What access method is preferred if IV access is difficult in the field?

• A. Peripheral IV access
• B. Intraosseous (IO) access
• C. Central venous line
• D. Subcutaneous catheter

Answer: (B)

When IV access is difficult in the field, intraosseous access is preferred because it provides rapid, reliable entry into the systemic circulation by delivering fluids and medications directly into the bone marrow. This bypasses collapsed or inaccessible peripheral veins and can be established in seconds with minimal equipment, making it ideal for emergent resuscitation in austere environments. It works for both adults and children and allows large-bore flow, which is essential for rapid fluid administration and emergency drugs.

Peripheral IV access can be unreliable when veins are hard to locate or collapsed from shock, so it may take longer or fail altogether. Central venous lines require more time, sterile technique, and equipment, with higher risk in field conditions, so they’re not practical as a first option in emergencies. Subcutaneous catheters don’t provide the rapid onset needed for urgent resuscitation. Intraosseous access sites include the proximal tibia or proximal humerus and can be established quickly with common IO kits.