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Intravenous Solutions, Equipment, and Calculations
Chapter 14
2
IV Components
Abbreviation Solution ComponentD 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
Total mL
Total hours
X mL
1 hour
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:
Total mL
Total h
X mL
1 hmL/h
250 mL
2 hX mL
1 hX 125 mL
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
Total mL ordered
Total min ordered
X mL/h
60 min/h
X mL/h
(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 2Total mL ordered
Total min ordered
X mL/h
60 min/h
50 mL
30 min
X mL/h
60 min/ h
30 X 3000
X 100 mL/h
17
IV Flow Rate: drops per min• Formula for IV flow rate for manually
regulated IVs ordered in mL per hour or for minutes
RCT
V
Volume (mL)
Time (min)
Calibration or drop factor (drops per mL)
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 min
mL 1
gtt 10
min 60
mL 125gtt/mL 10
min 60
mL 125
gtt/min 820.6
1
• 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
mL per gtt min 60
mL 60
50
50 drops per min
24
Drop Factor ConstantsDrop Factor Drop Factor Constant
10 drops per mL
15 drops per mL
20 drops per mL
60 drops per mL
610
60
415
60
320
60
160
60
25
min 3
gtt 125
Drop Factor Constants
• Administer 125 mL per hour IV with 20 drops per mL infusion set
gtt/mL 20min 60
mL 125
3
1
gtt/min 42gtt/min 641 .
26
IV Flow Rate Shortcut Method
• Shortcut to calculate IV flow rate is:
mL per hour
Drop factor constantgtt per min
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:
min per gtt CT
V
variation %min per gtt Ordered
min per gtt Orderedmin per gtt Adjusted
hour per mL edRecalculathours Remaining
volume Remaining
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
Remaining volume
Remaining hours
V
TC
40 mL
60 min60 gtt per mL
300 mL
7.5 h40 mL per hour
1
1
40 gtt per min
Adjusted flow rate
34
Calculation of IV Flow Rate Adjustment
Adjusted gtt per min Ordered gtt per min
Ordered gtt per min% variation
%. 202050
10
50
5040
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
desiredAmount X
desired Dosage
handon Amount
handon Dose
38
Calculation of IV PushIncremental 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 PushIncremental 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
4 mg
1 mL
3 mg
X mL4 X 3
X 0.75 mL
41
Calculation of IV PushIncremental Rate
• What is a safe infusion time?
3X2min X
mg 3
min 1
mg 2
2X
2
3
2
X 11
2 min
42
Calculation of IV PushIncremental Rate
• How much should you infuse every 15 seconds?– 1 min = 60 seconds– 1½ min = 1½ 60 = 90 seconds
43
Calculation of IV PushIncremental Rate
0.75 mL
90 secX mL
15 sec
90X 11.25
90X
90
11.25
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
44
IV Infusion Time
• To calculate IV infusion time– mL is known:
hours Total hour per mL
volume Total
Or, use ratio-proportion: mL
h
Total mL
X total h
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
V
TC R; “T” is the unknown
Or, use ratio-proportion: mL
h
Total mL
X total h
47
mL
h
Total mL
X total h
IV Fluid Volume
• To calculate total infusion volume– mL is known:
volume Totalhour per mLhours Total
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 unknownV
TC R;