This chapter extends the discussion of intravenous infusions to include administration. Calculating Flow Rates for Intravenous Medications.

Transcription

1 Capter Calculating Flow Rates for Intravenous Medications Learning Outcomes After completing tis capter, you will be able to 1. Describe intravenous medication adistration. 2. Calculate te rate of flow of intravenous piggyback medications. 3. Calculate te flow rate of intravenous solutions based on te amount of drug per ute or per our. 4. Detere te amount of drug a patient will receive IV per ute or per our. 5. Calculate IVPB flow rates based on body weigt. 6. Calculate IVPB flow rates based on body surface area. 7. Calculate te infusion time of an IVPB solution. 8. Calculate te rate of flow for a medication requiring titration. Tis capter extends te discussion of intravenous infusions to include adistration of intravenous medications. You will also learn ow to calculate te flow rates for IVs based on body weigt or BSA. 242

2 Intravenous Piggyback Infusions 243 Intravenous Adistration of Medications Intravenous adistration of medications provides rapid access to a patient s circulatory system, tereby presenting potential azards. Errors in medication, dose, or dosage strengt can prove fatal. Terefore, caution must be taken in te calculation, preparation, and adistration of IV medications. Typically, a primary IV line provides continuous fluid to te patient. Secondary lines can be attaced to te primary line at injection ports, and tese lines are often used to deliver continuous or intermittent medication intravenously. A secondary line is referred to as a piggyback or intravenous piggyback (IVPB). Wit intermittent IVPB infusions, te bags old generally of fluid containing dissolved medication and usually require utes to infuse. Like a primary line, an IVPB infusion may use a manually controlled gravity system or an electronic pump. A eplock, or saline lock, is an infusion port attaced to an indwelling needle or cannula in a periperal vein. Intermittent IV infusions can be adistered troug tese ports via IV lines connected to tese ports. An IV pus, or bolus (IVP), is a direct injection of medication eiter into te eplock/saline lock or directly into te vein. Syringe pumps can also be used for intermittent infusions. A syringe wit te medication is inserted into te pump. Te medication is delivered at a set rate over a sort period of time. A volume-control set is a small container, called a burette, tat is connected to te IV line. Burettes are often used in pediatric or geriatric care, were accurate volume control is critical. Te danger of overdose is limited because of te small volume of solution in te burette. Burettes will be discussed in Capter 12. ALERT An IV pus generally involves medications adistered over a sort period of time. Be sure to verify te need for te drug, route, concentration, dose, expiration date, and clarity of te solution. It is also essential to verify te rate of injection wit te package insert. Some medications (e.g., adenosine) require very rapid adistration, wereas oters (e.g., verapamil) are adistered more slowly. Intravenous Piggyback Infusions Patients can receive a medication troug a port in an existing IV line. Tis is called intravenous piggyback (IVPB); Figure Te medication is in a secondary bag. Notice in Figure 11.1 tat te secondary bag is iger tan te primary bag so tat te pressure in te secondary line will be greater tan te pressure in te primary line. Terefore, te secondary medication infuses first. Once te secondary infusion is completed, te primary line begins to flow. Be sure to keep bot lines open. If you close te primary line, wen te secondary IVPB is completed te primary line will not flow into te vein. A typical IVPB order migt read: cimetidine 300 mg IVPB q6 in 50 NS infuse over 30. Tis is an order for an IV piggyback infusion in wic 300 mg of te drug cimetidine diluted in 50 of a normal saline solution must infuse in 30 utes. So, te patient receives 300 mg of cimetidine in 30 utes via a secondary line, and tis dose is repeated every 6 ours.

3 244 Capter 11 Calculating Flow Rates for Intravenous Medications Figure 11.1 Primary and secondary (IVPB) infusion setup. Example 11.1 Te prescriber ordered: Ancef 1 g IVPB q4 Te package insert information is as follows: Add 50 sterile water to te bag of Ancef 1 g and infuse in 30. Te tubing is labeled 20 drops per milliliter. Calculate te flow rate in drops per ute for tis antibiotic. Te patient receives 50 in 30 utes. You want to cange tis flow rate from per ute to an equivalent flow rate in drops per ute gtt? Using te drop factor of 20 gtt/, you can do tis on one line as follows: gtt 1 = 100 gtt 3 = 33.3 gtt So, te flow rate is 33 drops per ute.

