Math for Medication Administration

17 Administering Medications IV Direct

Lesson

Learning Outcomes

By the end of this chapter, learners will be able to:

  • identify factors which affect the rate of administration of IV direct medications,
  • create a dose, volume, time table for use in administration of IV direct medications, and
  • label a syringe to help keep track of medication delivery rate.

IV Direct Administration Rates

It is essential for medications administered directly into an IV line to be given at the correct rate to prevent complications. Information describing the appropriate rate will be available in the health agency’s drug reference manual. Ensure all factors about the patient’s context are considered when reviewing rate information in the reference manual. For instance, the rate may be different for a neonate versus an adult. In some cases, a variable rate is given and you will need to use critical thinking skills to determine the most appropriate rate, often in discussion with your nursing instructor or the most responsible nurse for the patient.

To determine how fast to administer an IV direct medication, you will need the following information:

  • the medication order
  • information about the patient’s context (eg. age, reason for medication order, hepatic function…)
  • the administration information from the drug reference manual
  • the total volume of medication to be administered

Once the rate of administration of the drug is determined, the actual administration of the drug must be timed to ensure it is given at the correct rate. In order to administer the drug evenly over a particular period of time, nurses often calculate a volume of medication to be given over specific time intervals (for example, every 15 seconds) during the administration period. The drug information in the text box below will be used to exemplify this process. It is important to note the information presented here should not be used for direct patient care, always review your agency’s drug reference manual for up to date information regarding the drug and the administration policy of your institution.

diazepam

Status Epilepticus: 5-10 mg IV/IM q5-10min; not to exceed 30 mg, OR 0.5 mg/kg PR (using parenteral solution), THEN 0.25 mg/kg in 10 minutes PRN
IV Direct: Administer undiluted over 3 min; no more than 5 mg/min

https://reference.medscape.com/drug/valium-diastat-diazepam-342902

1. Gather the information which will affect the rate of administration.

Medication order: diazepam 10 mg
Rate information: over 3 min; no more than 5mg/min
Supply: the concentration of diazepam in a vial is 5 mg : 1 mL
Calculate the total volume to be administered:

[latex]x\text{ mL}=\dfrac{\text{1 mL}}{\text{5 mg}}\times\text{10 mg}[/latex]

[latex]x\text{ mL}=\dfrac{\text{1 mL}}{5\cancel{\text{ mg}}}\times10\cancel{\text{ mg}}[/latex]

[latex]x\text{ mL}=\dfrac{1\text{ mL}\times{10}}{{5}}[/latex]

[latex]x\text{ mL}=2\text{ mL}[/latex]

2. Determine what volume of medication will be given in each time interval:

When beginning to administer IV direct medications, it can be hard to ensure you are maintaining an even speed of delivery
over the whole time period. To stay within a consistent delivery speed, you can create a table to determine how much of the syringe volume should be given over smaller time intervals to ensure you have an even speed over the duration of the injection. This can be called a dose, volume, time table. Including the amount, volume and time interval in the table is helpful when checking to ensure you are meeting the criteria as laid out in the drug reference manual as rate information is often given in an amount (usually mg or mcg) per time interval (usually min or sec).
In this dose, volume and time table, the total amount, volume and time period is entered into the second row. Each subsequent value has been cut in half from the value above.
Amount (mg) Volume (mL) Time Interval
10 2 3 min (180 sec)
5 1 90 sec
2.5 0.5 45 sec
1.25 0.25 22.5 sec
This is not the only way to set up the table. Here is an alternate table in which each value has been divided by 3:
Amount (mg) Volume (mL) Time Interval
10 2 3 min
3.33 0.66  1 min (60 sec)
1.11 0.22 20 sec
And finally, a table where each value has been divided by 5:
Amount (mg) Volume (mL) Time Interval
10 2 3 min (180 sec)
2 mg 0.4 36 sec
1 mg 0.2 18 sec

In this example, clinical judgement must be used to determine which one will give a volume and time interval easiest for a nurse to follow. The middle table might be the easiest to use in practice, as watching a timer and noting how much you have given every 20 seconds is easier to follow than watching for every 22.5 or 18 seconds. You may also find any number you divide by gives a difficult number to measure with the available syringes. In this case, you will need to round the number so the volume can be measured easily on the syringe. For example, if you calculated the final volume to be 1.08 mL you could round to 1 mL. If you are rounding down, you are giving slightly less volume over the allotted time and should be safe for the client to receive. You must be very cautious about rounding up, as the medication would be given slightly faster. Make sure to discuss rationale for rounding with your preceptor or instructor to ensure you are making appropriate decisions.

Sample Exercise 17.1

Complete a dose, volume, time table when administering the following medication:

Medication Order: ketorlac 30 mg IV prn q8h
Rate Information: undiluted over 1-2 minutes
Supply: ketorlac 30 mg/mL

Answer:
Amount (mg) Volume (mL) Time Interval
30 1 2 min
15 0.5 1 min
7.5 0.25 30 sec

Sample Exercise 17.2

Create a dose, volume, time chart for the following medication order.

