Patient Safety Tip of the Week

February 7, 2012

Another Neuromuscular Blocking Agent Incident



In our January 31, 2012 Patient Safety Tip of the Week Medication Safety in the OR” we mentioned neuromuscular blocking agents (NMBA’s) as being high-alert medications in the OR. Most hospitals keep NMBA’s on their list of high-alert medications for the entire hospital but many took action steps years ago after an ISMP Safety Alert (ISMP 2005) to limit access to these drugs outside the OR and have not paid as much attention to them since. It’s been almost 5 years since we first did a column on NMBA risks (see our July 31, 2007 Patient Safety Tip of the Week “Dangers of Neuromuscular Blocking Agents” and our November 2007 What’s New in the Patient Safety World column “FMEA Related to Neuromuscular Blocking Agents”). Other than an excellent review by the Pennsylvania Patient Safety Authority in 2009 (PPSA 2009) the news and literature have been relatively quiet on NMBA’s.


But a recent incident in a hospital in Florida (ABC News 2011) has rekindled concern about NMBA’s. In the Florida case an order was written for 20 mg famotidine IV but a nurse gave by mistake 20 mg IV pancuronium. The patient subsequently became paralyzed and had a respiratory arrest. Though resuscitated, he suffered severe brain damage and eventually died. We don’t know the details of the case but apparently some safety steps such as barcoding verification, independent double checks, and monitoring were not done. In addition, the drug was available on the unit on which it was administered and perhaps should not have been (see below for recommendations about restricting access for these drugs to only certain units). The hospital apparently has subsequently removed the drugs from all areas other than the OR.


The PPSA review (PPSA 2009) noted that they had received 154 reports dealing with NMBA’s over a 5-year period. Most importantly, the percentage of cases where patient harm occurred was nearly 13 times higher than the percentage of harm seen in their overall drug-related incident database. Harm came to the patient in over 9% of cases, a figure similar to that found in a 2006 report from the MedMarx database. The vast majority of the PPSA reports involved either the wrong medication being given, i.e. an NMBA was given rather than a different intended drug, or an incorrect dose of an NMBA. Of course, the former is the most serious category because this usually involved patients who were not being mechanically ventilated and were at the greatest risk for respiratory arrest from NMBA administration.


But again – stories, not statistics! All the above statistics won’t help you remember the importance of safety regarding NMBA’s. But a few stories will!


A patient is in need of an emergency CT scan one night. There is no nurse available in the radiology suite so the ER resident accompanies the patient for the CT scan. The patient is in need of sedation for the scan and the resident inadvertently administers vecuronium IV to the patient, resulting in respiratory arrest necessitating rescuscitation.


A patient is undergoing a surgical procedure in the OR and the physician asks the CRNA to give IV antibiotic. The CRNA reaches into the anesthesia medicine drawer, where all the medications are kept, and pulls out a vial of vecuronium thinking it was the antibiotic and adds it to the IV bag. Shortly thereafter it’s noted that the patient is not breathing well and she requires intubation (PPSA 2009).


A syringe filled with an NMBA is not properly disposed of. It is later mistaken for a syringe full of normal saline and used as a saline flush on an infant who suffered a respiratory arrest as a result (ISMP 2005).


Seven infants receive subcutaneous doses of atracurium instead of hepatitis B vaccine. All developed respiratory distress. Five recovered but one suffered permanent injury and one died. An anesthesiologist had placed a vial of atracurium in the refrigerator of the nursery that had a similar appearance to vaccine vials (Koczmara 2007).


Obviously, the biggest risk of NMBA’s is in patients who are not being mechanically ventilated. There are a couple circumstances where NMBA’s may be inadvertently ordered and given in non-ventilated patients. We previously mentioned a case (see our June 19, 2007 Patient Safety Tip of the Week “Unintended Consequences of Technological Solutions”) where an unintended consequence of CPOE led to inadvertent administration of a neuromuscular blocking agent to a patient who was not being mechanically ventilated (ISMP 2007). In that case the physician was ordering from a remote site and inadvertently entered orders on the wrong patient. The other circumstance is when a patient in an ICU is extubated and weaned from a respirator and transferred to a regular floor and someone writes “continue all previous orders” not recognizing that such might include orders for NMBA’s in a now unventilated patient.


Look-alike/sound-alike (LASA) issues are root causes in many NMBA incidents. Very often the vials closely resemble vials of other more common medications and solutions. How and where drugs are stored is an important contributing factor in many of the adverse NMBA incidents. Many of the reported incidents involving NMBA’s being confused with another intended drug have involved NMBA’s that were stored in refrigerators, especially in refrigerators where such are not usually stored. The vials have been confused with vials of other substances like normal saline, heparin, and vaccines. The 2005 ISMP alert (ISMP 2005) had several examples. In one instance an anesthesiologist put a vial of an NMBA in a refrigerator on a different unit that does not usually stock NMBA’s and the vial was mistaken for hepatitis B vaccine and was inadvertently given to seven infants. In others, vials of NMBA’s looked similar to vials of either vaccines or the diluents used with those vaccines, resulting in multiple patients being exposed to the NMBA’s.


The sound-alike issues are also problematic. Norcuron (vecuronium) has been mistaken for Narcan, vecuronium for vancomycin, atracurium for Ativan, etc. In other cases, look-alike packaging has been a major contributing factor.



