Chapter 8 Calculation of Basic IV Drip Rates

MicrodripsMacrodrips

Types of Intravenous FluidsSterile plastic bagsSterile glass bottles

Careful to prepare our solutionsAvoid any errors – may result in patient

electrolyte imbalance

Written order – come from the physicianLabel may be different

D -> DextroseW -> WaterNS -> Normal Saline (0.9% saline-> 0.9 g per 100 mL water)

Written Supply1000 mL D5W 1000 mL D5%W500 mL D5S 500 mL D5%0.9NS250 mL D51/2NS 250 mL D5%0.45NS500 mL D51/3NS 500 mL D5%0.33NS500 mL NS 500 mL 0.9% NS1000 mL 1/2 NS 1000 mL 0.45%NS

Kinds of IV Drip Factors

Check Infusion Set: See needle in the chamber: microdrip Deliver to the patient 1mL fluid

60 drops = 60 gtt = 1mL

Infusion sets with no needle in the chamber – macrodrip

Baxter-Travenol macrodrip set to deliver 10gtt/mL

Abbott macrodrip set to deliver 15 gtt/mL

Tubing for the above sets can be clamped (opened or closed to set the drip rate)

Infusion pumps – need only two pieces of info1) total number of milliliters 2) number of milliliters per hour (infusion rate)

Can also do IVPB

Order: 500 mL D5W IV Run: 50 mL/hour

Primary versus SecondaryIVPBAmpicillin 2 g IVPB in 100mL NS over 1 hour

Labeling IVsLabel such that what drip rate is and what is being infused into the patient

Patient Katherine PapademasDate, Time 10/02, 1300Order 1000 mL D5W1/2NSTime 1300 to 0100Room 436BRate 50gtt/minRun 50 mL/hrInitials DD

Note: 1000 mLRun time: Finish time – start time = total hours IV runs

Calculating Basic IV Drip Rates

mL/hour

Step 1: Total number of mLs ordered = no. mL/hrNumber of hours to run

Step 2:Number of mLs/hr x Tubing Drip Factor (TF) = drops per minute (gtt/min)

Number of minutes

Order: 1000 mL Ringer’s Lactate IV 8am-8pmAvailable: an infusion pump

Logic:Run time: 12 hours

Step 1: 1000 mL/12 hours = 83.33

(round to nearest whole number)

Enter: total volume: 1000 mL mL/hr: 83

Order: 500 mL D5NS IV 12noon-4pmAvailable: microdrip at 60 gtt/mL;

Macrodrip at 20 gtt/mL

LogicRun time: 4 hr

Step 1: #mL/hr = 500 mL/4hr = 125 mL/hr

Step 2: Macrodrip calculation

#mL/hr x TF = 125mL/hr x 20 gtt/mL = 41.6 gtt/min

#min 60 min = 42 gtt/min

1 hr = 60 min

Step 2: Microdrip calculation

#mL/hr x TF = 125mL/hr x 60 gtt/mL = 125 gtt/min

#min 60 min

Which one should you choose?

Use Microdrip when …

IV administered over a long period of timeSmall amount of fluid to be infusedMacrodrops per minute are too few

Use Macrodrip when …

Large amount of fluid is ordered in a short timeMicrodrips per minute are too many and counting

the drip rate might be difficult for the nurse

Need for continuous observationCheck IV frequently

GravityPatient’s movements : kink the tubeWatch the flow of the fluid with respect to

where the needle has been inserted – check for infiltration

SwellingPainCoolnessPallor at the insertion site

Eg. Order: 500 mL D51/3NS IV KVO for 24◦Available: microdrip at 60 gtt/mL; macrodrip 10gtt/mLWill have to choose the IV set (as no infusion pump)

Step 1:

# mL/#hr = 500 mL/24 hr = 20.83 mL/hr = 21 mL/hr

Step 2: Macrodrip

#mL/#hr x TF = 21 mL/hr x 10 gtt/mL = 3.5 gtt/min60 min 60 min

= 4 gtt/min

Step 2: Microdrip

#mL/#hr x TF = 21 mL/hr x 60gtt/mL = 21 gtt/min

60 min 60 min

Which do we choose?????Macrodrip 4gtt/min too slow

Select microdrip infusion setSet drip rate at 21 gtt/min

No. 4 on p. 203

Order: 180 mL D5 1/3NS 12 noon – 6pmAvailable: macrodrip (10gtt/mL); microdrip (60 gtt/mL)

Step 1180 mL/6 hr = 30 mL/hr

Step 2 Macrodrip30mL/hr x 10gtt/ml = 5 gtt/min

60 min

Step 2 Microdrip30 mL/hr x 60 gtt/mL = 30 gtt/min

60 min

Choose microdrip

Determining hours an IV runs

Number of mLs ordered = run time (#hrs to run)Number of mLs/hr

Order: 500 mL NS IV; run 75 mL/hr

500 mL = 6.66hr -> 6.7 hr75 mL/hr

Order: aminophylline 500 mg in 250 mL D5W IV at 50mL/hr

250mL = 5 hr50 mL/hr

Adding Medications to IVWhen continuous IV order includes medication; add medication to IV and determine rate of flowEither pharmacist or nurse will add medication

Buretrol: IV delivery system with tubing and chamber (can hold 150 mL delivered as microdrip)

Medications ordered over several Hours

Order: 1000 mL D5W with 20 mEq KCl IV 10am-10pmAvailable: vial of KCl 40 mEq/20 mL, microdrip (60gtt/min), macrodrip (20 gtt/min)

