Flow-rate measurements and models for colloid and crystalloid flows in central and peripheral venous line infusion systems.

The resuscitation fluids, including crystalloids and colloids, were tested in an experimental module with 16-gauge central and peripheral catheters. Infusion pressures were ranged from the gravity driving 10 kPa (75 mmHg) to the pressurized driving 50 kPa (375 mmHg). The experiment results were correlated to obtain the empirical friction factors and the loss factors for the components commonly used in a fluid resuscitation system. The modified Bernoulli equation with the correlated friction factors and loss factors for the components were used to evaluate the pressure and flow relationship in the fluid resuscitation system with peripheral and central catheters. Fair agreements were observed from the comparison of the predictions of the total driving pressure and test results from water, crystalloid and colloid solutions. The modified Bernoulli equation is, therefore, applicable to evaluate the pressure-flow relationship for efficient fluid resuscitations. The coefficients of flow (F) and the square of flow (F2) for the binominal model are varied with the changes of geometry and size of the infusion components, fluid properties and the units of parameters. These coefficients for the fluids and catheters tested in this study were also listed for reference.