The concept of using the medullary (marrow) cavity of a bone for the administration of medications and fluids dates from 1920s when adults suffering from pernicious anaemia were transfused via their sternum. In the long bones, the medullary cavity consists of a network of venous sinusoids. These sinusoids drain into large medullary venous channels, which in turn, drain into nutrient or emissary vessels. These vessels exit the bone via the nutrient foramina and empty directly into the systemic venous circulation. As intravascular technology and surgical techniques developed, intraosseous cannulation fell from favour and by the 1950s had been largely superseded by other access routes. However, as advances in paediatric resuscitation have been made, the need for rapid circulatory access in collapsed children was highlighted and the intraosseous route has become the route of choice when the child has no other central access already in situ in a clinical emergency situation. (Resuscitation Council (UK), 2006; Advanced Life Support Group, 2005)
Using an EZ-10 electric drill to insert the catheter needle: Insertion is under 10 seconds. (right)
There is a paper that suggests intraosseous infusion in critically ill patients does not have to be performed in a bone that contains a medullary cavity but this is not currently accepted practice. Intraosseous Infusion is an effective alternative in Emergency Medicine when IV access cannot be obtained.
Intraosseous infusion is the process of injection directly into the marrow of the bone. The needle is injected through the bone's hard cortex and into the soft marrow interior.
Benefits:
- Stable and secure
- Drug delivery equivalent to central venous catheter
- Effective, safe, multi-site placement for patients of all sizes
- Battery power makes insertion easy and controlled
- Standard Luer-lock catheter
- Delivers medications directly into the vascular system with serum levels equivalent to IV and central venous administration
- Simple removal
The Paediatric BIG (Bone Injection Gun) was developed to help caregivers save lives by providing rapid, safe and easy intravascular access through the bone marrow. The Paediatric B.I.G. has been distributed and administered by healthcare providers since 2001.
B.I.G. (Bone injection gun - left)
Often the antero-medial aspect of the tibia is used as it lies just under the skin and can easily be palpated and located. Anterior aspect of the femur and the superior iliac crest are other sites that can be used.
This route of fluid and medication administration is an alternative to the preferred intravascular route when the latter can't be established in a timely manner especially during paediatric emergencies. When intravascular access cannot be obtained in paediatric emergencies, intraosseous access is usually the next approach. It can be maintained for 24-48 hours, after which another route of access should be obtained. Intraosseous access is used less frequently in adult cases due to greater difficulty penetrating denser adult bone.
Although intravascular access is still the preferred method for medication delivery in the pre-hospital 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 some areas, IO is now a preferred administration over ET (endotracheal) drug administration. This is also the current standard of care in New York City's 911 system in cardiac arrest patients where intravenous access attempts have failed.
Furthermore, the wider range of medications that can be introduced via IO has caused adult IO systems (most of which use a mechanical or powered drill to place the catheter) to become more common in the pre-hospital 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 (ET) administration allows only specific drugs that have relatively low toxicity to lung tissue, and must be restricted to relatively low volumes to prevent drowning the patient.
Effectiveness
This American Heart Association guideline cited two randomized controlled trials, one of 60 children and one of electively cannulated haematology/oncology patients. In addition, uncontrolled studies have been performed, one of which reported 72% to 87% rates of successful insertion.
Example of an intraosseous infusion:
- When intravenous access has proved impossible, an intra-osseous infusion can be life-saving. It can be used to administer anything that would normally be given intravenously, i.e. fluids, whole blood, packed cells, and drugs.
- Equipment shown: EZ-10
- Alcohol swabs.
- A small syringe and fine needle for giving local anaesthetic (unnecessary if patient is comatose).
- An 18-gauge needle with trochar (special needles are made for intra-osseous infusion). Alternatively a bone-marrow aspiration needle, or even a standard 17-21 gauge disposable needle, can be used, with care.
- An IV bottle and drip-set, or 50-ml syringe containing fluid for infusion.
- Local anaesthetic, e.g. 1% lidocaine.
- Procedure (with full sterile precautions)
- Choose a point for insertion of the infusion needle in the middle of the wide flat part of the tibia, about 2 cm below the line of the knee joint. Do not use a site of trauma or sepsis.
- If the patient is conscious, infiltrate the skin and underlying periosteum with local anaesthetic.
- With the needle at right angles to the skin, press firmly with and pull trigger until the needle enters the marrow cavity with a sudden give.
- Attach a 5-ml syringe and aspirate to confirm that the position is correct. The aspirate can be used for blood films, blood culture and blood glucose measurement.
- The infusion needle should be held in place using sticking plaster (or a plaster of Paris cast, as with scalp vein infusions) and the child's mother or carer entrusted with holding the leg.
- You can place an infusion in each leg, either simultaneously or in sequence, if necessary.
- An infusion allowed to drip through the needle in the usual way (by gravity) may go very slowly. For urgent administration use a 50-ml syringe to push in the required fluid in boluses.
Possible complications
- Sepsis. Do not leave an intra-osseous line in one site for more than 6-8 hours. After this time sepsis is increasingly likely to develop.
- Compartment syndrome. If the needle is allowed to pass entirely through the tibia, fluid may be infused into the posterior compartment of the leg causing swelling and eventually impairing circulation. Check circulation in the distal leg at intervals.
Sources:
http://circ.ahajournals.org/cgi/content/meeting_abstract/118/18_MeetingAbstracts/S_821-a
http://www.vidacare.com/ez-io/index.html
http://en.wikipedia.org/wiki/Intraosseous_infusion
http://www.fast1sternal.com/about-fast1/defense/
http://www.ich.ucl.ac.uk/clinical_information/clinical_guidelines/cpg_guideline_00049/
Article compiled and edited by John Sandham IEng MIET MIHEEM
Dec 2009
