McHenry Western Lake County EMS System Optional CE for Paramedics, EMT-B and PHRN s Calculating Medications

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1 McHenry Western Lake County EMS System Optional CE for Paramedics, EMT-B and PHRN s Calculating Medications Optional # There are different ways for pre-hospital care to administer medications. Medications can be administered by Intra-Nasal (IN), Intra-Muscular (IM), Orally (PO), Intra-Venous (IV), Intraosseus (IO) Inter Rectal (IR) or by Hand Held Nebulizer (HHN or Neb). Since the body will absorb the medication differently through each of these routes, the concentrations of the medications may be different. The other important consideration is that the medication dosage may be different than the actual amount of fluid that will be administered. Not all medications are given in a 1:1 medication to fluid ratio. It is very important to know how to calculate, draw up and administer the right amount of medication in the right amount of fluid. Where this is critical is in our pediatric patients. With the adult patient, we can estimate a weight and Ball Park the dosage, but a pediatric patient is a lot less forgiving when too much of a medication is given. Also, if we don t give enough, we will not make the change that is required. Metric System Pharmacology is based on the metric system. The metric system is based on powers of 10. To simplify numbers with a lot of zeros, the metric system refers to milli- (1/1,000), centi- (1/100), deci- (1/10) and will attach these references to what is being measured: grams (weight), liters (volume) and/or meters (distance). For example: Since all the medications are setup in the metric system, we need to convert the patient s weight into grams. This is easily done by dividing the patient s weight (in pounds) by 2.2. This will give the most accurate weight in Kilograms (kg). When a medication is given, the concentration of the medication is what is important. This can be in grams (g) or milligrams (mg). The amount of fluid that holds the medication concentration is what will be measured and given to the patient. This will be in milliliters (ml). Because these amounts are not

2 always the same, we have to make sure we are giving the proper amount of fluid for the proper amount of medication. Figuring out Medication Dosages and the Fluid amount Vials and Preloads There are 2 common methods to figure out medication dosages to fluid administration amounts. It is up to you which one you follow, just practice, practice, and practice some more. It does not matter which formula you use, but you will need to know Drug Order, Volume on Hand and Dosage on hand. Medications can be packaged in vials that need to be drawn up (IM/IN) or preloads that have the concentration already mixed (given IVP). With Preloaded medications, the calculations are done and you only need to put the syringe together. In some of the SOPs we are giving the entire preload to the patient. For a pediatric patient, we may only be giving a portion of that preload. Epinephrine 1mg/1ml is supplied in a 1:1 ratio. So if you give 1 ml of fluid, then you will give 1 mg of Epinephrine. If you give 0.3 ml of fluid, then you gave 0.3 mg of medication. That works when the concentration is 1:1. With Epinephrine 1mg/10ml, we are giving a different fluid amount for the concentration of the medication. 1 ml is now equal to 0.1 mg of Epinephrine. So if we need to give 0.3 mg of Epinephrine 1mg/10ml, we would give 3 ml of fluid. Formula #1 When we get to pediatric dosages, we will administer a percentage of the vial based on the patient s weight. That is why it is important to covert the patient s weight to kilograms (kg). If we want to give Epinephrine 1mg/1ml IM (0.01 mg/kg) to a 33 pound patient we figure out the fluid amount with the following formula: Our First step is to convert our patient s weight to kilograms. 33/2.2 = 15 kg So we need to give 0.01 mg/kg x 15 kg = 0.15 mg of Epi 1ml/1mg Since we know that this Epi is packaged 1mg/1ml we would give 0.15 ml of fluid. Now let s look at giving Atropine to a 48 lb. pediatric patient. Atropine is given 0.02 mg/kg for the pediatric patient. (FYI, with pediatric dosages, we don t exceed an adult dose. This applies to all medications. For Atropine, the adult dose is 0.5 mg.) So for our patient, we would give: 48/2.2 = 22 kg 0.02 mg/kg x 22 kg = 0.44 mg of Atropine Since Atropine is packaged 1 mg in 10 ml, we need to figure out how much fluid should be given to get 0.44 mg of Atropine. We can use the formula from above:

