Not So Rapidly

Here is another Normal Sinus Rhythm post. My apologies for being late, again. The topic this week is unthemed, but I found the last post by Peter at Street Watch: Notes of a Paramedic to be a very useful topic – Drips, Slow Pushes, since this is one area where EMS is a font of misinformation. Read the rest of the NSR Blog posts at NSR Week 8.

Writing about D50W (50% Dextrose in Water) Peter mentions difficulty obtaining the product label for D50W. This is not really a surprise. First a bit about medication information, then information about D50W. The PDR (Physicians’ Desk Reference, some information from Wikipedia about the PDR) is paid for by the drug manufacturers. You will not find D50W, atropine, and some other commonly used medications. These medications are usually only available as generic medications and there is no incentive to pay to advertise a drug with little profit potential. The old way to get the product label, or package insert, for these medications was to ask the staff at the pharmacy. Extremely helpful people. When they open a case of these drugs, there is a label inside. The individual boxes, such as the D50W (pictured at the end), do not include the label. The side panel on the D50W instructs you to refer to the label – “usual dosage: see insert.” The insert is not in this box, but it was in the bigger box that this box came in. Not very helpful if you do not go to the pharmacy and ask the pharmacists about the product information.

One of the other examples of the way the manufacturers use the PDR as a sales catalog is that the medications are not arranged by type of drug, or alphabetically, or by any other method that would be useful in patient care. They are arranged by manufacturer. This certainly makes it easier for the sales rep to go from one drug to the next without having to flip past any of the other manufacturers products that may be safer, more effective, or both.

Anyway, this post isn’t to whine about how manufacturers make it difficult to find information about the drugs we use, but to provide ways for you to be able to find that information from more reliable sources. The FDA (Food and Drug Administration) is responsible for the accuracy of the information on the drug labels, such as drug safety alerts and black box warnings. Unfortunately, the FDA web site is not easy to navigate. For an example of what a black box warning is and looks like, here is a link to the label for Inapsine (droperidol) and for 2 generic versions of droperidol (1 & 2). The thin black border around the warning is the black box. Not very impressive, but there are a lot of restrictions on the use of a black boxed drug, not just those in the warning. A web site called Formulary Productions has a section for looking these up. Oddly enough it is called Black Box Warnings. They do not seem to feel the need to make you have to jump through hoops to find some important information.

So far, the more commonly used relative of droperidol, haloperidol (Haldol) has not received a black box, but it has received some alerts about misuse. For comparison, look at the label for Haldol. No black lined box around the warnings, but there still are warnings. If you notice that there are a bunch of things written before the fda part of the web address, I have been using DailyMed a part of the NLM (National Library of Medicine), which is a part to the NIH (National Institutes of Health). I have only recently been using this site, but it is very useful. Much easier to navigate than the FDA site. Unfortunately, they do not include all drugs, but they claim they are expanding their listings. DailyMed will give you the information in a form that they feel is easier to use than the label that the drug manufacturers provide to the FDA, but they also have a link to the FDA approved label, if you prefer that. Yes, the FDA only approves the label, the manufacturer writes it. In the comments, Baby J mentions a site – British National Formulary – that is not available in the US. Access is free, with free registration, to residents of the UK and the developing countries listed here.

What about D50W?

This is one place where DailyMed is very useful, but you still need to search through the available formulations of dextrose products to find the 50% dextrose by injection. There are about 90 products that a “dextrose” search will return. Of those some are listed as “dextrose injection,” “dextrose injection, solution,” and there are other possibilities. If you recognize the brand that you use (Baxter, Braun, and Hospira are the only ones listed), that may help to narrow the search. The one I found most appropriate was dextrose (Dextrose) injection, solution [Hospira, Inc.]. Dextrose is the most confusing drug to locate easily, because so many different formulations are available. I don’t think any other drug comes close, so don’t let this intimidate you. They do not seem to have a way to search from the NDC (National Drug Code Directory) number. The FDA’s National Drug Code Query page will identify the drug based on the NDC number, but that does not link to anything informative. If you have the NDC number, you probably already know the name of the medication, the manufacturer, and the packaging.

Another method of finding a drug label is to use a search engine, put in the generic name of the drug, the word “label,” and “pdf” for the format. Many labels are printed as pdfs so that they can be printed out to read. One of Peter’s complaints was that the type is very small. I agree, the older I get the harder it is to read things that used to be effortless. The advantage of reading these on line is the ability to adjust the font. On the top of the sidebar I have listed information about adjusting the font size to something that is comfortable. This may not work in all browsers and is something that may need to be adjusted each time you view the page. You can also go into the browser settings and mess around in there (Tools -> Content -> Font, in Firefox). With a pdf it is easier, since the size adjustment is at the top of the page. It is easy to store pdf files on your computer to return to later. They have their own search engine built in for searching within that document.

