Which statement is an IO contraindication?

• A. Fractures at the IO site
• B. Nasal obstruction
• C. Osteoporosis
• D. Scar indicating prior sternotomy

Answer: (A)

Fractures at the IO entry site block intraosseous access because the bone needs to be intact to anchor the needle and allow delivery of fluids into the marrow. A fracture there compromises stability, increases the risk of needle misplacement or further injury, and can cause fluids to leak into surrounding tissue rather than flow into the vascular system. That’s why this is a contraindication for IO placement—you would choose a different site or a different access method.

Nasal obstruction doesn't affect intraosseous access since it concerns intranasal routes, not IO. Osteoporosis isn't an outright contraindication to IO; with careful site selection and technique, IO can still be performed. A scar from prior sternotomy likewise doesn't automatically prevent IO placement, as you can often use another bone site if needed.