenosis, including one case of bilateral stenosis, underwent computed tomography (CT) scans for CFD modelling. The pre- and postoperative airflow characteristics of the nasal cavity were simulated and analyzed. The narrowest area of the nasal cavity in all 20 patients was located within the nasal valve area, and the mean cross-sectional area increased from 0.39 cm2 preoperative to 0.78 cm2 postoperative (P<0.01). Meanwhile, the mean airflow velocity in the nasal valve area decreased from 6.19 m/s to 2.88 m/s (P<0.01). Surgical restoration of the nasal symmetry in the bilateral nasal cavity reduced nasal resistance in the narrow sides from 0.24 Pa.s/mL to 0.11 Pa.s/mL (P<0.01). Numerical simulation of the nasal cavity in patients with anterior nasal cavity stenosis revealed structural changes and the resultant patterns of nasal airflow. Surgery achieved balanced bilateral nasal ventilation and decreased nasal resistance in the narrow region of the nasal cavity. The correction of nasal valve stenosis is not only indispensable for reducing nasal resistance, but also the key to obtain satisfactory curative effect.

Assessment of regional lung ventilation by electrical impedance tomography in a patient with unilateral bronchial stenosis and a history of tuberculosis / Avaliacao da ventilacao pulmonar regional por tomografia de impedancia eletrica em paciente com estenose bronquica unilateral pos-tuberculose

Bronchial stenosis can impair regional lung ventilation by causing abnormal, asymmetric airflow limitation. Electrical impedance tomography (EIT) is an imaging technique that allows the assessment of regional lung ventilation and therefore complements the functional assessment of the lungs. We report the case of a patient with left unilateral bronchial stenosis and a history of tuberculosis, in whom regional lung ventilation was assessed by EIT. The EIT results were compared with those obtained by ventilation/perfusion radionuclide imaging. The patient was using nasal continuous positive airway pressure (CPAP) for the treatment of obstructive sleep apnea syndrome. Therefore, we studied the effects of postural changes and of the use of nasal CPAP. The EIT revealed heterogeneous distribution of regional lung ventilation, the ventilation being higher in the right lung, and this distribution was influenced by postural changes and CPAP use. The EIT assessment of regional lung ventilation produced results similar to those obtained with the radionuclide imaging technique and had the advantage of providing a dynamic evaluation without radiation exposure.

A estenose brônquica pode comprometer a ventilação pulmonar regional devido a limitações anormais e assimétricas ao fluxo aéreo. A tomografia de impedância elétrica (TIE) é uma técnica que possibilita a avaliação da ventilação pulmonar regional por imagem e, portanto, pode complementar a avaliação funcional dos pulmões. Relatamos o caso de uma paciente com estenose brônquica unilateral à esquerda, pós-tuberculose, em que se avaliou a ventilação pulmonar regional através da TIE, relacionando-a com a cintilografia de ventilação/perfusão. Foram estudados os efeitos das mudanças posturais e da aplicação de continuous positive airway pressure (CPAP, pressão positiva contínua nas vias aéreas) nasal, uma vez que a paciente usava esse tratamento para síndrome da apneia obstrutiva do sono. A TIE demonstrou distribuição heterogênea da ventilação pulmonar regional com maior ventilação no pulmão direito, sendo essa distribuição influenciada pelas mudanças de decúbitos e pela aplicação de CPAP. A análise da ventilação pulmonar regional pela TIE se mostrou similar aos achados da cintilografia pulmonar de ventilação com a vantagem de possibilitar uma avaliação dinâmica e sem exposição à radiação.

Evaluation of the mortality rate caused by different periods of selective portal vein occlusion in rats

Mortality from acute selective portal vein occlusion (SPVO) is a matter of concern for surgeons during the management of traumatic portal vein injury. However, mortality rates related to different periods of SPVO remains undetermined. PURPOSE: To determine the mortality rates resulting from different periods of acute SPVO in rats. METHODS: Wistar male rats were randomized into 8 experimental, and 8 control groups. Experimental animals underwent SPVO during 15 to 75 minutes, and control groups underwent sham procedures. All surviving animals were followed up to 14 days for assessment of mortality rate. RESULTS: Death rates varied from 0 percent in the 15 min SPVO group, to 100 percent with 65 and 75 minutes of SPVO. A strongly positive correlation was observed between mortality rates and SPVO periods (p<0.001) with either linear or quadratic regression analysis tests. All deaths in the 20min and 25min SPVO groups occurred after 75 min from the moment of clamping (or after 60 min from unclamping); death from 30 or more min SPVO occurred predominantly within 75 min from clamping moment (or within 60 min from unclamping). (Exact Fisher test, p=0.009). CONCLUSIONS: The mortality from SPVO in rats increases with longer duration of SPVO; with deaths occurring later for short periods (< 25 min) of SPVO and earlier for longer periods (> 30 min) of SPVO.

