Airway & Respiratory, Columns, Patient Care

A Comparison of IO and IV Methods

Review of: Von Hoff DD, Kuhn JG, Burris, HA 3rd, et al: “Does intraosseous equal intravenous? A pharmacokinetic study.” American Journal of Emergency Medicine. 26(1):31-38, 2008.

The Science
Cancer patients were selected to have an intraosseous (IO) medication delivery port placed in their iliac crest. This was done by a general surgeon. Within two weeks of having the port installed they received morphine for their pain. Maximum serum levels and speed to reach that level were measured. This information was compared to similar patients who received morphine intravenously.

From a pharmacokinetic perspective, they didn’t see difference between the IO and IV routes.

The Street
Several studies have already shown that the bioavailability of medications is equivalent with IO and IV administration. However, the majority of these studies involved animals. This is one of the first human studies to examine the two delivery modalities. But does it answer the question it poses in its title? Let’s examine the unanswered questions.

The study patients had their IO device implanted in the iliac crest. This not the site used by EMS. Is there a difference in the bioavailability of the iliac crest and the tibial tuberosity or the humeral head? I don’t know. Furthermore, although the authors don’t describe what type of IV access the patients had, it’s safe to assume that they more than likely had central lines such as a Hickman or other port because they are cancer patients. How does this delivery of medication compare to the 18-gauge IV in the arm? Again, I don’t know but suspect there is a difference.

And finally, these were relatively healthy patients with normal renal function and not in shock. Does shock change the bioavailability of medications administered intraosseously? I don’t know.

Although I support expanding use of IO drug administration, it would be nice to have more real-life data to use to support our assumptions.