Intraosseous infusion (IO) is the process of injecting directly into the marrow of a bone to provide a non-collapsible entry point into the systemic venous system. This technique is used in emergency situations to provide fluids and medication when intravenous access is not available or not feasible. A comparison of intravenous (IV), intramuscular (IM), and intraosseous (IO) routes of administration concluded that the intraosseous route is superior to intramuscular and comparable to intravenous administration.
The needle is injected through the bone's hard cortex and into the soft marrow interior which allows immediate access to the vascular system. An IO infusion can be used on adult or pediatric patients when traditional methods of vascular access are difficult or impossible. Often the antero-medial aspect of the tibia is used as it lies just under the skin and can easily be palpated and located. The anterior aspect of the femur, the superior iliac crest and the head of the humerus are other sites that can be used.
This route of fluid and medication administration is an alternative one to the preferred intravascular route when the latter cannot be established in a timely manner. When intravascular access cannot be obtained intraosseous access is usually the next approach. It can be maintained for 24–48 hours, after which another route of access should be obtained.
Although intravascular access is still the preferred method for medication delivery in the prehospital area, advances in IO access (such as the F.A.S.T.1 and the EZ-IO system) for adults has caused many systems to re-think their preferred secondary access route. In Massachusetts, for example, IO is now a preferred administration over endotracheal (ET) drug administration. In fact, the American Heart Association no longer recommends using the endotracheal tube for resuscitation drugs since the efficacy is unclear. Paramedics may perform intraosseous infusion in a cardiac arrest patient if no vein is clearly visible. The IO is becoming more and more common in emergency medical services (EMS) systems around the world.
Furthermore, any medication that can be introduced via IV can be introduced via IO. Because of this, adult IO systems (most of which use a mechanical or powered adjunct to place the catheter) have become more common across the United States in the prehospital setting. Intraosseous access has roughly the same absorption rate as IV access, and (unlike ET administration) allows for fluid resuscitation as well as high-volume drugs such as sodium bicarbonate to be administered in the setting of a cardiac arrest when IV access is unavailable. Endotracheal administration allows only specific drugs that have relatively low toxicity to lung tissue, and must be restricted to relatively low volumes to avoid drowning the patient.
Due to the rapid advance and adoption of superior intraosseous access technology, IO access has now become the preferred method of establishing vascular access for patients in whom traditional access is difficult or impossible. This includes patients experiencing cardiac arrest, major trauma, airway compromise, severe dehydration, and/or hypoperfusion (shock). IO is also an alternative route for patients who typically have poor peripheral vasculature or challenging vascular access such as diabetics, renal patients, burn victims, IV drug users, obese patients, dehydrated patients, the very young or elderly patients, and others. Many EMS services and hospitals are now using IO as their first line solution for vascular access in both adult and pediatric cardiac arrest victims, enabling administration of lifesaving drugs much earlier than previously possible with traditional peripheral IV placement.
IO Devices 
There are several FDA approved IO devices including Vidacare's battery-powered EZ-IO and Pyng's hand-powered FAST1 and (FAST-X) FAST-COMBAT and FAST-RESPONDER. Other devices include the spring-loaded WaisMed's BIG Bone Injection Gun (BIG), the COOK IO needle, and the Jamshidi 15G.
There have been at least two studies comparing the EZ-IO and the BIG. Another paper  compared the EZ-IO with the COOK IO needle. These three papers all found a minor preference for the EZ-IO. Another study  compared the Jamshidi 15G, the BIG 15G, and the FAST1, finding median insertion times of 38, 49 and 62 seconds respectively (p = 0.004).
The EZ-IO is used by 90 percent of US advanced life support ambulances and over half of US Emergency Departments, as well as the US Military, and is available in over 50 countries worldwide. The EZ-IO is FDA-cleared for use on adult and pediatric patients in medically necessary instances, including difficult vascular access situations, as well as resuscitation and shock. The EZ-IO can be inserted in the proximal tibia, proximal humerus and the distal tibia.
Pyng's FAST1 and FASTx (FAST-COMBAT, FAST-RESPONDER) is inserted into the manubrium (upper sternum). This device completely removes any guesswork during application. It is the only device that operates in this fashion, and is therefore deployable under limited visibility, in moving vehicles and under otherwise austere conditions. This device cannot be "over deployed," to penetrate the target bone (manubrium) and enter the anterior mediastinum; other devices that are hand drilled, or mechanically drilled have been confirmed as having done this in several post-mortem radiologic examinations.