Medication Order: furosemide 40 mg IV BID
Rate Information: administer undiluted at a rate of 20 mg/min
Supply: 20 mg/1 mL ampule

Answer:

First, calculate the total volume of the injection.

[latex]x\text{ mL}=\dfrac{\text{1 mL}}{\text{20 mg}}\times\text{40 mg}\\[/latex][latex]x\text{ mL}=\dfrac{\text{1 mL}}{20\cancel{\text{ mg}}}\times40\cancel{\text{ mg}}\\[/latex][latex]x\text{ mL}=\dfrac{\text{40 mL}}{20}\\[/latex][latex]x\text{ mL}=\text{2 mL}[/latex]

Enter the total amount, volume and period of time in the first row. In this case, the recommended rate of 20 mg/min is represented in the third row of the chart, and thus meets criteria for safe administration.
Next, choose an amount to divide each value by. In this answer, each value has been divided by 2.

Amount (mg) Volume (mL) Time Interval
40 2 2 min
20 1 1 min
10 0.5 30 sec

Syringe Labels for IV Direct Administration

It can be challenging for some people to focus on the amount of volume being administered in each short time interval while in the practice setting, even while watching a timer. Distractions such as alarms, conversation and/or questions from the patient or family and other interruptions can break the focus of the nurse during this process. When beginning to administer IV direct medications, it may be helpful to add a visual cue to the syringe label to help keep on track. In the image below, two components have been added to a syringe label for administration of furosemide. Lines to indicate every 0.5 mL on the syringe and numbers representing the seconds remaining at each interval are added. These correspond to the dose, volume, time table created in the sample exercise above, in which 0.5 mL is given every 30 seconds.

Critical Thinking Question

When comparing the same dose of a particular medication given by IV direct versus an intermittent IV infusion, do you anticipate any differences in the onset, peak and duration of the medication?

Answer:

The onset occurs when the medication enters the bloodstream and is able to take effect in the body. It varies with mechanism of action, dosage, and individual patient factors. The IV direct route is often delivered over a total shorter time than the intermittent IV route. If the medication is delivered into the vein more quickly, it is likely the onset will be earlier for IV direct than IV intermittent. It may effect the peak for some medications as well. The duration of effect is more variable. It’s possible the duration of IV intermittent is longer, especially for infusions which are given over longer periods of time. If you think variations in onset, peak and duration of various routes will affect the choice of route given to a patient, you should check the parenteral manual for guidelines on specific medications when preparing the medication.

Practice Set 17.1: Creating Dose, Volume, Time Tables

Practice Set 17.1: Creating Dose, Volume, Time Tables

Create a dose, volume, time table for the following scenarios.

  1. Medication Order: dexamethasone 4 mg IV q6h
    Rate Information: administer undiluted, no more than 8mg/min
    Supply: 20 mg/5 mL vial
  2. Medication Order: pantoprazole 40 mg IV OD
    Rate Information: administer over 2 minutes
    Supply: 40 mg powder in medication vial, to be reconstituted with 10 mL NS
  3. Medication Order: benzotropine 2 mg IV now
    Rate Information: administer undiluted over 1 minute
    Supply: 2 mg/2 mL ampule
  4. Medication Order: morphine 2 mg IV q2h prn
    Rate Information: dilute with 9 mL NS or SW for injection to give 1 mg/mL and give at a maximum rate of 2 mg/min
    Supply: 10 mg/mL ampule
  5. Medication Order: digoxin 0.25 mg IV once daily
    Rate Information: dilute each 1 mL with at least 4 mL NS and give over at least 5 minutes
    Supply: 0.25 mg/mL ampule
  6. Medication Order: furosemide 40 mg IV once daily
    Rate Information: give undiluted; doses 120 mg or less over 1-2 minutes
    Supply: 10 mg/mL ampule
  7. Medication Order: lorazepam 3 mg IV 20 minutes prior to surgery
    Rate Information: dilute with equal volume D5W, NS, or SW; give over 1 minute, max of 2 mg/min
    Supply: 4 mg/mL vial
  8. Medication Order: naloxine 0.2 mg IV q2-3 minutes until respiratory rate depression is resolved
    Rate Information: give undiluted over 30-60 seconds
    Supply: 0.4 mg/mL
  9. Medication Order: oxytocin 8 units once postpartum bolus
    Rate Information: may dilute with 3 mL NS, given slowly over at least 1 minute
    Supply: 10 units/mL vial
  10. Medication Order: haloperidol 2 mg IV push PRN.
    Rate Information: dilute with 5 mL SW and give rapid IV push over at least 1 minute.
    Supply: 5 mg/mL (1 mL) ampule.
Answers:
  1. First, calculate the total volume of the injection.
    [latex]x\text{ mL}=\dfrac{\text{5 mL}}{\text{20 mg}}\times\text{4 mg}\\[/latex][latex]x\text{ mL}=\dfrac{\text{5 mL}}{20\cancel{\text{ mg}}}\times4\cancel{\text{ mg}}\\[/latex][latex]x\text{ mL}=\dfrac{\text{20 mL}}{20}\\[/latex][latex]x\text{ mL}=\text{1 mL}\\[/latex]Enter the total amount, volume and period of time in the first row. Choosing to give 4 mg in 1 minute is giving the medication slower than the maximum rate of 8 mg/min, and meets criteria for safe administration.
    Next, choose an amount to divide each value by. In this answer, each value has been divided by 2.
    Amount (mg) Volume (mL) Time Interval
    4 1 1 min
    2 0.5 30 sec
    1 0.25 15 sec
  2. First, note the total volume of the injection (40 mg in 10 mL).
    Enter the total amount, volume and period of time in the first row.
    Next, choose an amount to divide each value by. In this answer, each value has been divided by 2.
    Amount (mg) Volume (mL) Time Interval
    40 10 2 min
    20 5 1 min
    10 2.5 30 sec
    5 1.25 15 sec
  3. First, note the total volume of the injection (2 mg in 2 mL).
    Enter the total amount, volume and period of time in the first row.
    Next, choose an amount to divide each value by. In this answer, each value has been divided by 2.
    Amount (mg) Volume (mL) Time Interval
    2 2 1 min
    1 1 30 sec
    0.5 0.5 15 sec
  4. First, calculate the total volume of the injection.[latex]x\text{ mL}=\dfrac{\text{10 mL}}{\text{10 mg}}\times\text{2 mg}\\[/latex][latex]x\text{ mL}=\dfrac{\text{10 mL}}{10\cancel{\text{ mg}}}\times2\cancel{\text{ mg}}\\[/latex][latex]x\text{ mL}=\dfrac{\text{20 mL}}{10}\\[/latex][latex]x\text{ mL}=\text{2 mL}\\[/latex]Enter the total amount, volume and period of time in the first row. Safety note: In this situation, you may have recognized the morphine is supplied in an ampule. Morphine is diluted by drawing up 9 ml of NS in a 10 mL syringe and then the 1 mL of morphine from the ampule. Before administering, the extra volume in the syringe must be wasted so only the calculated volume of 2 mL remains.
    Next, choose an amount to divide each value by. In this answer, each value has been divided by 2.
    Amount (mg) Volume (mL) Time Interval
    2 2 1 min (60 sec)
    1 1 30 sec
    0.5 0.5 15 sec

