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Ketamine case provides lessons on med safety in the OR
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Ketamine case provides lessons on med safety in the OR

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OR Safety

Maria G. Tanzi, PharmD

Check list.

Medication errors in the operating room (OR) can easily occur, with anesthesiologists and nurse anesthetists administering medications much more frequently than other medical staff. According to estimates,  an anesthesiologist may inject up to half a million doses of different medications in his or her professional career. 

In January 2021, the Agency for Healthcare Research and Quality’s Patient Safety Network posted a case report on their website about an unintentional ketamine overdose in a patient undergoing a rigid direct laryngoscopy.

A surgical resident working in the OR was instructed by the consulting physician anesthesiologist to administer ketamine to the patient as part of the general anesthesia protocol. The provider inadvertently located two vials of 100 mg/mL ketamine instead of the intended 10 mg/mL vials that are routinely used.

The patient received 950 mg of ketamine instead of 95 mg. He had delayed emergence from anesthesia that required prolonged intubation and a transfer to the ICU, where he was later extubated and discharged the following day.

Improving safety in the OR

Pharmacists have an important role to play in preventing drug administration errors in the OR. They can take several approaches to ensuring medication safety, including double-checking drugs before administration by a second provider, if feasible, and minimizing distractions when drawing up medications.

For every drug administered, providers should assess the “Five Rights”:  the right patient, the right drug, the right concentration, the right route, and the right time. Trainees should be properly supervised until they have obtained enough experience to perform tasks safely. Following are additional steps pharmacists can take.

Limit different concentrations of same drug

“Pharmacists can help by limiting the number of different concentrations of a drug available on the hospital formulary to the absolute minimum,” said Christian Bohringer, MD, professor of clinical anesthesiology in the Department of Anesthesiology and Pain Medicine at UC Davis Health. “The more ampules of different concentration that are available, the greater the chance of error.”

If different concentrations are necessary, they should not be stored right next to each other in ampules that look alike, Bohringer said.

He also suggested that concentrated medications should be provided by the manufacturer in smaller ampules to help differentiate them (e.g., 100 mg/mL ketamine in a smaller ampule than 10 mg/mL ketamine).

Use the same manufacturer

Bohringer also cautioned against changing drug manufacturers frequently to ensure that the ampule’s physical appearance and the concentration of the drug in the ampule remain the same.

“Medications are often sourced from different manufacturers to save money, but this high turnover unfortunately increases the risk of drug administration error,” he noted.

Use prefilled syringes

Using prefilled syringes from the manufacturer or from the pharmacy can also help providers avoid errors.Bohringer noted that while prefilled syringes from the manufacturer are generally more costly, they offer considerable benefits to anesthesia providers, including sterility, convenience, and perceived safety.

Syringes that are prefilled in the pharmacy can also be advantageous when allowing for the ampule to be split into appropriately sized doses. In addition, prefilling makes possible adequate labeling with large letters and numbers.

Use larger fonts

Bohringer advises relabeling ampules with large font so that anesthesia providers can clearly read the name and the concentration of the drug in the ampule.

“Lights are often dimmed or completely turned off in the operating room to improve operating conditions for the proceduralist during endoscopy, laparoscopy, or thoracoscopy, and this makes reading small font on drug labels very difficult,” Bohringer said.

“Lighting conditions in the pharmacy are better than in the operating room, and there may be less time pressure and distraction. When drugs are labeled in the pharmacy, the font is usually in large letters and is very easy to read even in reduced ambient lighting conditions.”



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