4 Intravenous Piggyback Infusions 245 (a) Figure 11.2 Packages of secondary IV tubing. (Courtesy of Baxter Healtcare Corporation. All rigts reserved. Potos by Al Dodge.) (b) Example 11.2 Te order is Mefoxin 1 g IVPB q6 in 50 over 30 utes. Read te label for te premixed Mefoxin in Figure 11.3 and find te drip rate if te drop factor is 10 gtt/. Te package insert indicates tat te Mefoxin sould be infused in 30 utes. Te label states: 1 g in 50. Tis entire solution must be infused in 30 utes. You want to cange te flow rate from 50 per 30 utes to an equivalent flow rate in drops per ute gtt? Figure 11.3 Drug label for Mefoxin. (Te labels for te products Mefoxin 1g are reproduced wit permission of Merck & Co.,Inc.,copyrigt owner.)

5 246 Capter 11 Calculating Flow Rates for Intravenous Medications Using te drop factor of 10 gtt/, you can do tis on one line as follows: gtt = 50 gtt 3 So, te flow rate is 17 drops per ute. = gtt Example 11.3 Te medication order reads: 1,000 5% D/W wit 1,000 mg of a drug at 1 mg>. Calculate te flow rate in drops per ute if te drop factor is 15 drops per milliliter. In tis example, te prescriber as specified te amount of solution and its strengt (1,000 of 5% D/W containing 1,000 mg of te drug) and also te rate at wic te patient receives te drug (1 mg/). Tis flow rate is not te usual volume per time (/ or gtt/), but it is in terms of weigt of drug per time (mg/). Given flow rate: Known equivalences: Flow rate you want to find: 1 mg/ (notice tat a flow rate always as time in te denoator) 1,000 mg/1,000 (strengt) 15 gtt/ (drop factor)? gtt/ You want to convert te flow rate from milligrams per ute to an equivalent flow rate in drops per ute. mg 1 gtt? You want to cancel mg. To do tis you must use a unit fraction containing mg in te denoator. Using te strengt, tis fraction will be 1,000 1,000 mg. 1 mg 1,000 1,000 mg =? gtt Now, on te left side is in te numerator, and it must be cancelled. Tis will require a unit fraction wit in te denoator. Using te 15 gtt drop factor, tis fraction will be. Now cancel and multiply te numbers 1 mg 1 1,000 1,000 mg 15 gtt 1 gtt = 15 So, you would adister 15 gtt/.

6 Intravenous Piggyback Infusions 247 Example 11.4 Te prescriber writes an order for 1,000 of 5% D/W wit 10 units of a drug. Your patient must receive 30 mu of tis drug per ute. Calculate te flow rate in microdrops per ute. Given flow rate: 30 mu/ (notice tat a flow rate always as time in te denoator) Known equivalences: 10 units/1,000 mu (strengt) 60 gtt/ (standard microdrop drop factor) 1 unit = 1,000 mu Flow rate you want to find:? mcgtt/ You want to cange te flow rate from milliunits per ute to microdrops per ute. mu 30 =? mcgtt You want to cancel mu. To do tis you must use a unit fraction containing mu in te denoator. Using te equivalence 1 mu = 1,000 units, 1 unit tis fraction will be 1,000 mu. 30 mu 1 unit 1,000 mu mcgtt =? NOTE 1 unit = 1,000 milliunits (mu) Now, on te left side unit is in te numerator, and it must be cancelled. Tis will require a unit fraction wit unit in te denoator. Using te 1,000 strengt, tis fraction will be 10 units. 30 mu 1 unit 1,000 mu 1, units mcgtt =? Now, on te left side is in te numerator, and it must be cancelled. Tis will require a unit fraction wit in te denoator. Using te 60 mcgtt drop factor, tis fraction will be. Now, cancel and multiply te numbers 30 mu 1 unit 1,000 mu So, you will adister 180 mcgtt/. 1, units 60 mcgtt mcgtt = 180 Example 11.5 Calculate te flow rate in milliliters per our if te medication order reads: Add 10,000 units of eparin to 1,000 5% D/W IV. Your patient is to receive 1,250 units of tis anticoagulant per our via an infusion pump. You want to cange te flow rate from units per our to milliliters per our. 1,250 units 1?

