Barbosa RAG, Santos SRCJ, White PF, Pereira VA, Silva Filho CR, Malbouisson LMS. Effects of cardiopulmonary bypass on propofol pharmacokinetics and bispectral index during coronary surgery. Clinics. 2009;64(3):215-21.
PURPOSE:Cardiopulmonary bypass is known to alter propofol pharmacokinetics in patients undergoing cardiac surgery. However, few studies have evaluated the impact of these alterations on postoperative pharmacodynamics. This study was designed to test the hypothesis that changes in propofol pharmacokinetics increase hypnotic effects after cardiopulmonary bypass. METHODS: Twenty patients scheduled for on-pump coronary artery bypass graft (group, n=10) or off-pump coronary artery bypass graft (group, n=10) coronary artery bypass grafts were anesthetized with sufentanil and a propofol target controlled infusion (2.0 µg/mL). Depth of hypnosis was monitored using the bispectral index. Blood samples were collected from the induction of anesthesia up to 12 hours after the end of propofol infusion, at predetermined intervals. Plasma propofol concentrations were measured using high-performance liquid chromatography, followed by a non-compartmental propofol pharmacokinetic analysis. Data were analyzed using ANOVA, considering p<0.05 as significant. RESULTS: After cardiopulmonary bypass, despite similar plasma propofol concentrations in both groups, bispectral index values were lower in the on-pump coronary artery bypass graft group. Time to extubation after the end of propofol infusion was greater in the on-pump coronary artery bypass graft group (334 ± 117 vs. 216 ± 85 min, p = 0.04). Patients undergoing cardiopulmonary bypass had shorter biological (1.82 ± 0.5 vs. 3.67 ± 1.15h, p < 0.01) and terminal elimination (6.27 ± 1.29 vs. 10.5h ± 2.18, p < 0.01) half-life values, as well as higher total plasma clearance (28.36 ± 11.40 vs.18.29 ± 7.67 mL/kg/min, p = 0.03), compared to patients in the off-pump coronary artery bypass graft group. CONCLUSION: Aside from the increased sensitivity of the brain to anesthetics after cardiopulmonary bypass, changes in propofol pharmacokinetics may contribute to its central nervous system effects.
Este trabalho objetivou avaliar o padrão atual de distribuição de Caatinga densa, identificando onde estão seus maiores fragmentos, através de procedimentos cartográficos e estatísticos no município de Caicó-RN. A partir de NDVI, gerou-se o mapeamento da cobertura vegetal e, em seguida, delimitou-se três intervalos de cotas altimétricas possibilitando-se traçar um perfil gradual. Os fragmentos de Caatinga densa foram submetidos a ANOVA e teste Tukey, estabelecendo uma significância de p<0,05, identificando se há diferença significativa entre os tamanhos desses fragmentos. Foi realizado um levantamento florístico visando a caracterizar as diferentes cotas amostradas. Como resultado, na cota de menor altimetria obteve-se 5.169,54ha, com a cota média, 2.850,20ha, e 1.753,08ha, para a maior altimetria. Em termos proporcionais com relação à área total de cada cota, foi justamente esta última que apresentou maior área ocupada por vegetação densa. Foi identificada diferença significativa entre esta cota e a primeira, mediante os tamanhos dos fragmentos. No tocante à flora, as espécies mais seletivas estão nas cotas superiores, com exceção das áreas de mata ciliar na menor altimetria onde predominam espécies generalistas. Neste trabalho foi comprovado estatisticamente que a Caatinga densa encontra-se bastante restrita às margens de corpos hídricos e em maciços, apresentando aumento gradual em termos altimétricos.
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