Abstract Objective: Hemodilution is a concern in cardiopulmonary bypass (CPB). Using a smaller dual tubing rather than a single larger inner diameter (ID) tubing in the venous limb to decrease prime volume has been a standard practice. The purpose of this study is to evaluate these tubing options. Methods: Four different CPB circuits primed with blood (hematocrit 30%) were investigated. Two setups were used with two circuits for each one. In Setup I, a neonatal oxygenator was connected to dual 3/16" ID venous limbs (Circuit A) or to a single 1/4" ID venous limb (Circuit B); and in Setup II, a pediatric oxygenator was connected to dual 1/4" ID venous limbs (Circuit C) or a single 3/8" ID venous limb (Circuit D). Trials were conducted at arterial flow rates of 500 ml/min up to 1500 ml/min (Setup I) and up to 3000 ml/min (Setup II), at 36°C and 28°C. Results: Circuit B exhibited a higher venous flow rate than Circuit A, and Circuit D exhibited a higher venous flow rate than Circuit C, at both temperatures. Flow resistance was significantly higher in Circuits A and C than in Circuits B (P<0.001) and D (P<0.001), respectively. Conclusion: A single 1/4" venous limb is better than dual 3/16" venous limbs at all flow rates, up to 1500 ml/min. Moreover, a single 3/8" venous limb is better than dual 1/4" venous limbs, up to 3000 ml/min. Our findings strongly suggest a revision of perfusion practice to include single venous limb circuits for CPB.

RESUMO O objetivo deste estudo é elaborar uma proposição de modelo conceitual sobre comprometimento organizacional, baseando-se no referencial teórico apresentado e nas especificidades brasileiras; e, posteriormente, constatar sua coerência frente às estratégias de Recursos Humanos adotadas por empresas que pretendem obter vantagem competitiva sustentável, com base no fator humano, em longo prazo. A pesquisa foi aplicada a duas empresas de culturas distintas: 525 colaboradores da Companhia do Metropolitano de São Paulo -Metrô e 180 colaboradores da Nortel Networks do Brasil responderam a um questionário de 153 questões sobre diversas variáveis precedentes ao comprometimento. Foram realizadas entrevistas com administradores das duas empresas para o desvendar das respectivas culturas organizacionais. Deste modo, pôde-se apreciar a relação existente entre as diferentes culturas e as principais variáveis explicativas do comprometimento dos colaboradores.

ABSTRACT The importance of the collaborator's commitment to the organization's objectives is evidenced by the new paradigm of industrial production: the integrated flexible automation. The several conceptual approaches and the respective theoretical sources in the investigation of organizational commitment results in an opportune study for the proposition of a large conceptual model, for the best understanding of that phenomenon. The research was applied to two companies of different cultures: 525 professionals of the Subway of São Paulo and 180 collaborators of Nortel Networks of Brazil answered a questionnaire of 153 subjects on several precedent variables to the commitment. The second stage of the research was accomplished throught interviews with people of administrative level for unmasking of the respective organizational cultures. Thus, the existent relationship can be appreciated between different cultures and the main explanatory variables of the collaborators’ commitment.