Several of the steps in administering a medication by the IV or IO route have already been highlighted, as they apply to other routes of administration. These include looking for casualty medication allergies, confirming the five “rights,” and reconstituting any medications that may have come in powdered formulations.
There are three primary delivery set-ups you are most likely to encounter. One is an IV saline lock, another is an IO extension set, and the third is an IV infusion, either connected to a saline lock or an IO extension set. The subtle differences in administration are based on which set-up is being used with your casualty.
In the case of an IV saline lock, you can use the same needle that you used to draw up the medication to push it through the saline lock (after sterilizing it). After the infusion, it is important to flush the saline lock for two reasons. One is to make sure none of the medication remains in the saline lock hub or catheter, and the other is to keep the lock patent and ready for the next infusion.
The rate of infusion can be important, so keep in mind that some medications can be infused rapidly, while others should be done by a slow (sometimes very slow) IV push. For example, the recommendation for ketamine is to give the 30 mg dose over one minute. Drawing from a vial with a concentration of 50 mg/ml, that would be 0.6 ml of ketamine. Infusing that over 60 seconds may be very difficult, given the small volume, so you may choose to dilute it so that your syringe has a greater volume and it is easier to gauge a 60-second infusion. Naloxone, on the other hand, can just be pushed without a timing consideration.
The IO extension sets do not routinely come with a saline lock hub but are often capped with a Luer-type cap and lock. The extension set should have a clamp between the cap and where the tubing enters the bone, and any time the cap is off while changing syringes or recapping, that clamp should be closed to prevent flow in or out of the casualty. In this scenario, you will need to remove the needle from the syringe with the medication and screw the syringe onto the IO extension adapter for administration. The same considerations with flushing and infusion rates apply, of course.
And when an IV line is already infusing fluids, that line can be used for IV medications. There should be a port close to the casualty for you to sterilize and use. To prevent the medication from flowing up the line, away from the casualty, you should clamp the IV line between the injection port and the fluid source, either with an IV clamp or by manually pinching the line. Once medication has been delivered, release the fluids and resume the baseline infusion.
Depending on the fluids being infused, they may serve as a flush, ensuring that the rate allows for a satisfactory bolus to be administered. But sometimes the fluids don’t serve as a good flush – for example, if blood products are being administered – and in those cases, it is still appropriate to do a syringe flush before resuming the infusion.
In the TFC setting, the five analgesia-related medications that are potentially delivered intravenously or intraosseously include ketamine, naloxone, ondansetron, fentanyl, and midazolam (with current recommendations that Combat Paramedic and provider level medics administer IV/IO fentanyl and/or midazolam, when indicated).