Since you want "mL" on top in your answer you won't go wrong starting with 250 mL/400 mg as a logical starting factor. First, determine the concentration of the amount on hand. What is the infusion rate in mL/hr? The problem is you have 400mg in 250ml of IV solution and it is infusing at 23ml/hr and the kg is 79.5. :uhoh21: allnurses is a Nursing Career, Support, and News Site. What dose of nitroglycerin (mcg/min) is the patient receiving? The pharmacy provides dopamine 800 mg in 250 mL of D5W. Note that weight is not used, extra details are often included in problems. The pharmacy has mixed 2 g of procainamide in 500 mL of solution. This requires calculating the number of drops per minute, as administered through basic IV tubing. =. 200,000 mcg Don’t round any numbers in the equation until you have the final answer. Find the concentration:
Lesson 7 – Utilizing Dimensional Analysis to Calculate Complex Dosages (i.e. Patient weighs 210 lb (95 kg). Another example is acceleration, which is measured in ft/sec/sec. Medication administration is a core competency for all nurses in every clinical setting. • You focus only on units of measure, not numbers, so math phobics can rejoice You are now ready to play a game called "plug in other factors to cancel out the units you don't want until you end up with the units you do want." But dividing is the same as inverting and multiplying, so inverting 2 to get 1/2 and multiplying you have 1/4 x … How much dopamine is the patient receiving in mcg/kg/min? What is the hourly IV pump rate? Example 4: Administer heparin 500 units per hour I.V. So remember the benefit of dimensional analysis is that we can do our calculations the same way every time, it works for every type of problem, from simple to complex. The volume (V) is the form and amount in which the drug is supplied (i.e. i need help calculating the problem below using dimensional anlaysis: dopamine 800 mg in 250 ml d5w is infusing at 12 ml/h in a patient weighing 195 lbs. i understand that i need to factor the mg to mcg, the lbs to kg, and the h to min. The standard IV mixture is 450 mg in 250 mL. Repeat until all units of measure not needed in the answer are cancelled out. Nurses should select one formula and practice to become proficient in that method. The amount on hand (H) is the dose on the container label. If the units cancel out properly, then your set up is correct and you can be quite sure the answer will be correct if you just manage to punch the right keys on your calculator. I need the formula for this type of problem. 800,000 mcg/250 mL x mL/hr x 1 hr/60 min ÷ 85.3 kg = 10 mcg/kg/min
The other important bit to realize in order to do DA is that 3 mcg/kg/min can also be written as 3 mcg/(kg x min). Plug in the information into the formula: 5 mcg/kg/min x 95 kg x 250 ml x 60 min = 36 ml/hr. To use this formula, divide the desired amount by the amount on hand and multiply by the volume. gtts = 60 gtts x 250 mL x 10 mcg x 100 kg x 1 mg I'm getting 37.5 or 38 gtts/min. If the pharmacy mixes 20 mg of Milrinone in 100 mL of total solution, what would be the rate of the infusion? 25%, rewrite as 25/100 with appropriate labels. The patient weighs 85.3 kg. This can be written as ft/(sec x sec) or, more familiarly, as ft/sec2. Example 4:
800 mg/250 mL x 1000 mcg/1mg x mL/hr x 1 hr/60 min ÷ 85.3 kg = 10 mcg/kg/min
I'll do the first one the long way, with explanations, then the rest as I would normally set them up. Specializes in Vents, Telemetry, Home Care, Home infusion. A key skill required to safely dispense drugs is the ability to perform accurate dosage calculations. (800 mg/250 ml) * (1000 mcg/1 mg) * (12 ml/1 hr) * (1 hr/60 min) * (1/195 lb) * (2.2 lb/1 kg). • No formulas to know, look up, or apply Then, use the universal formula to calculate the rate. Dopamine is running at 30 mL/hr. Example: Administer Dopamine 5 mcg/kg/min. I like to also just think about normal dose – which is 5-20 mcg/kg/min, so 12 makes sense. I had the weight as 195/1 instead of 1/195. mL/hr = 16 mL/hr. In this problem we are kindly given "mL/hr." How many mL will you need to administer a 0.5 mg dose? This method reduces errors and can be used for all dosage calculations. However, if there is a power outage, nurses need to know how to deliver fluids without the use of an infusion pump. allnurses.com, INC, 7900 International Drive #300, Bloomington MN 55425 If, however, med-math is still a bit of a struggle, consider using the technique preferred by chemists, physicists, and engineers for decades called, somewhat intimidatingly, "dimensional analysis" hereafter referred to as "DA. The first step is to convert the order per time to the amount required for this particular patient. Have a colleague or pharmacist check your work. Emily Dickinson. To find mcg/min:
