RESUMO Antecedentes: O núcleo cuneiforme está localizado no centro do circuito que media as respostas autonômicas ao estresse. A hipotensão hemorrágica leva à anóxia dos quimiorreceptores, que, consequentemente, resulta na redução da descarga dos barorreceptores e estimulação do quimiorreceptor. Objetivo: Utilizando a técnica de registro em unidade única, as atividades neuronais do núcleo cuneiforme foram investigadas em estados de hipotensão induzida por hemorragia e administração de um anti-hipertensivo (hidralazina). Métodos: Trinta ratos machos foram divididos nos grupos controle, hemorragia e hidralazina. A artéria femoral foi canulada, para o registro de respostas cardiovasculares, incluindo pressão arterial sistólica, pressão arterial média e frequência cardíaca. A hidralazina foi administrada na veia da cauda. O registro de unidade única foi realizado a partir do núcleo cuneiforme. Resultados: A pressão arterial sistólica máxima e a pressão arterial média diminuíram significativamente, e a frequência cardíaca aumentou significativamente após a aplicação de hidralazina, bem como a hemorragia seguinte, em comparação com o grupo controle. A hipotensão aumentou significativamente a taxa de disparo da população do núcleo cuneiforme em ambos os grupos de hemorragia e hidralazina, em comparação com o grupo de controle. Conclusões: Os presentes dados indicam que as atividades do núcleo cuneiforme após hipotensão podem desempenhar um papel crucial nos vasos sanguíneos e no tônus vasomotor.

Abstract Background: The cuneiform nucleus is located in the center of the circuit that mediates autonomic responses to stress. Hemorrhagic hypotension leads to chemoreceptor anoxia, which consequently results in the reduction of baroreceptor discharge and stimulation of the chemoreceptor. Objective: Using the single-unit recording technique, the neuronal activities of the cuneiform nucleus were investigated in hypotensive states induced by hemorrhage and administration of an anti-hypertensive drug (hydralazine). Methods: Thirty male rats were divided into the control, hemorrhage, and hydralazine groups. The femoral artery was cannulated for the recording of cardiovascular responses, including systolic blood pressure, mean arterial pressure, and heart rate. Hydralazine was administered via tail vein. The single-unit recording was performed from the cuneiform nucleus. Results: The maximal systolic blood pressure and the mean arterial pressure significantly decreased and heart rate significantly increased after the application of hydralazine as well as the following hemorrhage compared to the control group. Hypotension significantly increased the firing rate of the cuneiform nucleus in both the hemorrhage and hydralazine groups compared to the control group. Conclusions: The present data indicate that the cuneiform nucleus activities following hypotension may play a crucial role in blood vessels and vasomotor tone.

Background:Accumulation of bacteria in the pharynx is one of the risk factors of pneumonia due to ventilation. One of the methods of prevention from accumulation of bacteria in the pharynx is the use of oral solutions. Chlorhexidine is considered as the gold standard, but it has various side effects. Aim:Present study was aimed to determine and compare anti-bacterial effects of the chlorhexidine gluconate 0.2%, herbal mouthwash of Matrica® (chamomile extracts) 10%, PersicaTM 10% and normal saline in intensive care unit patients. Methods:In this double blind randomized clinical trial, 80 patients who were admitted in ICU divided into four groups of 20 patients each one. Researchers applied PersicaTM to group one, chlorhexidine gluconate mouth wash 0.2% to group two and third group received Matrica, finally in the control group, normal saline were used. In order to culturing of Staphylococcus aureusand S. pneumoniae,salivary samples were obtained without any stimulation after six minimums oral rinsing. The data were processed in SPSS17 software and analyzed by appropriate statistical tests. Results:Decreased rate of bacterial colonies after intervention in the whole four groups was significant (p < 0.001). The mouth wash of chlorhexidine (p < 0.001), PersicaTM (p: 0.008) and Matrica (p: 0.01) had a significant antibacterial effect on S. aureusand S. pneumoniae(p < 0.001). Conclusion:Herbal oral mouthwash of persica and matrica has the effect on S. pneumoniae and S. aureusof oropharynx area in mechanically ventilated patients. However, there is a need for further research to be considered as an alternative to chlorhexidine for prevention of VALP in ICU patients.

Introducción:La presencia y acumulación de bacterias en la cavidad oral es un factor de riesgo para el desarrollo de neumonía asociada a ventilación mecánica. Uno de los métodos para prevenir esta acumulación en la faringe es el uso de soluciones orales. Al respecto, clorhexidina es considerada el estándar de oro, pero tiene varios efectos colaterales. Objetivo:Determinar y comparar el efecto antibacteriano de gluconato de chorhexidina al 0,2%, aseo bucal con preparado en base a hierba matrica (extracto de chamomile) al 10%, Persica® al 10% y solución salina fisiológica (NaCl 9%0) en pacientes de la unidad de cuidados intensivos ingresados para ventilación mecánica. Métodos:Ensayo doble ciego, randomizado, sobre 80 pacientes ingresados en UCI, divididos en cuatro grupos de 20 miembros cada uno. El grupo I recibió Persica®, el grupo II aseo bucal con gluconato de clorhexidina al 0,2%, el grupo III recibió matrica y, finalmente, el grupo IV-control recibió solución salina fisiológica. Con la finalidad de cultivar Staphylococcus aureus yS. pneumoniae,se obtuvieron muestras de saliva sin efectuar estímulo alguno tras un mínimo de seis lavados bucales. Los datos fueron procesados en el software SPSS17 y analizados por tests estadísticos apropiados. Resultados:La disminución en el recuento de colonias bacterianas, después de la intervención, fue significativa en los cuatro grupos (p < 0,001). El aseo bucal con clorhexidina (p < 0,001), Persica® (p: 0,008) y matrica (p: 0,01) tuvo un significativo efecto antibacteriano sobre las especies S. aureusy S. pneumoniae(p < 0,001). Conclusión:El aseo bucal con solución en base a hierbas de Persica® y matrica tiene un efecto sobre S. pneumoniae y S. aureusde la cavidad oral en pacientes en régimen de ventilación mecánica. No obstante, se requiere de mayores estudios para considerarlo una alternativa a clorhexidina para la prevención de neumonías en pacientes de UCI.