Paralyzed by Mistakes: Preventing Errors with Neuromuscular Blocking Agents

September 22, 2005

Problem: Neuromuscular blocking agents have been inadvertently administered to patients who were not receiving proper ventilator assistance. Because the respiratory muscles were paralyzed, some patients have died or sustained serious, permanent injuries. In fact, the USP-ISMP Medication Errors Reporting Program has received well over than 50 reports concerning misuse of these agents over the past several years. Unfortunately, the true incidence of injuries from accidental administration of neuromuscular blocking agents is likely much higher than reflected by error reports.

While some errors have occurred in the operating room (OR), most have taken place outside this setting, in emergency departments (EDs), interventional radiology departments, intensive care units (ICUs), and other medical, surgical, and psychiatric units. Many errors can be attributed to one or more common root causes. Consider the following examples.

Look-alike packaging and labeling

Nurses mistakenly reconstituted measles and BCG vaccines with pancuronium and administered the vaccines to healthy infants. One infant died after experiencing seizures and respiratory arrest. The pancuronium vial looked very similar to a vial of the correct diluent, sodium chloride injection.
An ED nurse administered pancuronium instead of influenza vaccine to several patients. The vials were the same size, and the labels were quite similar. The look-alike vials had been stored next to each other in the refrigerator. The patients experienced dyspnea and respiratory depression but, fortunately, sustained no permanent injuries.
Vials of pancuronium were misplaced in a bin holding vials of heparin flush solution. An ICU nurse failed to notice the mistake and flushed a patient's central line with the neuromuscular blocking agent. The patient arrested after the injection but fortunately recovered after 10 hours on a ventilator.
An adult patient received cisatracurium intended for a ventilated infant. The cisatracurium infusion had been delivered by accident to a medical unit along with three bags of antibiotics. A nurse had verified that the first three bags in the stacked pile of piggybacks were the prescribed antibiotics, but she was interrupted before checking the fourth bag, which contained cisatracurium. When she returned to the medication room, the nurse glanced at the yellow label, similar to the other labels on the antibiotics, and administered the neuromuscular blocking agent, believing it was an antibiotic. The patient experienced a respiratory arrest and required ventilation for a few hours.

Look-alike drug names

A physician prescribed vancomycin 1.5 g IV every 12 hours for a patient, which the nurse transcribed correctly onto the medication administration record. However, the pharmacist misread the faxed copy of the handwritten order and entered vecuronium into the pharmacy computer. A technician prepared the 1.5 g dose in 250 mL using 15 vials (100 mg/10 mL) of vecuronium. The checking pharmacist did not recognize the error, so the bag was dispensed to the unit. Fortunately, the technician had affixed a vivid alert sticker stating, "Neuromuscular blocker, patient must be intubated" to the bag, which the nurse noticed, thereby averting a serious medication error.

Drug administration after extubation

A ventilated ICU patient was receiving vecuronium and a potassium chloride infusion. After the patient was extubated, vecuronium was discontinued. An infusion bag containing vecuronium remained in the room and was mistaken as a potassium chloride infusion. Soon after the medication was started, the patient arrested, requiring intubation and ventilation for 6 hours.

Unlabeled syringes

Commercially prepared saline flush syringes were not available in the ED, so nurses prepared a supply of syringes each day from multiple-dose vials. Vecuronium had been prepared for a trauma patient in the ED, but it was not used. The syringe was not labeled and was inadvertently placed with the saline flush syringes. The syringe containing vecuronium was later used to flush the IV line of an alert 3-year-old child. The child became flaccid and respiratory efforts ceased. She was quickly intubated and ventilated, so permanent harm was averted.

Unsafe storage

Atracurium was administered subcutaneously instead of hepatitis B vaccine to seven infants. The infants developed respiratory distress within 30 minutes. Five infants recovered, one sustained permanent injury, and another died. Neuromuscular blocking agents had never been available as floor stock in the nursery. For convenience, an anesthesiologist from a nearby OR had placed the vial of atracurium in the unit refrigerator near vaccine vials of similar appearance.
In a pediatric ICU, a respiratory therapist obtained what he thought was a sterile water vial to prepare a nebulizer treatment. As he was piercing the stopper, he fortunately noticed that he had accidentally grabbed a vial of atracurium that someone had inadvertently returned to a respiratory box in the refrigerator. The atracurium and sterile water vials both had similar purple color accents.
Unknown to pharmacy, an anesthesiologist had ordered trial supplies of mivacurium from a drug representative. When the product was delivered to the pharmacy, it was stocked next to look-alike bags of metronidazole. Both solutions were encased in foil wrappers. Believing metronidazole was the only product in foil wrappers in the pharmacy, a technician labeled several mivacurium bags as metronidazole. The pharmacist missed the mistake and four patients received mivacurium instead of metronidazole; all experienced respiratory arrest. One patient died, another was seriously injured, and two recovered.

