To patch pump or not to patch pump? That is the question…

Ever since the Omnipod appeared, the question over what type of pump to use has been a constant question from both new users and those coming to the end of a contract.

The patch pump appears to offer an all in one device that can be applied and removed every three days with no external, fiddly, surface catching tubes and a much simpler set up all round.

The traditional style of pump typically provides a larger reservoir and wider variety of cannulas to optimise the human/pump interface.

While I acknowledge that there is no 100% correct answer, here are a few of my thoughts after using both pump types. And it’s perhaps a little more nuanced than we generally consider.

I’m going to look at this in four areas that I think encompass the key aspects from my experience.

• Maintenance
• Cannulae
• Physical factors
• Continuity planning

Let’s kick this off…

Maintenance

Maintenance is the day to day management of the pump (not the user interface or the ability to deliver insulin). Things like filling, changing components and their lifespan, etc.

Lifespan of consumables

On a patch pump, officially at least, you use the pump for three days then bin it. All self contained and very easy. However, if you use either a lot of insulin, or very little insulin, you may find you leave some in the pump or have to change more frequently, dependent on the reservoir size of the pump.

On the other hand, with a tubed pump, each of the cannula, reservoir and tube are separate components. As separate items it means you don’t need to consistently change them all together. The manufacturer stated 3 day change over is as much (in my view) a revenue generator as it is derived from clinical need.

Let’s look at why.

Tubes: Many manufacturers ship these separately from the cannula. Why? Because they last a lot longer than three days with no issues and it’s far more convenient not to have to change them every time you do a set change.

Reservoirs: The primary concern with reservoirs is insulin degradation and plastic contamination. There are multiple examples in literature where this has been tested extensively and been found that in plastic syringe-type reservoirs, 7 day life is perfectly reasonable. Aspart/Novolog/Novorapid and Lispro/Humalog can be found by following these links.

In glass reservoirs, in theory, it should be even longer (given we normally store insulin in glass). This allows for a change to be just the cannula, with other components potentially done less frequently.

While for some, changing everything every three days makes for a straightforward routine that’s easy to manage, for others, the level of flexibility that individual components allows is helpful, and not having to refill a reservoir every three days may also be beneficial.

Filling the pump

Typically, you need a syringe of some sort to fill a patch pump through a small hole in the base of the pump, as shown in this shot of the Omnipod manual.

For most people, this way of filling a patch pump isn’t going to cause too many issues, however, if you have sight or mobility issues with your hands, it may be more difficult than some of the mechanisms provided for filling a reservoir in a tubed pump.

Reservoirs in tubed pumps are typically the equivalent of a syringe (except for those from Tandem) without a needle and a detachable plunger arm. They have a snap on filling guide that makes loading easy, as shown in the following Medtronic image.

For many this isn’t a big thing, however, it might make a difference in certain circumstances.

Beyond these two items, I think you’re perhaps more into some of the other things I identified in the introduction, but I think the flexibility of a tubed pump (whether it’s tiny like a Mobi or more like an Ypsopump) is often massively under-realised by prospective users.

Cannulae

Let’s be honest, this is the weak point in the Patch pump. If you want one then you have to go with one cannula. There are no options.

If you’ve never tried another type, you’d never know whether they might work better for you.

So if you’ve used the Omnipod from day one and had concerns over tunneling, insulin leakage, etc, and still have those even with the tegaderm/flexifix fix, but don’t want to use a tubed pump, then it’s a bit tough. Similarly, if you find you get day 1 high insulin usage, there’s not much you can do, other than change pump system.

If you use a tubed pump then there is normally a range of cannulae, in terms of material, length and angle. You should be able to try all of them and see which works best for you, or more importantly, if one doesn’t work, there are alternatives.

Physical factors

There are three areas to think about in the physical factors topic.

• Control
• Visibility
• Everything else

That last one seems like a huge topic, but it will make sense when we get to it.

