Collaborative Hypertext of Radiology

contrast media

side-effects from high osmolality / viscosity (fluid shifts from different compartments)
- vasodilatation
- heat
- pain
- osmotic diuresis
- hemodynamic changes
pharmacokinetics
- distribute volume into extracellular space
- clearance by glomerular filtration and renal excretion
physiologic reaction
- increased plasma osmolality causes fluid shift from RBCs and pulmonary tissue leading to increased plasma volume
- then osmolar gradient reverses with passage of contrast bolus -> pulmonary capillary endothelium leaks protein into pulm interstitium --> increased pulmonary edema
- transient cardiovascular changes (magnitude increased with tonicity of medium)
  - increased PAP
  - increased CO with decreased peripheral/pulmonary vascular resistance
  - decreased systemic arterial pressure (variable)
- may activate gen receptors causing side effects

Ruth Carlos, MD - 10 January 1996
Last updated: 1 October 2013