Hemofiltration: determinants of drug loss and concentration

Ultrafiltration has proven to be an effective method of reducing post-cardiopulmonary bypass edema and the inflammatory response associated with activation of the complement cascade. Recently, a modified ultrafiltration process has been developed which allows further hemoconcentration after weaning from bypass. Both of these procedures can have an effect upon the concentrations of many of the pharmaceutical agents being used either pre- or perioperatively. Based upon work done by other investigators in the field of dialysis, we have developed sieving coefficients for many cardiovascular drugs in order to provide an estimation of their loss during extended periods of hemofiltration. Our study utilized the pharmacological and physical characteristics for volume of distribution and protein binding to determine the movement of drugs through a hemofilter. Our results demonstrated that concentrations of certain drugs used during open heart surgery may be significantly increased or decreased with the use of hemofiltration techniques.