Jim, et al, I've been trying to craft a short answer to how the
phamacy-related fatality in that story occurred, but there isn't any
short answer. The fatal outcome may have started with the measurement
error, but other forces in the pharmacy contributed to the tragedy.
The subject is a pharmacist. She is presumed, by her education, to be
fluent in metric. But she, like her fellow humans, can make mistakes,
confusing the "m's." I often find myself in conversation saying
"milligram" out loud, when I do indeed mean the smaller unit,
"microgram." This error involved a confusion of units, but more
important, involved a confusion of scale. The additive in question,
zinc, is a trace metal, zinc, being added to a drug product known as
total parenteral nutrition, or TPN (the deprecated term for TPN is
"hyperalimentation" or "hyperal"). TPN just what it says it is: total
feeding through the vein. It is given to patients who have some kind of
stomach or bowel problem, either from surgery or disease, and must rest
these organs. The medication order was for a newborn. For an adult,
trace metals are added to TPNs in a bulk mixture of different metals,
commonly 5 mL of a trace metal mixture. But, because of the nature of
newborn metabolism, trace metals must be added to TPNs in pure form and
on an individualized basis. I've never had to prepare a neonatal TPN,
but I do prepare a lot of adult ones, as well as deal with a lot of
adult and pediatric doses of medications, and I know instinctively that
330 mg, presumably meaning 330 mg of zinc sulfate, is an adult daily
dose of the mineral. Even if the order was illegibly handwritten, a
skilled pharmacist would know which unit was intended by the prescriber.
We don't work without a context.So, no matter how the computer software
required the entry to be made, the pharmacist should have paid close
attention to getting the amount of this trace metal entered in
micrograms. Apparently, the problem with the Summerlin pharmacy was
that it was poorly run and very chaotic, and I guess the person wasn't
watching what she was doing.
End measurement discussion. Now, to what happened after that.
There is a safety rule-of-thumb in pharmacy (it's really common sense)
that if you need too many dosage units to make up a dose, something is
wrong, and you better check. Let's say that a prescriber orders 1000 µg
of oral levothyroxine (yeah, right;probably an overdose), and a
pharmacist in my department enters that order just as it is written. A
technician pulls the dose, and hands me ten 100 µg levothyroxine tablets
labeled with the patient name and dose, for me to check. After I finish
saying, "What the heck is this?" I will call the prescriber and see
what he/she meant by this high dose (300 µg is the highest dose of this
that I've ever seen), and what has usually happened is that he/she
mistakenly added an extra zero to the value, and meant only 100 µg. In
practice, the technician wouldn't even stop to pull the drug; she'd just
look at the printout sheet, go wide-eyed, and say, "Does somebody
really want 10 of these?"
Applying this common sense would have saved the child's life. When the
pharmacist working on the TPN entered 330 mg of zinc instead of 330 µg,
the information was sent to the I.V. laboratory's auto-mixing machine.
This machine tells the pharmacy technicians how much of each product is
to be added to the TPN solution. I don't know how much zinc sulfate is
in one vial, because, as I said, we don' t make neonatal TPNs at my
facility. But it must be in microgram quantities. The I.V. room
technician working on the TPN responded to numerous requests from that
machine to add more zinc, add more zinc, add more zinc. In my
department, the tech would have come running out of the room complaining
that there was something very wrong, at which point I would have looked
at the order entry and corrected the units. This apparently
inexperienced technician continued to fill the bag with the huge zinc
overdose. Also, apparently, the fluid volume of all that zinc made for a
bulging TPN bag, which should have also been a red flag---to the
pharmacist, the technician, and the nurse--that something was wrong. I
don't ignore a nurse's complaint. If the nurse questions what she gets
from us, we stop and find out what's going on. In this Summerlin
hospital, all of the usual checks and balances were absent, and a child
died of a tragic error.
I do apologize for the length of this post, but I felt obligated to
explain that there can be more than one root cause of a medication
error. Measurement was a factor here, but it wasn't the whole story.
Paul T.
James Frysinger wrote:
My feeling is that mcg is easier to confuse with mg than μg is. The
FDA mandates using mcg for microgram, however
What I do not know about this case is whether the pharmacist was
reading a handwritten Rx or one that was electronically generated. And
I do not know whether mcg or μg was used there.
Jim
James Frysinger wrote:
Hospital Pharmacy Error Blamed for Preemie's Death
Tuesday , February 19, 2008
An error by a hospital pharmacy led to the death of a premature baby
who at one time was thriving, ABC News reported.
Alyssa Shinn was born 14 weeks early to Kathleen and Richard Shinn.
She was frail and tiny but grew stronger in the neonatal intensive
care unit at Summerlin Hospital in Las Vegas, according to the
report, which was published on Monday.
"She was doing excellent," Richard Shinn told ABC. "She had just come
off the ventilator. She was gaining weight. She was starting to take
milk. They just gave her a few drops of milk a day, in a little
dropper. And everything was good to go."
But after the Shinns went home to get some rest on Nov. 8, 2006,
something went wrong. Upon returning to the hospital the next morning
at 9 a.m., the Shinns found their daughter was lethargic and not
moving. Kathleen Shinn said she could sense her daughter was on the
brink of death, according to the report.
It was later discovered that the lead pharmacist on duty at the
hospital the night before made a fatal mistake prescribing to Alyssa
330 milligrams of zinc, a nutritional supplement to help the baby's
metabolism, ABC reported.
The dosage was 1,000 times the 330 micrograms of zinc that the baby
was supposed to receive.
Source:
http://www.foxnews.com/story/0,2933,331164,00.html
--
Paul Trusten, R.Ph.
Public Relations Director
U.S. Metric Association (USMA), Inc.
www.metric.org
3609 Caldera Blvd., Apt. 122
Midland TX 79707-2872 US
+1(432)528-7724
mailto:[EMAIL PROTECTED]