D x S = AHDesire: 20mEqHave: 40mEq Supply: 20 mL

a) 20mEq x 20mL = 10 mL (dosage amount) 40mEq

b) Calculate drip factor

Step 1: #mL/#hr = 1000 mL/12 hr = 83 mL/hr

Step2: Macrodrip83 mL/hr x 20 gtt/mL = 28 gtt/min 60 min

Step 2: microdrip83 mL/hr x 60 gtt/mL = 83 gtt/min

60 min

Class chose macrodripAdd 10 mL KCl to the IV bag

Order: 5 milliunits penicillin G in 1000 mL D5W IV q8hrAvailable: macrodrip (10 gtt/mL), microdrip (60gtt/mL)

Logic:

Milliunit -> million units 5 milliunits -> 5000000 units of Penicillin G potassium

Supply: 5-milliunits vial of powderDirections: reconstitute with 100 mL Order is safeUse a 10-mL syringe to remove fluid aseptically from 1000-mL bag D5WInject 10mL into vial containing powder – make sure all liquid!!!!!!!Inject the new supply into the bag (990 mL + 10 mL)

Now that medication has been added – calc the drip factors and choose!!!!

Step 1: 1000mL/8hr = 125 mL/hr

Step 2:Macro

125mL/hr x 10 gtt/mL = 20.83 gtt/min =21gtt/min

60 min

Micro125mL/hr x 60gtt/mL = 125 gtt/min

60 min

p. 207-208buretrol = microdripOrder: aminophylline 250 mg in 250 mL D5W; run at 50 mL/hrAvailable: ampule of aminophylline 1g in 10mL; Buretrol that delivers 60 gtt/mL

Logic: Ampule – 1g /1000 mL = 1000 mg/1000 mL(1) Use Formula Rule

250 mg x 10 mL =2.5 mL want to administer1000 mg

(2) Preparation: draw up 2.5 mL of drug and inject it into 250 mL D5W. Label the bag.

Buretrol: microdrip 60 gtt/mL(3) Determine drip rate

mL/hr x TF = 50 mL/hr x 60 gtt/min = 50 gtt/min 60 min 60 min

(4) Label IV Bag: Rate, 50 mL/hr

Eg. Self Test 3 – No. 3

Order: 250 mg hydrocortisone sodium succinate in 1000 mL 8AM – 12 midnightAvailable: vial of hydrocortisone sodium succinate labeled 250 mg with a 2mL diluent; microdrip tubing

1) determined total time8am – 12 midnight = 16 hours

2) determine #mL/hr = run time1000 mL/16 hours = 62.5 mL/hr -> round to 63 mL/hr

3) #mL/hr x TF = 63 mL/hr x 60 gtt/min = 63 gtt/min

60 min 60 min

4) Label IV:

Medications for Intermittent Intravenous Administration

IVPB q4h, q6h, or q8h = time intervals

most in powder formcheck dr’s order (drug, route, time interval)

nurse must research manufacturer’s directions for amount and type of diluent and time for infusion to run

Rule to solve IVPB same as rule to solve IV

#mL x TF = gtt/min#min

# mL = type and amount of diluent stated on label/insert

TF: tubing for IVPB-> called secondary administration set and has a macrodrip factor. Shorter than main line IV tubing – check label for Tubing drip factor

#min -> if number of min not given for IVPB, then general rule: 30 minutes for every 50 mL solution for adults

Eg. Order: cefazolin 1 g IVPB q6hSupply: package insert for IVPB dilution of cefazolin sodium:Reconstitute with 50 to 100 mL sodium chloride injection or other solution listed (D5W, D10W, D5LR, D5NS)

Use 50 mL D5WAs no time given: use 30 min for 50mL

#mL x TF = gtt/min #min

50mL x 10 gtt/min = 16.6 = 17 gtt/min 30 min

Use reconstitution device (sterile implement containing 2 needles that connects vial and 50 mL bag)

Admixture IVsIf health care pharmacy reconstitutes and prepares IVPB in a sterile environment using laminar flow hood – you as nurse still need to check for proper labeling etc.Check dose, check expiration date, etc.

Changing the Intravenous drip RateIf kinking of tube, movement of patient, placement of needle/catheter, gravity affect flow – then might have to recalculate IV drip

Eg.Label on IV: 1000 mL D5W IV to run 8am – 4pmTubing is macrodrip (10gtt/mL); rate set at 20gtt/minTime now: 1pm

Amount of fluid you observe left in IV bag: 600 mLChange drip?

LogicStep 1: calculate #ml/hr

1000ml/8hr =125 mL/hr = delivery rate

Step 2: calculate how many hours have elapsed5 hours have elapsed125 mL/hr x 5 hr = 625 mL should have been

delivered

Step 3: Make an educated decisionStep 3: As 600 mL left in IV, only 400 mL were delivered (rather than the 625mL)

625 mL – 400 mL = 225 mL behind

Conclude: make judgment to increase IV drip rate – call the doctor

Recording intake : keep accurate account of parenteral intake as well as liquids taken orally/enterally (tube feedings)!

Ex.#8. p 213IV of D5W 1000 mL infusing at 125 mL/hr

1000mL/125 mL/hr = 8 hr

#4Order: 500 mL aminophylline 0.5g to infuse at 50 mL/hr.How mg patient receive per hour

0.5 g = 500 mg500 mg in 500 mL -> 1mg/mL (concentration of drug)

1mg/mL x 50 mL/hr - 50 mg per hour