Limiting access to NMBA’s is arguably the most import intervention to prevent incidents. Many hospitals restrict them to the OR and pharmacy. In those areas where they might be needed emergently (eg. in the ER or ICU where they may be needed for emergent intubations) the drugs can be “sequestered” or sealed in the intubation kits so that they are available only at the time of intubation.


But while restricting access is important, keep in mind those incidents above where NMBA’s popped up in areas where they were not supposed to be. So there clearly must be other safety measures taken and you need to be ever vigilant to items showing up where they are not supposed to be.


Storage of NMBA’s in automated dispensing machines can be especially problematic. Probably most important is only storing them in areas where they are clearly needed. Where needed, they should be kept in single access drawers. But there needs to be a special warning that the NMBA should not be used in patients who are not intubated/mechanically ventilated. Such a message could be delivered in those automated systems having the capability of messaging when an NMBA is selected for removal from a drawer. Similarly, the type of CPOE error noted earlier might be avoided by programming in an alert ensuring the patient is intubated/ventilated when the physician enters an order for an NMBA.


Most important are warning labels for vials, syringes, bags, or storage boxes containing NMBA’s. Both ISMP and the PPSA recommend using fluorescent red labels that state “Warning: Paralyzing Agent – Causes Respiratory Arrest”.


The ISMP Canada review (Koczmara 2007) notes that a form of confirmation bias often is a contributing factor. Specifically, because the vials and labels may look similar to those of the “expected” medication, we tend to see what we expect to see rather than what we actually see. The phenomenon is also sometimes known as “inattentional blindness” (ISMP 2009).


Part of your medication safety program should include education and communication about NMBA’s. They should never be referred to as “muscle relaxants” and should never be allowed to be ordered on a “prn” basis (PPSA 2009). Similarly, the phrase “renew all previous orders” should never be allowed. Rather, when patients are transferred from one unit to another, the physician should write out each of the orders as if they were brand new orders. The same applies when the physician is using CPOE. While some CPOE systems have functions (or workarounds) that facilitate renewal of a large number of orders, beware that such can give rise to unintended consequences.


Prompt disposal of unused NMBA’s is also essential. Several of the previously mentioned incidents involved use of NMBA preparations that had been poorly labeled and left behind from use with one patient, then were inadvertently administered to other patients. ISMP recommends that unused NMBA’s (whether in vials, bags, or syringes) be placed in a sequestered bin for immediate pickup by pharmacy


Obviously, use of traditional medication safety measures, such as barcoding, are important and NMBA’s, being high-alert drugs, should require independent double checks before being dispensed and before being administered.


Lastly, you may find 2 other resources on NMBA’s helpful. In our July 31, 2007 Patient Safety Tip of the Week “Dangers of Neuromuscular Blocking Agents” we recommended this is a good issue to address in FMEA (Failure Mode and Effects Analysis) in your organization. Susan Paparella (Paparella 2007), from ISMP, did exactly that in the Journal of Emergency Nursing (see our November 2007 What’s New in the Patient Safety World column “FMEA Related to Neuromuscular Blocking Agents”). The ED staff had recognized NMBA’s as high-alert drugs and were contemplating their removal from ED stores, to be replaced in kits prepared for rapid-sequence intubation. FMEA is especially useful in such situations where change is to take place, because it helps identify potential unintended consequences. The article nicely describes how you do a FMEA exercise and provides examples for scoring probability and severity and use of a hazard scoring matrix. Lastly, one of the AHRQ M&M Conference cases (Weinger 2003) on an NMBA incident had 2 terrific downloadable videos addressing some of the communications issues in that case. It is well worth reading and watching the videos.


Again, consider adding NMBA Safety to your list of things you look for in your Patient Safety Walk Rounds and consider doing a FMEA on NMBA use in your organization.



Update: See our December 9, 2014 Patient Safety Tip of the Week “More Trouble with NMBA’s






ISMP (Institute for Safe Medication Practices). Paralyzed by mistakes. Preventing errors with neuromuscular blocking agents. ISMP Medication Safety Alert Acute Care Edition 2005;  September 22, 2005 issue



PPSA (Pennsylvania Patient Safety Authority). Patient Safety Advisory.

Neuromuscular Blocking Agents: Reducing Associated Wrong-Drug Errors

Pa Patient Saf Advis 2009; 6(4): 109-14.



ABC News (Caron C.) Nurse Gives Patient Paralytic Instead of Antacid. November 21, 2011



Koczmara C, Jelincic V. Neuromuscular blocking agents: Enhancing safety by reducing the risk of accidental administration. ISMP Canada 2007 in the Spring 2007 publication of the Canadian Association of Critical Care Nurses (CACCN).



ISMP (Institute for Safe Medication Practices). Remote CPOE error-a situation that's more than remotely possible. ISMP Medication Safety Alert Acute Care Edition 2007; May 31, 2007



ISMP (Institute for Safe Medication Practices). Inattentional blindness: What captures your attention?  ISMP Medication Safety Alert Acute Care Edition 2009; February 26, 2009



Paparella, Susan RN, MSN Failure Mode and Effects Analysis: A Useful Tool for Risk Identification and Injury Prevention. Journal of Emergency Nursing. 33(4):367-371, August 2007



Weinger MB, Blike GT. Intubation Mishap. AHRQ Web M&M. September 2003














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