7 248 Capter 11 Calculating Flow Rates for Intravenous Medications Using te strengt of te solution (10,000 units/1,000 ) you do tis on one line as follows: 1,250 units 1 So, your patient will receive 125 per our. In Examples 11.6, 11.7, and 11.8, you are given te flow rate in milliliters per our, and you need to detere te amount of medication te patient will receive in a given amount of time. Example , , units Calculate te number of units of Regular insulin a patient is receiving per our if te order is 500 NS wit 300 units of Regular insulin and it is infusing at te rate of 12.5 per our via te pump. You want to convert te flow rate from per our to units per our Using te strengt of te solution (300 units/500 ) you do tis in one line as follows: units 37.5 units = So, te patient is receiving 7.5 units per our. = 1, units? or 7.5 = 125 units Example 11.7 Order: eparin 40,000 units continuous IV in 1,000 of D5W infuse at 30 /. Find te flow rate in units/day and detere if it is in te safe dose range te normal eparinizing range is between 20,000 to 40,000 units per day. You want to convert te flow rate from milliliters per our to units per day units? day Using te strengt of te solution (40,000 units/1,000 ) and tat tere are 24 ours in a day, you do tis on one line as follows: 30 40,0 0 0 units 24 units = 28,800 1,0 0 0 day day So, your patient is receiving 28,800 units of eparin per day. Tis rate is witin te safe dosage range of 20,000 to 40,000 units per day. Example 11.8 Your patient is receiving an IV of 1,000 of NS wit 1,000 mg of te broncodilator aopylline. Te flow rate is 50 /. How many milligrams per our is your patient receiving?

8 Calculating Flow Rates Based on Body Weigt 249 You want to convert te flow rate from milliliters per our to milligrams per our. 50 mg? 1 Using te strengt of te solution (1,000 mg/1,000 ) you do tis on one line as follows: , mg 1, = 50 mg So, your patient is receiving 50 of aopylline per our. Calculating Flow Rates Based on Body Weigt In Capter 6 you calculated dosages based on body weigt alone. Suppose a patient weiging 100 kg is to receive a drug at te rate of 2 micrograms per kilogram (2 mcg/kg). You could convert te single unit of measurement (kg) into te single unit of measurement (mcg), and te patient would receive 200 mcg of te drug as te following computation sows: 100 kg 2 mcg = 200 mcg kg In tis capter you will see tat some IV medications are not only prescribed based on te patient s body weigt, but te amount of drug te patient receives also depends on time. For example, an order migt indicate tat a drug is to be adistered at te rate of 2 micrograms per kilogram per ute (2 mcg/kg/). Tis means tat eac ute te patient is to receive 2 mcg of te drug for every kilogram of body weigt. Terefore, te amount of medication te patient receives is based on bot body weigt and time. For computational purposes tis new type of rate (compound rate) is written as 2 mcg kg Suppose tat a patient weiging 100 kg is receiving a drug at te rate of 2 mcg/kg/. If you multiply te weigt of tis patient (a single unit of measurement) by te compound rate, you obtain a rate wic depends only on time as follows: 2 mcg 200 mcg 100 kg = kg So, te patient is receiving te drug at te rate of 200 mcg/. Example 11.9 Te prescriber ordered: 250 5% D/W wit 60 mg Aredia mg/kg/ IVPB. Te patient weigs 75 kg, and te drop factor is 20 gtt/. Calculate te flow rate for tis antiypercalcemic drug in drops per ute. Given: 75 kg (weigt of te patient) Known equivalences: mg/kg/ (order) 60 mg/ (strengt) 20 gtt/ (drop factor) Find:? gtt/ (flow rate)

9 250 Capter 11 Calculating Flow Rates for Intravenous Medications As sown, multiplying te weigt of te patient by te order will yield a rate based on time. Tis rate can ten be converted to te desired flow rate (drops per ute). So you want to start wit te weigt of te patient (kilograms) and convert to drops per ute. 75 kg = gtt> You want to cancel kg. To do tis you must use a fraction containing kg mg in te denoator. Using te order, tis fraction will be kg. 75 kg mg kg =? gtt Now, on te left side mg is in te numerator, but you don t want mg. You need a fraction wit mg in te denoator. Using te strengt of 250 te solution, te fraction is 60 mg. 75 kg mg kg mg gtt =? Now, on te left side is in te numerator, but you don t want. To cancel te you need a fraction wit in te denoator. Using 20 gtt te drop factor, te fraction is Now cancel and multiply te numbers. 75 kg mg kg mg 20 gtt gtt = 37.5 So, te flow rate is 38 gtt/. Titrating Medications Sometimes medications must be titrated. Tat is, te dose of te medication must be adjusted until te desired terapeutic effect (e.g., blood pressure maintenance) is acieved. Te following example includes a drug tat is titrated. Example Order: Intropin (dopae) 2 mcg/kg/ IVPB, titrate to maintain SBP above 90, increase by 5 mcg/kg/ q utes. Maximum dose 20 mcg/kg/. Monitor BP and HR q 2 5 utes during titration. Te label on te 500 medication bag states 800 mcg/, and te patient weigs 175 pounds. (a) How many mcg/ of Intropin sould te patient receive initially? (b) Calculate te initial pump setting in /.

