Basic Intravenous Calculations

ESSAY

1. State the names of the following solutions:

a. NS:

b. D5W:

c. LRS:

d. D10W:

e. 0.45 NaCl sol:

ANS:

a. Normal saline

b. 5% Dextrose in water

c. Lactated Ringer’s solution

d. 10% Dextrose in water

e. Half-strength sodium chloride solution or half-strength normal saline solution. Note: 0.45% is one-half of 0.9% (normal saline).

2. Directions: Calculate the IV flow rates with DA equations where requested. For credit, show work. Label all answers. Label flow rates in milliliters per hour or drops per minutes, as needed.

Ordered: LRS 2 L IV q24h.

a. Is this an intermittent or continuous order?

What flow rate will the nurse set on an infusion pump?

b. DA equation:

c. Evaluation:

ANS:

a. Continuous

c. Equation is balanced. mL per hour remains.

3. Directions: Calculate the IV flow rates with DA equations where requested. For credit, show work. Label all answers. Label flow rates in milliliters per hour or drops per minutes, as needed.

Ordered: NS IV at 100 mL per hr. Available: NS 500 mL. How many hours (and minutes, if applicable) will the infusion last?

ANS:

4. Four types of IV administration sets are available: DF10, DF15, DF20, and DF60.

a. Which DF will deliver the largest drops?

b. Which DF will deliver the fewest drops per milliliters?

c. Which DF is used for a microdrip or pediatric IV administration set?

d. Which IV administration set would be used to administer blood?

e. Why?

ANS:

a. DF10

b. DF10

c. DF60

d. DF10

e. Because blood is viscous and would need wider tubing for a larger drop.

5. Directions: Calculate the IV flow rates with DA equations where requested. For credit, show work. Label all answers. Label flow rates in milliliters per hour or drops per minutes, as needed.

Ordered: D5W IV at 125 mL per hr. Available: D5W 1000 mL; gravity device with DF10 administration set.

What flow rate will the nurse set?

a. DA equation:

b. Evaluation:

ANS:

b. Equation is balanced. Only drops per minute remain. Note: When the hourly rate is known, it can be entered in the equation. The total volume available (1000 mL) will not be needed in the equation.

6. Directions: Calculate the IV flow rates with DA equations where requested. For credit, show work. Label all answers. Label flow rates in milliliters per hour or drops per minutes, as needed.

Ordered: D5LRS IV at 40 mL per hr. Available: D5LRS 500 mL; gravity device with microdrip administration set.

a. What is the DF for a microdrip administration set?

How many hours (and minutes, if applicable) will the infusion last?

b. DA equation:

What flow rate will the nurse set?

c. Estimated flow rate:

d. DA equation:

e. Evaluation:

ANS:

a. 60

c. 40 drops per minute because IV with DF60 the mL per hour rate equals the number of drops per minute

e. Equation is balanced. Estimate supports answer.

7. Directions: Calculate the IV flow rates with DA equations where requested. For credit, show work. Label all answers. Label flow rates in milliliters per hour or drops per minutes, as needed.

Ordered: NS IV at 75 mL per hr. Available: NS 1000 mL; IV administration set with DF15.

a. Where is the DF written?

What flow rate will the nurse set?

b. DA equation:

c. Evaluation:

ANS:

a. On the outside of the tubing administration set container

c. Equation is balanced. Only drops per minute remain.

8. Directions: Calculate the IV flow rates with DA equations where requested. For credit, show work. Label all answers. Label flow rates in milliliters per hour or drops per minutes, as needed.

Ordered: IVPB antibiotic. Available from the pharmacy: antibiotic diluted in 25-mL solution. Administer over 30 minutes. Equipment: microdrip infusion set.

a. Estimated flow rate:

b. DA equation:

c. Evaluation:

ANS:

a. 50 mL per hr (will deliver 25 mL in 30 minutes)

c. Equation is balanced. Estimate supports answer.

9. Directions: Calculate the IV flow rates with DA equations where requested. For credit, show work. Label all answers. Label flow rates in milliliters per hour or drops per minutes, as needed.

Ordered: IVPB antibiotic. Available from the pharmacy: antibiotic diluted in 50-mL solution. Administer over 20 minutes. Equipment: infusion pump.

a. Estimated flow rate:

b. DA equation:

c. Evaluation:

ANS:

a. 150 mL per hr (three 20-minute periods in 1 hour)

c. Equation is balanced. Estimate supports answer.

10. Directions: Calculate the IV flow rates with DA equations where requested. For credit, show work. Label all answers. Label flow rates in milliliters per hour or drops per minutes, as needed.

Ordered: IVPB antineoplastic. Available from the pharmacy: antineoplastic diluted in 50-mL solution. Administer over 60 minutes. Equipment: infusion pump.

a. Estimated flow rate:

b. DA equation:

c. Evaluation:

ANS:

c. Equation is balanced. Estimate supports answer.

11. Name and give the abbreviations for three isotonic solutions commonly ordered.

ANS:

5% Dextrose in water (D5W); normal saline (0.9 NaCl); lactated Ringers (L/R)

12. Where does the nurse find tubing factor information?

ANS:

The tubing factor information is found on the label of the equipment package.

