RPh, FASCP
Medication Safety Analyst
at the Institute for Safe Medication Practices,
Philadelphia, PA.
PROBLEM
In 1998, a study reported by the Institute for Safe Medication Practices (ISMP)
revealed that 11% of serious medication errors involved the administration of
insulin.
A report from the United States Pharmacopoeia(USP), based on MedMARX
2001 data, also indicated that insulin remains the drug most commonly
involved in harmful medication errors. For example, insulin has been
mistakenly administered in place of other medications or has been given as
an overdose. The ISMP has received reports of both types of errors.
Two reports involved misinterpre-tation of the dose when the abbreviation "u"
was used for "units." In one report, a pharmacist preparing total parental
nutrition (TPN) misinterpreted the dose as 100 units when a dietitian wrote an
order to add U of regular insulin to each TPN bag." In a similar case, a new
pharmacy technician who was entering orders misinterpreted a sliding scale
when insulin was ordered and the letter "u" was used for units.
Although the pharmacist who checked the technician`s order entry did not
detect the error, a nurse intercepted the 10-fold overdose while reviewing the
computer-generated medication administration record (MAR).
The other two errors occurred when the staff experienced a mental lapse and
confused insulin with other products. In the first case, a nurse incorrectly
transcribed a verbal order to "resume an insulin drip" as "resume heparin
drip." A pharmacy technician entered the order and labeled a premixed
heparin solution.
The pharmacist caught the error when he noticed a flow rate of 1.5 units/hour
and recognized the patient`s name froma recent call for help that involved
calculating an insulin flow rate.
The other error resulted in significant patient harm when a double
concentration of a critical-care drug was ordered for a cardiac patient in the
intensive-care unit(ICU). A nurse called the pharmacy and inadvertently
requested a double concentration of insulin. During order entry, the
pharmacist did not notice that diabetes mellitus was not listed as a patient
diagnosis. Then, without seeing a copy of the order, he prepared and
delivered the insulin infusion. Further, while in the ICU, he did not obtain a
copy of the order or review the patient`s chart to verify hyperglycemia. When
the nurse hung the insulin, a second nurse did not independently verify the
drug, concentration, infusion rate, or line attachment. No prominent cautionary
labeling was present on the infusion to alert staff that it contained insulin. The
double concentration of insulin was administered at the rate intended for the
critical-care drug. The patient experienced permanent central nervous system
impairment.
SAFE PRACTICE
RECOMMENDATION
Insulin is a high-alert medication that carries a risk of causing serious injury.
As such, special safety considerations are essential when it is being used. The
first two errors described earlier are clear examples of the need to educate all
practitioners-including dietitians and others who communicate drug
information-to always write out the word "units."
The last two errors demonstrate the human tendency toward mental
confusion and mixing up products that are used routinely, especially if two or
more drugs are measured in units, as is the case with heparin and insulin.
Thus, measures must be implemented to make these errors visible before they
affect patients.
Verbal orders should not be accepted for intravenous(IV) insulin. Instead,
orders should be sent by fax when the prescriber is off-site. If no alternative
exists, a second person should be on hand to listen and to accept emergency
telephone orders, transcribing the order directly onto an order form and
repeating it back for clarification.
As another contributing factor to the last error described in the article, the
standard insulin concentration (0.25 units/㎖) used in this hospital was quite
low. Using a concentration of 1 unit/㎖ can eliminate the need for most double
concentrations, making such orders unusual and subject to scrutiny.
The following precautions are advised:
· Ensure that all insulin infusions are prepared in the pharmacy.
· Never dispense or administer insulin without an independent check using
the actual order and verifying that the patient needs insulin or has
hyperglycemia.
· Make special auxiliary labeling, such as "contains insulin," available to alert
the staff to the presence of insulin in IV solutions.
· Educate patients and include them in a double-check system to detect any
errors.
기사요지
미국안전의학연구소(ISMP) 안전의학분석가 매튜 그리싱거 박사가 인슐린 투여시 발생가능
한 의료사고와 대책에 대해 논한 글로 자매지인 `메디메디아 USA` 발간 `P&T(Pharmacy
and therapeutics)` 10월호에 게재됐다.
1998년 ISMP 조사자료에 의하면, 원내 의료사고의 11% 정도가 인슐린 투여와 관계된 것으
로 밝혀졌다. 관련 의료사고는 인슐린이 다른 약물과 혼용되거나 과다용량이 투여되는 경우
가 대부분이다.
이같은 의료사고를 줄이기 위한 방법으로 그리싱거 박사는 ▲ 인슐린 투여와 관련된 모든 준비
는 원내조제실에서 진행할 것 ▲ 인슐린 투여시 반드시 처방전이나 환자의 상태 등을 미리 확
인할 것 ▲ 병원직원들이 확인할 수 있도록 `인슐린이 담겨있다`는 추가표식을 달 것 ▲ 의료사
고 방지를 위한 이중확인시스템을 가동하고 환자 및 의료진 교육을 강화할 것 등을 권고했다.
정리·이상돈 기자
sdlee@kimsonline.co.kr