3 0.44 mg x 10 ml = 0.44 mg x 10 ml = 4.4 ml = 4.4 ml of fluid for 0.44 mg of Atropine 1 mg 1 mg 1 Formula #2 (with the same information.literally) When we get to pediatric dosages, we will administer a percentage of the vial based on the patient s weight. That is why it is important to covert the patient s weight to kilograms (kg). If we want to give Epinephrine 1mg/1ml IM (0.01 mg/kg) to a 33 pound patient we figure out the fluid amount with the following formula: Drug Ordered x Dosage on Hand Volume to be Volume on hand Delivered Our First step is to convert our patient s weight to kilograms. 33/2.2 = 15 kg So we need to give 0.01 mg/kg x 15 kg = 0.15 mg of Epi 1ml/1mg Since we know that this Epi is packaged 1mg/1ml we would give 0.15 ml of fluid. Now let s look at giving Atropine to a 48 lb. pediatric patient. Atropine is given 0.02 mg/kg for the pediatric patient. (FYI, with pediatric dosages, we don t exceed an adult dose. This applies to all medications. For Atropine, the adult dose is 0.5 mg.) So for our patient, we would give: 48/2.2 = 22 kg 0.02 mg/kg x 22 kg = 0.44 mg of Atropine Since Atropine is packaged 1 mg in 10 ml, we need to figure out how much fluid should be given to get 0.44 mg of Atropine. We can use the formula from above: 0.44 mg 1mg = 0.44 mg x 10 ml = 4.4 ml = 4.4 ml of fluid for 0.44 mg of Atropine X 10 ml = X x 1 mg = 1 Either formula will give you the same answer. Drip Rates Not all medications are packaged in preloaded syringes. Some medications are administered as an IV Bag with the medication given as a drip, not a one-time push (IVP/IM/IN). With most IV bag administrations, you will need to figure out a drip rate for the administration over a fixed period of time. An example is Amiodarone for a Wide Complex Tachycardia with a Pulse. This medication can be given in 150mg/7ml slow (IVP/IO) or 150mg/50ml (IVBP). Both administrations are over 10 minutes. To setup the drip rate for the IV, you need to know the following things: 1) volume to be infused (ml), period of

4 time for the administration (minutes) and the drops per minute that the IV tubing can administer (or Infusion set - 60 gtts/ml, 15gtts/ml or 10gtts/ml). We know that the drug dose is 150mg. The formula to figure out the drip rate is: Let s plug Amiodarone into the formula: 50 ml x 60 gtts/ml = 50 ml x 60 gtts/ml = 50 x 60 gtts = 3,000 gtts = 300 gtts/minute 10 minutes 10 minutes 10 minutes 10 minutes With a micro set of IV Tubing (60 gtts/ml), we would administer 300 gtts/minute for 10 minutes. 50 ml x 15 gtts/ml = 50 ml x 15 gtts/ml = 50 x 15 gtts = 1,500 gtts = 75 gtts/minute 10 minutes 10 minutes 10 minutes 10 minutes With a macro set of IV Tubing (15 gtts/ml), we would administer 75 gtts/minute for 10 minutes. 50 ml x 10 gtts/ml = 50 ml x 10 gtts/ml = 50 x 10 gtts = 500 gtts = 50 gtts/minute 10 minutes 10 minutes 10 minutes 10 minutes With a macro set of IV Tubing (10 gtts/ml), we would administer 50 gtts/minute for 10 minutes. IV Medications For a medication that is prepackaged as an IV Bag (like Dopamine), we need to figure out a drip rate to administer the desired amount of the medication. (For other medications, we may still need to figure out the dosage by using the previous formulas.) The formula to do this combines both of the previous formulas. For a Dopamine administration, we would always use a micro drip set (60gtts/ml). The patient s weight is 200 lbs. and we want to give 5mcg/kg/min. The Dopamine package is 400mg/250 ml. We will need to figure out the mg per ml to put into the formula. Weight: 200/2.2 = 90.9 or 91 kg mg per ml: 400/250 = 1.6 mg/ml but we need mcg, so 1600 mcg/min

5 5 mcg/kg/min x 91 kg x 60 gtts/ml = 5 mcg/kg/min x 91 kg x 60 gtts/ml = 5/min x 91 x 60 gtts = 1600 mcg/ml 1600 mcg/ml ,300 gtts/min = gtts/min or 17 gtts/min 1600 For Dopamine, there is a quick Field Calculation to figure out the drip rate at 5mcg/kg/min. Take the patient s weight in pounds and drop the last digit. Subtract 2 from that number. That number becomes the gtts/min that is needed. Because of rounding, the Field Calculation should get you within 1 gtts/min. For our patient above: 200 becomes = 18 gtts/min If the Dopamine dose changes to 10mcg/kg/min; you would double the 5mcg/kg/min answer. (or 36 gtts/min) This has been a review of how to calculate medications and the fluid amounts that will be given to our patient. Remember to document the medication dosage (mg) that was given, not the fluid amount. Though there are easier ways to figure out the dosage for a patient (charts, apps, etc.), we may not always have access to them. With practice, you ll be able to go through these formulas quickly and be able to use the charts/apps to verify your answer. Reference used: Bledsoe, Bryan E., Porter, Robert S., Cherry, Richard A., (2013). Paramedic Fundamentals. Paramedic Care, Principles & Practice Vol. 2 (pp ).

