My last post talked about how we made the decision to get Miss Chief an insulin pump, rather than multiple daily injections, and this week sees the end of a long wait - we get our pump on Thursday!
But what exactly is a pump, how does it differ from injections and what's the big deal?
What is an insulin pump? As our educator puts it, pumping is just a posh way of delivering insulin. It connects to the body via an infusion set, which consists of tubing plus a cannula. The cannula is either a flexible Teflon needle or a firm stainless steel needle, with an adhesive patch and a plastic connector. The cannula goes into the skin anywhere you would normally inject. Insulin is always injected subcutaneously, i.e. just under the skin, and not intramuscularly and once the cannula is in you can barely feel it. The adhesive dressing secures the plastic connector in place and this is what the tubing is attached to. Tubing, and therefore the pump, can be disconnected and a small plastic plug put in its place, during certain activities, such as playing on the beach, or contact sports. The other end of the tubing connects to a cartridge of insulin which screws into the pump. The pump itself is about the size of two old cassettes, or just larger than a mini-disc player. Or in today's terms, a slightly shorter, thicker smartphone. Maybe if you cut your phone in half and put the 2 pieces back to back you'd be getting close to the right size and shape. It can be clipped onto your waist band, worn in a Lycra band against the skin under the clothes, or carried in a bum-bag style pouch over the clothes.
A steel cannula and infusion set
Steel cannulas are literally just pushed into the skin. Some come with an extra adhesive patch, called an anchor, connected via a short bit of tubing to the cannula. The main tubing then connects to the anchor. This prevents pulling on the needle if the pump is knocked or dropped. Teflon cannulas, being flexible, require insertion via a larger introducer needle and generally come with an automated insertion device. You spring load the housing, place it on the skin and squeeze the sides. The device is released and shoots the needle into the skin super quick. You then remove the housing, including the introducer needle and all that remains is the plastic cannula with its adhesive patch and plastic connector. In my limited experience these flexible needles are more comfortable. They can also be left in for longer - 3 days as opposed to 2 for the steel. They are prone to kinks, however, which can disrupt the flow of insulin. In an attempt to get Chief to have a needle in her tummy rather than her buttocks I made up a rule that Teflon cannulas go in the tummy and steel ones in the bottom. Despite the fact that the connector for the Teflon infusion set comes in a rather fetching pink, Miss Chief is adamant that she will only use steel.
How does it work? The pump uses only rapid acting insulin. You set up a basal rate and it delivers tiny amounts of insulin more or less constantly. Chief's starting basal rate is 0.2 units per hour. As a comparison she currently has 2.5 units of long-acting insulin twice a day. In addition to this, during set up you tell the pump how much insulin you think is required to bring her blood glucose levels down a certain number of mmol/l (correction factor) and how much is required to cover grams of carbs (insulin to carb ratio). Each time you check a BGL you enter it into the pump and it uses these settings to calculate whether a correction is required. If eating, you also enter the grams of carbs and the pump will include this in its calculations.
Pump with infusion set connected
Why do we want one? The insulin regime with a pump is very similar to the multiple daily injection (MDI) basal-bolus regime Chief is currently on but with what we perceive will be the following benefits:
Fewer needles: 1 every 2-3 days instead of 10-15.
Easier and more frequent corrections, especially overnight as it doesn't mean an extra needle. Hopefully this means less disturbed sleep patterns for the Chief too.
Smaller more accurate doses of insulin. Currently, we often have to decide between giving her very low carb snacks, an extra needle (which may require more carbs than we would ideally give in order to match the lowest possible insulin dose), or allowing her glucose levels to ride a little higher than desired until the next needle. The pump should remove this Sophie's Choice. Additionally, as the insulin is infused via a needle that remains under the skin she should get the entirety of doses; currently we find drops of insulin on the end of the needle and on her skin and we're never entirely sure exactly how much insulin she's had.
Having the pump calculate doses instead of us, saving us much time. We'll still need to measure BGLs and count carbs but won't need to worry about calculating doses. There are smart phone apps that will do this for you too but as we knew we were moving to a pump we never bothered buying and setting one up.
More accurate basal dosing as amounts can be temporarily increased or lowered according to needs, rather than staying in the system for 14-24 hours, which tends to lead to more conservative doses.
More flexibility with food amounts. Instead of having to guess how much Chief might want to eat before a meal we can input any extra food she ends up eating afterwards. Or if she is high before a meal we can correct the BG, plus give a small amount for food, adding the remaining amount after the meal according to what she has eaten.
Fewer hypos followed by highs when eating low GI food such as pasta. The pump has various options for delivering bolus (or mealtime) insulin doses. For example, you can opt to give a portion of your insulin with your meal, and then gradually deliver the rest over the next few hours without any extra needles.
More freedom with food at afternoon tea. Currently Chief is limited to extremely low carb meals at afternoon tea because by this time she is all out of lunchtime insulin. On special occasions, such as birthdays she will have an extra needle in order to enjoy some cake but most days if she has anything much more than 5g carbs without a needle she will have slightly elevated levels. Usually it's not enough to worry about but you wouldn't want to do it every day. On the pump she can have carbs if she wants with no extra needles.
There are downsides to using the pump too. For example, because there is no long lasting insulin in use, should anything go wrong with the pump you have an increased chance of elevated ketones due to not receiving insulin over an extended period of time. Therefore frequent testing is more important on a pump, particularly at night. We test 8-10 times a day anyway, and most nights, so it isn't much of a change for us. Some people experience kinks in the flexible cannulas. When high levels are noticed on a pump there is an added element of confusion in first determining whether there is a kink in the cannula or air bubbles in the line. There is the inconvenience of having to carry the pump around everywhere and remembering to reconnect if you remove it to take a bath. Also pumping is more expensive. Whilst our private health insurance will cover the cost of the pump, we need to pay a fee, albeit subsidised, for cartridges and infusion sets costing approximately $30 a month. It's more stuff to store in the cupboard. And yet we still need pens and needle tips as back up in case anything goes wrong with the pump.
I am pleased to have had the last 6 months learning the ropes with MDI though. It has taught me a lot about diabetes and how to manage it and helped immensely with preparation for the pump. I feel comforted that at any time we can ditch the pump and return to needles, be it for a day, a week or longer and we have the confidence to do that.
Whilst I am extremely excited about this new phase in our diabetes journey I would like to point out that pumping isn't for everyone, and that's fine. There is no perfect solution that doesn't involve a working pancreas and it is perfectly possible to get excellent control on MDI. I have an amazing friend who does just that and we have been slowly getting better at it, resulting in much better behaviour from the Chief. I have even been tempted to think that pumping is a lazy way of dealing with diabetes. But at the end of the day diabetes is hard work, no matter how you manage it. And when you have other children, a house and a career to manage too then why not make life a bit simpler if you can. Pumping may not be the simple solution for everyone but I'm hoping it will be for us.