Another Pump Issue – This time it Animas
Yesterday Animas, a unit of Johnson and Johnson (NYSE:JNJ), sent out a letter to that stated: “We have learned of several cases in which pumpers have accidentally delivered excessive insulin when they ignored pump warnings and did not disconnect from their infusion set before loading the pump cartridge. In each of these cases, the pump had been damaged. Because of this damage, the pump delivered the whole cartridge of insulin during the “load cartridge” step of the priming sequence.”
According to company officials this issue only occurs when the pump has somehow been damaged and has only occurred in handful of cases. When Diabetic Investor looked through the FDA’s MAUDE database we could only find two reports which addressed this issue. Thankfully there have been no deaths associated with this issue and Animas is taking the proper steps to inform their patients.
The strange part about all this is the Animas 2020 pump has several warning screens telling the patient to disconnect from their infusion set when they are replacing the insulin cartridge. The issue becomes even stranger as Animas provides patients with 6 hours of pump training from a certified pump trainer and both the trainer and patient must sign off that the trainer has been completed. Looking over the Animas Pump Training Checklist, under the section Safety Systems and Alarms it specifically covers the procedure for disconnecting when priming. Simply put disconnecting while priming is pump training 101.
The one possible issue here the company may have to address are the fail safe systems built into the pump. Being a medical device an insulin pump is not unlike a computer where the software that runs the pumps monitors the pump itself. This is not unlike when a person starts their car and the car’s computer checks the engine, braking system, oil level, etc. If any issue occurs a warning light comes on informing the driver there may be an issue with their car. It is then up to the driver to investigate this possible issue.
An insulin pump is really no different, the software monitors the hardware. Without getting overly technical when a pump patient loads a new insulin cartridge they typically take the following steps:
1. Disconnect the pump from the infusion set.
2. Fill a new insulin cartridge.
3. The new insulin cartridge is placed in the pump and the plunger/piston that pushes the insulin from the cartridge through the tubing moves into position. Most pumps are designed with sensors that detect when the plunger/piston feels pressure and is therefore delivering insulin to the tubing. Or put another way, the pump knows when a cartridge is in place.
4. The patient waits until they see drops of insulin coming through the infusion set, reconnects the set to their body and starts pumping.
While it may be overly obvious the reason patients are instructed to disconnect while priming is to avoid the possibility of delivering too much insulin, which as we all know could lead to a hypoglycemic event; a potentially serious, possibly life threatening event.
Given the explanation given by Animas that this issue only occurs when the pump has somehow been damaged, Diabetic Investor believes that this damage somehow renders the sensor which is supposed to detect when a cartridge is in place, inoperable. Therefore the plunger/piston does not detect the cartridge and continues to move forward pushing more and more insulin into the infusion set. This isn’t a problem when the infusion set is not attached to the body but a major problem when it is attached to the body.
What Diabetic Investor does not understand is why a fail-safe system is not built into the pump that would prevent this issue from occurring. Should the system fail to detect that a cartridge is in place it would not allow the plunger/piston to move forward. Simply put the system would shut down and not allow insulin to be delivered. As we are seeing here, even with the many warnings screens and extensive training received by the patient, the patient is not protected when their pump is damaged. Based on the letter Animas sent it seems quite possible that patient would be unaware their pump is damaged.
This is not the first time this issue has occurred. Some may recall when Medtronic (NYSE:MDT) experienced a similar issue when their pumps where in close proximity to an MRI. While it should seem like a no-brainer that a patient should not wear their pump during an MRI or that the personal performing the MRI would tell the patient to disconnect before the procedure; the issue did occur. Like Animas, Medtronic clearly warned patients not to wear their pump during an MRI in the pump manual. But just as Animas had to send a letter so did Medtronic, basically reinforcing the message to disconnect before undergoing an MRI procedure. Medtronic took the additional step of sending out warning labels that could placed on the pump telling both the patient and MRI staff to disconnect prior to this procedure.
Back when this MRI issue came to light Diabetic Investor checked with several pump manufacturers who indicated that they built in fail-safe systems so that their pumps would not automatically deliver insulin without being instructed to do so by the patient. It’s important to note that when a pump is working properly the pump will not deliver additional insulin until instructed to do so by the patient. While the pump is continually delivering insulin (this is called the basal rate), additional insulin is delivered at mealtimes or when the patients glucose levels are out of the target range (this is called bolus). Simply put some pumps have built in systems that will not allow the patient to bolus unless instructed to do so, if the system detects that a non-instructed bolus it automatically shuts down to prevent the possibility of the over delivery of insulin.
The question here is why the Animas pumps do not have such a system. Speaking with the manufacturers who do have such a system their rationale is simple; better safe than sorry. They realize while the patient needs insulin, if the pump is somehow malfunctioning the patient does have other insulin delivery options. In fact it is not unusual for an insulin pump patient to carry with them syringes to protect them should their pump malfunction. Experienced pump patients and pump trainers know that the pump is still a machine and machines sometimes breakdown.
Diabetic Investor does not believe this is an overly serious issue for Animas. Furthermore the company should be commended for taking quick and decisive action once they discovered the problem. It should also be noted that several events need to occur in succession for this problem to surface. We do however believe that steps should be taken to insure events such as these do not occur in the future. Frankly, fail-safe systems should be built into every insulin pump.
Finally we cannot leave this issue without, once again, reiterating that situations such as these only reinforces our view that a true closed-loop insulin deliver system will be difficult to achieve. Once the patient is taken out of the loop all it takes is one break in the chain for a major problem to occur. This is perhaps the most misunderstood aspect of those who advocate the development of a closed-loop system. It’s not that Diabetic Investor believes that a closed-loop system is bad for the patient, quite the contrary. However, the fact is a closed loop system involves a series of systems working in concert, working properly 100% of the time. The fact is machines malfunction and insulin is a dangerous drug.
As Diabetic Investor pointed earlier today last year alone there were 136 deaths associated with insulin pump usage. Already this year from January 1 through February 27th, we have seen another 24 deaths associated with insulin pumps. While it would irresponsible to blame each and every death on the pump and it would be equally irresponsible to state that insulin pump therapy should not be used. There are numerous studies that prove the benefits of insulin pump therapy. However, when it comes to insulin delivery it is dangerous to believe that any machine or in reality a series of machines, will function 100% of the time without the possibility for malfunction.
Diabetic Investor strongly supports giving patient’s better tools to manage their diabetes and we also believe there are many advantages of a semi-closed loop insulin delivery system, provided it is the patient who is in control of when and how much insulin is delivered. Or as Havelock Ellis put it; “The greatest task before civilization at present is to make machines what they ought to be, the slaves, instead of the masters of men.”