6 McHenry Western Lake County EMS System Optional CE for Paramedics, EMT-B and PHRN s Calculating Medications Optional # NAME: DEPT. DATE: Convert the following weights into Kilograms (Kg) (don t use field method): lbs lbs lbs lbs lbs. 6) You need to give an IM of Epinephrine 1mg/1ml. The dose required is 0.6 mg. What is the amount of fluid that will be injected to the patient? a ml b ml c mg d. 0.6 ml 7) You need to give Diphenhydramine IM to a Pediatric patient. The Patient s weight is 42 lbs. The dosage is 1mg/kg. The Diphenhydramine is packaged 50mg/1ml. What is the dosage and how much fluid will be injected into the patient? a. 19 mg/0.38 ml b. 22 mg/0.44 ml c. 42 mg/0.38 ml d. 42 mg/0.84 ml 8) You need to administer Amiodarone (2.5mg/kg) to a pediatric patient in V-Fib. The patient s weight is 110 lbs. The Amiodarone is packaged in 150 mg/3 ml. How much fluid of Amiodarone will be administered in the IV? a ml b ml c ml d. 5.5 ml

7 9) You need to administer Atropine (0.02mg/kg) to a 44 lbs. pediatric patient. Atropine is packaged 1 mg/10ml. What would the dosage amount be and how much fluid will be administered in the IV? a. 0.2 mg/ 2 ml b. 0.4mg/ 4 ml c. 0.5 mg/ 5 ml d. 1.4 mg/ 14 ml 10) You are giving repeat dose of Adenosine to a 90 lbs. pediatric patient. The second dose is 0.2 mg/kg. The Adenosine is packaged in 12mg/2ml. What are the dosage and the amount of fluid that will be administered in the IV? a. 8.2 mg / 1.36 ml b. 8.5 mg / 1.41 ml c. 18 mg/ 2.0 ml d. 20 mg/ 2.0 ml 11) You are setting up a Dopamine drip for a patient. You need to administer 5mcg/kg/min using a 60 gtts/min drip set. The patient weighs 180 lbs. The Dopamine is packaged as 400mg/250ml. What are the drips per minute that will be given to this patient? a. 9 gtts/min b. 12 gtts/min c. 15 gtts/min d. 17 gtts/min 12) You are setting up a Dopamine drip for a patient. The patient weighs 180 lbs. You need to administer 10mcg/kg/min using a 60 gtts/min drip set. The Dopamine is packaged as 400mg/250ml. What are the drips per minute that will be given to this patient? a. 10 gtts/min b. 15 gtts/min c. 31 gtts/min d. 62 gtts/min 13) You need to administer Ondansetron 0.15 mg/kg IM on a pediatric patient. The Pt. weight 48 lbs. Ondansetron is packaged 4 mg/2ml. What is the total amount of medication and fluid that will be administered to this patient? a. 1.0 ml b. 1.7 ml c. 2.0 ml d. 2.5 ml

8 14) You are working V-fib on a pediatric patient. The Epinephrine you are going to administer is 1mg/10ml. The dose you will be giving is 0.01 mg/kg. The patient s weight is 95 lbs. What is the total amount of Epinephrine you will administer and what is the fluid amount? a ml b ml c ml d ml 15) You will be administering Magnesium 25mg/kg (Slow IVP). The Magnesium is packaged 2g/40ml. Your patient s weight is 90 lbs. This will be given over 10 minutes. What is the medication dosage and what is your drip rate per minute? a mg (1.0g), 20 ml, 120 gtts/min b mg (1.5g), 30 ml, 180 gtts/min c mg (1.7g), 34 ml, 204 gtts/min d mg (2.0g), 40ml, 240 gtts/ min IF YOU ARE NOT A MEMBER OF THE MCHENRY WESTERN LAKE COUNTY EMS SYSTEM, PLEASE INCLUDE YOUR ADDRESS ON EACH OPTIONAL QUIZ TURNED INTO OUR OFFICE. WE WILL FORWARD TO YOUR HOME ADDRESS VERIFICATION OF YOUR CONTINUING EDUCATION HOURS. IF YOU ARE A MEMBER OF OUR EMS SYSTEM, YOUR CREDIT WILL BE ADDED TO YOUR IMAGE TREND RECORD. PLEASE REFER TO IMAGE TREND TO SEE YOUR LIST OF CONTINUING EDUCATION CREDITS. ANY QUESTIONS REGARDING THIS CAN BE ADDRESSED TO THE EMS OFFICE AT 815/ THANK YOU.