Two new studies from the
Johns
Hopkins Children's Center show that computerizing the
ordering of chemotherapy and other types of intravenous
drug infusions for children greatly reduces the risk of
potentially dangerous medical errors.
An online infusion calculator and a computerized drug
ordering system, developed under the leadership of
Christoph Lehmann, director of clinical information
technology at the Children's Center, have been in use at
the center for about three years, but this is the first
time that their impact on medication errors has been
measured.
Children are three times more likely than adults to be
victims of medication errors, Lehmann said, because both
ordering and dosing are more complex in children. In
children, dosing is calculated by factoring in age, height
and weight, and miscalculations and rounding errors could
cause life-threatening harm. Dosing errors also cause more
ill effects in children because still-developing bodies
absorb, metabolize and excrete drugs at different rates
than adults' and thus have lower tolerance for medication
overdose. Children undergoing treatment for cancer are at
even greater risk because the general dangers of potent
chemicals are compounded by the dosing challenges.
"Our findings reveal that using a Web-based calculator
makes it less likely to order and give a child the wrong
dose or commit other errors, such as omitting patient
information, weight parameters or infusion rates," said
Lehmann, lead author of the Web-based calculator study,
which appears in the May 8 issue of Pediatric Critical
Care Medicine. "Our calculator stops ordering errors
before they can even reach the pharmacy, let alone the
patient."
The calculator computes all doses, advises and warns of
drug interactions, and automatically offers "default" doses
and drug dilutions to help doctors avoid over-or
underdosing.
For the study, researchers compared handwritten and
calculator-generated orders before and after the online
calculator was put into use. Twenty-seven percent of
handwritten orders were incorrect, with an error rate of 45
errors per every 100 written orders. By contrast, 94
percent of the calculator-generated orders were correct,
with an error rate of 6 per 100. The most frequent errors
in handwritten orders were wrong dosage and wrong
concentration, both of which are considered high-risk
errors. None of the calculator-generated orders contained
such errors.
To measure the effect on pediatric chemotherapy orders of
the computerized provider order entry system, researchers
compared 1,259 handwritten orders to 1,116 electronic ones,
finding that chemotherapy orders generated with the
computerized sysem were less likely to contain dose
miscalculations and had fewer omissions of cumulative
doses, which is the maximum dose of a medication that can
be safely given to a patient over a specific time period.
Computerized orders were also less likely to have
incomplete nurse safety checklists. Researchers estimate
that the computerized system prevented 17 to 18 such errors
per every 100 chemotherapy orders.
"Most of these errors may have been caught by pharmacists
or nurses before they could have hurt a patient,"
emphasized Lehmann, "but we wanted to prevent providers
from making errors in the first place because some of them
may reach the patient."
The chemotherapy order system uses calculators that
automatically adjust dosage to the patient's age and
weight, thus eliminating the need for complex calculations
and reducing the risk of calculation errors. The program
reduces the need for handwritten information and free text
by forcing providers to make selections from a dropdown
menu.
On a cautionary note, researchers found the risk for
mismatching medication orders to treatment plans was
slightly higher with the use of the electronic chemo order
system, probably because current versions do not allow
users to match a specific drug order to a recommended one,
and because new or experimental drugs do not appear on the
system's dropdown menu. This shortcoming will be eliminated
in the near future after a hospitalwide adoption of a new
computer provider order entry system, researchers said.
"One of the important lessons from this study is that
machines alone do not prevent errors and, in fact, may
initially introduce new potential hazards," said
co-investigator Robert Arceci, director of pediatric
oncology for the Johns Hopkins Kimmel Cancer Center. "It
takes a whole culture of safety and vigilance to prevent
errors."
However, the tradeoffs of correct dosing, legible orders
and adherence to safety procedures all outweigh the
negative effects, researchers said.
Because pediatric chemotherapy is such a complex process,
the researchers said it was crucial for them to know
exactly where mistakes were most likely to occur before
they designed the program. To do so, Lehmann and colleagues
used a model called failure modes and effects analysis,
originally developed by the military. FMEA analysis showed
them what kinds of errors occurred, where they were most
likely to occur and what the potential for harm was. The
most frequent errors were misidentification of patients and
entering incorrect patient information, such as weight and
height. Less frequent were dosage miscalculations and
dosing errors due to mismatching drug orders to
chemotherapy protocols. Lehmann designed the software
application in a manner that precision-targeted these
areas.
Based on their findings, researchers recommend the adoption
of digitized systems for intravenous drug infusions, as
well as chemotherapy orders, in high-risk clinical areas
such as pediatric oncology centers, pediatric intensive
care units and emergency rooms.
"What we found extends well beyond pediatric oncology and
has potential application in all areas of medicine," said
George Kim, lead author of the chemotherapy study, adjunct
faculty in the School of Nursing and faculty in the
Division of Health Sciences Informatics. "This system is
part of a whole new culture of safety that requires not
only change in the system but also change in the
mindset."
Co-investigators in the chemotherapy study included Allen
Chen, Sandra Mitchell, Michelle Kokoszka and Denise
Daniel.
Co-investigators in the online calculator study were George
Kim, Marlene Miller, Renmeet Gujral, Michael Veltri and
John Clark.