How many ml/hr will the nurse administer? Give a fine print as a gift that could hang around for a hundred years. Again, check out the complex calculations lesson to see more like this. What should the ordered dose be in milligrams per minute? Infidel Guides: Islam, Theism, Atheism, ... San Pedro Valley Community Cultural Center, Making Tree of Life: Fun with phylogenetics, Making Boxes for Rock & Mineral Collection, 3. The initial rate is ordered at 1000 units per hour. Then, depending on how the drug is ordered, use one of the formulas below. She weighs 58 kg. 3,200 mcg/mL x mL/hr x 1 hr/60 min ÷ 85.3 kg = 10 mcg/kg/min
In this example, solve for mL/hr. Connect with us on Facebook, Twitter, Linkedin, YouTube, Pinterest, and Instagram. The patient is receiving nitroprusside at 23 mL/hr. Example 1:
Pumps like to be programmed in mL/hr, so mL/hr are your answer units. Use the formula for mcg/min and divide by patient’s weight (kg). mL/hr = 853 mcg/min x 1 mL/3,200 mcg x 60 min/hr
Start with the labels needed in the answer to determine what unit of measure is needed to begin setting up the calculation. Has 5 years experience. I can't seem to get the units to cancel out correctly or find a problem which has an answer I can look at. Also, convert hours to minutes. The other important bit to realize in order to do DA is that 3 mcg/kg/min can also be written as 3 mcg/(kg x min). Pounds or kilograms. Continuous IV drip calculations are more complex. By using the site you agree to our Privacy, Cookies, and Terms of Service Policies. Thanks! I figured out from your post what I was doing wrong. The dopamine is mixed as 400 mg in 250 mL of solution. An IV solution containing 2 grams of Lidocaine in 500 mL of D5W is infusing at 15 mL per hour. Th pharmacy supplies the heparin infusion as 20,000 units in 500 mL D5W. T°C = (T°F – 32) x 5/9
Temperature Conversion:
20,000 units/500 mL = 40 units/mL
Dimensional Analysis (DA) or factor-label method: uses a series of conversion factors of equivalency from one system of measurement to another but doesn’t require memorizing specific formulas (Koharchik & Hardy, 2013). WWW Collection of Favorite String Figures, Alternative Handwriting & Shorthand Systems, 14 Mindfulness Trainings of Thich Nhat Hanh, Buyer's Guide to Food Preparedness Products, Sustainability Issues: 50 mg/500 mL x 1000 mcg/1 mg x 8 mL/1 hr x 1 hr/60 min
Then consider the unit in which your drug is measured (units/hour, mg/hour, mg/min, mcg/min, or mcg/kg/minute). The patient weighs 100 kg. Continuous IV infusions are delivered via infusion pumps. Support this site: Visit our Zazzle store featuring ultra hi-res images of artworks, Hubble/ESA/NASA space images, Mandelbrot fractals, maps and more.
I know you convert the mg to mcg (multiply by 1000) and convert the hour to 60 minutes. Th pharmacy supplies the heparin infusion as 20,000 units in 500 mL D5W. hope it gets formatted ok when you view it. However, nurses cannot rely completely on these advances. I'm nobody! To find units/hour:
Build the calculation by placing information with the same label as the preceding denominator into the equation in the numerator to cancel out the unwanted labels. You need to start a continuous drip of amiodarone at 1 mg per minute (by pump). This may seem a little weird, but if asked to divide 1/4 by 2 you have 1/4/2. Reset. mL? Step 1: What unit of measure (label) is needed? The most twisted of med-math problems devised by the most fiendish minds can be solved, bing-bang-boom, in this manner. tablet, capsule, liquid). Using the same examples above, let’s use the dimensional analysis method. Specializes in ICU. If your amount on hand is in milligrams (mg), convert mg to micgrograms (mcg) by multiplying by 1,000. you would document that the patient is receiving _______ mcg / kg / min. you would document that the patient is receiving _____ mcg / kg / min. • All calculations done at one time; no rounding errors The patient weighs 67 kg. Calculate to determine the correctly labeled numeric answer. What is the infusion rate in mL/hr? The label on the bottle reads 50 mg in 500 mL 0.9% sodium chloride solution. It is included as a reference for nurses working in specialty… Dimensional Analysis (DA) or factor-label method: uses a series of conversion factors of equivalency from one system of measurement to another but doesn’t require memorizing specific formulas (Koharchik & Hardy, 2013). Use the universal formula, but some conversions are usually necessary. IV rate (mL) Dose available (mg) Volume of dose available. If this introduction to DA is too brief, visit the following nursing math website for more: http://www.alysion.org/dimensional/analysis.htm. The patient weighs 73 kg. 1-612-816-8773. Since you want kg, a unit of weight (mass) on the bottom, starting with pounds on the bottom makes sense. The "wrong" answer of 1407 mikes/kilo/min would be a LOT more exciting! • Stepwise approach makes solving almost all problems a virtual no-brainer. What dosage of nitroprusside in mcg/kg/min is the patient receiving? Step 3: Place information with the same label as the preceding denominator into the equation in the numerator to cancel out the unwanted labels.