Impossible math problems, kind of long....

[WindyhillBSN]

hey folks! 90% of the class got these questions wrong and i still can't figure it out. here it is......

order: pitocin, iv for induction. start the infusion at 4 milliunits/minute and increase by 4 miliunits q 30 min. until contractions are adequate. 6 ml/hr is equal to 1mu/min. it's time to increase the infusion. the fhr is 120-130 w/moderate variability and no decels. contractions are q 4-5 min. apart lasting 60-70 seconds and are of moderate intensity upon palpation. the infusion is presently at 72 ml/hr. should the infusion be increased, and if so what will the ml/hr and mu/min be after the increase?

if you get the answer please show your work

thanks!

the other one....

order: mag. sulfate, 50g in 600 ml of d5w. infuse 4g over 30min. as a bolus, then maintain infusion at 2g/hr. what is the infusion rate in ml/hr for the bolus dose_____ml/hr and the maintenance dose____ml/hr?

please show work, thanks!

answers #1) yes, 96, 16

#2) 96 , 24

[edisongirl25]

Ok, so far, I got the first one.

If it is currently running at 72ml/hr divide that by 6 (per milliunit) and get 12 milliunits currently running. Add 4 to get 16 and 4 times 6 (again per milliunit) to get 24 for the ml/hr.

Angel

will try the second one next.

[edisongirl25]

Ok, the second one...

you have 600ml divided by 50g is 1g/12ml....4g would be 4 times 12ml is 48mil an hour....to go in 30min multiply by 2 is 96. to maintain at 2g multiply 2g by 12 (each g is 12 ml) and get 24ml/hr.

Hope this helps, I do a lot of work in my head and sometimes have trouble explaining how I got it.

[morte, LPN, LVN]

50/600 : 4/x

50x= 2400

x= 48

48X2 =96

96/4=24

what were the common answers? thereby to figure the common errors...

[brissie]

you need Daytonite

[WindyhillBSN]

50/600 : 4/x

50x= 2400

x= 48

48x2 =96

96/4=24

what were the common answers? thereby to figure the common

errors...

for the first one many didn't answer it. the second common anwers were 1.6 and 0.4 ml/hr.

thanks for all you guys' help!

[WindyhillBSN]

Anyone willing to explain the first one in a different way?

Thanks!

[onyx77]

i'll do what i can here. i do use dimensional analysis, so if you're not used to it, it may be confusing. but, i hope not. well, here goes.......

#1. order: start @ 4mu/min and increase by 4mu q 30min

6ml/hr = 1mu/min

presently set at 72ml/hr

so, we want to increase by 4mu. we know that 6ml = 1mu. so, 4mu = 24ml. then add this to the 72ml.

4 mu x 6 ml = 24 ml 72 ml + 24 ml = 96 ml/hr

1 mu

then we need to convert the 96 ml/hr to mu/min.

96 ml x 1 hr x 1 mu = 16 mu

1 hr 6 ml 1 min min

#2. order: bolus = 4g in 30 min maintenance = 2g/hr

available: 50g in 600ml d5w

for bolus amount... start with the order and figure in what's available. don't forget to convert min to hr.

4 g x 600 ml x 60 min = 96 ml

30 min 50 g 1 hr hr

for the maintenance amount... again start with what is ordered.

2 g x 600 ml = 42 ml

1 hr 50 g hr

i hope this all makes sense to you!!!

[onyx77]

sorry!!! when that last post posted the set up was screwed up! :trout:

#1. first one should be...

4mu x (6ml/1mu) = 24 ml

second one shoud be...

(96ml/1hr) x (1hr/6ml) x (1mu/1min) = 16mu/min

#2. first one should be...

(4g/30min) x (600ml/50g) x (60min/1hr) = 96ml/hr

second one should be...

(2g/1hr) x (600ml/50g) = 24ml/hr

[WindyhillBSN]

Thanks everyone!