A mortalidade da oclusão seletiva da veia porta (OSVP) preocupa os cirurgiões durante o tratamento de lesão traumática da veia porta. Entretanto, as taxas de mortalidade decorrentes de diferentes períodos de OSVP não estão determinadas. OBJETIVO: Determinar a mortalidade Decorrente de diferentes períodos de oclusão seletiva da veia porta (OSVP) em ratos. MÉTODOS: Ratos Wistar machos foram randomizados em 8 grupos experimentais e 8 controles. Os experimentais foram submetidos a OSVP por períodos de 15 a 75 minutos, seguidos de observação até o óbito, e os sobreviventes até 14 dias. Os grupos controles receberam idênticos procedimentos, exceto a OSVP. RESULTADOS: A mortalidade, a partir do momento da oclusão, aumentou progressivamente, de 0 por cento no grupo de 15min, atingindo 100 por cento nos grupos de 65min e 75min de OSVP. Houve alta correlação positiva entre mortalidade e duração da OSVP (p<0.001; tanto em teste de Regressão linear quanto quadrática). Os óbitos decorrentes de 20 e 25 min de OSVP ocorreram após 75min do clampeamento (ou após 60 min do desclampeamento); os decorrentes de 30min ou mais ocorreram predominantemente antes de decorridos 75 min do clampeamento (ou 60 min do desclampeamento). (Teste exato de Fisher, p<0.05). CONCLUSÕES: A mortalidade da OSVP em ratos aumenta com a maior duração da oclusão; os óbitos ocorrem mais tardiamente após oclusões breves (< 25 min), e mais precocemente nas oclusões mais prolongadas (> 30 minutos).

Accidente cerebro-vascular en la enfermedad de Fabry: algo más que una simple estenosis / Stroke in Fabry disease: more than a simple stenosis

Se analiza la evidencia existente a la fecha sobre los mecanismos fisiopatológicos que puedem generar accidentes cerebrovasculares en la enfermedad de Fabry. Esta entidad es el resultado de la deficiencia de alfa-galactosidasa A, lo que resulta en depósito patológico de glicoesfingilípidos en distintas poblaciones celulares. Asociados a la insuficiencia renal y cardíaca, los accidentes cerebrovasculares pueden derivar en la muerte de los pacientes. Durante mucho tiempo el único mecanismo generador de daño vascular informado fue la oclusión vascular por depósito lipídico a nivel endotelial. En la actualidad se describen otros mecanismos. El advenimento de la terapia de reemplazo enzimático ha generado gran expectativa en cuanto la posibilidad de reversión de estos mecanismos. Si bien la evidencia es escasa y son necesarios más estudios a largo plazo, algunos informes demuestran que luego de meses, el tratamiento ha logrado revertir algunos de los mecanismos implicados

The objective is to analyze the updated evidence on the physiopathological mechanisms that can generate cerebrovascular damage in Fabry disease. Fabry disease is the result of the deficiency of alpha-galactosidasa A, which causes pathological storage of glycosphingolipids, in different cells. Associated to renal and cardiac insufficiency, cerebrovascular complications can derive in the death of the patients. During a long time the only reported mechanism was the vascular occlusion by deposit of lipids at endothelial level. At the present time, other mechanisms are postulated. The arrival of enzyme replacement therapy has generated great expectation on the possibility of reversion of these alterations. Although the evidence is scarce and more long-term studies are necessary, some reports demonstrate that after months, the treatment has managed to revert some of the mechanisms involved

Estudio morfológico-informático de las estenosis de las arterias femorales humanas para su aplicación como complemento diagnóstico / Morphological and informatical study of human femoral arteries stenoses for its application as diagnostic complement

El presente trabajo estudia el comportamiento del flujo sanguíneo a partir de arterias femorales humanas estenóticas con distintos grados de obstrucción, extraídas de autopsias y de amputaciones quirúrgicas y de simulaciones producidas por un programa computacional simulador original basado en el método de los elementos finitos para líquidos newtonianos, homogéneos e incompresibles. Su empleo produjo numerosas curvas de máxima resumidas en un único gráfico de aplicación sencilla para el profesional. Más allá de la evaluación del origen y del impacto de los remolinos analizando las distintas variables intervinientes (esto es: presión, velocidad y tensiones), los resultados aquí reportados pueden constituir un útil complemento diagnóstico junto a los demás métodos usados actualmente, a los que no contraviene ni invalida.

Safety and predictive value of exercise stress testing within three days after percutaneous transluminal coronary angioplasty.

The safety and efficacy of exercise stress testing within three days of successful coronary angioplasty was evaluated in 226 patients with coronary artery disease; 137 patients had single-vessel disease (SVD) and 89 had multi-vessel disease (MVD). Comparisons were made between patients with SVD and MVD and between patients whose vessels restenosed and those whose vessels remained patent. The post-angioplasty exercise test was positive in 48% of SVD and 49% of MVD patients. However, a positive result did not predict future restenosis. There was a significantly [p = 0.004] higher proportion of patients in the MVD group, compared with the SVD group, who exhibited greater than or equal to 2mm ST-depression, but again this was not indicative of restenosis. No complications as a direct result of having an early exercise test occurred. Exercise stress testing proved safe and was effective in demonstrating relief from angina in most patients early after coronary angioplasty. It did not, however, predict restenosis.