# Math for ALS



## Gents82 (Aug 6, 2006)

BLS here with a question in regard to the math expectancies of a paramedic. I want to go to a paramedic program as prepared as possible to make the studies run a hair smoother so I'm thinking of taking a few math courses to help me prepare. I hear that paramedics use math for medicine calculations and such. Maybe more? I don't have a clue. Can anyone tell me what kind of math classes would be best to take? I'd greatly appreciate it.


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## Guardian (Aug 6, 2006)

You need to know basic arithmetic.  Being proficient at the basic algebra level might help a little but really isn't necessary.


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## rescuecpt (Aug 6, 2006)

Know your fractions, that is important, for example, finding lowest common denominators, multiplying fractions, etc.  Also, basic algebra is a good thing, because a lot of drug math is taking what you have and comparing it to what you need to figure out how much to give.


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## Guardian (Aug 6, 2006)

rescuecpt said:
			
		

> Know your fractions, that is important, for example, finding lowest common denominators, multiplying fractions, etc.  Also, basic algebra is a good thing, because a lot of drug math is taking what you have and comparing it to what you need to figure out how much to give.



good point


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## Ridryder911 (Aug 6, 2006)

Most math for pharmacology is actually performed at a Algebra equation. For example to set a Dopamine drip one must first perform weight conversion, concentration mixture, then figure drip chamber to get drops per minute, then if they are really profient, number of micro drops per 15 seconds. 

As my Paramedic professor always taught us, it does not matter how you get the equation, as long it is right every time... this is what you are putting in your patent's vein.. yes, a mess up can kill some one . 

R/r 911


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## Guardian (Aug 7, 2006)

Rids right as usual.  I just want to make one last point.  EMTs and others ask me about ems math all the time because they're afraid of it.  To anyone reading this, please don't let your math anxiety forestall your aspiration of becoming a paramedic.  The math we use isn't as hard as you think.  If you can learn a couple of simple formulas and then plug in the numbers and do the arithmetic (add, subtract, multiply, and divide), you'll be fine.  If your still worried about it, google it (ems math) and see for yourself.  If your wondering what math classes to take as prerequisites, I would recommend having a good grasp of all the pre-algebra concepts.  Although not necessary, if you have time, take a basic algebra class because overkill in this case couldn't hurt.


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## ResTech (Sep 2, 2006)

Dopamine is simple -  
dose (mcg) x weight(kg) x drip set (60gtts)
_____________________________________
    Total concentration (1600mcg)

Total concentration pre-hospital is normally always 1600mcg as 400mg Dopamine in 250cc NSS = 1600mcg. Memorize!

Or be smarter yet and use a chart! All those conversions are essential for written tests but you dont have time to calculate all that in the field... keep it as intuitive and simple as possible.  

Lidocaine is simpler yet - 1-4mg/min based on a clock using a 60gtts set. 
15gtts - 1mg/min
30gtts - 2mg/min
45gtts - 3mg/min
60gtts - 4mg/min

Again, usually always 2g in 500cc which is 4mg/ml. 

To many ppl want to make it harder then it has to be.


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## Ridryder911 (Sep 2, 2006)

ResTech said:


> Dopamine is simple -
> dose (mcg) x weight(kg) x drip set (60gtts)
> _____________________________________
> Total concentration (1600mcg)
> ...



I agree... but the problem is NOT ALL CONCENTRATIONS ARE THE SAME... the above calculations is based upon local protocol concentrations. Many, do not use the 1600 mcg/ml concentrations Dopamine nor the 4mg/ml Lidocaine concentration... So do not presume or assume all medications are mixed alike... That is why having a fully and understandable math for pharmacology is essential for anyone allowed providing care using medications. 

True, not harder just know how to perform the job ...


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## mikie (Jun 9, 2008)

*Medic Math*

So math has never really been my forté ...and I am going on beyond Basic so I would like to know in the medic (and for an RNs out there) setting, what kind of math is involved and is it very difficult? 

