Effects on extravascular lung water of lung protective ventilation strategy applied on piglets with acute respiratory distress syndrome induced by paraquat / 中华劳动卫生职业病杂志

Objective: To study the effects on extravascular lung water of lung protective ventilation strategy applying on piglets with acute respiratory distress syndrome (ARDS) induced by paraquat (PQ) under pulse indicating continuous cardiac output (PiCCO) monitoring. Methods: The piglets models with ARDS induced by PQ were established in June 2020 and all of them were received mechanical ventilation and divided into three groups according to tidal volume (V(T)) : small V(T) group (6 ml/kg) , middle V(T) group (10 ml/kg) and large V(T) group (15 ml/kg) , there were 5 piglets in each group. The positive end expiratory pressure (PEEP) were all setup on 10 cmH(2)O. The indexes such as arterial blood gas analysis, oxygenation index (OI) , extravascular lung water index (ELWI) and pulmonary vascular permeability index (PVPI) were monitored at time of before the model was established (baseline) , time of the model was established (t(0)) and 2 h (t(2)) , 4 h (t(4)) , 6 h (t(6)) after mechanical ventilation. Lung tissue were punctured at time of baseline, t(0) and t(6) to be stained by Hematoxylin-eosin (HE) staining and pulmonary pathology were observed under light microscopy. Results: The heart rate (HR) , mean arterial pressure (MAP) and partial pressure of carbon dioxide (PaCO(2)) of all groups were higher than the base value while the pH values, partial pressure of oxygen (PaO(2)) and OI were lower than the base value when the models were established (P<0.05) . After mechanical ventilation, the HR and MAP values of all groups at t(2), t(4) and t(6) were lower than t(0) while the PaCO(2) of t(4) and t(6) were all higher than t(0), the differences were statistically significant (P<0.05) . The PaO(2) and OI of all groups showed a trend of rising at first and then decreasing after mechanical ventilation. The MAP, PaO(2), PaCO(2) and OI of the middle V(T) group and large V(T) group were apparently lower than that of the small V(T) group at t(2), t(4) and t(6) (P<0.05) . The ELWI and PVPI at t(0) of all groups were higher than that of baseline (P<0.05) . The ELWI of the small V(T) group at t(6) were lower than t(0) of the same group and t(6) of the middle V(T) group and large V(T) group (P<0.05) . HE staining showed congestion and edema of alveolar tissue, swelling of capillaries, exudation of red blood cells and widening of alveolar septum in piglets after successful modeling. And further widening of alveolar septum and rupture of alveolar septum could be seen in the lung tissues of each group at t(6), and the injury was the slightest in the small V(T) group. Conclusion: The lung protective ventilation strategy can alleviate the extravascular lung water and ARDS induced by PQ and improve oxygenation.

Cuantificación de lecitina en líquido amniótico mediante el efecto lítico de la lisolecitina / Quantification of lecithin in amniotic fluid by the litic effect of lysolecithin

Se describe un método para determinar lecitina en líquido amniótico, el cual se basa en la acción de la fosfolipasa A2 sobre la lecitina originando lisolecitina, que en presencia de una suspensión de eritrocitos, produce ruptura de la membrana de los mismos. La concentración de lecitina se obtiene espectrofotométricamente a 500 nm, determinando la disminución de absorbancia que se produce entre los 20 y 100 segundos. El método es relativamente sencillo, rápido, económico, preciso, exacto y requiere solamente 100 µL de muestra. El análisis comparativo con un método enzimático mostró un coeficiente de correlación r = 0,943 y una ecuación de regresión lineal y = 0,975x + 0,486. El método presenta coeficientes de variación día a día de 3,5 y 4,7 por ciento para concentraciones de lecitina de 14,0 y 5,3 mg/dL, respectivamente. El intervalo analítico es de 15,0 mg/dL. La sangre, meconio y hemoglobina producen interferencia negativa

Respuesta pulmonar tardia a la infusion de ácidos grasos libres: rol del radical superóxido / Late pulmonary response to the infusion of free fatty acids: role of the superoxide radical

La infusión intravenosa de ácidos grasos libres (AGL) en conejos producem edema pulmonar por aumento de la permeabilidad, reacción inflamatoria y aumento del surfactante alveolar. Con el objetivo de definir el rol del anión super-óxido (O2-) en el daño pulmonar difuso producido por EGL, se evaluó el efecto de la superóxido dismutasa (SOD). Se estudiaron 4 series de conejos que recibieron: a) AGL (n = 6): 10 mg AGL/Kg/min.i.v. durante 15 minutos. b) Vehículo de AGL (n=5)i.v. durante 15 y 25 minutos AGL + SOD (mg/Kg i.v. durante 15 y 25 minutos respectivamente (n = 6); d) Vehículo + SOD durante 15 y 25 minutos respectivamente (n = 7). Al cabo de 96 horas los conejos fueron sacrificados, determinándose en el lavado bronquioalveolar: proteínas, fosfatidilcolina disaturada (DPPC) y el recuento celular. Hubo un aumento significativo de DPPC del recuento de células en todas las seires en comparación a la serie vehículo (b). SOD no modificó las alteraciones inducidas por AGL, aunque "per se" aumentó la DPPC y el recuento de células en el LBA. La histología pulmonar mostró edema perivascular e intra-alveolar en los animales inyectados con AGL. Estas alteraciones fueron francamente disminuidas por la SOD. Estos resultados sugieren que el O2- tendria un rol sólo secundario en el daño pulmonar difuso por AGL, ya que SOD protegió solo parcialmente al pulmón de este daño