Below I have included some low quality pictures of the outside of the D50W box. As you can see, the manufacturer is not listed anywhere on the front of the box. The side panel that demonstrates how to put the syringe together is clearly only for those who have not seen Emergency!, where they pop the caps off simultaneously. Of course, it is more difficult with D50W than with epinephrine.

How do you give D50W? Do you dilute it?

D50W is given to people who have had their blood sugar drop and are experiencing confusion, that appears to be due to the low blood sugar. I was taught, and still use this method. I look for the largest vein that looks good for an IV site. The label recommends a small needle in a large vein. I prefer a large needle. If you have ever pushed D50W through a 20 gauge catheter, you understand part of the reason. It takes a lot of effort. If you have ever pushed D50W through a 22 gauge catheter, you are insane (or management). An additional reason to use a large bore catheter is that I want to aspirate blood back into the IV tubing, every 5 ml, to try to make sure that there is not leakage (extravasation) into the surrounding tissue. Highly concentrated dextrose, and 50% is very highly concentrated for injection, can cause death of the tissue (necrosis) in the area where it leaks out of the vein. This prevents the dextrose from getting to the cells where it is needed. As long as you can aspirate blood back every few ml, you can be pretty sure that the line is patent (intact). By stopping the drug push, drawing back blood into the IV tubing, and then resuming the push, there should be a lot of dilution taking effect. Using a large bore catheter makes aspiration of blood easier, because molasses is not the only thing difficult to move through a small catheter. Think about what you would use to infuse blood, it would not be a small needle.

Is it effective at diluting the dextrose?

I don’t know. This is the way I was taught and have always done it. I would like to hear from anyone who has looked into this. With medications that are slow push, giving a bit, pausing, coming back and giving some more, repeating as necessary, is one way to minimize side effects. Most side effects seem to be rate related (rate of administration, not heart rate, or any other rate). With many medications, I prefer to set the drip rate, push my initial dose into the IV tubing and observe. This avoids the problem of being tied to the syringe. Another method is to keep the syringe hooked up to the tubing, pushing a bit more every 15/30/60 seconds, depending on what the medication is. This does have the potential for accidentally giving the entire syring in one dose. If you limit this to drugs that are on the less dangerous side, where you are more concerned about side effects that are uncomfortable, not side effects that are life threatening, then this can be used safely. JCAHO would never approve, but I have never had a problem. It can help to tape the syringe to the IV tubing, so that they do not become separated.

An amusing example of misunderstanding what rate of administration means was something I first observed when I was still a basic EMT. It was obvious that the person giving the medication had never thought about what was being done. This was in a big city level 1 trauma center. I’m taking the patient to another facility (I do not remember any of the details), the nurse wants to give some morphine to the patient before transport. This is something that is good. The nurse clamped the IV tubing to prevent it from flowing while the morphine was being given. Then the nurse held the syringe for about 2 minutes, pushing v e r y slowly for the whole time. My forearm was becoming sore, just watching this. Immediately after this, the nurse grabs a syringe of saline and pushes the saline to flush the line.

WTF?

The majority, if not all, of the morphine was still in the IV tubing. The nurse spent 2 minutes pushing the morphine into the IV tubing, just pushing out the IV solution. Then slammed the drug into the patient with a flush that served no purpose, other than to demonstrate a lack of understanding of drug administration. The good thing for the patient was that the morphine dose was probably only 2 mg. So the side effects would be minimal with rapid administration. The bad thing for the patient was that morphine dose was probably only 2 mg. So the benefit of treatment is as unlikely to produce benefit as it is unlikely to produce side effects.

Pushing drugs like morphine, fentanyl, midazolam, lorazepam, and others where the dose is in a small volume, often only about 1 ml, makes it almost pointless trying to hang a bag to dilute the drug, but pushing the dose into the IV tubing – if you can control the rate – is not a bad idea. The volume is small enough that all of the medication remains in the tubing. You need some way of marking where the medication begins. Some medications are different in appearance and this is easy. Others are indistinguishable from the IV fluid, so on method is to use a tiny air bubble to mark the beginning of the medication. No, a small air bubble is not going to be harmful, no matter how many alarms it would set off with an infusion pump.

That is more than enough for one post.

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