CHAPTER 198 Intraosseous Vascular Access

One of the most frustrating and difficult challenges faced by a clinician is the establishment of vascular access in the critically ill patient. Establishment of peripheral intravenous (IV) access is often difficult in the patient who is in shock or cardiac arrest, and is notoriously difficult in the small pediatric patient. For children younger than 5 years of age, thin bones and a vascular marrow make intraosseous vascular access (IOVA) a fairly simple alternative. For years, plain hypodermic needles, spinal needles, or bone marrow aspiration needles (e.g., Jamshidi) were used for IOVA. Eventually, special IOVA needles with a handle and a screw tip were developed. Later models were developed with flanges to better secure them to the patient with tape after insertion. Recently, kits combining IOVA needles with either a small, portable, battery-powered drill or a spring-loaded disposable needle gun have increased the use of this technique in adults. In fact, many hospitalists now use IOVA in adults more often than in children. Using IOVA, after the needle traverses the cortex, the venous plexus in the marrow cavity (Fig. 198-1) functions as a rigid “vein” or conduit for fluid; it does not collapse with hypovolemia or even shock. This procedure is now so successful that many national and international organizations have recommended its use as the primary or secondary method of obtaining and maintaining vascular access in the critically ill patient. Use of IOVA is also increasingly common and accepted as an alternative to a central line for short-term infusions in nonemergent situations.

Figure 198-1 Intramedullary venous system. With intraosseous venous access, the marrow cavity functions as a “vein” that will not collapse.

IOVA was originally described in the 1920s. However, with the introduction of plastic catheters and improved peripheral IV access skills, the need and interest for IOVA diminished. In the 1980s, IOVA saw a resurgence in use as a rapid method for vascular access in pediatric shock emergencies. It was also studied for use with regional anesthesia in Europe. IOVA has now been studied and proven to be a safe, reliable, and rapid temporary method for vascular access in adult shock emergencies, especially compared with percutaneous IV access. The American Heart Association, the American Academy of Pediatrics, and the American College of Surgeons recommend vascular access by IOVA in emergency situations when venous access is not immediately possible. Any medication or fluid that can be given IV can also be administered by IOVA. After a 5- to 10-mL flush with normal saline, medications are immediately absorbed into the systemic circulation; drug concentrations and onset of action match those given through a central venous line during cardiopulmonary resuscitation (CPR). In addition to serving as a route for fluid administration, the IOVA needle may be used for obtaining blood type, cross-matching, and blood chemistry determinations from the marrow cavity. Serum electrolyte, blood urea nitrogen, creatinine, glucose, and calcium levels are very similar to those in samples obtained from an IOVA aspirate.

One disadvantage of IOVA is the temporary nature of the procedure (it should not be used for more than 24 to 48 hours). Another, disadvantage is that infusion rates may be limited; however, rates can also reach more than 150 mL/min with a 16-gauge needle and a pressure infusor bag (blood pressure cuff inflated to 300 mm Hg around the IV fluid bag), an infusion pump, or with forceful manual pressure. The rate-limiting factor is usually the size of the marrow cavity. IOVA also is not universally successful; however, in the past, success rates were limited in older children and adults because needles often bent when attempting to penetrate thicker bones. Success rates have improved since the development of kits specially designed for this procedure.

One retrospective study of pediatric cardiopulmonary arrest patients revealed that, although the time to obtain peripheral IV was occasionally minimal, the average time was a disappointing 7.9 ± 4.2 minutes. The overall peripheral IV success rate was only 17%. Of all techniques used, the success rate was highest with IOVA (83%), next most successful was surgical cutdown (81%), and central venous line placement (CVP; 77%) came in third. The average time required to establish vascular access was 4.7 minutes for IOVA (using older equipment not specially designed for this procedure), followed by 8.4 minutes for CVP, in turn followed by 12.7 minutes for venous cutdown. Using newer kits specially designed for IOVA, the success rate has significantly improved over the prior 83%.

In the cardiopulmonary arrest situation, it is reasonable to use IOVA as the initial approach for vascular access because of the high success rate and the rapidity of the procedure. In fact, all providers of emergency care (including hospitalists) should be familiar with IOVA because in certain situations it may be the only available means of obtaining vascular access. It should be noted that since the last edition of this textbook was published (2003), this procedure has been moved from the Pediatrics section to the Hospitalist section; again, many hospitalists use IOVA in adults more often than in children. To learn the procedure or to maintain skills for IOVA, clinicians can practice on cadavers, raw chicken drumsticks, swine ribs, or piglet tibias. Mannequins are also available for practice from the manufacturers of the special IOVA kits.

The proximal tibia (Fig. 198-2), just below the growth plate, is the preferred site for IOVA for children younger than 5 years of age. At this level, the tibial tuberosity is a broad, flat surface close to the skin and there are few intervening muscles, nerves, and blood vessels; therefore, bony landmarks are easily recognized.

Figure 198-2 Proximal tibial needle insertion.

Recently, IOVA kits with either a battery-operated drill (EZ-IO; Vidacare, Dallas) or a spring-loaded needle gun (Bone Injection Gun [BIG]; WaisMed, Houston) have been demonstrated to be effective for use in the proximal humerus; having vascular access above the diaphragm during CPR is considered important by many clinicians. The distal tibia (Fig. 198-3), just above the medial malleolus, the lateral or medial malleolus, the distal radius, ulna, or femur (Fig. 198-4), the anterior-superior iliac spine, and the sternum are alternate sites for IOVA. Whereas the distal tibia is a good choice because the bone and tissues are thin, the distal femur is covered with muscles and fat, often making palpation of bony landmarks difficult. The distal femur should probably be reserved for those cases in which other sites cannot be used. The sternum and ilium are seldom used in children because the width of the marrow space is inadequate if younger than 3 years of age, and insertion may be technically difficult and dangerous. In children and adults, the sternal site carries a risk of mediastinal puncture.