10 Calculating Flow Rates Based on Body Surface Area 251 (a) You want to convert te weigt of te patient (175 pounds) to micrograms of Intropin per ute. 175 lb? mcg Using 1 kg = 2.2 lb and te order (2 mcg/kg/), you can do tis on one line as follows: ALERT Drugs tat are titrated are adistered according to protocol. Terefore, it is necessary to know te institution s protocols. 175 lb 1 kg 2.2 lb 2 mcg kg = 159 mcg So, initially te patient will receive 159 mcg/. (b) Now, convert 159 mcg to. Using te strengt of te solution (800 mcg/) and 1 = 60 you can do tis on one line as follows: 159 mcg mcg 60 = So, te pump would initially be set at 12 /. Calculating Flow Rates Based on Body Surface Area As you know, certain medications are ordered based on body surface area (BSA). Capter 6 discussed ow to detere BSA. Te following examples sow ow to calculate flow rates for tis type of medication order. Example Te order is 100 mg/m 2 IVPB in 50 NS. Te patient as BSA of 1.55 m 2. Te package insert indicates tat te infusion sould be given in 30 utes. Te label on te vial indicates tat te strengt of te reconstituted drug is 38 mg/. (a) How many mg of te drug would te patient receive? (b) How many of te drug would you need to take from te vial? (c) Wat is te total volume (in ) to be infused? (d) Wat is te flow rate in /? (e) If te drop factor is 10 gtt/, wat is te rate of flow in gtt/? (a) You want to cange te size of te patient (in m 2 ) to te number of milligrams of te drug m 2? mg 1.55 m mg = 155 mg m 2

11 252 Capter 11 Calculating Flow Rates for Intravenous Medications NOTE Verify te institution s policy concerning IV medications tat are reconstituted for adistration. Detere weter in te calculations, te total volume to be infused must include te volume of te added reconstituted medication. For example, in Example if te volume of te reconstituted drug added to te IVPB bag (4.1 ) ad been ignored in te calculations, te answer to part (d) would ave been ( 50 > 1 2 ) 100 / instead of /. So, te patient would receive 155 mg of te drug. (b) You want to convert te amount of drug (in mg) to te volume of drug (in ). 155 mg? Te label indicates tat te strengt of te reconstituted te drug is 38 mg/. 155 mg 1 38 mg = 4.1 Since your patient sould receive 4.1 of te drug, 4.1 sould be witdrawn from te vial. (c) Since te 4.1 of te drug must be added to te 50 bag, te total volume to be infused will be ( ) (d) Since te entire volume must infuse in 30 utes ( 2 our), te flow rate, in milliliters per our, is 54.1 = (e) Since te drop factor is 10 gtt = 1, te flow rate found in part (d) can be converted to gtt/ as follows: gtt 1 60 = gtt So, te flow rate, in drops per ute, is 18 gtt/. Example Order: Camptosar 125 mg>m 2 IVPB in 250 of NS over 90 utes once weekly for 4 weeks. Te patient as a BSA of 1.67 m 2. Read te label for tis antineoplastic drug in Figure 11.4 and detere te pump setting in milliliters per our. First cange te size of te patient (BSA) to te number of milliliters needed to be taken from te Camptosar vial m 2? From te order, you need to use 125 mg>m 2 ; and from te label, te concentration of te Camptosar is 100 mg/5. Figure 11.4 Drug label for Camptosar m mg m mg = 10.4 So, 10.4 is taken from te Camptosar vial and is added to te 250 bag. Tis means tat te total volume of te infusion is ( ) 260.4, and te patient would receive of Camptosar in 90 utes.

12 Calculating Flow Rates Based on Body Surface Area 253 Now, cange te flow rate of So, te pump is set at 174 /. Example to /. Order: Infuse 50 IVPB in 2 our. After 20 utes, it is discovered tat 30 still remain to be infused. Recalculate te rate of flow in gtt/ if te drop factor of te adistration set is 20 gtt/. Since te remaining volume (30 ) must infuse in te remaining time (10 utes), te flow rate is 30 /10 utes. You want to cange 30 /10 utes to gtt/ute. Since te drop factor is 20 gtt/: gtt gtt = gtt So, te flow rate is 60. Example = > Te prescriber ordered Vancomycin 1.5 g in 200 of D 5 W. Infuse in 60 utes, te label reads: 1.5 g of Vancomycin. Te vial available is used wit a reconstitution device similar to tat sown in Figure Te tubing is labeled 15 drops per milliliter. Calculate te flow rate in drops per ute. You want to cange te flow rate from milliliters per ute to gtt/. 200 Dextrose 5% in water IVPB Bag Reconstitution device Vancomycin 1.5 g Vial Figure 11.5 Reconstitution system Do tis in one line as follows: gtt 60 So, te flow rate is 50 gtt/.? drops = 50 gtt> Tere are reconstitution systems tat enable te ealt care provider to reconstitute a powdered drug and place it into an IVPB bag witout using a syringe. One suc device is sown in Figure Wit tis device, wen te IVPB bag is squeezed, fluid is forced into te vial, dissolving te powder. Te system is ten

