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Patient Safety Tip of the Week

January 26, 2021

This Freezer Accident May Cost Lives



Generally, when we talk about alarm-related incidents, we immediately think about alarms that are attached to things directly attached to patients (like ventilators, physiologic monitors, etc.). But we’ve also done several columns where it was alarms on freezers that malfunctioned or went unheeded (see, in particular, our Patient Safety Tips of the Week for February 4, 2014 “But What If the Battery Runs Low?”, May 1 2018  “Refrigerator Alarms”, and October 8, 2019 “Another Freezer Accident”).


Now there has been an incident where multiple doses of COVID-19 vaccine were lost because of a freezer malfunction. Almost 2000 COVID-19 vaccine doses were ruined when a freezer malfunctioned at the Jamaica Plain VA Medical Center in Boston (Folk 2021, Fox 2021, CBS News 2021, WBZ 2021).


As is usual in such incidents, a cascade of events led to the untoward outcome. A 6-inch chiller pipe burst and flooded pharmacy where vaccines were kept. Contractors were brought in and, while doing cleanup and abatement, pulled the freezer out and apparently pulled out the electrical plug in doing so. They presumably were unaware they had dislodged the plug. The freezer did have an alarm but, apparently, it did not work. As a result, about 1900 doses of Moderna COVID-19 vaccine were compromised and are no longer viable. (The WBZ link (WBZ 2021) has a video which shows the freezer and both the electrical plug and the alarm setup.)


The VA hospital has since fixed the alarm but is looking for root causes. They rewired and reactivated the alarm and added a bracket to the electrical plug to prevent it from being inadvertently pulled out. They also have staff now checking on the freezer every hour.


While the supply of COVID-19 vaccines may be replenished at that particular facility, it means that there are 1900 fewer doses available to the US system as a whole, at a time when there is a critical shortage of vaccine doses. Both Moderna and Pfizer-BioNTech's COVID-19 vaccines require extremely cold temperatures for storage. Temperature issues have caused problems for vaccine rollouts in other states. Recently, health officials in Maine and Michigan said more than 16,000 doses spoiled because of temperature control problems during delivery and would probably have to be disposed of. Nearly 12,000 Moderna doses that were being shipped to Michigan also were spoiled after getting too cold. And, in Wisconsin, a pharmacist was charged with deliberately ruining hundreds of doses by removing them from refrigeration.


Our prior columns discussed incidents where freezer alarm issues led to loss of stem cells for pediatric cancer patients, embryos in fertility clinics, blood products, and orthopedic implants.


Though we don’t know full details about the current Boston incident, there are multiple lessons from the other incidents and several may be applicable to the Boston incident.


One important observation from other incidents worth reiterating is that periods around maintenance of equipment are vulnerable times. We discussed this in our August 7, 2007 Patient Safety Tip of the Week “Role of Maintenance in Incidents”, in which we discussed the excellent work of James Reason and Alan Hobbs plus that of Don Norman. In one of the fertility clinic incidents mentioned previously, maintenance issues may have played a role. Also, in our March 5, 2007 Patient Safety Tip of the Week “Disabled Alarms” and several other columns on alarms, we noted instances where the oxygen blender alarms on ventilators had been disabled during maintenance and were not corrected prior to use in patients. The current incident obviously occurred following maintenance for the burst chiller pipe and consequent flooding. When maintenance is done on any equipment, we recommend staff doing maintenance have a checklist to remind them of things they must do. And one of those items would be to restore any alarms they might have disabled during the maintenance. Don’t expect your outside contractors who come in to clean up after flooding to be aware of the nuances of your healthcare operation. They are there to mop up and disinfect and likely have not been trained about potential dangers to your equipment. Therefore, your internal staff responsible for the area where the maintenance is done also need to inspect all critical pieces of equipment and their electrical connections and any associated alarms.


The alarm then failed to either detect the rise in temperature or failed to trigger an alert that would have summoned attention to the freezer. We do not know details about the particular alarm used there. Some freezer alarms are wired, and others are not wired (they often use WiFi). Some may run on AC electrical power, but others are battery operated. Either of the latter setups can be associated with its own problems.


It is worth repeating some of our observations and recommendations in our Patient Safety Tips of the Week for February 4, 2014 “But What If the Battery Runs Low?” and May 1, 2019 “Refrigerator Alarms”. In such cases, alarms would be set to trigger when a temperature sensor showed the freezer temperature had risen above a specified level. It should be no surprise that a freezer might fail or that a sensor might fail. So, you have to make sure your alarm will trigger when the freezer fails and that the alarm will trigger if the sensor were to fail or become disconnected. That calls for redundancy and backup systems.


The technology is available to indicate a sensor malfunction or disconnection. We get a “your motion camera has been disconnected” message by email and text message every time our motion detection camera gets disconnected from our WiFi system. We would assume similar capabilities should exist to alert someone when a freezer alarm system has been disconnected (but keep in mind there could also be an event that disables both your refrigerator alarm and your WiFi system).