    Alternately, if the decision is made to administer the morphine slower than the maximum rate, the following table could be set up:

    Amount (mg) Volume (mL) Time Interval
    2 2 2 min (120 sec)
    1 1 1 min (60 sec)
    0.5 0.5 30 sec
    0.25 0.25 15 sec
  5. First, calculate the total volume of the injection. [latex]x\text{ mL}=\dfrac{\text{1 mL}}{\text{0.25 mg}}\times\text{0.25 mg}\\[/latex][latex]x\text{ mL}=\dfrac{\text{1 mL}}{0.25\cancel{\text{ mg}}}\times0.25\cancel{\text{ mg}}\\[/latex][latex]x\text{ mL}=\dfrac{\text{0.25 mL}}{\text{0.25}}\\[/latex][latex]x\text{ mL}=\text{1 mL}\\[/latex]Enter the total amount, volume and period of time in the first row.
    Next, choose an amount to divide each value by. In this answer, each value has been divided by 5 to start and then by 2 to get down to 15 second increments.
    Amount (mg) Volume (mL) Time Interval
    0.25 1 5 min
    0.05 0.2 1 min
    0.025 0.1 30 sec
  6. First, calculate the total volume of the injection. [latex]x\text{ mL}=\dfrac{\text{1 mL}}{\text{10 mg}}\times\text{40 mg}\\[/latex][latex]x\text{ mL}=\dfrac{\text{1 mL}}{10\cancel{\text{ mg}}}\times40\cancel{\text{ mg}}\\[/latex][latex]x\text{ mL}=\dfrac{\text{40 mL}}{10}\\[/latex][latex]x\text{ mL}=\text{4 mL}\\[/latex]Enter the total amount, volume and period of time in the first row.
    Next, choose an amount to divide each value by. In this answer, each value has been divided by 2.
    Amount (mg) Volume (mL) Time Interval
    40 4 2 min
    20 2 1 min
    10 1 30 sec
    5 0.5 15 sec
  7. First, calculate the total volume of the injection.[latex]x\text{ mL}=\dfrac{\text{1 mL}}{\text{4 mg}}\times\text{3 mg}\\[/latex][latex]x\text{ mL}=\dfrac{\text{1 mL}}{4\cancel{\text{ mg}}}\times3\cancel{\text{ mg}}\\[/latex][latex]x\text{ mL}=\dfrac{\text{3 mL}}{4}\\[/latex][latex]x\text{ mL}=\text{0.75 mL}\\[/latex]Due to how this medication needs to be diluted, the total volume that will be give needs to be doubled.
    [latex]\text{0.75 mL}\times2=\text{1.5 mL}[/latex]
    Enter the total amount, volume and period of time in the first row.
    Next, choose an amount to divide each value by. In this answer, each value has been divided by 2.
    Amount (mg) Volume (mL) Time Interval
    3 1.5 1 min
    1.5 0.75 30 sec
  8. First, calculate the total volume of the injection.[latex]x\text{ mL}=\dfrac{\text{1 mL}}{\text{0.4 mg}}\times\text{0.2 mg}\\[/latex][latex]x\text{ mL}=\dfrac{\text{1 mL}}{0.4\cancel{\text{ mg}}}\times0.2\cancel{\text{ mg}}\\[/latex][latex]x\text{ mL}=\dfrac{\text{0.2 mL}}{\text{0.4}}\\[/latex][latex]x\text{ mL}=\text{0.5 mL}\\[/latex]Enter the total amount, volume and period of time in the first row.
    Next, choose an amount to divide each value by. In this answer, each value has been divided by 2.
    Amount (mg) Volume (mL) Time Interval
    0.2 0.5 60 sec
    0.1 0.25 30 sec
  9. First, calculate the total volume of the injection. [latex]x\text{ mL}=\dfrac{\text{1 mL}}{\text{10 units}}\times\text{8 units}\\[/latex][latex]x\text{ mL}=\dfrac{\text{1 mL}}{10\cancel{\text{ units}}}\times8\cancel{\text{ units}}\\[/latex][latex]x\text{ mL}=\dfrac{\text{8 mL}}{10}\\[/latex][latex]x\text{ mL}=\text{0.8 mL}\\[/latex]Enter the total amount, volume and period of time in the first row.
    Next, choose an amount to divide each value by. In this answer, each value has been divided by 2.
    Amount (units) Volume (mL) Time Interval
    8 0.8 1 min
    4 0.4 30 sec
    2 0.2 15 sec
  10. First, calculate the total volume of the injection.[latex]x\text{ mL}=\dfrac{\text{6 mL}}{\text{5 mg}}\times\text{2 mg}\\[/latex][latex]x\text{ mL}=\dfrac{\text{6 mL}}{5\cancel{\text{ mg}}}\times2\cancel{\text{ mg}}\\[/latex][latex]x\text{ mL}=\dfrac{\text{12 mL}}{5}\\[/latex][latex]x\text{ mL}=\text{2.4 mL}\\[/latex]Enter the total amount, volume and period of time in the first row.
    Next, choose an amount to divide each value by. In this answer, each value has been divided by 2.
    Amount (mg) Volume (mL) Time Interval
    2 2.4 1 min
    1 1.2 30 sec
    0.5 0.6 15 sec