13 254 Capter 11 Calculating Flow Rates for Intravenous Medications placed in a vertical configuration wit te vial on top and te IVPB bag on te bottom. Te IVPB bag is ten squeezed and released, tereby creating a negative pressure, wic allows te newly reconstituted drug to flow into te IVPB bag. Anoter reconstitution device is te ADD-Vantage system, wic employs an IV bag containing intravenous fluid. Te bag is designed wit a special port, wic will accept a vial of medication. Wen te vial is placed into te bag port, te contents of te vial and te fluid mix to form te desired solution. Example A patient wo weigs 55 kg is receiving a medication at te rate of 30 /. Te concentration of te medication is 400 mg in 500 of D5W. Te recommended dose range for te drug is 2 5 mcg/kg/. Is te patient receiving a safe dose? Metod 1 Convert te safe dose range of 2 5 mcg/kg/ to (of te drug)/our. First, use te imum recommended dose (2 mcg/kg/) and start wit te weigt of te patient to detere ow many / te patient sould imally receive as follows: 55 kg 2 mcg kg Now, use te maximum recommended dose (5 mcg/kg/) and start wit te weigt of te patient to detere ow many / te patient sould maximally receive as follows: 5 mcg 55 kg kg mg 1,000 mcg 1 mg 1,000 mcg mg mg = 8.3 = 20.6 Min Max So, te safe dose range for tis patient is /. Since te patient is receiving 30 /, te patient is not receiving a safe dose, but is receiving an overdose. Metod 2 Convert te 30 /, wic te patient is receiving, to mcg/kg/ and ten compare tis to te safe dose range of 2 5 mcg/kg/. Tis may be a matematically more sopisticated approac, but it requires fewer calculations. Realize tat wat you are looking for, mcg/kg/, is in te form of amount of drug/weigt of patient/time. An amount of drug (30 ) is being adistered to a (55 kg) patient over a period of time (1 our). So, te patient is receiving 30 /55kg/1. NOTE Wenever your calculations indicate tat te prescribed dose is not witin te safe range, you sould verify te order wit te prescriber. You want to cange 30 /55kg/1 to mcg/kg/, wic can be done in one line as follows: kg mg 500 1,000 mcg mcg = mg kg Te safe dose range for tis patient is 2 5 mcg/kg/, and since te patient is receiving 7.3 mcg/kg/, te patient is not receiving a safe dose, but an overdose.

14 Case Study Summary In tis capter, te IV medication adistration process was discussed. IVPB and IVP infusions were described, and orders based on body weigt and body surface area were illustrated. A secondary line is referred to as an IV piggyback. IV pus, or bolus, medications can be injected into a eplock/saline lock or directly into te vein. Te IV bag tat is ung igest will infuse first. An order containing mg/kg/ directs tat eac ute, te patient must receive te stated number of milligrams of medication for eac kilogram of te patient s body weigt. For calculation purposes write mg/kg/ as mg kg Wen calculating rates of flow of infusions based on body weigt or BSA, start wit te patient s size, as measured by weigt or BSA. Wen looking for mg/kg/, start wit te amount of drug/weigt/time. Wen titrating medications, te dose is adjusted until te desired terapeutic effect is acieved. Case Study 11.1 A woman is admitted to te labor room wit a diagnosis of preterm labor. Se states tat se as not seen a pysician because tis is er tird baby and se knows wat to do wile se is pregnant. Her initial workup indicates a gestational age of 32 weeks, and se tests positive for Clamydia and Strep-B. Her vital signs are: T 100 F; P 98; R 18; B/P 140/88; and te fetal eart rate is Te orders include te following: NPO IV fluids: D5/RL 1,000 q8 Electronic fetal monitoring Vital signs q4 dexametasone 6 mg IM q12 for 2 doses Bretine (terbutaline sulfate) 0.25 mg subcutaneous q30 utes for 2 Rocepin (ceftriaxone sodium) 250 mg IM stat Penicillin G 5 million units IVPB stat; ten 2.5 million units q4 Zitromax (azitromycin) 500 mg IVPB stat and daily for 2 days 1. Calculate te rate of flow for te D5/RL in /. 2. Te label on te dexametasone reads 8 mg/. How many milliliters will you adister? 3. Te label on te terbutaline reads 1 mg/. How many milliliters will you adister? 4. Te label on te ceftriaxone states to reconstitute te 1 g vial wit 2.1 of sterile water for injection, wic results in a strengt of 350 mg/. How many milliliters will you adister? 5. Te instructions state to reconstitute te penicillin G (use te imum amount of diluent), add to 100 D5W, and infuse in one our. Te drop factor is 15. Wat is te rate of flow in gtts/? See te label in Figure 11.6 Figure 11.6 Drug label for penicillin G. (Reg.Trademark of Pfizer Inc. Reproduced wit permission.)

