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Department: MEDICATION ERRORS

Medication Errors

Cohen, Michael R. ScD, MS, RPh

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doi: 10.1097/01.NURSE.0000651668.55636.06
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ACUTE ISCHEMIC STROKE

Dosing card contributes to error

While being treated for an acute ischemic stroke (AIS), a patient received the incorrect dose of Activase (alteplase) after a practitioner utilized the alteplase dosing card supplied by Genentech. Alteplase is a tissue plasminogen activator indicated to treat AIS. As shown below, the card expresses the weight in both pounds (lb) and kilograms (kg), side by side in a dosing window. Moving the card's slide up or down matches the patient's weight with the correct dose. On the card, “(LB)” and “(KG)” are both printed just beneath the window, so if one is not careful, the proper unit of mass may be missed.

Figure
Figure:
Based on a misinterpretation of this dosing card, a patient weighing 122 kg received a dose appropriate for a 122 lb person.

In this case, the patient weighed 122 kg but the nurse administered a dose based on a weight of 122 lb (55.4 kg). Consequently, instead of the correct dose of 90 mg, the patient received only 50 mg. Using the same dosing card, three nurses verified the dose before administration, all missing the error. Fortunately, the patient's AIS signs resolved and additional alteplase was unnecessary. This event took place in an inpatient area, but two ED pharmacists at the same hospital experienced similar close-call events.

In a 2017 survey, the Institute for Safe Medication Practices (ISMP) looked at compliance with ISMP's Targeted Medication Safety Best Practices for Hospitals. Nearly half (47%) of respondents stated they had fully implemented Best Practice #3—to measure and document patient weights in metric units only—and 44% had at least partially implemented the practice. At the hospital where this error happened, the policy is to obtain metric weights only. Alteplase labeling also expresses dosing using the metric system. With that in mind, one must ask, why does the dosing card include weight in pounds at all? Safety would be improved if the “LB” column on the slide were blocked with black tape to avoid potential mix-ups. In addition, given that three nurses missed the error while checking the dose, the hospital should examine its independent double-check process.

STERILE WATER

Wrong choice, tragic consequences

As part of the process for in vitro fertilization, a young woman with no significant health history went to an outpatient surgery center for egg retrieval. The procedure went well. About an hour later, the team decided to administer an additional liter of I.V. fluids before discharging the patient. When the nurse went to hang the second liter of I.V. fluids, she discovered that the first liter that had been hung was sterile water for inhalation. By then, the entire liter of sterile water had infused. The patient developed hemolysis and eventually became anuric. She now requires daily dialysis and may not ever recover renal function.

In this facility, sterile water was used during cystoscopies to fill the bladder. Bags of sterile water for inhalation were kept on the same shelf as bags of 0.9% sodium chloride and other common I.V. fluids.

One of ISMP's Targeted Medication Safety Best Practices for Hospitals calls for the elimination of 1,000 mL bags of sterile water of any type (injection, irrigation, or inhalation) from all areas outside of the pharmacy. ISMP recommends using alternative size and/or shape containers of the product, such as 2,000 mL (2 L) bags of sterile water for injection, irrigation, or inhalation if available; bottles of sterile water for irrigation; or vials of sterile water for injection. These containers vary greatly in appearance from 1,000 mL bags of common I.V. fluids and are much less likely to be confused as an I.V. solution than a 1,000 mL bag of sterile water. Additional strategies to prevent errors include establishing a policy that 1,000 mL bags of sterile water be ordered only by a pharmacy purchaser for pharmacy compounding purposes, and not stocking these 1,000 mL containers of sterile water in clinical locations. If sterile water must be available in a clinical location, it should be purchased whenever possible in pour bottles or other plastic containers that are distinctly different in appearance from flexible plastic bags containing I.V. fluids.

Review other recommendations from ISMP's Targeted Medication Safety Best Practices for Hospitals at www.ismp.org/node/160.

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