When the pump quits and the sensor lies: trusting tech that sometimes fails

For everything pumps and sensors have done to make life with Type 1 easier, they are still machines, and machines pick their moments. A pump that quietly stops in the night. A sensor shrieking that you are low when you feel perfectly fine. The frustration and the fear these cause are completely real, and Type 1 communities are full of the stories, from “insulin pump horror stories” threads to the blunt “Dexcom is evil” vent. What stops a device failure turning into a genuine emergency is rarely luck. It is a backup plan put in place before anything goes wrong.

The particular dread of being let down by your kit

There is a specific kind of anger that comes from trusting a device with your safety and having it fail. People describe lying awake furious at a sensor, or shaken after a pump problem sent them somewhere dangerous. If you have felt that, you are not being dramatic and you are not alone; it is one of the most relatable experiences in the whole community. Naming it honestly matters, because the fear is what pushes people to build the safety net that follows.

Why a pump stopping is urgent, not just annoying

This is the part worth understanding clearly. A pump only ever delivers rapid-acting insulin, in tiny amounts through the day. It carries no long-acting reserve, so if the tubing or cannula blocks (an occlusion) or the pump fails, your insulin supply can stop within the hour with nothing holding your glucose down. Levels climb, and because there is now almost no insulin on board, the body starts breaking down fat and producing ketones, which are acids that build up in the blood. This can tip into DKA (diabetic ketoacidosis), and it can develop within hours, including overnight while you sleep.

The red flags that mean an emergency are worth knowing by heart: being sick, feeling drowsy, breathing heavily or fast, stomach pain, and breath that smells fruity or like pear drops, alongside a high glucose. If those are there, that is 999 or A&E straight away, and checking a number must never delay the call. Short of that, if your glucose is high and you feel unwell, check for ketones (blood or urine) and contact your diabetes team or NHS 111. A high ketone result is itself a reason to seek urgent help quickly.

Why the community never fully trusts the sensor

The other half of the story is the sensor that lies. A common cause is a compression low, where lying on the sensor squashes the tissue underneath and it reports a low that is not real, which is why people wake to an alarm and feel completely fine. Sensors can also read off for the first day after going on, and they can occasionally just be wildly wrong. The rule people live by is simple: if the number does not match how you feel, or you are about to act on it in a big way, treat a low, correct a high, get behind the wheel, confirm it with a finger-prick blood test first. A meter check takes a minute and settles the argument.

The backup kit that turns a disaster into an inconvenience

The stories almost always end the same way: the people who came through a device failure calmly were the ones who had backups within reach. What the community keeps stocked, at home and out and about, tends to be the same short list:

• Insulin pens as a fallback, so you can inject if the pump is out of action
• A finger-prick meter and spare strips, because a sensor you cannot trust needs a second opinion
• Ketone testing (strips or a meter) for exactly the situation above
• Spare fast-acting sugar, plus spare infusion sets and sensors

Set the plan up before you need it

The single most useful thing is to ask your diabetes team, at a calm appointment, for a written pump-failure and sick-day plan: how to switch to injections if your pump dies, and what to do as ketones rise. That plan is worked out with you in advance, so a 2am failure becomes a set of steps you already have rather than a panic. Keep the backup kit somewhere you will actually find it half asleep. The tech is genuinely brilliant most of the time; the plan is simply what you reach for on the rare day it is not.