Sevoflurane preconditioning during myocardial ischemia-reperfusion reduces infarct size and preserves autonomic control of circulation in rats

PURPOSE:To investigate the myocardial ischemia-reperfusion with sevoflurane anesthetic preconditioning (APC) would present beneficial effects on autonomic and cardiac function indexes after the acute phase of a myocardial ischemia-reperfusion.METHODS:Twenty Wistar rats were allocated in three groups: control (CON, n=10), myocardial infarction with sevoflurane (SEV, n=5) and infarcted without sevoflurane (INF, n=5). Myocardial ischemia (60 min) and reperfusion were performed by temporary coronary occlusion. Twenty-one days later, the systolic and diastolic function were evaluated by echocardiography; spectral analysis of the systolic arterial pressure (SAPV) and heart rate variability (HRV) were assessed. After the recording period, the infarct size (IS) was evaluated.RESULTS:The INF group presented greater cardiac dysfunction and increased sympathetic modulation of the SAPV, as well as decreased alpha index and worse vagal modulation of the HRV. The SEV group exhibited attenuation of the systolic and diastolic dysfunction and preserved vagal modulation (square root of the mean squared differences of successive R-R intervals and high frequency) of HRV, as well as a smaller IS.CONCLUSION:Sevoflurane preconditioning better preserved the cardiac function and autonomic modulation of the heart in post-acute myocardial infarction period.(AU)

Evaluation of the positioning of the tip of the Veress needle during creation of closed pneumoperitoneum in pigs / Avaliação do posicionamento da agulha de Veress durante o estabelecimento do pneumoperitônio pela técnica fechada em porcos

PURPOSE: Erroneous punctures and insufflations are frequent with the use of the Veress needle. Mistaken injections of gas in the preperitoneal space are not rare. The purpose of this research is to evaluate the correct positioning of the tip of the needle during creation of pneumoperitoneum. METHODS: The needle was inserted into the peritoneal cavity. Tests to assess the positioning of the needle tip were carried out. Pressure, flow rate and volume were periodically recorded and the needle was removed, being immediately reinserted into the right hypochondrium and placed in the preperitoneal space. RESULTS: The liquid flow test was always positive in the peritoneal cavity. No resistance to saline injection into the peritoneal cavity was observed, but increased resistance to saline injection into the preperitoneal space was observed in 45.5% of the cases. Some saline was recovered in 63.5% of the cases in the peritoneal cavity, and in 54.5% in the preperitoneal space. Saline drop test was positive in 66.6% of the cases in the peritoneal cavity and in 45.5% in the preperitoneal space. In the peritoneal cavity, initial pressure lower than 5 mm Hg was observed, and this pressure gradually increased during 123 seconds until reaching 15 mm Hg. In the preperitoneal space, initial pressure was 15 mm Hg. CONCLUSIONS: Aspiration, liquid flow and saline drop tests are important, whereas recovery test is inconclusive. Initial pressure of approximately 5 mm Hg indicates that the tip of the needle is in the peritoneal cavity. The peritoneal cavity should hold ten times as much volume of gas as the preperitoneal space. The increase in pressure and volume in the peritoneal cavity can be predicted by statistics.(AU)

OBJETIVO: Estabelecer parâmetros fidedignos do posicionamento adequado da agulha de Veress na cavidade peritoneal durante o estabelecimento do pneumoperitônio pela técnica fechada. MÉTODOS: Em 11 porcos a agulha foi introduzida na cavidade peritoneal através do hipocôndrio esquerdo. Provas de posicionamento da ponta do instrumento foram efetuadas. Insuflou-se CO2 e registraram-se periodicamente pressões, fluxos e volumes. A posição intraperitoneal da agulha foi confirmada e esta foi retirada, sendo re-introduzida no hipocôndrio direito e posicionada sob visão direta no espaço pré-peritoneal. Os mesmos parâmetros foram aferidos. RESULTADOS: A prova do escoamento foi sempre positiva no peritônio. Não se encontrou resistência à introdução de soro no peritônio em nenhum caso, mas sim em 45,5% dos casos no pré-peritônio. Soro algum foi recuperado em 63,5% no peritônio e em 54,5% no pré-peritônio. O gotejamento fluiu livremente em 66,6% das vezes no peritônio e em 45,5% dos casos no pré-peritônio. No peritônio, pressões iniciais de 5,20 mmHg aumentaram progressivamente durante 123 segundos até atingir 15 mmHg. No pré-peritônio a pressão inicial foi de 15,60 mmHg e oscilou entre 12 e 15,60 mmHg. O volume de gás injetado no peritônio foi de 1500 ml e de 100 ml no pré-peritônio. CONCLUSÕES: Aspiração e observação do escoamento e do gotejamento são importantes; recuperar ou não o soro é inconclusivo. Pressão inicial d" 5 mm é indicativo da ponta da agulha no peritônio, onde devem caber dez vezes mais gás que no pré-peritônio. No peritônio os aumentos das pressões e dos volumes pode ser previstos mediante estatísticas.(AU)