A calculator is the last thing I want to have strapped to my belt!  Just kidding.  I'm not really that bad but would like to know what kind of math I'm getting into.

Thanks!


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## mikeylikesit (Jun 9, 2008)

Multiplication, division, addition and subtraction. basic algebra for drug doses. Conversion of weights and volumes and decimal conversion to fractions are essential. A calculator no but your field guide will help you out immensely. 

Just one decimal point can mean the difference between life and death, between helping and hurting.


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## Ops Paramedic (Jun 9, 2008)

I would have to agree with Mikey.Simple basic maths apply.  What will make on good with these calcutions is practice, practice and some more practice.  Do so on paper as well as physical (Drawing up the the drugs, and you can use various color deys and expired vaculitres and expired drugs).  

Good luck...


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## MSDeltaFlt (Jun 9, 2008)

The algebra you'll use in the field is converting pounds to kilograms, figuring up milligrams per kilogram (even micrograms per kilogram), milligrams per kilogram per minute, milliliters per ideal body weight.

The first 3 should be able to be performed in your head with lights and sirens.  The last two, and the like, can be used with a calculator or field guide.


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## Ridryder911 (Jun 9, 2008)

The minimum requirement for Paramedic level should be College Algebra. Yes, most equations can be made by simple math, unfortunately that is where it leaves us .. simplistic. Field guides are for reminders, not replacements of having the knowledge. Alike calculators, it should be used as a adjunct tool.  Murphy' Law will happen, when one counts on aids.

I give a math for pharmacology test yearly, and employees have to pass as part of their evaluation process. Yes, no calculators and Field Guides allowed. Even basic & Intermediates are tested over IV drip calculations. 

I do not care what formula is used, as long as it is the right answer... the dosage that goes into the patient. 

R/r 911


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## JPINFV (Jun 9, 2008)

Understand what dimensional analysis is and how it is used. For example, say a dose is 5 mL/kg and you have a 50kg patient. The total equation becomes (5)(50)(mL/kg)(kg). kg/kg=1, so you can essentially drop (or cross out) the kg. This leads to your dose in mL. 



Ridryder911 said:


> The minimum requirement for Paramedic level should be College Algebra.



Just curious since I keep hearing college algebra here and on other forums. How exactly does college algebra differ from high school algebra 1 and 2? The lowest math course my undergrad offered was pre-calc and that didn't even go towards satisfying breadth requirements (units did go towards meeting minimum units for graduation).


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## fma08 (Jun 9, 2008)

in all honesty the best way i learned to do the math used for drip rates and such was taking chemistry, not algebra, or other math classes, it made more sense to me for some reason, but like mentioned above, a good understanding of unit conversion/dimensional analysis/whatever else you call it will help you immensely, plus a good understanding of the basics of algebra. know your conversion rates like the back of your hand.


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## Arkymedic (Jun 9, 2008)

JPINFV said:


> Understand what dimensional analysis is and how it is used. For example, say a dose is 5 mL/kg and you have a 50kg patient. The total equation becomes (5)(50)(mL/kg)(kg). kg/kg=1, so you can essentially drop (or cross out) the kg. This leads to your dose in mL.
> 
> 
> 
> Just curious since I keep hearing college algebra here and on other forums. How exactly does college algebra differ from high school algebra 1 and 2? The lowest math course my undergrad offered was pre-calc and that didn't even go towards satisfying breadth requirements (units did go towards meeting minimum units for graduation).


 
Just remember for many in EMS, it may have been a while since HS and college algebra builds on the foundation and since alg is diff everywhere in each region, it is hard to tell what the differences are.


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## mikie (Jun 11, 2008)

So could some of you guys give some examples of field math knowledge?

thanks everyone!


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## Ridryder911 (Jun 11, 2008)

1 Heparin is infusing at 15 ml/hr on an infusion pump. The bag has 25,000 U. of heparin sodium in 250 cc of D5W. How many units/hr is the client receiving? 
   100 U/hr 
   15000 U/hr 
   1500 U/hr 
   25 U/hr. 


