Establishment of access to the circulation is a critical component of resuscitation. The preferred venous access site during cardiopulmonary resuscitation (CPR) is the largest, most accessible vein that does not require the interruption of resuscitation. Peripheral venous access is attempted before attempting other forms of vascular access if peripheral veins can be readily seen or palpated. (See "Vascular (venous) access for pediatric resuscitation and other pediatric emergencies" and "Peripheral venous access in adults".)
Intraosseous infusion, a technique for vascular access, was described first in 1922 and was widely used for drug administration in children in the 1940s [1-6]. It fell out of favor during the 1950s and 1960s, when disposable intravenous catheters were developed and techniques for insertion improved. In the 1980s, after the publication of numerous clinical reports of its effective use in children and animal models [7-10], the practice of intraosseous infusion increased. Use in adults has also grown, especially in the prehospital setting [11,12]. Today, the procedure is reserved for acute, life-threatening or medically necessary situations when standard venous access methods cannot be rapidly achieved and as the first attempt at vascular access in cardiopulmonary arrest or severe shock.
Intraosseous (IO) infusion is possible because of the presence of veins that drain the medullary sinuses in the bone marrow of long bones (figure 1) . These veins, supported by the bony matrix, do not collapse in patients with shock or hypovolemia. The major vessels into which the intramedullary veins drain depend upon the insertion site. The following list provides the site and draining vessels for the most commonly used sites:
- Proximal tibia – Popliteal vein
- Femur – Branches of the femoral vein
- Distal tibia (medial malleolus) – Great saphenous vein
- Proximal humerus – Axillary vein
- Manubrium (upper sternum) – Internal mammary and azygos veins
The anterior inferior iliac spine, clavicle, and distal radius have also been used successfully for IO vascular access as have bones without medullary cavities, including the calcaneous and radial styloid [14-16].