Need help with these 2 math problems.

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STAR3URY

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1. Pt. gets Potassium Chloride 20% 15mL TID. How many milliequivalents of potassium will the patient receive in 1 day? (Potassium chloride MW: 74.5, potassium atomic weight 39)


2. The pharmacist is asked to provide a cyclic rate for a home TPN. The dosage is 2000mL over 12 hours with a titrate up rate of 80 mL/hour for 1 hour and taper-down rate of 40 ml/h for 2 hour. Administration time is 10pm to 10am. What is the calculated rate in mL/hr at 1am rounder to the nearest whole number.

😕
 
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1. Pt. gets Potassium Chloride 20% 15mL TID. How many milliequivalents of potassium will the patient receive in 1 day? (Potassium chloride MW: 74.5, potassium atomic weight 39)

20g/100ml x 15ml/dose x 3 doses/day = 9g/day

MW KCl = 74.5
valence = 1
therefore...
mEq = 74.5mg/1 = 74.5mg

9g => 9000mg

9000mg/74.5mg => 120.8 mEq/day <===ANSWER

I'm pretty sure this is the answer you're looking for for number 1.
 
1. Pt. gets Potassium Chloride 20% 15mL TID. How many milliequivalents of potassium will the patient receive in 1 day? (Potassium chloride MW: 74.5, potassium atomic weight 39)

20g/100ml x 15ml/dose x 3 doses/day = 9g/day

MW KCl = 74.5
valence = 1
therefore...
mEq = 74.5mg/1 = 74.5mg

9g => 9000mg

9000mg/74.5mg => 120.8 mEq/day <===ANSWER

I'm pretty sure this is the answer you're looking for for number 1.


This is where I'm confused...because I know how to get that answer but they ask specifically for potassium so I dont know what to do.
 
If they are asking about potassium specifically, I just interpret it as them asking the mEq with respect to K+'s valence. Which is one. mEq just has to do with charges. mOsmols is particles.

If they ask for mEq of Ca++... the valence is two. Just simplify it like that. That's a harder question than what you'd get on the Naplex, even though its a good concept to understand.

I used this site when I was studying the SDN 120... http://sitemaker.umich.edu/tutorial/files/handout_milliequiv.pdf

Helped me understand it better.
 
This is where I'm confused...because I know how to get that answer but they ask specifically for potassium so I dont know what to do.

I got 120.8 mEq as well.

For what it's worth:

Whenever a problem asks for mEq I go right to mmol.

mmol x valance = mEq

So in this problem I would:
1. Solve for mmol of KCl
2. Break up KCl into its ions: K+ and Cl- and see that 1mmol of KCl = 1 mmol of K+ (and therefore 1 mmol of Cl-)
3. 1 mmol of K+ x its valance of 1 = 1 mEq of K+

It gets more complicated when certain ionic compounds have charges greater than 1.

For example, Calcium Chloride is CaCl2.

CaCl2 breaks down into its ions: 1 ion of Ca++ and 2 ions of Cl-

therefore: 1 mmol of CaCl2 = 1 mmol of Ca++ and 2 mmol of Cl-
1 mmol of CaCl2 x valance of 2 (the highest charge on the compound is 2) = 2 mEq CaCl2
1 mmol of Ca++ x valance of 2 = 2 mEq Ca++
2 mmol of Cl- x valance of 1 = 2 mEq Cl-
 
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2. The pharmacist is asked to provide a cyclic rate for a home TPN. The dosage is 2000mL over 12 hours with a titrate up rate of 80 mL/hour for 1 hour and taper-down rate of 40 ml/h for 2 hour. Administration time is 10pm to 10am. What is the calculated rate in mL/hr at 1am rounder to the nearest whole number.

😕

1. During the 1st hour you titrate up using 80 mL/ hr so you've lost 80 mL

2. During the last 2 hours you're running at 40mL/ hr so you've lost 80 mL

3. You spent 3 out of the 12 hours "titrating" losing a total of 160 mL during those 3 "titration hours".

4. You have 9 hours remaining to administer 1840 mL (2000 mL originally- 160 lost to titration) of the bag.

5. 1 AM falls within that 9 hour range

6. 1840 mL/ 9 hours = ~204 mL/ hour is what I'm getting as the final answer.

FWIW this question was on my pre-naplex.
 
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1. During the 1st hour you titrate up using 80 mL/ hr so you've lost 80 mL

2. During the last 2 hours you're running at 40mL/ hr so you've lost 80 mL

3. You spent 3 out of the 12 hours "titrating" losing a total of 160 mL during those 3 "titration hours".

4. You have 9 hours remaining to administer 1840 mL (2000 mL originally- 160 lost to titration) of the bag.

5. 1 AM falls within that 9 hour range

6. 1840 mL/ 9 hours = ~204 mL/ hour is what I'm getting as the final answer.

FWIW this question was on my pre-naplex.

That's how I did it in the other thread where this question was posed. I have to believe this is correct, because I don't see any other way to do it that's any easier.
 
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