15 256 Capter 11 Calculating Flow Rates for Intravenous Medications 6. Te instructions for te azitromycin state to reconstitute te 500 mg vial wit 4.8 until dissolved, and add to 250 of D5W and adister over at least 60 utes. Wat rate will you set te infusion pump if you coose to adister te medication over 90 utes? 7. Te patient continues to ave uterine contractions, and a new order as been written: magnesium sulfate 4g IV bolus over 20 utes, ten 1g/. Te label on te IV bag states magnesium sulfate 40 g in 1,000. (a) Wat is te rate of flow in / for te bolus dose? (b) Wat is te rate of flow in / for te maintenance dose? Te patient continues to ave contractions and er membranes rupture. Te following orders are written: Discontinue te magnesium sulfate. Pitocin (oxytocin) 10 units/1,000 RL, start at 0.5 mu/ increase by 1 mu/ q20 utes. Stadol (butorpanol tartrate ) 1 mg IVP stat. 8. Wat is te rate of flow in / for te initial dose of Pitocin? 9. Te Pitocin is infusing at 9 /. How many mu/ is te patient receiving? 10. Te vial of butorpanol tartrate is labeled 2 mg/. How many milliliters will you adister? Workspace Practice Sets Te answers to Try Tese for Practice, Exercises, and Cumulative Review Exercises appear in Appendix A at te end of te book. Ask your instructor for answers to te Additional Exercises. Try Tese for Practice Test your compreension after reading te capter. 1. Order: Tagamet (cimetidine) 300 mg IVPB q6 in 50 NS infuse over 30. Te drop factor is 15 gtt/. Find te flow rate in gtt/. 2. Te order is for a continuous infusion of teopylline at a rate of 25 mg/. It is diluted in 5% dextrose to produce a concentration of 500 mg per 500. Detere te rate of te infusion in /. 3. A 500 D5W solution wit 2 g of Pronestyl (procainamide HCl) is infusing at 15 / via a volumetric pump. How many mg/ is te patient receiving? 4. Order: Dobutrex (dobutae) 250 mg in 250 of D5W at 3.5 mcg/kg/. Detere te flow rate in mcgtt/ for a patient wo weigs 120 pounds. 5. A patient is receiving eparin 1,200 units/our. Te directions for te infusion are, add 25,000 units of eparin in 250 of solution. Detere te flow rate in /. Exercises Reinforce your understanding in class or at ome. 1. Te patient is to receive 20 meq of KCl (potassium cloride) in 100 of IV fluid at te rate of 10 meq/. Wat is te flow rate in microdrops per ute?