Control

To use a patch pump, you need a device to send instructions to it. Whether that’s a phone app or a handheld device will depend where you are and what pumps are available. Omnipod and Medtrum have both available, but not in all locations.

If you need to take an extra device, then without it, you’re stuffed for meals. It has to become part of your daily pack. If it’s on your phone, you’re guaranteed to need a power pack to ensure that you’ve always got “control juice”.

If you’re using a regular pump, you can always revert to the pump to control things, without needing to use the app provided by many manufacturers, that again depends on jurisdiction.

Ultimately, with the tubed pump, in general you’re less likely to have an issue if you forget a handset, or your phone dies.

Visibility

Here’s where patch pumps generally have the greatest benefits. They can be placed somewhere out of sight and there’s no tube to hide, and no need for easy access to give a bolus. In this respect, except for the tubed pumps with apps, the patch pumps generally win easily.

Having said that, when an Omnipod goes wrong, you and everyone else know about it. They’re called screamers for a reason. With most tubed pumps, you can turn the noise off. With a pod, you need to remove it and depress the correct button, or destroy it with a hammer. This can be a little disconcerting if you’re in a packed theatre!

Everything else

First up, what is everything else? It’s a catch all for the various aspects of physical differences that are hard to categorise.

• You will never catch the tube on a door handle and rip the cannula out with a patch pump. On the other hand, you might damage the patch pump andove the cannula by bashing it against something hard.
• When you’re in bed, you can push the tubed pump out of rolling range and you won’t lie on it. With the patch pump in certain places, it may wake you in the night when you lie on it.
• Depending on where your patch pump is, you may need to get creative during sex to make your partner comfortable, whereas you can remove the lumpy bits of the tubed pump.
• Festival toilets where you don’t want the risk of dropping the pump somewhere unspeakable. You may need to detach a tube and store the pump safely with a tubed pump. This simply isn’t an issue with the patched pump.
• When you’re playing certain sports, something hard hitting a patch pump potentially causes damage, where a tubed pump might be removed and leave only the cannula. Conversely, with watersports, the patch could remain in place where you might remove the tubed pump.
• If you have a largish dog, and they jump.at you, they will either damage the tube or rip the patch pump.off. It’s evens on that front. A cat, on the other hand, can’t chew through the tube of a patch pump…

I’m sure the list goes on. That’s a short list of examples that I can recall that have happened to me. Some of those may be more problematic for some people than others…

Continuity Planning

Whilst in both cases, the ultimate plan is spare insulin and pens/syringes, for each type of pump specifically, there are notable differences.

We’ve already mentioned that for any type of app or handheld device you need to ensure you can manage either without the device or maintain charge for the phone the app comes on.

But what about unexpected pump failure. What do you do?

The simple answer is “Carry spares”.

So what does that look like?

As the picture shows, it’s a lot easier with the patch pump as there’s a lot less to carry.

However, with most pumps, you could argue that the only spare you need is a syringe or two.

Pumps carry their own insulin supply, so in the worst case scenario you should be able to extract it from the pump and inject it periodically to avoid dangerously high glucose levels until you can replace the pump/cannula/reservoir/tube.

What are your takeaways from this?

There are both pros and cons to both types of pump. Proponents of one type will always tell you they are better than the other.

The real takeaway is that which type you might choose is much more nuanced. And until you’ve tried both, you really won’t know which you prefer and why.

Unfortunately, with the model that we have in place in most countries, where there is a four year contract paid for by the medical payment system, the ability to try different options is especially difficult with tubed pumps, due to the upfront cost of these devices.

As a result of the above, I’d always seek out options for trying a patch pump before making a choice. In many places, you can get a free trial of some of the offerings and even if you don’t like them, it can help with making a decision.

Once you’ve got your system though, I’m sure you’ll be happier with the outcomes, and if it’s an AID based system, relieved at the peace of mind.