Manually setting drip rates

[fiznat]

I've been a practicing paramedic for just about 3 years now, and thinking back, I haven't had many opportunities to set up medication infusions for my patients. I've done dopamine a few times, a couple cardizem drips and lidocane, but really I don't have too much first hand experience with it.

On a whim I decided to set up a 250 NS bag with on a 60 gtt set and try my hand at setting drip rates the "old school" way (IE without a pump of any kind, just counting drips in the chamber). I've been using a little metronome I had around the house and I've found that this is actually an EXTREMELY difficult thing to do accurately. Even with the metronome and as controlled conditions as I can create, I'm having difficulty keeping the drip rate within 5 and 10 percent of the desired dose.

For example, if I want to set up a 5 mcg/kg/minute dopamine infusion for a 220 lb patient that is 20 gtt/minute on a 60 drip set. That means that if I am off by even ONE DROP over a whole minute, I am over or under dosing by 5 percent. Increase that error to two drops in a minute, now that's 10 percent I am over or under dosing. That is a significant amount of error.

I've found that changing the drip rate by only a few drops per minute is an extremely small adjustment on the "flow rate wheel," and a really easy error to make. You can move it an amount that isn't even really visible to the eye, and the drip rate changes by an easy 10 or 20 percent. This makes it really really difficult to set an accurate drip.

I was wondering how many of you folks have tried doing this to such a degree of accuracy. In the back of the ambulance I'll be the first to admit that in the past I have fudged drip rates a little bit, estimating approximate rates and adjusting as I go along. ....But now that I have taken a set and started to count things out under controlled conditions I've seen how a tiny change can have such a profound effect on the actual dosage. It is no wonder that everywhere else in medicine these kinds of things are done on electronic pumps -- because it seems virtually impossible to be very accurate using the manual method!!

I've spoken with a few old school nurses about this, and they largely agreed. Most have admitted that setting up a drip this way took at least 5+ minutes at the bedside rolling that wheel as well as several "check backs" on the patient using "tape counts" to make sure everything was moving according to plan. This isn't really feasible in the ambulance-- at least where I work.

I'd like to hear what other people's experiences have been with setting up infusions, and whether anyone has any trips or tricks in getting these rates more precise without a pump.

[ccmedoc]

I've been a practicing paramedic for just about 3 years now, and thinking back, I haven't had many opportunities to set up medication infusions for my patients. I've done dopamine a few times, a couple cardizem drips and lidocane, but really I don't have too much first hand experience with it.

On a whim I decided to set up a 250 NS bag with on a 60 gtt set and try my hand at setting drip rates the "old school" way (IE without a pump of any kind, just counting drips in the chamber). I've been using a little metronome I had around the house and I've found that this is actually an EXTREMELY difficult thing to do accurately. Even with the metronome and as controlled conditions as I can create, I'm having difficulty keeping the drip rate within 5 and 10 percent of the desired dose.

For example, if I want to set up a 5 mcg/kg/minute dopamine infusion for a 220 lb patient that is 20 gtt/minute on a 60 drip set. That means that if I am off by even ONE DROP over a whole minute, I am over or under dosing by 5 percent. Increase that error to two drops in a minute, now that's 10 percent I am over or under dosing. That is a significant amount of error.

I've found that changing the drip rate by only a few drops per minute is an extremely small adjustment on the "flow rate wheel," and a really easy error to make. You can move it an amount that isn't even really visible to the eye, and the drip rate changes by an easy 10 or 20 percent. This makes it really really difficult to set an accurate drip.

I was wondering how many of you folks have tried doing this to such a degree of accuracy. In the back of the ambulance I'll be the first to admit that in the past I have fudged drip rates a little bit, estimating approximate rates and adjusting as I go along. ....But now that I have taken a set and started to count things out under controlled conditions I've seen how a tiny change can have such a profound effect on the actual dosage. It is no wonder that everywhere else in medicine these kinds of things are done on electronic pumps -- because it seems virtually impossible to be very accurate using the manual method!!