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2 Order: Give lidocaine(Xylocaine) 2 gm in 250 ml D5W at 3 mg/min. 
At what flow rate will this medication be infused? 
   0.375 
   32.8 or 33 
   15 
   22.5 or 23 


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3 The physician orders dopamine (Intropin) 400 mg in 250 mg D5W TRA 5 mcg/kg/min.
For the client who weighs 110 lbs, how many ml /hr will the pump be set? 
   9.375 0r 9 cc/hr 
   1.6 cc/hr 
   9375 cc/hr 
   93.75 cc/hr 


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4 Nitroglycerin is infusing at 16 ml/hr. The bag has 50 mg NTG in 250 ml D5W. How many mcg/min is the client receiving? 
   5.33 mcg/min 
   53.3 mcg /min 
   32 mcg/min 
   18 mcg/min 


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5 O: Heparin sodium 25,000 U in 250 ml D5W and infuse at 2000 U/hr.
How many cc/hr will the pump be set? 
   15 
   35 
   27.2 
   20 


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6 Dopamine (Intropin) is infusing at 15 cc/hr. The bag has 200 mg / 250 cc D5W. The client weighs 145 lbs. How many mcg/kg/min is the client receiving? 
   6.04 
   1.03 
   3.03 
   4.06 


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7 Sodium nitroprusside (Nipride) 50 mg / 250 ml of D5W is hanging. The physician orders include titrating the Niprideto keep Mr. Granger's systolic BP <140 mm Hg. The IV is infusing at 20 ml / hr. Mr. Granger weighs 56 kg. What is the dosage (mcg / kg / min the client is receiving? 
   3.6 
   1.2 
   2.4 
   0.8 


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8 Mr. Greer has an order for Nipride (sodium nitroprusside) 3 mcg / kg / min. The Paramedic checks the label on the bag hanging and finds 50 mg in 250 ml D5. If Mr. Greer's weight is 124 lbs, what infusion rate will the nurse set the pump? 
   37 cc/hr (37 gtt/min) 
   43 cc/hr (43 gtt/min) 
   29.5 cc/hr (29.5 gtt/min) 
   51 cc/hr (51 gtt/min) 


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9 Mr. Collins has an order for 800 U. of heparin sodium per hour. Premixed 500 ml bags containing 25,000 U of heparin are available in the pharmacy stock area. At what rate will the nurse set the infusion pump to deliver the dosage? 
   32 
   13 
   16 
   8 


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10 Mr. Collins' heparin dosage needs to be changed to 1000 U/hr. At what rate will the nurse set the infusion pump? 
   22 
   20 
   18 
   24 


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11 Mr. Rouse is admitted to CCU for chest pain. A nitroglycerine drip is started at 12 ml/hr. The label indicates 100 mcg/ml. How many mcg/min of nitroglycerin is he receiving? 
   10 mcg/min 
   18 mcg/min 
   32 mcg/min 
   20 mcg/min 


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12 Mr. Andersen weighs 150 lbs. The physician orders dopamine (Intropin) at 8 mcg/kg/min. The unit standard admixture in pharmacy is 400 mg/250 ml D5. What will be the flow rate? 
   10.2 
   20.4  
   15 
   16 


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13 Ms. Caldwell is post-op CABGx3. She has an order of dobutamine 3 mcg/kg/min. The 250 ml bag of D5 indicates 250 mg of Dobutrex. Her weight is 130 lbs. What is the flow rate? 
   10.6 or 11 ml/hr 
   13.5 or 14 ml/hr 
   8.3 or 8 ml/hr 
   6.8 or 7 ml/hr 


