Comparative study between propofol and sevoflurane anaesthesia for cerebral protection in cardiac surgery

Despite advances in anaesthesia and surgical techniques, cerebral injury remains a major source of morbidity after cardiac surgery. In this study, we evaluated the effect of two anaesthetic techniques, sevoflurane/fentanyl versus propofol/fentanyl on neurological outcome and S100S Protein levels and its correlation to secretion of cytokine IL-6 in patients undergoing coronary artery bypass grafting surgery [CABG]. Thirty patients undergoing CABG, randomly allocated into two groups, were enrolled in this prospective study. Sevoflurane was used in group S and propofol in group P. Neurological examination was performed preoperatively and on the third and sixth postoperative days. Blood samples for analysis of S100B Protein and IL-6 were collected before anaesthesia [TO], after heparinization and before CPB [Tl], after aortic declamping [T2], end of CPB [T3] and 24 hours after the operation [T4] in all patients. S-100B, Protein levels increased with the beginning of surgery in both groups but did not reach a pathological level except after aortic declamping [T2]. Maximum levels were reached at the end of operation [T3] and decreased to baseline levels at 24 hr postoperatively [T4]. The increase was statistically significant in both groups [at T2 and T3] but no significant difference was observed between the two groups. IL-6 level was significantly higher in Group S than in Group P before the start of cardiopulmonary bypass [Tl]. After aortic declamping [T2], concentration of IL-6 started to increase significantly and peaked at the end of operation [T3] but there were no differences between groups after cardiopulmonary bypass or postoperatively. There was a positive correlation between IL-6 and S-100B in both groups. Despite the increase in S-100B protein levels, no difference in deterioration of neurological examination after the operation was seen between groups. We conclude that propofol appears to offer no advantage over Sevoflurane for brain protection during CPB in this preliminary study. Also we concluded that the choice of anaesthetic technique may affect the pro-inflammatory cytokine response to surgery. However, neither technique could modify the cytokine response to the effect of the ischemia- reperfusion phenomenon or CPB itself

Environmental exposure of commuters in Mexico City to volatile organic compounds as assessed by blood concentrations, 1998

OBJETIVO: Evaluar la exposición a compuestos orgánicos volátiles en usuarios de transporte no expuestos ocupacionalmente en la Ciudad de México. MATERIAL Y MÉTODOS: Se determinaron las concentraciones sanguíneas de benceno, tolueno, etilbenceno, m/p-xileno, o-xileno y metil-terbutil éter en muestras obtenidas de participantes después del traslado matutino. RESULTADOS: Las concentraciones promedio de benceno en sangre (0.11µg/l), etilbenceno (0.081µg/l), m-/p-xileno (0.32µg/l) y tolueno (0.56µg/l) en los participantes de la Ciudad de México son aproximadamente dos veces más elevadas que en la submuestra de no fumadores de la Tercera Encuesta de Nutrición y Salud (Third National Health and Nutrition Examination Survey) en la población de Estados Unidos de América. Por otro lado, la mediana de los niveles de Compuestos Orgánicos Volátiles fueron similares a las medianas observadas en otros estudios de viajeros en ciudades de los Estados Unidos de América, no obstante el hecho de que sólo la mitad de los participantes de la Ciudad de México viajan en vehículos de uso personal, en comparación con los viajeros de los Estados Unidos de América. CONCLUSIONES: Estos resultados reflejan el problema de la contaminación ambiental en la Ciudad de México, donde la topografía que la rodea incrementa los problemas causados por el tráfico vehicular intenso, el bajo control de emisiones en los vehículos viejos y las pobres prácticas de mantenimiento. Los niveles altos de componentes de gasolina en la sangre de los viajeros no expuestos ocupacionalmente enfatizan la necesidad de iniciativas regulatorias y alternativas para disminuir el tráfico que reduzcan las emisiones de hidrocarburos y, en consecuencia, el riesgo de exposición no ocupacional para los residentes de la Ciudad de México.