13. What is the meaning of dF 15?

ANS:

A drop factor of 15 (15 drops per mL calibration)

14. Which is larger drop: dF 10 or dF 60?

ANS:

dF 10 delivers the larger drops.

15. What is the difference between microdrip and macrodrip tubing?

ANS:

Microdrip tubing has smaller diameter and delivers smaller drops (60 drops per mL). Macrodrip tubing has larger diameter and delivers larger drops (10, 15, or 20 drops per mL).

16. A gravity device with microdrip (pediatric) tubing is ordered for 30 mL per hr. How many drops per minute will be set on the device?

ANS:

30 drops per minute. Microdrip tubing (60 drops per mL) delivers the same number of drops per minutes as mL per hr.

17. A maintenance IV is of 1000 mL D5W is ordered every 24 hours on an EID.

a. What is mL per hr to nearest 0.5 mL? ____________

b. Estimate:

c. DA equation:

d. Evaluation:

e. Is this considered a continuous or an intermittent infusion?

ANS:

a. 42 mL per hr

b. Estimate: Less than 50 mL per hr (10 hours would be 100 mL per hr, 20 hours 50 mL per hr)

c. DA equation: 41.66, rounded to 42 mL per hr (nearest 0.5 mL)

d. Evaluation: Estimate supports answer.

e. This is a continuous infusion.

18. What is another name for a medicated intermittent infusion?

ANS:

IV piggyback (IVPB)

19. An IV of 1000 mL at 100 mL per hr is started at 1200 hours. At 1800 hours, 400 mL have been infused. How many mL should have been infused? How could this have been prevented?

ANS:

600 mL should have been infused. Monitoring IV infusion rates and volume infused frequently, at least every hour or more often, and during every visit to bedside, can prevent this type of error.

20. If an IV solution, medicated or unmedicated, falls behind or gets ahead of the ordered schedule, what should and shouldn’t the nurse do? What are some of the concerns?

ANS:

The nurse should not automatically readjust the flow rate. The prescriber orders the flow rate based upon the contents of the IV, patient heart, lung and renal function, diagnoses, and purpose of the IV, among other things. There are no approved “catch- up formulas” for any patient. The nurse is not prepared to evaluate all this. The patient condition must be assessed for symptoms of fluid or medication overload or underload. It’s best to consult the prescriber promptly about adjustments. Even abruptly slowing down a medicated IV can cause problems. Never open the IV to full flow to “catch up.”

21. Agency policy states that blood is to be administered at 2 mL per minute for the first 30 minutes. How many mL per hr will be set on the EID?

ANS:

120 mL per hr (2 mL × 60 min)

22. Why is blood administered slowly for the first 15 to 30 minutes?

ANS:

To monitor for adverse reactions, which can be very serious.

23. What solution is hung with blood and administered on Y tubing before and after blood administration. What is the purpose?

ANS:

Normal saline is hung on Y tubing and to establish a patent line. The refrigerated blood is added after the line is established. If there is an untoward reaction during the transfusion, the blood is discontinued and the saline infused immediately to maintain the IV line and to prevent further reaction until additional measures are determined.

24. What is a PCA pump used for?

ANS:

PCA pumps are used to for IV pain control administration by the patient.

25. What assessments should the nurse make when checking an infusing IV?

ANS:

Patency of IV, insertion site, flow rate and amount infused, and any new adverse symptoms since IV start.

26. What the purpose of a volume control burette device?

ANS:

To prevent fluid and/or medication overload.

27. If IV of 100 mL is ordered for every 5 hours and an agency policy is that 1-hour volume is the maximum amount that can be placed in the volume control device, how much will the nurse place in the device?

ANS:

20 mL (100 mL ÷ 5 hr = 20 mL per hr)

28. An IVPB of 50 mL is ordered to be infused over 30 minutes. What flow rate will the nurse set on the EID in mL per hr?

ANS:

100 mL per hour will deliver 50 mL in 30 minutes ( hr)

29. A medicated IVPB 30 mL is ordered to be infused over 60 minutes. What flow rate will the nurse set on the EID in mL per hr?

ANS:

30 mL per hr (60 minutes = 1 hour)

30. A medicated IVPB of 50 mL is ordered to be infused over 20 minutes. What flow rate will the nurse set on the EID in mL per hr?

Estimate:

DA equation

Evaluation.

ANS:

150 mL per hr (20 min × 3 = 60 min) (50 mL × 3 = 150 mL)

31. The flow rate for a gravity infusion is counted in what measurement terms?

ANS:

Drops per minute

32. An IV of 500 mL at 50 mL per hr is started at 0830 hours. What time will should it be completed (in 24-hour clock time)?

ANS:

1830 hours

33. A medicated IV of 100 mL is ordered to infuse in 2 hours. What is the flow rate in mL per hr?

ANS:

50 mL per hr

34. A maintenance IV of 1000 mL D5LR is ordered to infuse in 8 hours. What is the flow rate in mL per hr?

ANS:

125 mL per hr

35. An IV of 100 mL at 50 mL per hr is started at 1000 hours. About what time should the nurse set an alarm to discontinue or replace the IV if the nurse wants a 10-minute warning for this slow flow rate?

ANS:

1150 hours (1 hour and 50 minutes after start)