The high cost of sensitivity commercial calorimeters may represent an obstacle for many calorimetric research groups. This work describes the construction and calibration of a batch differential heat conduction calorimeter with sample cells volumes of about 400 μL. The calorimeter was built using two small high sensibility square Peltier thermoelectric sensors and the total cost was estimated to be about US$ 500. The calorimeter was used to study the excess enthalpy of solution of binary mixtures of liquids, as a function of composition, for the following binary systems of solvents: water + 1,4-dioxane or + dimethylsulfoxide at 298,2 ± 0,5 K.

CONTEXTO: Na isquemia crítica, a artéria femoral profunda pode tornar-se a opção mais distal como origem de fluxo para derivações distais em casos de oclusão da origem da artéria femoral superficial associada a prega inguinal hostil. OBJETIVO:Avaliar, retrospectivamente, a artéria femoral profunda como doadora de fluxo para derivações infrageniculares. MÉTODOS: De 2000 a 2005, 129 derivações infrageniculares apresentaram anastomose proximal nas artérias femorais, comum (40), superficial (72) e profunda (17). O presente estudo teve como foco a artéria femoral profunda, e suas indicações foram: prega inguinal hostil (seis casos), limite da extensão do substituto (seis casos) e ambos os fatores (outros cinco casos). Foram abordadas a primeira e a segunda porção em 12 casos e a terceira porção em cinco casos. As cirurgias foram secundárias em 47% dos casos, e os substitutos utilizados foram veias do membro superior em 11 casos, safena interna em cinco e safena externa em um caso. RESULTADOS: No total dos enxertos (129), as estimativas de perviedade primária e salvamento do membro foram: 68,0% e 84,7%, respectivamente, com erro padrão (EP) aceitável (0,1) em 36 meses. Quando o grupo foi estratificado, as artérias femorais comum, superficial e profunda apresentaram resultados comparáveis de perviedade primária (63,3, 70,2 e 64,7%; p = 0,63) e salvamento do membro (83,1, 82,4 e 92,3%; p = 0,78). A perviedade dos enxertos com origem nas porções proximal e distal da artéria femoral profunda, bem como das cirurgias primárias e secundárias, foram comparáveis, sem diferença estatística significante (p = 0,89 e p = 0,77, respectivamente). CONCLUSÃO: A artéria femoral profunda mostrou ser acessível e efetiva como origem de fluxo de enxertos infrageniculares, com resultados satisfatórios de perviedade e salvamento do membro.

BACKGROUND: Deep femoral artery can be the most distal technical option as donor site in patients with critical limb ischemia presenting superficial artery occlusion and hostile groins. OBJECTIVE: To retrospectively assess the deep femoral artery as an inflow site for infragenicular bypass grafts. METHODS: From 2000 to 2005, 129 infragenicular bypass grafts with proximal anastomosis located in femoral arteries were performed. Forty were located in the common femoral artery (CFA), 72 in the superficial femoral artery (SFA) and 17 in the deep femoral artery (DFA). Indications for using the DFA as inflow were hostile groin (six cases), limited arterial substitute length (six cases) or both (five cases). Anastomosis site was located in the first or second portion in 12 cases, and in the third in five cases. The surgery was secondary in 47% of the cases, and the arterial substitutes used were arm veins (11), greater saphenous vein (five) and lesser saphenous vein (one). RESULTS: Primary patency and limb salvage rates were 68.0 and 84.7%, respectively, with acceptable standard error (0.1) in 36 months. The results of patency divided by inflow artery were similar (CFA, 63.3%; SFA, 70.2%; DFA 64.7%; p = 0.63), as well as limb salvage rates (CFA, 83.1%; SFA, 82.4%; DFA 92.3%; p = 0.78). Analyzing the deep femoral group, no difference of patency rates was observed when the anastomotic site was compared (proximal vs. distal portions of the DFA) or between patients with or without previous grafts. (p = 0.89 and 0.77, respectively). CONCLUSION: Deep femoral artery is a feasible and effective option as donor site for infragenicular bypass grafts, with satisfactory patency and limb salvage rates.