This American Heart Association guideline cited two randomized controlled trials, one of 60 children and one of electively cannulated hematology/oncology patients. In addition, uncontrolled studies have been performed, one of which reported 72% to 87% rates of successful insertion.
- Tobias JD, Ross AK (2010). id=PMID 19897801 "Intraosseous infusions: a review for the anesthesiologist with a focus on pediatric use". ANESTHESIA & ANALGESIA 110 (2): 391–401.
- Moore GP, Pace SA, Busby W (1989). "Comparison of intraosseous, intramuscular, and intravenous administration of succinylcholine". PEDIATRIC EMERGENCY CARE 5 (4): 209–210. PMID 2602189.
- Vreede E, Bulatovic A, Rosseel P, Lassalle X (December 1, 2000). "Intraosseous Infusion" (PDF). Update in Anaesthesia (World Federation of Societies of Anaesthesiologists) 12: 38–40. ISSN 1353-4882. Retrieved 2010-07-03.
- "EZ IO system".
- Leidel BA, Kirchhoff C, Braunstein V, Bogner V, Biberthaler P, Kanz KG (August 2010). "Comparison of two intraosseous access devices in adult patients under resuscitation in the emergency department: A prospective, randomized study". Resuscitation 81 (8): 994–9. doi:10.1016/j.resuscitation.2010.03.038. PMID 20434823.
- Shavit I, Hoffmann Y, Galbraith R, Waisman Y (September 2009). "Comparison of two mechanical intraosseous infusion devices: a pilot, randomized crossover trial". Resuscitation 80 (9): 1029–33. doi:10.1016/j.resuscitation.2009.05.026. PMID 19586701.
- Brenner T, Bernhard M, Helm M, et al. (September 2008). "Comparison of two intraosseous infusion systems for adult emergency medical use". Resuscitation 78 (3): 314–9. doi:10.1016/j.resuscitation.2008.04.004. PMID 18573590.
- Hartholt KA, van Lieshout EM, Thies WC, Patka P, Schipper IB (2010). "Intraosseous devices: a randomized controlled trial comparing three intraosseous devices". Prehosp Emerg Care 14 (1): 6–13. doi:10.3109/10903120903349861. PMID 19947861.
- Bloch SA, Bloch AJ, Silva P. Adult intraosseous use in academic emergency departments and simulated comparisons of emergency vascular access techniques. Annals of Emergency Medicine 2010;56(3):S152.
- Internal marketing data, Vidacare Corporation, Shavano Park, TX. Verbal communication, Steve Dralle, Director of Marketing.
- Sarkar D, Philbeck T. The use of multiple intraosseous catheters in combat casualty resuscitation. Mil Med 2009;174:106-8.
- Cooper BR, Mahoney PF, Hodgetts TJ, Mellor A. Intra-osseous access (EZIO ®) for resuscitation: UK military combat experience. JR Army Med Corps 2008;153:314-6.
- www.vidacare.com (http://www.myvidacare.com/purchase/index.aspx). Accessed January 3, 2010.
- Banerjee S, Singhi SC, Singh S, Singh M (1994). "The intraosseous route is a suitable alternative to intravenous route for fluid resuscitation in severely dehydrated children". Indian pediatrics 31 (12): 1511–20. PMID 7875811.
- Brickman KR, Krupp K, Rega P, Alexander J, Guinness M (1992). "Typing and screening of blood from intraosseous access". Annals of Emergency Medicine 21 (4): 414–7. doi:10.1016/S0196-0644(05)82661-7. PMID 1554180.
- Frascone RJ, Jensen JP, Kaye K, Salzman JG (2007). "Consecutive field trials using two different intraosseous devices". Prehospital emergency care : official journal of the National Association of EMS Physicians and the National Association of State EMS Directors 11 (2): 164–71. doi:10.1080/10903120701205851. PMID 17454802.
- Davidoff J, Fowler R, Gordon D, et al. (2005). "Clinical evaluation of a novel intraosseous device for adults: prospective, 250-patient, multi-center trial". Journal of Emergency Medical Services 30 (10): suppl 20–23. PMID 16382512.
- B.I.G- First Automatic Intraosseous Devices by WaisMed Ltd.
- Pyng Medical's F.A.S.T.1 Intraosseous Infusion System
- Vidacare intraosseous infusion products
- MeSH E05.300.510.560