Inadequate knowledge of drug action

A trauma patient was admitted to the ED for stabilization before transfer to a local trauma center. The physician gave a verbal order for vecuronium and midazolam and intubated the patient after the medications had been administered. He then mistakenly entered electronic orders for these medications onto an oncology patient's record. While this patient's nurse was taking a break, an ED nurse administered the medications to the oncology patient without recognizing that vecuronium would paralyze the respiratory muscles. After she left the room, the patient arrested. The ED team responded, but the patient could not be resuscitated.
A physician prescribed NARCAN (naloxone) for a lethargic patient to reverse the effects of morphine. An ICU nurse did not recognize the drug on the automated dispensing cabinet screen because it was listed by its generic name. She intended to ask a coworker for Narcan's generic name, but she became confused and instead asked her coworker for the generic name of NORCURON. Her coworker told her that Norcuron was vecuronium, which the nurse then administered. The patient arrested, was resuscitated and placed on a ventilator, and later fully recovered.

Failure to assure ventilator support

An ED physician ordered a neuromuscular blocking agent to sedate a combative patient. However, a nurse administered the drug too soon, before the patient could be intubated. The patient arrested and suffered permanent anoxic injury.

Safe Practice Recommendation

Neuromuscular blocking agents are considered high-alert drugs because misuse can lead to catastrophic injuries or death. These drugs should be given your highest attention, just as you've done with cancer chemotherapeutic agents. To reduce the risk of harm from neuromuscular blocking agents, consider the following recommendations.

Limit access. When possible, dispense neuromuscular blocking agents from the pharmacy as prescribed for patients. Allow floor stock of these agents only in the OR, ED, and critical care units where patients can be properly ventilated and monitored.

Segregate storage. When these agents must be available as floor stock, have pharmacy assemble the vials in a sealed box with warnings affixed as noted below. Sequester the boxes in both refrigerated and non-refrigerated locations.

Warning labels. Affix fluorescent red labels that note: "Warning: Paralyzing Agent-Causes Respiratory Arrest" on each vial, syringe, bag, and storage box of neuromuscular blocking agents. Commercially available labels can be purchased from United Ad Label Co. (see photo below).

Call 1-800-992-5755 and order item # AM282. (Incidentally, neuromuscular blocking agents were available as floor stock outside the OR in 80% of hospitals that responded to the 2004 ISMP Medication Safety Self Assessment. When available outside the OR, these drugs were not sequestered from other floor stock items or labeled with auxiliary warnings by 59% of respondents.)

Safeguard storage in the pharmacy. Sequester and affix warning labels to vials of neuromuscular blocking agents stocked in the pharmacy. Be sure they do not obscure the vial label in any way.

Manufacturer warnings. Use brands of neuromuscular blockers that clearly differentiate the vials from other products via warnings on the package label, vial cap, and metal ferrule around the rubber stopper. (As of October 1, 2005, all manufacturers of these agents will be required to provide this cautionary labeling.)

Standardize prescribing. Do not accept neuromuscular blocking agent orders for "use as needed for agitation." Establish order sets to prevent misinterpretation of handwritten orders. Include the need for ventilation support during and after administration, and a protocol that stipulates automatic discontinuation of these agents after extubation and removal from a ventilator. Never accept orders to "resume the same medications" upon patient transfer.

Computer reminders. Build alerts in the pharmacy computer to verify the patient's location when neuromuscular blocking agents are entered. If the patient is not in a critical care unit, ED, OR, or invasive procedure area, question the order and verify ventilatory assistance before dispensing the drug. If possible, establish computerized crosschecking of the patient's location when entering neuromuscular blocking agents (and other drugs limited to administration on a specific unit). Cautionary messages should also appear on automated dispensing cabinet screens when applicable. A pop-up box that asks, "Is the patient being ventilated?" may also be helpful.

Redundancies. Before dispensing and administering neuromuscular blocking agents, require an independent double check of the drug against the actual order.

Supervision during initial administration. Require bedside attendance of a licensed practitioner who has experience with intubation and airway management during initial administration of a neuromuscular blocking agent.

Drug verification. Implement point-of-care bar coding to verify drugs, doses, routes of administration, and patients before administration of medications.

Prompt removal of discontinued products. Place vials, bags, and syringes of neuromuscular blocking agents in a sequestered bin for immediate pharmacy pick-up after the patient has been extubated or the drug has been discontinued.

Increase awareness. Educate staff about the risk of serious errors with these high-alert drugs. Provide staff with a list of both generic and brand names for all neuromuscular blocking agents available at your location. Also use the information above to assess your safety practices.