Practice Set 17.2: Creating Dose, Volume, Time Tables

Practice Set 17.2: Creating Dose, Volume, Time Tables

Create a dose, volume, time table for the following scenarios. Identify the final volume and time interval you would use when administering the medication.

  1. Medication Order: dexamethasone 15 mg IV once
    Rate Information: max rate of 8 mg/min
    Supply: 4 mg/mL vial
  2. Medication Order: diphenhydrinate 35 mg IV push q4h.
    Rate Information: dilute every 50 mg with 10 mL NS and administer over 2-4 minutes.
    Supply: 50 mg/mL (1 mL) vial.
  3. Medication Order: meropenum 600 mg IV q8h.
    Rate Information: reconstitute with 20 mL NS or D5W and give over 3-5 minutes.
    Supply: 1 g (powdered) vial.
  4. Medication Order: thiamine 100 mg IV push once daily for 5 days.
    Rate Information: give undiluted over 1 minute.
    Supply: 100 mg/mL (1 mL) vial.
  5. Medication Order: morphine 2.5 mg IV push q4h.
    Rate Information: max rate of 2 mg/mL, diluted to 1 mg/mL with NS (10 mL of fluids).
    Supply: 10 mg/mL
  6. Medication Order: flumezanil 0.2 mg for suspected benzo overdose, possibly giving additional doses if inadequate results.
    Rate Information: give over 30 seconds.
    Supply: 0.1 mg/mL (5 mL) vial.
  7. Medication Order: ampicillin 25 mg/kg/dose, for a 15 kg child, IV push for a mild infection.
    Rate Information: give over 4 minutes at a max rate of 100 mg/minute, diluted to 250 mg/2.5 mL.
    Supply: 250 mg (powdered) vial.
  8. Medication Order: ketorolac 20 mg q4h IV push.
    Rate Information: give over 1-2 minutes undiluted.
    Supply: 30 mg/mL (1 mL) vial.
  9. Medication Order: diazepam 8 mg q3h.
    Rate Information: give undiluted 2-5 mg/minute.
    Supply: 5 mg/mL (2 mL) ampule.
  10. Medication Order: midazolam 0.2 mg/kg IV push loading dose, repeating q5 minute until seizure stops. This is for a 65 kg adult.
    Rate Information: given at a rate of 2 mg/minute.
    Supply: 1 mg/mL
Answers:
  1. First, calculate the total volume of the injection. [latex]x\text{ mL}=\dfrac{\text{1 mL}}{\text{4 mg}}\times\text{15 mg}\\[/latex][latex]x\text{ mL}=\dfrac{\text{1 mL}}{4\cancel{\text{ mg}}}\times15\cancel{\text{ mg}}\\[/latex][latex]x\text{ mL}=\dfrac{\text{15 mL}}{4}\\[/latex][latex]x\text{ mL}=\text{3.75 mL}\\[/latex]In this answer, in the table set up, each value has been divided by 2.
    When you calculate a volume that is not a round decimal number, round to the the number that you can measure in the syringe that you are using.
    Amount (mg) Volume (mL) Rounded Volume (mL) Time Interval
    15 3.75 3.8 2 min
    7.5 1.875 1.9 1 min
    3.75 0.9375 1.0 30 sec
    1.875 0.46875 0.5 15 sec
  2. First, calculate the total volume of the injection.[latex]x\text{ mL}=\dfrac{\text{10 mL}}{\text{50 mg}}\times\text{35 mg}\\[/latex][latex]x\text{ mL}=\dfrac{\text{10 mL}}{50\cancel{\text{ mg}}}\times35\cancel{\text{ mg}}\\[/latex][latex]x\text{ mL}=\dfrac{\text{350 mL}}{\text{50}}\\[/latex][latex]x\text{ mL}=\text{7 mL}\\[/latex]Enter the total amount, volume and period of time in the first row.
    Next, choose an amount to divide each value by. In this answer, each value has been divided by 2.
    Amount (mg) Volume (mL) Time Interval
    35 7 4 min
    17.5 3.5 2 min
    8.7 1.75 1 min
    4.4 0.88 30 sec
    2.2 0.44 15 sec