16 Practice Sets A maintenance dose of Levoped (norepineprine bitartrate) 2 mcg/ IVPB as been ordered to infuse using an 8 mg in 250 of D5W solution. Wat is te pump setting in /? 3. Te patient is receiving lidocaine at 40 /. Te concentration of te medication is 1 g per 500 of IV fluid. How many mg/ is te patient receiving? 4. Order: dopae 400 mg in 250 D5W at 3 mcg/kg/ IVPB. Calculate te flow rate in / for a patient wo weigs 91 kg. 5. A drug is ordered 180 mg>m 2 in 500 NS to infuse over 90 utes. Te BSA is 1.38 m 2. Wat is te flow rate in /? 6. How long will a 550 bag of intralipids take to infuse at te rate of 25 /? 7. Te patient is receiving eparin at 1,000 units/our. Te IV as been prepared wit 24,000 units of eparin per liter. Find te flow rate in /. 8. Order: Humulin R 50 units in 500 NS infuse at 1 / IVPB. How many units per our is te patient receiving? 9. An IVPB of 50 is to infuse in 30 utes. After 15 utes, te IV bag contains 40. If te drop factor is 20 gtt/, recalculate te flow rate in gtt/. 10. Te patient is receiving Nipride (nitroprusside) 50 mg in 250 of D5W for ypertension. Te rate of flow is 20 /. If te patient weigs 75 kg, detere te dosage in micrograms/kilogram/ute te patient is receiving. 11. Order: Coumadin (warfarin sodium) 4 mg IVP stat adister over 1 ute. Te available 5 mg of Coumadin is in a vial wit directions tat state to dilute wit 2 of sterile water: (a) How many mg will te patient receive? (b) How many will you adister? (c) How many / will be infused? 12. Te patient is to receive Aldomet (metyldopa) 500 mg IVPB dissolved in 100 of IV fluid over 60 utes. If te drop factor is 15 gtt/, detere te rate of flow in gtt/. 13. Te patient is to receive Isuprel (isoproterenol) at a rate of 4 mcg/. Te concentration of te Isuprel is 2 mg per 500 of IV fluid. Find te pump setting in /. 14. Te patient is receiving aopylline at te rate of 20 /. Te concentration of te medication is 500 mg/1,000 of IV fluid. How many mg/ is te patient receiving? 15. Nipride 3 mcg/kg/ as been ordered for a patient wo weigs 82 kg. Te solution as a strengt of 50 mg in 250 of D5W. Calculate te flow rate in /. 16. A medication is ordered at 75 mg>m 2 IVP. Te patient as BSA of 2.33 m 2. How many milliliters of te medication will be adistered if te vial is labeled 50 mg/? 17. A liter of D5> 1 4 NS wit 10 units of Regular insulin is started at 9:55 A.M. at a rate of 22 gtt/mim. If te drop factor is 20 gtt/, wen will te infusion finis? 18. Mefoxin 2 g in 100 NS IVPB. Infuse in 1 our. After 30 utes, 70 remain in te bag. Reset te flow rate on te pump in /. Workspace

17 258 Capter 11 Calculating Flow Rates for Intravenous Medications Workspace 19. Order: eparin sodium 40,000 units IV in 500 of 2 NS to infuse at 1,200 units/our. Wat is te flow rate in /? 20. Te patient is receiving Dobutrex (dobutae) at a rate of 18 mcgtt/. Te concentration is 250 mg/250 of IV fluid. Detere te dosage in microdrops/kilogram/ute tat te 150-pound patient is receiving. 1 Additional Exercises Now, test yourself! 1. Pysician s order: Dobutae (Dobutrex) 500 mg in 500 D 5 W, 6 mcg/kg/ IVPB. Weigt 145 lb. (a) Set te flow rate on te infusion pump in milliliters per our. (b) If te above infusion begins at 6 A.M., wen will it be completed? 2. Order: Amiodarone 160 mg in 20 D 5 W IVPB; infuse over 10 utes. Te label reads 50 mg>. Te drop factor is 60 mcgtt>. Calculate te flow rate in mcgtt/. 3. Te dose of amiodarone (Cordarone) in Question 2 is increased to 720 mg in 24 ours in 500 D 5 W. Set te rate on te infusion pump in milliliters per our. 4. Pamidronate disodium (Aredia), an antiypercalcemic drug, 0.09 g IV as been prescribed. Te label reads: Add 10 to a 90 mg vial. (a) How many milliliters contain te prescribed dose? (b) Add te correct amount of Aredia to 1,000 of 0.45% NaCl and infuse in 24 ours. Set te flow rate on te infusion pump in milliliters per our. 5. Order: lidocaine HCl IV drip 0.75 mg/kg in 500 D5W. Te patient weigs 150 pounds. (a) How many milliliters of lidocaine 2% will be needed to prepare te IV solution? (b) Calculate te flow rate in / in order for te patient to receive 5 mg/. 6. Order: Diltiazem (Cardizem) 0.25 mg>kg IV pus over 2. Te label on te vial reads 5 mg>. Te patient weigs 210 pounds. (a) How many milligrams of Cardizem will te patient receive? (b) How many milliliters contain te dose of medication? 7. Pysician s order: Penytoin (Dilantin) 500 mg IV pus over 10 Te label on te vial reads 50 mg/. (a) How many milliliters will you prepare? (b) Calculate te flow rate in microdrops per ute. 8. Te loading dose of digoxin is 0.25 mg IV pus q6 for 4 doses. Te label on te ampule reads 0.5 mg>. How many milliliters contain tis dose?

