TUESDAY, May 29, 2007 (HealthDay News) -- The vast majority of potentially harmful errors in chemotherapy for children with cancer do find their way to these young patients, a new study finds. And they are more often caused by dispensing or administration mistakes than by prescribing mix-ups, the researchers found.
In total, 85 percent of these drug errors were not spotted until the child received the medication, according to a study led by Dr. Marlene Miller, associate professor of pediatrics at the Johns Hopkins School of Medicine, Baltimore. These errors do not always cause harm to the child, the authors added, but they are always worrisome.
Their analysis of the United States Pharmacopeia's voluntary medication error-reporting database, MEDMARX, also found that prescribing errors accounted for only 10 percent of cases occurring in patients under 18 years of age from 1999 to 2004. Instead, most of the mistakes arose from dispensing errors by pharmacy staff or administration blunders by nurses and other health care workers.
A total of 310 chemotherapy errors for pediatric patients were logged during the study period, from 69 different institutions. (As of 2004, 616 institutions were participating in the MEDMARX program, up from 56 in 1999.) More than eight out of 10 of these incidents reached the patient, meaning they were not caught prior to administration, and about 16 percent required an escalation of care as a result, Miller said.
Surprisingly, prescribing errors accounted for just one in 10 cases. Most errors (48 percent) involved mistakes in administration, followed by errors in dispensing (30 percent). The most commonly cited types of error were mistakes in dose or quantity (23 percent), or time of administration (23 percent), followed by omission errors (that is, failing to deliver the drug at all, 14 percent) and improper administration technique or route (12 percent). By far the biggest cause of error was "performance deficit" -- human error -- at 41 percent.
The research was published online May 25 in the journal Cancer, and is expected to be published in the July 1 print issue.
Children generally are more susceptible to medication errors than adults, Miller said, because unlike with adults, there is no "usual" dose for children; pediatric dosages generally are based on body size.
The problem is even more pronounced for anticancer medications, however, because these drugs are so potent and their so-called therapeutic window is so narrow.
"I can give four times the normal dose of Motrin, and you will be fine," Miller said as an example. "You cannot do that for chemo; they have a very narrow safety window."
Many hospitals use computer systems to compute proper dosages and reduce such errors, but, Miller said, these systems often do not include chemotherapy agents, as the rules for dosing and the protocols for administering the drugs are constantly being revised as new clinical trial data appear.
"The dosing [for chemotherapeutics] is so different, so the vendors haven't built in the logic of how to do this," Miller said. "So, we have lots of interventions and tools to improve patient safety, but chemo falls off the radar screen."
Even when such safety systems are in place, errors can still occur.
At the University of California, San Francisco, for instance, a computer system is used to calculate dose based on a patient's height and weight for a particular protocol and then produce appropriate electronic orders, as Dr. Katherine Matthay, chief of pediatric hematology-oncology at the UCSF Children's Hospital , explained. These orders are then checked by a nurse practitioner, an oncologist, and a pharmacist, checked again as the medicine is prepared, and yet again by the nurse who actually administers the drug.
"Despite this, occasionally errors are made in timing or due to faulty equipment or human error as noted in the article," Matthay said.
Miller stressed that this study in no way reports the actual rate of chemotherapy errors. To calculate that, she would need to know the total number of chemotherapy doses administered, which she does not have. In addition, MEDMARX is a voluntary database, and some errors undoubtedly go unreported. Indeed, that 85 percent of the reports cited in this study reach the patient could well be due to the fact that hospitals are more likely to report incidents that reach patients than those that are caught in time, she said.
Yet Miller expressed the hope that this study could lead to the development of what she called "targeted interventions" -- specific systems that can lower the likelihood of medication errors.
"It is impossible to be vigilant on everything, to never make an error, never be late. It's impossible. So, our struggle is to introduce something to make it more error-free," she said, citing as examples anything from new computer software, to enhancements in teamwork between the pharmacist, nurse, and physician, to standardizing protocols for administration of a particular drug.
Another expert called chemotherapy error monitoring "a huge issue."
Sarah Scarpace, a pediatric clinical pharmacist at UCSF Children's Hospital, said staff often have to contend with an additional level of confusion in administering chemo -- the fact that protocols sometimes differ in how they number their days. For example, one protocol may begin on "day 0" while another begins on "day 1," and staff can get confused -- the drug a patient gets on day 1; is that really their first day or their second?
Scarpace suggests standardizing the numbering of days in protocols and using barcoding technology to ensure the correct drug goes to the correct patient. "Certainly the barcoding thing may help to ensure you get the right drug to the right person at the right time," she said.
And one more thing: "Everyone should take a 'time out' to verify this is the right thing [drug]," she said. A "time out" is that moment when everyone steps back and makes sure the correct drug is being given at the right time, dose, to the right patient, Scarpace explained.
Parents can be key players in maintaining safety, too, Miller added. She advised parents to be active participants in their children's care. "Question each dose. Be empowered. Know what's going on. Know the drugs, doses, times, and routes, so when the nurse comes in to administer the drug, you know it is right, and you can help troubleshoot," she said.
For more on dealing with chemotherapy, visit the National Cancer Institute.