Flow Rates with Intraosseous Catheterization

Patients who receive intraosseous (IO) infusion may require large infusions of crystalloid fluid, blood products, and other high-volume medications during emergent resuscitation to treat hypotension or other conditions associated with low intravascular fluid volume. Consequently, the maximal rate at which fluids can be safely infused through an IO catheter is an important determinant of the appropriateness of IO vascular access for hemodynamically unstable patients. Factors that influence the rate of flow through an IO catheter include the length and gauge of the IO infusion catheter, the amount of pressure used to infuse the fluid, the length and intrinsic resistance to flow associated with IV tubing, the resistance to flow within the medullary space, and the rate of egress from the marrow into the venous circulation. This chapter discusses how these and other variables affect the rate of fluid infusion through an IO catheter, as well as the relative advantages and disadvantages for various infusion methods as they relate to flow rate. Various strategies for enhancing the flow rate achievable with IO infusion will be reviewed, including how these strategies relate directly to anatomic, physiologic, and device-specific considerations.