18 Practice Sets Te prescriber ordered cefuroxime 18 mg/kg IVPB in 200 NS. Infuse in 1.5 ours. Te patient weigs 80 kg. Te label on te vial states tat after reconstitution te strengt is 3 g/32. (a) How many milligrams of cefuroxime will te patient receive? (b) How many milliliters of cefuroxime will you add to te 200 of NS? (c) Calculate te flow rate in milliliters per our. Workspace 10. Adenocor, (adenosine) 6 mg IV pus over 1-2 seconds as been prescribed for your patient. Te label on te vial reads 3 mg/. How many milliliters will you prepare? 11. Te order for cefuroxime is 500 mg in 100 D 5 W IVPB q8; infuse in 20. Te vial states: add 77 of sterile water, and te concentration is 750 mg/8. (a) How many milliliters of cefuroxime contain tis dose? (b) Calculate te flow rate in milliliters per ute. 12. Your patient as developed bradycardia, and Atropine gr 1 60 IV pus stat is ordered. Te label reads 0.5 mg/. How many milliliters will you adister? 13. Ritodrine HCL (Yutopar) 150 mg added to 500 D 5 W as been ordered for a patient wo is aving premature uterine contractions. (a) Calculate te flow rate in microdrops per ute over a 15-our period. (b) Cange te flow rate to milliliters per our. 14. A patient as been admitted to te ER wit a diagnosis of lead poisoning. Te pysician orders edetate calcium disodium (calcium EDTA) 1.5 g>m 2 IV. Te BSA is 2.0 m 2. Te label on te vial reads 200 mg>. Add te prescribed amount of drug to 250 D 5 W and infuse at a rate of 11 /. At wat time will te infusion finis if it begins at 10 A.M.? 15. Te order is cefuroxime 1.5 g added to 100 NS infuse in 60 utes IVPB. Te strengt of te cefuroxime is 750 mg per 8. (a) How many milliliters of cefuroxime will you add to te normal saline solution? (b) Calculate te milligrams per ute te patient is receiving. 16. Te order is Narcan maxolone (a narcotic antidote) 2 mg IV pus. Te vial reads 0.4 mg/. How many milliliters will you give te patient? 17. Prescriber order: Sufentanil 6 mcg/kg IVPB in 100 D 5 W, infuse over 30 utes. Weigt 172 lb. Te label states tat te concentration is 50 mcg/. Eac ampule contains 1. (a) How many milliliters contain te prescribed dose? (b) How many ampules of tis drug will you need? (c) How many microdrops are infused per ute?

19 260 Capter 11 Calculating Flow Rates for Intravenous Medications Workspace 18. Te prescriber ordered morpine sulfate 50 mg to be added to 250 of NS IVPB. Infuse in 5 ours. Te strengt of te morpine is 1 mg/. (a) How many milliliters contain te prescribed dose? (b) Calculate te flow rate in milliliters per our. (c) After 90 utes, te patient ad breaktroug pain, and te pysician increased te morpine to 15 mg/. Recalculate te flow rate. Figure 11.7 Drug label for Regular insulin. (Reproduced wit permission of GlaxoSmitKline.) 19. Te prescriber ordered a continous IV insulin drip of 500 units of Regular insulin added to % NaCl q12. Read te information on te label in Figure Calculate te flow rate in units per our. 20. You ave an infusion of eparin 50,000 units in 500 D 5 W. Te patient is receiving 1,500 units/. Wat is te setting on te pump? Cumulative Review Exercises Review your mastery of earlier capters. 1. Te patient weigs 130 pounds. Te medication order for a drug is 150 mcg/kg of body weigt. Te label reads 2 mg/. How many milliliters of solution are equal to te medication order? 2. Te prescriber ordered 0.04 mg of Metergine (metylergonovine maleate) PO q6. How many tablets will you prepare if te label reads 0.02 mg/tab? 3. Te patient must receive 1,500,000 units of penicillin IM, and te vial contains 20,000,000 units (in powdered form). Te directions are as follows: Add 38.7 to vial; 1 = 500,000 units. How many milliliters will equal 1,500,000 units? 4. A patient must receive 0.5 mg of scopolae IM, a parasympatetic antagonist. Te label on te ampule reads 0.3 mg/. How many milliliters will you adister to tis patient? 5. Te prescriber ordered cefprozil 200 mg PO q12 for 10 days. Te bottle is labeled 100 mg/5. How many milliliters of tis antibiotic will you give your patient?

20 Cumulative Review Exercises If you ave a vial labeled 120 mg/, ow many milliliters would equal 1.2 g? 7. If tablets are 250 mg eac, ow many tablets equal 0.5 g? 8. Te prescriber as requested tat you give 40 meq of potassium cloride (K- Lor) PO to a patient from a bottle labeled 10 meq/5. How many milliliters are needed? 9. 2,400 = L Workspace mg = gr > = mcgtt/ pt = qt mcg = mg T = t = oz MediaLink Animated examples, interactive practice questions wit animated solutions, and callenge tests for tis capter can be found on te Prentice Hall Dosage Calculation Tutor tat accompanies tis text.additional, unique, interactive resources and activities can be found on te Companion Website.