    From the table, 0.44 is not an easy volume to track over 15 seconds when giving a direct IV. Instead, you can round this number to 0.4 to track the volume your are giving better.

  3. First, calculate the total volume of the injection. [latex]x\text{ mL}=\dfrac{\text{10 mL}}{\text{500 mg}}\times\text{600 mg}\\[/latex][latex]x\text{ mL}=\dfrac{\text{10 mL}}{500\cancel{\text{ mg}}}\times600\cancel{\text{ mg}}\\[/latex][latex]x\text{ mL}=\dfrac{\text{6000 mL}}{\text{500}}\\[/latex][latex]x\text{ mL}=\text{12 mL}\\[/latex]Enter the total amount, volume and period of time in the first row.
    Next, choose an amount to divide each value by. In this answer, each value has been divided by 5 to start and then by 2 to get to 15 second increments.
    Amount (mg) Volume (mL) Time Interval
    600 12 5
    120 2.4 1
    60 1.2 30 sec
    30 0.6 15 sec
  4. First, we know the volume of the dose due to the supply and we will enter the total amount, volume and period of time in the first row.
    Next, choose an amount to divide each value by. In this answer, each value has been divided by 2.
    Amount (mg) Volume (mL) Time Interval
    100 1 1 min
    50 0.5 30 sec
    25 0.25 15 sec
  5. First, calculate the total volume of the injection.[latex]x\text{ mL}=\dfrac{\text{1 mL}}{\text{1 mg}}\times\text{2.5 mg}\\[/latex][latex]x\text{ mL}=\dfrac{\text{1 mL}}{1\cancel{\text{ mg}}}\times2.5\cancel{\text{ mg}}\\[/latex][latex]x\text{ mL}=\dfrac{\text{2.5 mL}}{1}\\[/latex][latex]x\text{ mL}=\text{2.5 mL}\\[/latex]Enter the total amount, volume and period of time in the first row.
    Next, choose an amount to divide each value by. In this answer, each value has been divided by 3 to start and then divided by 2 to get to 15 second increments.
    Amount (mg) Volume (mL) Time Interval
    2.5 2.5 1.5 min
    0.8 0.8 30 sec
    0.4 0.4 15 sec
  6. First, calculate the total volume of the injection.[latex]x\text{ mL}=\dfrac{\text{1 mL}}{\text{0.1 mg}}\times\text{0.2 mg}\\[/latex][latex]x\text{ mL}=\dfrac{\text{1 mL}}{0.1\cancel{\text{ mg}}}\times0.2\cancel{\text{ mg}}\\[/latex][latex]x\text{ mL}=\dfrac{\text{0.2 mL}}{\text{0.1}}\\[/latex][latex]x\text{ mL}=\text{2 mL}\\[/latex]Enter the total amount, volume and period of time in the first row.
    Next, choose an amount to divide each value by. In this answer, each value has been divided by 2.
    Amount (mg) Volume (mL) Time Interval
    0.2 2 30 sec
    0.1 1 15 sec
  7. First, calculate the dose in mg from the weight of the patient given. [latex]\text{25 mg}\times\text{15 kg}=\text{375 mg/dose}[/latex]
    Then, calculate the total volume of the injection.
    [latex]x\text{ mL}=\dfrac{\text{2.5 mL}}{\text{250 mg}}\times\text{375 mg}\\[/latex][latex]x\text{ mL}=\dfrac{\text{2.5 mL}}{250\cancel{\text{ mg}}}\times375\cancel{\text{ mg}}\\[/latex][latex]x\text{ mL}=\dfrac{\text{937.5 mL}}{\text{250}}\\[/latex][latex]x\text{ mL}=\text{3.75 mL}\\[/latex]Enter the total amount, volume and period of time in the first row.
    Next, choose an amount to divide each value by. In this answer, each value has been divided by 4 to start and then by 2 to get to 15 second increments.
    Amount (mg) Volume (mL) Time Interval
    375 3.75 4 min
    93.75 0.94 1 min
    46.9 0.47 30 sec
    23.4 0.23 15 sec

    From the table, 0.23 is not an easy volume to track over 15 seconds when giving a direct IV. Instead, you can round this number to 0.2 to track the volume your are giving better.

