1. Intravenous Solutions, Equipment, and Calculations
Chapter 14

2. IV Components Abbreviation Solution Component D Dextrose W Water S
Saline NS
Normal Saline (0.9% NaCl)
NaCl
Sodium Chloride RL
Ringer’s Lactate LR
Lactated Ringer’s

3. Normal Serum Osmolarity
Hypotonic
Used to dilute excess serum electrolytes
e.g.: 0.45% Saline
Isotonic
Used to expand volume and maintain normal tonicity
e.g.: 0.9% Saline, Lactated Ringer’s, 5% Dextrose

4. Normal Serum Osmolarity
Hypertonic
Used to correct electrolyte imbalances
e.g.: 5% Dextrose and 0.9% Saline; 5% Dextrose and Lactated Ringer’s

5. IV Solution Label

6. Standard Straight Gravity Flow IV

7. IV with Piggyback (IV PB)

8. IV Flow Rate: mL per hour
Regulate an IV volume by electronic infusion pump or controller calibrated in mL per hour
(rounded to a whole number)

9. Calculation of IV Flow Rate: mL per hour
Order reads: D5W 250 mL IV over the next 2 hours by infusion pump

10. Calculation of IV Flow Rate: mL per hour
Step 1 - Think
Pump is set by the rate of mL per hour.
So, if 250 mL is to be infused in two hours, how much will be infused in one hour?
125 mL will be infused in one hour
You would set the pump at 125 mL per hour

11. IV Flow Rate: mL per hour
Step 2 - Use ratio-proportion formula:
Therefore, set pump at 125 mL per hour (125 mL per hour)

12. IV Flow Rate in mL per hour: Infusion Rate is less than 1 hour
(rounded to a whole number)

13. Calculation of mL per hour: Infusion Rate is less than 1 hour
Order:
Ampicillin 500 mg IV in 50 mL D5½NS in 30 min by controller

14. Calculation of mL per hour: Infusion Rate is less than 1 hour
Step 1 – Think
Controller is set by the rate of mL per hour
If 50 mL is to be infused in 30 minutes
100 mL will be infused in 60 minutes

15. Calculation of mL per hour: Infusion Rate is less than 1 hour
Step 1 – Think
Because 100 mL is twice as much as 50 mL and 60 minutes is twice as much as 30 minutes
Set rate of controller at 100 mL per hour to infuse 50 mL per 30 min

16. Calculation of mL per hour: Infusion Rate is less than 1 hour
Step 2

17. IV Flow Rate: drops per min
Formula for IV flow rate for manually regulated IVs ordered in mL per hour or for minutes
Calibration or drop factor (drops per mL)
Volume (mL)
Time (min)
gtt per min

18. IV Flow Rate: drops per min
Carry calculations to one decimal.
Round drops per min to the nearest whole number.
Watch - count only whole drops

19. Calculation of drops per min
Physician orders:
D5W IV at 125 mL per hour
Infusion set is calibrated for a drop factor of 10 drops per mL
Calculate IV flow rate in drops per min
Notice that the mL cancel out, leaving drops per min

20. Calculation of drops per min1 6
Use your watch to count drops and adjust roller clamp to deliver 21 drops per min

21. Calculation of drops per min: Microdrip Drop Factor
When IV drop factor is 60 drops per mL (microdrip sets)
Flow rate in drops per min is same as volume ordered in mL per hour

22. Calculation of drops per min: Microdrip Drop Factor
Order:
D5W NS IV at 50 mL per h
Drop factor is 60 drops per mL
Notice order, 50 mL per hour, is the same as the flow rate of 50 drops per min when drop factor is 60 drops per mL

23. Calculation of gtt per min: Microdrip Drop Factor

24. Drop Factor Constants Drop Factor Drop Factor Constant 10 drops per mL

25. Drop Factor Constants
Administer 125 mL per hour IV with 20 drops per mL infusion set 1 3

26. IV Flow Rate Shortcut Method
Shortcut to calculate IV flow rate is:

27. Adjusting IV Flow Rate
Check for institutional policy regarding correcting off-schedule IV rates and the percentage of variation allowed.
Variation should not exceed 25 percent

28. Adjusting IV Flow Rate If adjustment is permitted
Use following formula to recalculate the mL per hour and gtt per min for the time remaining and the percentage of variation.

29. Adjusting IV Flow Rate
Step 1:
Step 2:
Step 3:

30. Adjusting IV Flow Rate
% variation will be positive (+) if administration is slow and rate has to be increased
Negative () if administration is too fast and rate has to be decreased

31. Calculation of IV Flow Rate Adjustment
Order: 500 mL LR to run over 10 hour at 50 mL per hour
Drop factor is 60 drops per mL and IV is correctly infusing at 50 drops per min
After 2½ hours, 300 mL is remaining
Almost half of total volume infused in one-quarter the time

32. Calculation of IV Flow Rate Adjustment
IV infusion is ahead of schedule
Compute a new rate of 300 mL to complete IV fluid order in remaining 7½ hours.
Patient would require close assessment for fluid overload

33. Calculation of IV Flow Rate Adjustment
Adjusted flow rate 1 1

34. Calculation of IV Flow Rate Adjustment

35. IV Push Rate Calculation
Caution:
IV drugs are potent and rapid acting.
Never infuse IV push drugs more rapidly than recommended.

36. IV Push Rate Calculation
Caution:
Some drugs require further dilution after reconstitution.
Read package inserts and drug resources for administration guidelines.

37. IV Push Rate Calculation

38. Calculation of IV Push Incremental Rate
Order: Ativan 3 mg IV Push 20 min preoperatively
Supply: Ativan 4 mg per mL with drug literature guidelines of “IV infusion not to exceed 2 mg/min”

39. Calculation of IV Push Incremental Rate
How much Ativan should you prepare?
Step 1. Convert
No conversion is necessary
Step 2. Think
You want to give less than 1 mL

40. Calculation of IV Push Incremental Rate
How much Ativan should you prepare?
Step 3. Calculate

41. Calculation of IV Push Incremental Rate
What is a safe infusion time?

42. Calculation of IV Push Incremental Rate
How much should you infuse every 15 seconds?
1 min = 60 seconds
1½ min = 1½ = 90 seconds

43. Calculation of IV Push Incremental Rate
X = mL = 0.13 mL of Ativan 4 mg per mL infused IV push every 15 seconds will deliver 3 mg of Ativan

44. IV Infusion Time To calculate IV infusion time mL is known:
Or, use ratio-proportion:

45. IV Infusion Time To calculate IV infusion time
Flow rate in drops per min
Drop factor and volume are known

46. IV Infusion Time
Or, use ratio-proportion:
“T” is the unknown

47. IV Fluid Volume To calculate total infusion volume mL is known:
Or, use ratio-proportion:

48. IV Fluid Volume To calculate IV volume
Flow rate (drops per min), drop factor, and time are known:
“V” is the unknown