I can still remember, as a resident, learning how to calculate IV infusions for drugs commonly used in emergency situations. And relearning how to do it every time I was in the ICU. Something about the 'rule of 6s'...
|IV infusions Formula:|
desired dose (mcg/kg/min)
desired rate (cc/hr)
|* wt (kg) =||
100 cc fluid
The Medical Wizards Drip Calculator is a bare-bones program, created by an Emergency Physician, that makes it easy to calculate IV infusions on your Palm PDA. If you are a doctor, nurse, medical student or work on a transport team and need to easily, quickly and accurately calculate IV infusions for emergency medicines, then this program is for you.
One of the first problems that I encountered with the program is that it is only available for computers running Windows. There is no Macintosh installer. Although the Macintosh market is small as compared to Windows, shipping the Palm files without an installer would make it compatible with all computers.
Once installed (I used Virtual PC on my Macintosh to install the files), you Hotsync to install three files on your Palm, Cdata.prc and Cdata1.prc, which are the data files, and Cdrips.prc, the actual drip calculator. These files will be listed on your Palm Operating System Device as Drips, DBase1 and DBase2. Next, you just run the Drips program and it runs and installs the other two programs, which then get deleted. The resulting Drips program takes up about 130KB, and although strange to watch, this process only happens the first time you use the program.
Now, when you launch the Drips program, after seeing an introductory screen, you are presented with a list of drugs in the database, including dobutamine, dopamine, epinephrine and many others, including some Pediatric drugs. This list includes drugs used to treat "Acute Coronary Syndrome, Myocardial Infarction, Blood Pressure Control (both pressors and anti-hypertensives), Cardiac Arrhythmias and Stroke". After choosing a drug, you then select whether you want to use pounds or kilograms and you then select your patient's weight from a scrolling menu (you can't enter the weight in manually). These weights are rounded off at increasing smaller increments at lower weights. So, for example, 0.5 kg increments are used at the lowest weights, while 4 kg increments are used at higher weights.
The method of selecting the whether you want to use pounds or kilograms is one of the reasons I described the program as bare-bones. While it is nice to have a choice between using pounds or kilograms, I think most users will choose one of these methods exclusively, and are unlikely to use pounds one time and kilograms the next. This being the case, it would be useful to be able to set, as a preference, whether you would like to use pounds or kilograms. Unfortunately, you can not set any preferences in this program.
After selecting the drug you want to use and your patient's weight, you next choose the concentration of the infusion you want to use. You only have this option for drugs that can be infused in different concentrations, such as for Dopamine, which is shown in this image. The program also informs you of the most commonly used concentration by using the two asterisks around the concentration.
These asterisks highlight another reason why I describe the program as bare-bones. Unlike most other Palm applications, Drip Calculator does not take advantage of menus, which are usually accessed by tapping the Palm Menu icon or tapping in the title area of the screen. These menus commonly include a 'Get Info' menu that describes the program, its version number, and contact information. Many programs also have a help menu or tips icon to look for additional information. While testing this program, I wasn't sure what the asterisks meant, and I futilely looked for a help menu to tell me what they were for.
After choosing a concentration, when appropriate, you now can choose an infusion rate in mcg/kg/min. In most cases, you can choose among standard infusion rates, which include a description, such as for dopamine with a 'standard starting dose' of 5 mcg/kg/min, or a 'high dose' of 15-20 mcg/kg/min. You can also sometimes 'Select a Rate Not Listed' and enter whatever rate you want in increments of 1 mcg/kg/min.
Lastly, you are presented with a 'Confirmation Screen,' which includes all of the information that you have entered. I like this summary, since you can catch mistakes, such as entering the wrong weight. You can also choose to learn 'How to Mix' and 'How to Infuse' the drug. These screens give you all of the information you need to write your infusion orders for your patient. In this example, we prepared a drip of Dopamine, using a concentration of 1600 mcg/ml, running at 5 mcg/kg/min.
What if your patient deteriorates and you have to now increase the infusion to 15 mcg/kg/min? All right, that is an easy one. You are tripling the infusion rate (in mcg/kg/min), so you just triple the rate you are running the infusion (in ml/hr). But if you are going from 5 to 12.5 or some other rate that is not easily deducible? You have to start over, enter the same drug, concentration, your new infusion rate and check 'How to Infuse' for your new rate. It would be useful if you could save your patient's settings, so that you could easily come back to that screen and have an option to change the infusion rate.
The 'Comments/Compatibility' screen shows some very basic information about the drug and what other drugs can be infused through the same IV line. Additional information in this section would be useful, including therapeutic considerations, especially the mechanism of how the drug works and indications. A help page with the formulas to calculate the drips manually might also be useful, especially for users who want to double check their numbers when they first start using the program and for medical students and residents who are just learning how to calculate drips.
Although some commonly used Pediatric medications are included, a separate Pediatric Calculator is in the works and should be released in March 2000.
Overall, I think this is an excellent resource for medical professionals who have to calculate infusion rates for drugs and I feel the program meets its goal of reducing "the stress, time and mental effort involved in initiating treatment with all 21 intravenous infusion drugs used in the Emergency and Critical Care setting". In addition to saving time, it should also help to reduce medical errors that can be introduced by doing these calculations by hand.
I have described the program as bare-bones, but it also comes with a reasonable and bare-bones price of just $24.99, which includes a year of free updates. A 14 day free demo is also available from the Medical Wizards web site. A desktop version is also available (for Windows).
I just wish that I had this program and a similar program to calculate TPN when I was a resident...
Dr. Iannelli is the author of The Pediatric Pilot Page and has created many databases of free and shareware software, including drug databases, formularies, immunization schedules, and simple census trackers.
Discuss this Article!