Wednesday, June 08, 2011

5% solution

we do a lot of calculations in medicine. maybe that's why maths is an entry requirement to med school.
for example, patients are prescribed dextrose 5% as an intravenous drip. what this contains is 5g of dextrose (aka sugar) in 100mls of solution. this equals 5000mg in 100mls, or 50mg per ml.

similarly, normal saline or 0.9% saline contains 0.9g of sodium chloride (aka salt) in 100mls of solution, which equals to 900mg sodium chloride in 100mls, or 9mg per ml.

so, 5% of any medication equals to 50mg of that medication in 1ml of solution.

yesterday, i prescribed a 0.5% of a local anaesthetic to a patient to be given in the ward. the solution is prepared & labelled as 5mg per ml from the manufacturer. so this nurse called up the pharmacy & asked if they could prepare a 0.5% solution for the ward. the pharmacy assistant said they couldn't do it & asked the nurse to do it herself. feeling lost, she reverted to me on my instruction, saying the local anaesthetic only came in 5mg per ml preparation & not 0.5%.

if you go by the previous example, 5% solution is the same as 50mg per ml, so 0.5% is the same as 5mg per ml. which means, the nurse should have just used the solution as prepared.

this is a basic calculation which everyone prescribing, preparing & dispensing medication should be familiar with. fortunately or unfortunately, the responsibility of giving the right dose to the patient falls squarely on the doctors' shoulder.

don't you think an A in maths should be a compulsory requirement for entry into med school & a strong credit for nursing & pharmacy school?

after all, you don't want to to be on the receiving end of a 10-time higher dose of medication, right?

26 comments:

Yvonne Foong said...

Yeah, true. A strong credit in math and science should be the basic requirement for entry into med school. I hope the A or strong credit is a high quality one too. Because we can have As and strong credits out of a low standard education.

I have experience with the importance of intravenous solutions. When I did not wake up in the ICU immediately after surgery, the anesthesiologist was so concerned. They checked the intravenous drip given to me and adjusted it, and they brought me out of seizure to full consciousness in this way.

doc said...

Yvonne,

with the lives of people on our hands, we need to equip ourselves appropriately for the task.

i was aghast when i found out some of our nursing students are from the arts stream. how did they get in???

is it too simplistic to blame a failed education system?

Medie007 said...

woo. i learnt something new. :P

poor basics. sigh.

Yan said...

I confess I am totally lost with all the figures!

I always "disqualified" those applying for a job (say journalist) in my organization if they don't even bother to write a letter. The resume may come in with an inch thick, but it just makes no sense to me!

And recently, scholarship applications come in without covering letters. And these are from the many many "A"s students! Into the "KIV" tray?

Yvonne Foong said...

A failed education system would have low standards and requirements for entry into medical school.

Should we blame the nursing schools for profiteering this way? Or should we blame the people for creating the demand?

I believe not having enough nurses to care for patients in Malaysia is no reason to lower standards. We should improve their career incentives and support.

Like I always point out, the ward that my dad was in at UMMC was not even full! Nurses were moving like snails. They can't think fast and they can't make decisions for themselves. That's why they are unable to care for more than one patient at a time. This creates the illusion that public hospitals are over-crowded when nurses are unable to care for patients timely.

wenn said...

calculation is indeed important in life.

doc said...

Medie,

you will have to learn this when you're a house-officer.

doc said...

Yan,

those As students haven't developed their communication skills yet & will need to be groomed to take on the world. i would think they deserve a 2nd look.

doc said...

Yvonne,

the demand for nurses is real, created by exodus to greener pastures overseas & mushrooming of private hospitals, so when demand exceed supply, that's always a great opportunity to make a quick buck.

but those days of well-trained nurses headed by a mean, lean ward sister are over. nurses from arts stream & sisters that do more admin job than mentoring do not help their cause.

doc said...

Wenn,

esp in business, right?

Yan said...

doc,

Because you have faith, I will forget about the communication skills of these aced students for the scholarship application.

ilene said...

DOC, just don't know what to say anymore.

There was this one time when a nurse asked the patient: "pagi tadi you makan itu ubat ini warna kan .. so betul la ini warna ubat you makan lagi satu kali sekarang! I just froze with my eyes and mouth wide opened!

Yvonne Foong said...

ilene: That nurse sounds like she was talking down at you,

doc said...

Yan,

Do not withhold good from those to whom it is due, when it is in your power to act. (prov 3:27)

may God bless you for the good that you do.

doc said...

Ilene,

there's always a few in every profession that will bring down the good name.

Michelle Mak said...

i tot a strong credit was a must for the entry requirement? wat on earth the staff nurse trying to do.. ish!

Cara Lim said...

Doc,
This is scary. I am not sure if I should let my FIL know about this as he is scheduled for a routine colonscopy on Monday. I can imagine him insisting that the nurse show him both the written doc presciption and the medication before she does anything. Added to that, he's abit of a hypochondriac
. *LOL*

doc said...

Mich,

the staff nurse didn't know that the two concentrations are the same.

a strong credit can be meaningless since A+'s are a dime a dozen these days.

doc said...

Cara,

you can't be too careful these days. i can imagine what's going in his mind everytime the doctor lets out a "umm!" as he negotiates the colonoscope around the bowels.

you can read my own experience here: http://doc1s1n.blogspot.com/2009/12/finally-f-word.html

ilene said...

Yvonne, I was with my mum whose bed was diagonally opposite from where that patient was. But the way the nurse spoke, it was loud enough for everyone in the ward to hear with much displeasure!

I suppose you're right DOC. It's even happening here in the legal fraternity!

Jishou said...

but thank god.. she called u... to double confirm before proceed which i dono wat will happen to the patient.. some of them will just pandai pandai proceed and when things goes wrong... *no eye see*

Michelle Mak said...

eh sorry sorry it was me before tat sign in under the name jishou :D i am away in jakarta holiday-ing -michelle-

missyc said...

haha the mean lean mean ward sisters are indeed rare breed & they are a real gem.

once anaesthetized you don't even know what they put in you, keep fingers X ! with all that "salt & sugar" solution, no wonder one goes wonky & cranky post op :D

btw I do have a blog, only its for myself timebeing :)

doc said...

Ilene,

with standards so low, what used to be back-door entry is now literally open-door policy!!

doc said...

Mich,

enjoy your break & blog about it, ok?

doc said...

MissyC,

that's because salt & sugar solutions are not natural food for the human body!!

what you have is a personal diary/journal because a blog (or a web log) is by definition a series of entries with frequent updates maintained online for access to the general public. although you are writing for an audience of 1 for now, we await the moment you choose to open your heart.

:)