  8. First, calculate the total volume of the injection.[latex]x\text{ mL}=\dfrac{\text{1 mL}}{\text{30 mg}}\times\text{20 mg}\\[/latex][latex]x\text{ mL}=\dfrac{\text{1 mL}}{30\cancel{\text{ mg}}}\times20\cancel{\text{ mg}}\\[/latex][latex]x\text{ mL}=\dfrac{\text{20 mL}}{\text{30}}\\[/latex][latex]x\text{ mL}=\text{0.67 mL}\\[/latex]Enter the total amount, volume and period of time in the first row.
    Next, choose an amount to divide each value by. In this answer, each value has been divided by 2.
    Amount (mg) Volume (mL) Rounded Volume (mL) Time Interval
    20 0.67 0.7 2 min
    10 0.33 0.3 1 min
    5 0.16 0.2 30 sec
    2.5 0.08 0.1 15 sec
  9. First, calculate the total volume of the injection.[latex]x\text{ mL}=\dfrac{\text{1 mL}}{\text{5 mg}}\times\text{8 mg}\\[/latex][latex]x\text{ mL}=\dfrac{\text{1 mL}}{5\cancel{\text{ mg}}}\times8\cancel{\text{ mg}}\\[/latex][latex]x\text{ mL}=\dfrac{\text{8 mL}}{5}\\[/latex][latex]x\text{ mL}=\text{1.6 mL}\\[/latex]Enter the total amount, volume and period of time in the first row.
    Next, choose an amount to divide each value by. In this answer, each value has been divided by 2.
    Amount (mg) Volume (mL) Time Interval
    8 1.6 2 min
    4 0.8 1 min
    2 0.4 30 sec
    1 0.2 15 sec
  10. First, calculate the dose in mg from the weight of the patient given. [latex]\text{0.2 mg}\times\text{65 kg}=\text{13 mg/dose}[/latex]
    Then, calculate the total volume of the injection.
    [latex]x\text{ mL}=\dfrac{\text{1 mL}}{\text{1 mg}}\times\text{13 mg}\\[/latex][latex]x\text{ mL}=\dfrac{\text{1 mL}}{1\cancel{\text{ mg}}}\times13\cancel{\text{ mg}}\\[/latex][latex]x\text{ mL}=\dfrac{\text{13 mL}}{1}\\[/latex][latex]x\text{ mL}=\text{13 mL}\\[/latex]Enter the total amount, volume and period of time in the first row.
    Next, choose an amount to divide each value by. In this answer, each value has been divided by 13 to start and then by 2 to get to 15 second increments.
    Amount (mg) Volume (mL) Time Interval
    13 13 6.5 min
    1 1 30 sec
    0.5 0.5 15 sec

Practice Set 17.3: Creating Dose, Volume, Time Tables

Practice Set 17.3: Creating Dose, Volume, Time Tables

Create a dose, volume, time table for the following scenarios. Identify the final volume and time interval you would use when administering the medication.

