Dosage Calculation - Volume/Time - IV Drop Rate Questions

Source Website: http://www.dosagehelp.com/iv_rate_drop.html
By DosageHelp.com

Volume/Time - IV Drop Rate Questions

Given a certain amount of liquid, a time period, and a drop factor (gtts/mL), what is the necessary IV flow rate in gtts/min? Measurement used when IV is regulated manually. Because it is not possible to give a patient a fraction of a drop, it is typical to round answers for these problems up or down to the nearest whole number. 

Formula:

$$\boxed{\frac{\mathbf{Volume\; (mL)}}{\mathbf{Time\; (min)}}x\mathbf{Drop\; Factor\; (gtts/mL)}=\mathbf{Y(Flow\; Rate\; in\; gtts/min)}}$$

Example: Calculate the IV flow rate for 1200 mL of NS to be infused in 6 hours. The infusion set is calibrated for a drop factor of 15 gtts/mL.

$$\frac{\mathbf{Volume\; (mL)}}{\mathbf{Time\; (min)}}x\mathbf{Drop\; Factor\; (gtts/mL)}=\mathbf{Y(Flow\; Rate\; in\; gtts/min)}$$

Convert 6 hours to minutes.
    min ← hr    ( x by 60 )
    6 hr x 60 = 360 min

$$\frac{\mathbf{1200\; mL}}{\mathbf{360\; min}}x\mathbf{15\; gtts/mL}=\boxed{\mathbf{50\; gtts/min}}$$

Example: Calculate the IV flow rate for 200 mL of 0.9% NaCl IV over 120 minutes. Infusion set has drop factor of 20 gtts/mL.

$$\frac{\mathbf{Volume\; (mL)}}{\mathbf{Time\; (min)}}x\mathbf{Drop\; Factor\; (gtts/mL)}=\mathbf{Y(Flow\; Rate\; in\; gtts/min)}$$

$$\frac{\mathbf{200\; mL}}{\mathbf{120\; min}}x\mathbf{20\; gtts/mL}=\boxed{\mathbf{33\; gtts/min}}$$

Question (16): (From Ngee Ann Polytechnics Dosage Calculation Worksheet)
ORDER: I/V Normal Saline 1000 mL over 24 hours. Drop Factor = 60 gtts/mL.

$$\mathbf{\text{Rate:}}\underline{}\mathbf{\text{gtts/min}}$$

$$\frac{\mathbf{Volume\; (mL)}}{\mathbf{Time\; (min)}}x\mathbf{Drop\; Factor\; (gtts/mL)}=\mathbf{Y(Flow\; Rate\; in\; gtts/min)}$$

Convert 24 hours to minutes.
    min ← hr    ( x by 60 )
    24 hr x 60 = 1440 min

$$\frac{\mathbf{1000\; mL}}{\mathbf{1440\; min}}x\mathbf{60\; gtts/mL}=\boxed{\mathbf{41.7\; gtts/min}}$$

Answer rounded to the nearest whole number = 42 gtts/min

Question (18): (From Ngee Ann Polytechnics Dosage Calculation Worksheet)
I/V D5% 1000 mL over 8 hours. Drop Factor = 20 gtts/mL.

$$\mathbf{\text{Rate:}}\underline{}\mathbf{\text{gtts/min}}$$

$$\frac{\mathbf{Volume\; (mL)}}{\mathbf{Time\; (min)}}x\mathbf{Drop\; Factor\; (gtts/mL)}=\mathbf{Y(Flow\; Rate\; in\; gtts/min)}$$

Convert 8 hours to minutes.
    min ← hr    ( x by 60 )
    8 hr x 60 = 480 min

$$\frac{\mathbf{1000\; mL}}{\mathbf{480\; min}}x\mathbf{20\; gtts/mL}=\boxed{\mathbf{41.7\; gtts/min}}$$

Answer rounded to the nearest whole number = 42 gtts/min

Question (19): (From Ngee Ann Polytechnics Dosage Calculation Worksheet)
ORDER: I/V gentamycin 80 mg/100 mL N/Saline over 1 hour. Drop Factor = 60 gtts/mL.

$$\mathbf{\text{Calculate Rate:}}\underline{}\mathbf{\text{gtts/min}}$$

$$\frac{\mathbf{Volume\; (mL)}}{\mathbf{Time\; (min)}}x\mathbf{Drop\; Factor\; (gtts/mL)}=\mathbf{Y(Flow\; Rate\; in\; gtts/min)}$$

Convert 1 hours to minutes.
    min ← hr    ( x by 60 )
    1 hr x 60 = 60 min

$$\frac{\mathbf{100\; mL}}{\mathbf{60\; min}}x\mathbf{60\; gtts/mL}=\boxed{\mathbf{100\; gtts/min}}$$

Question (20): (From Ngee Ann Polytechnics Dosage Calculation Worksheet)
ORDER: I/V Osmofundin 20% 100 mL over 30 Minutes. Drop Factor 60 gtts/mL.

$$\mathbf{\text{Rate:}}\underline{}\mathbf{\text{gtts/min}}$$

$$\frac{\mathbf{Volume\; (mL)}}{\mathbf{Time\; (min)}}x\mathbf{Drop\; Factor\; (gtts/mL)}=\mathbf{Y(Flow\; Rate\; in\; gtts/min)}$$

$$\frac{\mathbf{100\; mL}}{\mathbf{30\; min}}x\mathbf{60\; gtts/mL}=\boxed{\mathbf{200\; gtts/min}}$$

Continue (Go to Volume/Time - IV mL Rate Questions)



Reference 
[1] Advanced Formatting, Ry’s MathML Tutorial, http://rypress.com/tutorials/mathml/advanced-formatting.
[2] MathML, Presentation MathML, https://en.wikipedia.org/wiki/MathML.
[3] MathJax in Blogger (II), Posted on Tuesday, 12 July 2011, http://irrep.blogspot.sg/2011/07/mathjax-in-blogger-ii.html
[4] MathJax, http://docs.mathjax.org/en/latest/start.html
[5] MathML Fundamentals (Colours), W3C recommendation, http://www.w3.org/TR/MathML/chapter2.html 

• http://www.dosagehelp.com/iv_rate_drop.html