Intraosseous access is indicated when which of the following conditions exist?

• A. There is trauma to the extremities, for small children and after two unsuccessful IV attempts on a combat casualty with altered mental status and absent radial pulses.
• B. Only for adults with rapid blood loss.
• C. Only for chest injuries with no IV access.
• D. Never used in the field.

Answer: (A)

The main idea here is that intraosseous access is a rapid alternative route when veins are not readily accessible, especially in injured or shocked patients and in young children. Establishing IV access can be time-consuming or impossible in a combat casualty with poor perfusion, so an IO line through the bone marrow provides fast, reliable access to fluids and medications.

The scenario fits this exactly: there is trauma to the extremities, there is a small child, and there have already been two unsuccessful IV attempts in a casualty with altered mental status and absent radial pulses. Altered mental status and no pulse in the periphery indicate shock and very poor venous filling, making IV access unreliable and slow. In that situation, intraosseous access is indicated to deliver fluids and drugs quickly to stabilize the patient.

The other options are not correct because they unnecessarily limit IO use to adults, to chest injuries, or claim it’s never used in the field. In reality, IO access is widely used in the field, including in children, and is not restricted to chest trauma. It’s chosen precisely because IV access is difficult or failed and rapid administration is needed.