  1. Medication Order: diltiazem 0.25 mg/kg IV direct for a 55kg adult.
    Rate Information: give undiluted over 2 minutes.
    Supply: 5 mg/mL (10 mL) vial.
  2. Medication Order: hydromorphone 0.5 mg IV direct q6h.
    Rate Information: dilute to 5 mL with NS administer slowly over 2 minutes.
    Supply: 2 mg/mL vial.
  3. Medication Order: labetalol 7 mg IV initial dose in a hypertensive emergency.
    Rate Information: give over 2 minutes.
    Supply: 5 mg/mL (20 mL) vial.
  4. Medication Order: propofol 18 mg IV direct bolus.
    Rate Information: given over 3 minutes.
    Supply: 10 mg/mL (20 mL) ampule.
  5. Medication Order: metoclopramide 10 mg IV for prophylactic postoperative vomiting.
    Rate Information: given over 2 minutes.
    Supply: 5 mg/mL (2 mL) vial.
  6. Medication Order: hydrocortisone 200 mg IV direct.
    Rate Information: dilute with 2 mL SW (diluted to 125 mg/mL), given over 1.5 minutes.
    Supply: 250 mg vial.
  7. Medication Order: ephedrine 20 mg IV repeat q5-10 minutes according to blood pressure response.
    Rate Information: given over 10 mg/minute as a max rate.
    Supply: 50 mg/mL (1 mL) vial.
  8. Medication Order: meperidine 15 mg IV direct q4h PRN for severe pain.
    Rate Information: diluted to 10 mg/mL, given over 5 minutes.
    Supply: 50 mg/mL (1 mL) ampule.
  9. Medication Order: fentynal 75 mcg intrapartum q30 minutes IV direct.
    Rate Information: given undiluted over 2 minutes.
    Supply: 50 mcg/mL (5 mL) ampule.
  10. Medication Order: octreotide 2 mg/kg/dose IV direct bolus for a 20 kg toddler with a severe gastrointestinal bleed.
    Rate Information: given undiluted over 2 minutes.
    Supply: 100 mcg/mL (1 mL) ampule.
Answers:
  1. First, calculate the dose in mg from the weight of the patient given.
    [latex]\text{0.25 mg}\times\text{55 kg}=\text{13.75 mg}[/latex]
    Then, calculate the total volume of the injection.
    [latex]x\text{ mL}=\dfrac{\text{1 mL}}{\text{5 mg}}\times\text{13.75 mg}\\[/latex][latex]x\text{ mL}=\dfrac{\text{1 mL}}{5\cancel{\text{ mg}}}\times13.75\cancel{\text{ mg}}\\[/latex][latex]x\text{ mL}=\dfrac{\text{13.75 mL}}{5}\\[/latex][latex]x\text{ mL}=\text{2.75 mL}\\[/latex]Enter the total amount, volume and period of time in the first row.
    Next, choose an amount to divide each value by. In this answer, each value has been divided by 2.
    Amount (units) Volume (mL) Rounded Volume (mL) Time Interval
    13.75 2.75 2.75 2 min
    6.875 1.37 1.4 1 min
    3.437 0.68 0.7 30 sec
    1.718 0.34 0.3 15 sec
  2. First, calculate the total volume of the injection.[latex]x\text{ mL}=\dfrac{\text{5 mL}}{\text{2 mg}}\times\text{0.5 mg}\\[/latex][latex]x\text{ mL}=\dfrac{\text{5 mL}}{\cancel{2\text{ mg}}}\times0.5\cancel{\text{ mg}}\\[/latex][latex]x\text{ mL}=\dfrac{\text{2.5 mL}}{2}\\[/latex][latex]x\text{ mL}=\text{1.25 mL}\\[/latex]Enter the total amount, volume and period of time in the first row.
    Next, choose an amount to divide each value by. In this answer, each value has been divided by 2.
    Amount (units) Volume (mL) Time Interval
    0.5 1.25 2 min
    0.25 0.63 1 min
    0.125 0.31 30 sec
    0.0625 0.16 15 sec

    From the table, 0.16 is not an easy volume to track over 15 seconds when giving a direct IV. Instead, you can round this number to 0.2 to track the volume your are giving better.

  3. First, calculate the total volume of the injection.[latex]x\text{ mL}=\dfrac{\text{1 mL}}{\text{5 mg}}\times\text{7 mg}\\[/latex][latex]x\text{ mL}=\dfrac{\text{1 mL}}{5\cancel{\text{ mg}}}\times7\cancel{\text{ mg}}\\[/latex][latex]x\text{ mL}=\dfrac{\text{7 mL}}{5}\\[/latex][latex]x\text{ mL}=\text{1.4 mL}\\[/latex]Enter the total amount, volume and period of time in the first row.
    Next, choose an amount to divide each value by. In this answer, each value has been divided by 2.
    Amount (units) Volume (mL) Time Interval
    7 1.4 2 min
    3.5 0.7 1 min
    1.75 0.35 30 sec
    0.875 0.175 15 sec

    From the table, 0.175 is not an easy volume to track over 15 seconds when giving a direct IV. Instead, you can round this number to 0.2 to track the volume your are giving better.

  4. First, calculate the total volume of the injection.[latex]x\text{ mL}=\dfrac{\text{1 mL}}{\text{10 mg}}\times\text{18 mg}\\[/latex][latex]x\text{ mL}=\dfrac{\text{1 mL}}{10\cancel{\text{ mg}}}\times18\cancel{\text{ mg}}\\[/latex][latex]x\text{ mL}=\dfrac{\text{18 mL}}{10}\\[/latex][latex]x\text{ mL}=\text{1.8 mL}\\[/latex]Enter the total amount, volume and period of time in the first row.
    Next, choose an amount to divide each value by. In this answer, each value has been divided by 3 to start and then divided by 2 to reach 15 second increments.
    Amount (units) Volume (mL) Time Interval
    18 1.8 3 min
    3 0.6 1 min
    3 0.3 30 sec
    1.5 0.15 15 sec
  5. First, calculate the total volume of the injection.[latex]x\text{ mL}=\dfrac{\text{1 mL}}{\text{5 mg}}\times\text{10 mg}\\[/latex][latex]x\text{ mL}=\dfrac{\text{1 mL}}{5\cancel{\text{ mg}}}\times10\cancel{\text{ mg}}\\[/latex][latex]x\text{ mL}=\dfrac{\text{10 mL}}{5}\\[/latex][latex]x\text{ mL}=\text{2 mL}\\[/latex]Enter the total amount, volume and period of time in the first row.
    Next, choose an amount to divide each value by. In this answer, each value has been divided by 2.
    Amount (units) Volume (mL) Time Interval
    10 2 2 min
    5 1 1 min
    2.5 0.5 30 sec
    1.25 0.25 15 sec
  6. First, calculate the total volume of the injection.[latex]x\text{ mL}=\dfrac{\text{2 mL}}{\text{250 mg}}\times\text{200 mg}\\[/latex][latex]x\text{ mL}=\dfrac{\text{2 mL}}{250\cancel{\text{ mg}}}\times200\cancel{\text{ mg}}\\[/latex][latex]x\text{ mL}=\dfrac{\text{400 mL}}{\text{250}}\\[/latex][latex]x\text{ mL}=\text{1.6 mL}\\[/latex]Enter the total amount, volume and period of time in the first row.
    Next, choose an amount to divide each value by. In this answer, each value has been divided by 2 and then divided by 3 to reach 15 second increments.
    Amount (units) Volume (mL) Time Interval
    200 1.6 1.5 min
    100 0.8 45 sec
    33.3 0.27 15 sec

