Intravenous Solutions,
Equipment, and Calculations
Chapter 14
IV Components
Abbreviation
Solution Component
D
W
S
NS
Dextrose
Water
Saline
Normal Saline (0.9% NaCl)
NaCl
RL
Sodium Chloride
Ringer’s Lactate
LR
Lactated Ringer’s
2
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
3
Normal Serum Osmolarity
• Hypertonic
– Used to correct electrolyte imbalances
• e.g.: 5% Dextrose and 0.9% Saline; 5% Dextrose
and Lactated Ringer’s
4
IV Solution Label
5
Standard Straight Gravity Flow IV
6
IV with Piggyback (IV PB)
7
IV Flow Rate: mL per hour
• Regulate an IV volume by electronic
infusion pump or controller calibrated in
mL per hour
Total mL
X mL

Total hours
 mL per hour
1 hour
(rounded to a whole number)
8
Calculation of IV Flow Rate:
mL per hour
• Order reads: D5W 250 mL IV over the
next 2 hours by infusion pump
9
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
10
IV Flow Rate: mL per hour
• Step 2 - Use ratio-proportion formula:
Total mL
X mL

 mL/h
Total h
1h
250 mL
X mL

2h
1h
X  125 mL
Therefore, set pump at 125 mL per hour (125 mL
per hour)
11
IV Flow Rate in mL per hour:
Infusion Rate is less than 1 hour
Total mL ordered
X mL/h

Total min ordered
60 min/h
X  mL/h
(rounded to a whole number)
12
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
13
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
14
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
15
Calculation of mL per hour:
Infusion Rate is less than 1 hour
• Step 2
Total mL ordered
X mL/h

Total min ordered
60 min/h
50 mL
X mL/h

30 min
60 min/ h
30 X  3000
X  100 mL/h
16
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)
V
CR
T
gtt per min
17
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
18
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
19
Calculation of drops per min
1
125 mL
125 mL 10 gtt
 10 gtt/mL 

60 min
60 min 1mL
6
 20.8 gtt/min
• Use your watch to count drops and adjust
roller clamp to deliver 21 drops per min
20
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
21
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
22
Calculation of gtt per min:
Microdrip Drop Factor
50 mL
 60 gtt per mL
60 min
 50 drops per min
23
Drop Factor Constants
Drop Factor
10 drops per mL
15 drops per mL
20 drops per mL
60 drops per mL
Drop Factor Constant
60
6
10
60
4
15
60
3
20
60
1
60
24
Drop Factor Constants
• Administer 125 mL per hour IV with 20
drops per mL infusion set
1
125 gtt
125 mL
 20 gtt/mL 
3 min
60 min
3
 41.6 gtt/min  42 gtt/min
25
IV Flow Rate Shortcut Method
• Shortcut to calculate IV flow rate is:
mL per hour
 gtt per min
Drop factor constant
26
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
27
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.
28
Adjusting IV Flow Rate
• Step 1: Remaining volume  Recalculat ed mL per hour
Remaining hours
• Step 2: V  C  gtt per min
T
• Step 3:
Adjusted gtt per min  Ordered gtt per min
 % variation
Ordered gtt per min
29
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
30
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 onequarter the time
31
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
32
Calculation of IV Flow Rate
Adjustment
Remaining volume 300 mL

 40 mL per hour
Remaining hours
7.5 h
V
40 mL 1
C
 60 gtt per mL  40 gtt per min
T
60 min
1
33
Calculation of IV Flow Rate
Adjustment
Adjusted gtt per min  Ordered gtt per min
 % variation
Ordered gtt per min
40  50  10

 0.2  20%
50
50
34
IV Push Rate Calculation
• Caution:
– IV drugs are potent and rapid acting.
– Never infuse IV push drugs more
rapidly than recommended.
35
IV Push Rate Calculation
• Caution:
– Some drugs require further dilution
after reconstitution.
– Read package inserts and drug
resources for administration guidelines.
36
IV Push Rate Calculation
Dose on hand
Dosage desired

Amounton hand X Amountdesired
37
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”
38
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
39
Calculation of IV Push Incremental
Rate
• How much Ativan should you prepare?
– Step 3. Calculate
4 mg 3 mg

1 mL X mL
4 X3
X  0.75 mL
40
Calculation of IV Push
Incremental Rate
• What is a safe infusion time?
2 mg
3 mg

1 min
X min
2X  3
2X 3

2
2
1
X  1 min
2
41
Calculation of IV Push
Incremental Rate
• How much should you infuse every 15
seconds?
– 1 min = 60 seconds
– 1½ min = 1½  60 = 90 seconds
42
Calculation of IV Push
Incremental Rate
0.75 mL X mL

90 sec
15 sec
90X  11.25
90X 11.25

90
90
• X = 0.125 mL = 0.13 mL of Ativan 4 mg per mL
infused IV push every 15 seconds will deliver 3
mg of Ativan
43
IV Infusion Time
• To calculate IV infusion time
– mL is known:
Total volume
 Total hours
mL per hour
Or, use ratio-proportion: mL  Total mL
h
X total h
44
IV Infusion Time
• To calculate IV infusion time
• Flow rate in drops per min
– Drop factor and volume are known
45
IV Infusion Time
Or, use ratio-proportion: mL
Total mL

h
X total h
V
 C  R; “T” is the unknown
T
46
IV Fluid Volume
• To calculate total infusion volume
– mL is known:
Total hours  mL per hour  Total volume
mL
Total
mL
Or, use ratio-proportion:

h
X total h
47
IV Fluid Volume
• To calculate IV volume
– Flow rate (drops per min), drop factor, and time
are known:
V
 C  R; “V” is the unknown
T
48