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In his third week after a cholecystectomy, a patient developed a fistula and his temperature spiked to 1020 F. (38.90 C.). The attending doctor ordered 1.5 million (1,500,000) units of intravenous penicillin G potassium to be given every 4 hours.
The pharmacist dispensed four vials of the penicillin, each labeled 5,000,000 (5 million) units ... the smallest containers of this drug the pharmacy had in stock. He intended the vials to be given over 2 days.
When the medication nurse was ready to administer the penicillin, she mentally calculated, "The order is for 1.5 million units; 5 plus 5 plus 5 equals 1.5 million. " Then she took three of the vials from the patient's bin, added them to a solution of D5 W, and piggybacked the solution into the patient's primary infusion.
When she was charting what she'd administered, she casually mentioned to another nurse, "We'll have to order more penicillin for Mr. Lanford. We have only one vial left. "
The second nurse had seen the four vials when they were delivered and knew they were more than enough for one dose. So she asked the medication nurse what she had given the patient. Immediately, the medication nurse realized that by calculating quickly in her head, she'd misplaced a decimal point. Instead of giving 1.5 million units, she'd given 15 million units.
The nurse called the doctor right away, and they both checked the patient. Although the drug had completely infused, the patient was not harmed. But the doctor ordered all other doses of penicillin withheld through the night.
To avoid making similar errors, always calculate doses on paper, not in your head. Then you'll be sure all decimal points are placed correctly. Also, read vial labels carefully, especially if large amounts-written with several zeros-are involved.
Finally, recheck your calculations if you must use several vials or ampules to prepare one dose. Usually, this is a clue that you're preparing too much medication.