In many cases, the alarm system is battery-powered. How do you know the alarm is powered and active?  In our February 4, 2014 Patient Safety Tip of the Week “But What If the Battery Runs Low?” we gave the following anecdote: You have an alarm that responds to the temperature in a refrigerator dropping below a set value to protect against loss of the medical products inside. You took great care to make sure the thermometer was not on the same electrical supply as the refrigerator. However, the battery on the thermometer had not been checked recently and had no charge when the refrigerator actually lost power. All the medical products in the refrigerator are lost. The smoke detector or carbon monoxide detector in your home has a button you press that indicates the alarm is functional. Is there a similar capability on these freezer alarms? More importantly, is there a visual indicator of remaining battery capacity on such alarms? And then, do you have a protocol that requires someone to check that battery level every day?


What if your alarm is supplied by AC electrical current? Since an electrical failure could affect power to both the refrigerator and the alarm system, you probably don’t want both on the same circuit. We’ve previously discussed incidents where physiologic alarms were attached to the same electrical outlets as ventilators and when a circuit breaker tripped, removing power from the ventilator, the alarms also failed because their power had been cut off (see, for example, our September 15, 2020 Patient Safety Tip of the Week “An Eerily Familiar Incident”).


We don’t know whether the alarm in question actually failed to alarm or whether its alarm failed to trigger a response. So, let’s discuss the notification and response limbs of the alarm process. You can bet that an event might take place at a time when there is no one physically working near the freezer who might hear an audible alarm (did staff avoid working near this area because of the flooding?). So, you need to route the alarm to someone physically able to respond in a timely fashion. You’d expect this freezer alarm to notify pharmacy staff first. But what if that pharmacy is not staffed 24x7? In most hospitals, that “after hours” alert would probably go to the on-duty nursing supervisor, though it could also be someone in your 24x7 security department. They might be notified by a text message alert or other means, but you’ll also have to regularly test that such linkage is working. But now you need to make sure the person receiving the alert knows how to respond. There should be a checklist and set of instructions informing the person responding to the alarm what to do. Probably the best place to put this is right on the freezer unit. You don’t want to bury it in a thick policy manual where the respondent may not even find it in a timely fashion.


You also want to make sure that you have an appropriate “escalation” practice (i.e. who to call next if the first person called fails to respond in a timely fashion). While we have such escalation procedures in place for clinical staff, many facilities are less deliberate with regard to non-clinical staff escalation procedures.


Hopefully, the Jamaica Plain VA Medical Center will publish (or otherwise make available) the results of their root cause analysis (RCA) so that others may learn from this incident. The Boston incident already has highlighted one intervention most facilities should consider. That has to do with the ease with which an electrical plug can be dislodged when the freezer is moved for whatever reason. They installed a bracket to make it difficult for such dislodgement to occur when the freezer is moved.


It’s important to pay attention to safety issues regarding your freezers and refrigerators. They are usually being used to store items that are important for patient care. You need to ensure that they have all the protections that you would use if you were dealing with equipment directly attached to patients. The Boston incident is unfortunate but there are lessons that could (and should) help other hospitals and healthcare facilities from experiencing similar incidents.


Your facility probably has some refrigerators or freezer units that store important blood or tissue specimens or vaccines (we also know your IT server farm relies on optimal temperature ranges and could be vulnerable to similar alarm-related issues). But how many of you have ever questioned what would happen if there was an alarm malfunction in one of these units? Have you done a FMEA (failure mode and effects analysis) of such alarm systems? Do you look at these alarms when you are doing Patient Safety Walk Rounds? Are the appropriate people alerted when these alarms are triggered? Do those people know how to respond when such alarms trigger? Is there a checklist that helps responders take all necessary steps when such an alarm triggers? Do you know how such alarms are powered and what the impact of a power failure or battery failure might be? Do you have backup systems in place? If the alarm uses WiFi, what would happen if your facility WiFi system is down?


So, what should you be doing?



When we see an incident like this, you should be saying “Wow! I bet that could occur here! Far better to learn from incidents that occurred elsewhere rather than waiting to do a root cause analysis (RCA) on one that occurs in your own facility.



Prior Patient Safety Tips of the Week pertaining to alarm-related issues:







Folk Z. Nearly 2,000 COVID-19 vaccines spoiled after Boston VA cleaner accidentally unplugs freezer. NY Post 2021; January 22, 2021



Fox JC. COVID-19 vaccine doses spoiled at Jamaica Plain VA facility. Boston Globe 2021; ,Updated January 21, 2021



CBS News. 1,900 COVID vaccine doses ruined at Boston VA hospital after freezer accidentally unplugged. CBS News 2021; January 22, 2021



WBZ (Boston). Investigation Underway After COVID Vaccines Compromised At VA Hospital. January 22, 2021






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