IO (Intraosseous) Infusion

IO (Intraosseous): This route involves the injection of medications or fluids directly into the marrow cavity of a bone. It is a quick and effective method to administer substances, especially in emergency situations where intravenous (IV) access is challenging or time-consuming. The intraosseous route is commonly used in critical care settings like cardiac arrest or severe trauma, where rapid access to the circulation is crucial.

Common IO Infusion Sites

• Proximal Tibia: The most common site, located just below the knee. The insertion point is approximately 2 cm below the patella and 1 cm medial to the tibial tuberosity. It's favored for its ease of access and the minimal amount of subcutaneous tissue, which facilitates rapid infusion.
• Distal Tibia: Accessed about 3 cm above the medial malleolus (the bump on the inner side of the ankle). This site is often used in infants and small children under the age of 6, where the proximal tibia might be less accessible.
• Proximal Humerus: This site is increasing in popularity, especially in adults, because it is close to the heart, allowing for rapid circulation of infused medications. The insertion is at the greater tubercle of the humerus, which is felt at the upper aspect of the arm.

Specific Sites to Avoid:

• Distal Radius and Ulna: These sites are less commonly used due to the higher risk of complications and the smaller bone marrow space, which may not facilitate effective fluid and medication administration.
• Pelvis or Iliac Crest: These are generally not recommended due to the difficulty in accessing and securing the IO device, as well as the potential for injury to surrounding organs.

Sites to Avoid for IO Access

• Areas with obvious fractures or previous orthopedic procedures: Inserting an IO needle into a fractured bone or a limb with hardware (screws, plates) can cause further damage and complications.
• Infected or burned skin: These areas pose a high risk of introducing infection directly into the bone marrow and systemic circulation.
• Areas with compromised circulation or significant soft tissue injury: These might interfere with the efficacy of fluid and medication delivery.

When selecting an IO insertion site, it is vital to consider both the benefits and potential risks associated with each anatomical location. Proper training and adherence to best practices in IO infusion are essential to maximizing effectiveness and minimizing complications in emergency and critical care settings.