Bone Injection Gun
Bone Injection Gun
Here is a review for the Bone Injection Gun which we are currently carrying on our units. These devices are far superior to the old twist and drill style devices many of us have used since we began performing this procedure.
Long Bone Physiology and The Principle Behind Intraosseous Infusion
As we all know, bones are living, functioning organs, just like the other organs of the body. Bones require oxygen and glucose in order to produce energy and the metabolic products (red blood cells, endogenous factors of the immune system, etc.) unique to this system. The supply of oxygen and glucose is derived through blood vessels, which are distributed from the hard structure of the bone cortex through the softer skeletal centers.
In each of the long bones (tibia, femur) there are a number of openings through which arteries enter the bone, as well as a number of openings where veins exit the bone, which serve to drain the blood back into the vascular system. Most of these openings are concentrated in the area called the Epiphysis, located in the upper part or endpoint of the bone (the joint area). Another feature of the Epiphysis is that the cortex tissue in this area is usually thinner than in the main part of the bone.
The structure of the bone cortex is interesting unto itself, being composed of a series of transport blood vessels called the Haversian canal system, situated in tubular centers called Minerlized Matrix which make up most of the hard cortex, and the Volkman canal system, which crosses through those tubular centers. Looking even deeper inside the space within the bone, we find a system of tubes called the Trabecular space.
This system is too complex for a simple explanation, but it is important to note that it diffuses dissolved materials in the blood, and performs osmosis on larger volumes of fluid to accommodate the system of blood vessels that enter and exit the bone.
Priciples of Intraosseous Technique
The fundamental principle behind any Intraosseous technique is based on this unique complex of blood vessels. A system that penetrates into the Trabecular space and introduces liquids at a positive pressure will cause increased diffusion "with the current" and in fact pass on quantities of water into the blood system, which drain the Trabecular cavities.
In simple terms, we are introducing material into a filtering system with adaptable permeability.
Why the adaptable permeability? For the simple reason that, as the pressure of the flow into the system increases, the molecules that make up the cell membranes of the Trabecular canals, the Haverisan canals and the Volkman canals expand, causing larger drainage spaces for permeability. The result, naturally, is a higher flow volume.
Once the introduction of fluid at high pressure is stopped, the system immediately returns to its original size, and will continue to enable transmission of fluids, although at a slower rate, as long as the external pressure created by the fluid is higher than the pressure inside the bone.
These two configurations enable the healthcare provider to supply the rate of flow according to the patient's condition. For example, a patient requiring medication through a drip counter will not need a high-pressure flow. However, a patient who is in hypovolemic shock can receive the necessary quantities of fluids through high-pressure infusion.
This short overview can be summarized by the importance of the channeled structure of the bone interior through which accelerated diffusion allows fluids and medications to be introduced into the blood system.
Things to remember about this procedure and our protocols:
- This procedure is for children 6 years of age or younger with a life threatening illness or injury after effective ventilations is established.
- Must be preformed by a Paramedic.
- Contraindications include burn, fracture and infection.
- Site is to be cleaned thoroughly with betadine.