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14 Mr. Corinthos is being treated for shock. The dobutamine infusion is set at 34 ml/hr. The medication label indicates Dobutrex 250 mg in 250 ml D5. His weigh is 190 lbs. What is the dosage of dobutamine the client is receiving? 
   2.5 mcg/kg/min 
   9.4 mcg/kg/min  
   3.22 mcg/kg/min 
   6.56 mcg/kg/min 


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15 Ms. Abrams weighs 128 lbs. The IV bag label indicates dopamine 800 mg in 500 ml D5. The infusion pump is set at 15 (ml/hr). What is the dosage of dopamine the client is receiving? 
   4 mcg/kg/min 
   18 mcg/kg/min 
   6.87 or 6.9 mcg/kg/min 
   12.4 or 12 mcg/kg/min


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## Jon (Jun 11, 2008)

Rid... that's easy... just hook them up to the MiniMed pump... it'll figure it all out.

I find that I sometimes need to just pull out a paper and pen and work the equations out using basic math and BASIC algebra skills. That works for me, it may not work for you.


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## GonnaBeEMT (Jun 11, 2008)

My handy little Palm TX with emedic drip calculator loaded on it figures all that out real fast.    I took college algebra and chemistry, and I think that chemistry prepared me for the conversions and rates of delivery more than algebra did.


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## tydek07 (Jun 18, 2008)

To do drug calcs you just have to know how to use simple math skills. Not very hard. Some people need to practice more then others at it, but that goes for pretty much everything.


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## Wonderwoman (Sep 17, 2008)

If I have had Pharmacy calculations when I was studying to be a Pharmacy technician will that be helpful or hurtful?


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## Ridryder911 (Sep 17, 2008)

Math for pharmacology is the same.. math is math. 

R/r 911


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## Zippo1969 (Oct 12, 2008)

wow rid just gave me a paramedic school flashback.  yuck.

I don't think I would waste time or money on a math class, unless you find it hard to figure out the 15% tip on your quesadillas.

The best advice is, do it how they tell you in class, and don't listen to the 1,400 paramedics who will try to tell you they 'have a better way of doing drug calcs'.  And trust me, they will.


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## marineman (Oct 12, 2008)

We just went through drug math about a month ago in school but I wrote it out for every problem in school and still scratch it down in the field. I can do it on paper in about the same time it takes my partner to find their calculator. When you write it out and then as long as all of your units cancel and you did your math right the answer will be correct. 

That palm pilot software sounds nice but personally I'm not ready to throw my career on the line for a piece of technology just yet.


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## VentMedic (Oct 13, 2008)

Math is not only for pharmacology. 

I know understanding mechanism of injury, torque and force of impact are not being emphasized much in EMT or Paramedic school but it can help with your scene and patient assessment. Unfortunately, for some, it may involve a little math.

Some get a little lost when different variables such as MAP for both BP and airway are discussed. Much of the confusion is not understanding how these variables are derived.

It is also embarrassing to see someone struggling with a basic O2 cylinder calculation for duration of the tank at x liters. 

Even the theory and basic principles behind CPAP and all the other O2 devices work off of mathmatical equations. That is why 2 L NC may not give the same O2 percentage on different people. This is what the "recipes" fail to explain and instructors forget to teach as they are busy giving you info to MEMORIZE and not always to understand.

Then, you get people that want to do CCT or Flight. They think all you need to do is ride on an ALS truck for a couple of years without much other prep. The many calculations that go into Critical Care Medicine is pretty astounding. Sure there are calculators but one should have a working knowledge of the formula for the understanding of how it is derived. 

On another forum for flight professionals, I get questions and requests from people who just want the recipe and not much more for various ventilator applications. Once formulas are introduced to accompany the various protocols and the factors that influence which mode is used, some still want just a "cheat sheet" to avoid all that "extra stuff". Again, I will use the word knobologist for those that don't have enough math background to get the basic concepts but still want to say "they can set up a ventilator".

Math is also an asset when it comes to reading medical journals (not JEMS). Too many are intimidated by the statistics, numbers and formulas and avoid the chance to read the wheres, whys and hows some of our data is derived.


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