I think a more accurate (if weirder) simile would be: A young vet's first overnights feel like riding a bike without training wheels blindfolded through a ravine. Hooray!
That being said, I learned several important truths:
1) Do not panic. Everything is worse if you panic. Nothing is better.
2) Your only job is to keep everyone alive (who you aren't euthanizing) until the morning.
3) Despite your best efforts re: #2, sometimes patients will die anyway.
I also learned how to reliably calculate and put together CRIs.
To those of you who say, "Alacrity, how are you almost four months into your internship and you just learned this?", I say, "Hush, fools. CRIs are tricky."
For those of you who don't know, a CRI is a continuous rate infusion of a drug. Any drug. We use CRIs for pain control, anesthesia, sedation, drugs to promote gastrointestinal motility, some chemotherapeutic agents, et cetera.
I discovered that I knew how to set up CRIs way better than I thought I did on my last overnight before switching back to days. I had this patient whose heart was doing a crazy thing, and I called the criticalist at about 4am for some advice. She told me to put him on a diltiazem CRI.
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| via flickr - supertroopers |
Friends, here is how you do this:
1) Look up the dose of your drug. Every CRI dose that you find will be formatted somewhat like this:
(units of drug) per (units of animal weight) per (units of time)
This looks like:
3 mcg/kg/min or 50mg/kg/day or 0.01U/lb/hour
2) Go weigh your patient. Convert the weight to kilograms (there are 2.2 pounds in 1 kilogram).
3) Multiply the units of drug by the weight of your patient. Now you have the total dose of the drug for your patient per unit of time.
4) Convert the unit of time to "per hour". The dose may have already been given to you in "per hour", which is awesome. If not, convert. If it's in minutes, multiply by 60. If it's in days, divide by 24.
5) Figure out how (physically) you're going to deliver your drug. Will it be diluted (hint: probably)? In what fluid/by how much? Some options for this are "in a 60 mL syringe" or "in a 1L bag of LRS", "in a 250 mL bag of saline", et cetera.
6) Figure out how to make your delivery system/vehicle last a logical amount of time (I use about a day). For example, a 60 mL syringe of (whatever) running at 2mL per hour lasts 30 hours. A 250 mL bag of saline running at 10 mL per hour lasts 25 hours. This is so your technicians aren't re-making the CRI every 6 hours.
7) Make sure your drug won't react badly with whatever fluid you use to dilute it (doy).
8) So, now you have a dose of drug for your patient per hour, and a delivery system/vehicle that lasts a known number of hours. Figure out how many "hour doses" of drug go into your delivery system/vehicle so the hours match. For example, if you are running a 60 mL syringe at 2mL per hour to get 30 CRI hours, you need 30 hour-sized doses of drug to go into that syringe.
The way you do this with math is you multiply your hourly dose for your patient by the number of hours in your delivery system/vehicle to get the total amount of drug to add to the bag/syringe.
9) Figure out the concentration of the drug (usually in units/mL). Convert your total dose to a total volume. Remove an equivalent volume of diluent fluid from your delivery system/vehicle so your math isn't wrong once you add the drug. For example, if you're adding 50 mL of drug to a 250 mL bag of saline and you did your "how long will this bag last" calculation based on 250 mL, remove 50 mL of saline before you add the 50 mL of drug so you don't end up with 300 mL total.
10) Check all your math.
11) Write your shit down in a logical way for your technicians.
12) GO!
Does this make sense?