    From the table, 0.27 is not an easy volume to track over 15 seconds when giving a direct IV. Instead, you can round this number to 0.3 to track the volume your are giving better.

  7. First, calculate the total volume of the injection.[latex]x\text{ mL}=\dfrac{\text{1 mL}}{\text{50 mg}}\times\text{20 mg}\\[/latex][latex]x\text{ mL}=\dfrac{\text{1 mL}}{50\cancel{\text{ mg}}}\times20\cancel{\text{ mg}}\\[/latex][latex]x\text{ mL}=\dfrac{\text{20 mL}}{\text{50}}\\[/latex][latex]x\text{ mL}=\text{0.4 mL}\\[/latex]Enter the total amount, volume and period of time in the first row.
    Next, choose an amount to divide each value by. In this answer, each value has been divided by 2.
    Amount (units) Volume (mL) Time Interval
    20 0.4 2 min
    10 0.2 1 min
    5 0.1 30 sec
    2.5 0.05 15 sec
  8. First, calculate the total volume of the injection.[latex]x\text{ mL}=\dfrac{\text{1 mL}}{\text{10 mg}}\times\text{15 mg}\\[/latex][latex]x\text{ mL}=\dfrac{\text{1 mL}}{10\cancel{\text{ mg}}}\times15\cancel{\text{ mg}}\\[/latex][latex]x\text{ mL}=\dfrac{\text{15 mL}}{10}\\[/latex][latex]x\text{ mL}=\text{1.5 mL}\\[/latex]Enter the total amount, volume and period of time in the first row.
    Next, choose an amount to divide each value by. In this answer, each value has been divided by 5 to start and then divided by 2 to reach 15 second increments.
    Amount (units) Volume (mL) Time Interval
    15 1.5 5 min
    3 0.3 1 min
    1.5 0.15 30 sec
    0.75 0.075 15

    From the table, 0.075 is not an easy volume to track over 15 seconds when giving a direct IV. Instead, you can round this number to 0.1 to track the volume your are giving better.

  9. First, calculate the total volume of the injection.[latex]x\text{ mL}=\dfrac{\text{1 mL}}{\text{50 mg}}\times\text{75 mg}\\[/latex][latex]x\text{ mL}=\dfrac{\text{1 mL}}{50\cancel{\text{ mg}}}\times75\cancel{\text{ mg}}\\[/latex][latex]x\text{ mL}=\dfrac{\text{75 mL}}{\text{50}}\\[/latex][latex]x\text{ mL}=\text{1.5 mL}\\[/latex]Enter the total amount, volume and period of time in the first row.
    Next, choose an amount to divide each value by. In this answer, each value has been divided by 2.
    Amount (units) Volume (mL) Time Interval
    75 1.5 2 min
    37.5 0.75 1 min
    18.75 0.375 30 sec
    9.375 0.1875 15 sec

    From the table, 0.1875 is not an easy volume to track over 15 seconds when giving a direct IV. Instead, you can round this number to 0.2 to track the volume your are giving better.

  10. First, calculate the dose in mg from the weight of the patient given.
    [latex]\text{2 mcg}\times\text{20 kg}=\text{40 mcg/dose}[/latex]
    Then, calculate the total volume of the injection.
    [latex]x\text{ mL}=\dfrac{\text{1 mL}}{\text{100 mcg}}\times\text{40 mcg}\\[/latex][latex]x\text{ mL}=\dfrac{\text{1 mL}}{100\cancel{\text{ mcg}}}\times40\cancel{\text{ mcg}}\\[/latex][latex]x\text{ mL}=\dfrac{\text{40 mL}}{\text{100}}\\[/latex][latex]x\text{ mL}=\text{0.4 mL}\\[/latex]Enter the total amount, volume and period of time in the first row.
    Next, choose an amount to divide each value by. In this answer, each value has been divided by 2.
    Amount (mcg) Volume (mL) Time Interval
    40 0.4 2 min
    20 0.2 1 min
    10 0.1 30 sec
    5 0.05 15 sec

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A Guide to Numeracy in Nursing by Julia Langham is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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