I've spoken with a few old school nurses about this, and they largely agreed. Most have admitted that setting up a drip this way took at least 5+ minutes at the bedside rolling that wheel as well as several "check backs" on the patient using "tape counts" to make sure everything was moving according to plan. This isn't really feasible in the ambulance-- at least where I work.

I'd like to hear what other people's experiences have been with setting up infusions, and whether anyone has any trips or tricks in getting these rates more precise without a pump.

You wont get very precise in the back of an ambulance, it is near impossible in the controlled settings of hospital. Any variance.. vibrations, bending of the arm or wrist, movement of the patient, raising or lowering the infusion; affects the drip rate.

I feel the "titrate to effect" is most often practiced here, and put to a pump as soon as possible; dubious practice at best.. All of the drips used in the prehospital seem to be very tight tolerance; as far as dose/effect. Gravity drips manually set are very labor intensive and impractical for everyday use. Necessity is the only reason I can see these used. It is (has been) routine in one of our hospitals to infuse ABX and less touchy infusions by this method. This has since been stopped.

There are no real tricks to setting one up, it is just foolish to expect to "set it and forget it"...it wont happen that way..

Vasoactive drugs are labor intensive on a pump, let alone on a gravity drip..

[fiznat]

You wont get very precise in the back of an ambulance, it is near impossible in the controlled settings of hospital. Any variance.. vibrations, bending of the arm or wrist, movement of the patient, raising or lowering the infusion; affects the drip rate.

Yeah. I have to say that this wasn't all that obvious to me until I tried to actually set up some infusions under controlled conditions. Now that I know how easy it is to change a dose by 10% or 20%, it is amazing to me that our collective medical control doctors have had so few issues with EMS running "off pump" infusions in the field. If we can't even get close to the desired dose with any degree of accuracy, how are we still allowed to do this??

[JPINFV]

Just curious, how good are the "dial a flo" variable resistance IV tubings?

[spenac]

Just curious, how good are the "dial a flo" variable resistance IV tubings?

My understanding is they are not accurate if they are vibrated, moving etc, so not a good choice for EMS.

[JPINFV]

My understanding is they are not accurate if they are vibrated, moving etc, so not a good choice for EMS.

I wonder if something like a microphone "shock mount" would help reduce the vibration enough to be viable.

[ccmedoc]

I wonder if something like a microphone "shock mount" would help reduce the vibration enough to be viable.

They are kind of crud anyhow (my opinion). The drop(drip) factor was at issue last I heard; not exactly consistent. At any rate, on an ambulance it doesn't really matter, short of a pump you will not get any consistency. The only study on these 'dial a flo' I was aware of was done on HEMS.

[Kiwiology]

The only drips we hang are amiodarone (150mg/30min) and adrenaline (1mg:1,000cc NS start at 2gtt/s and titrate) so to that end its not very hard at all from our end here in Kiwi

[CBEMT]

Dial-A-Flows were required equipment for ALS ambulances in my state until a few years ago. No one used them. Not because they eyeballed it, but because no one hung drips (that would require a med control order, knowing what the hell you're doing, and a transport time longer than most services have here).

During a major protocol update, Dial-A-Flows were banned, and pumps required for all drips. Most services still don't carry them, because drips are considered optional- despite the fact that stable VT has no treatment in our protocols except a drip- as well as the previously mentioned reasons. It affected private services the most, since they were the ones making critical transfers that would be most likely to be running infusions. Most 911 services (90% fire) that had a patient that needed a drip (assuming they could even tell) just drove faster.

My service recently got them, and even sprung for the pre-mixed drips. We're one of the few that could actually have time to use and/or need them.

[fiznat]

Dial-A-Flows were required equipment for ALS ambulances in my state until a few years ago. No one used them. Not because they eyeballed it, but because no one hung drips (that would require a med control order, knowing what the hell you're doing, and a transport time longer than most services have here).

Yeah, I guess hanging med infusions here isn't as common as it could be, but not for lack of protocol for it. I just feel like if we are going to have this as an option (and we should), then we should have the equipment to do it properly. How much do those mini med pumps cost anyways?