Distance between PDM and pod?

Can anyone expand a bit about the distance between the pod and the controlling pdm? I know they state 5 feet? That is a really short distance. I have had my pdm downstairs and myself upstairs in bed overnight with no issues, although I was lucky in that my programming didn’t really change during those hours, meaning my basal rate was the same… can I assume that as long as I don’t need a bolus or a change to the basal rate, that I can be a bit distant from the pdm?

Any info that you may have to truly expand on this would be helpful.

You only need to be within 5 feet when you are telling it what to do. Once the pod is told what to do you can be as far away from the PDM as you want.

The PDM proximity only comes into play when you need a bolus. Basal rates operate automatically without input from the PDM. Sometimes I leave the PDM at home when I am going to be out for short periods and know I won't need a bolus.

All the info re: basal rates, carb/insulin ratios, etc. are downloadid into the pod itself during the priming process, so as Tracy Sue and Jim say, unless you need a bolus (or a bg check) it doesnt matter how far away you get! Good luck and PEACE.

I agree w/ Steve and the others. You bolus w/ the PDM. You make temporary basal adjustments (such as decreased basal for exercise) with the PDM.

Otherwise you do not need the PDM near the pod to have it go through your normally programmed basal layout throughout the day, etc.

Great, the sure alleviates some fears I had with this thing. I hate being tied to anything… no beeper (do folks remember what those were?) no cell phone, etc. So being tied to the pdm is a drag to me. However, having said that, having the pdm around has made things quite a bit easier.

No cell phone?! O_O Seriously, I agree, these little pods are WAY better than MDI.

I remember those days :)

I still wish they'd get over the false need for security and allow the pods to be controlled by cell phone though. That way I'd only have one device to haul around. Oh well.

I'm not sure that will ever get by the FDA. Too many variables for an essential medical device that could actually kill you if it malfunctioned.

It would also download parameter changes to the pod when they are made. Ie, when you change a basil rate or other I/C type parameter, it would have to save them and download the new values immediately. I assume thats why you need to suspend insulin delivery while making these types of changes, then resume it afterwards to have the values take effect on the pod. I agree with leaving the PDM - I often leave it at home if I go for a motorcycle ride or go to the store - when I know I won’t need to bolus.

The distance varies according to what you are doing.

When activating a new pod the PDM has to be within something like 12 inches of the pod, with nothing substantial in the way (this is based on my own experience.)

At other times 6 feet/2 metres is an upper limit on the distance, based on my own tests. That distance only works if there is no intervening object (including my own body). Even then I believe the distance may depend on the relative orientation of the PDM and the pod; I sometimes get "communication failure" over distances as little as 3 feet with, apparently, direct line of sight between the two.

The PDM *only* communicates when it is doing a status update and when something has been confirmed. This can be shown by using a scanner to monitor the frequency that is used.

I believe the words "confirm" and "status" are the keys to knowing that the PDM is about to communicate, as well as the initial status update when it is turned on. It doesn't emit radiation at any other time (so far as I can detect.)

The pod, however, will attempt to communicate with the PDM at certain points. The most common ones are the pod change and low reservoir warnings. The PDM also wakes up to do pod change warnings, but so far as I can see both devices are doing this in parallel. The low reservoir warning happens just in the pod (I think.) There are other things of course like occulusions and, maybe, the end of a temporary basal.

If the PDM doesn't get these warnings the pod seems to stack them up, to some level, and deliver them when the PDM is next within range and turned on. I don't think the pod can wake the PDM.

The new pods apparently have a greater range. Since I haven't got new pods I don't know whether there are other changes. It may be that the new pods can wake the PDM, otherwise I don't see the point to a greater range. (Though I've heard other people complain about the range it's never been an issue for me.)

John Bowler

John, I don't know if you're on the new pods yet, but the recommendation for new pods is to leave them in the tray, position the tray so the pod is on the left side, and have the PDM touch the tray to the left of it. That's much more exact a process than with the old pods.

Well, thank you all for the info. As I said, I don't have to worry too much about it now.

Yes, I have the new ust400 so I have the new pods, thus no way to compare between the new and old. Since I just started on 6/12/2013 I guess it holds that "new" users/owners are started with the newer pdm at this stage of things. No worries though, I was in the first stage of testing on the Mini-med infusion pumps. Basically what I am saying is that I paid my dues back then. Testing new cannulas every other month it seemed as the older ones were way too long a needle, non-flexible etc. In fact, I have been offered money for that old model even though it no longer works.

Back then, insurance would NOT cover the minimed pump itself, only the supplies. From what I have been told, the cost of supplies has not changed much except for inflation over the last 25-30 years. The various pumps have also not changed in price, still $5k for the basic pumps, up to 8k for whatever gets considered the newest technology now. So much for research and development expenses lowering price as time goes on.

With the old solid cannulas, on the mini-med, I kept developing anti-bodies to different types of insulin, since EVERY injection site would get infected. 3 times I ended up in a coma from sugar levels being over 800 for extended periods of time... as in weeks. Since humalin came out, these newer insulin's don't seem to be causing me as much trouble though. I have a 2nd blood disorder called palgar huet, which just means "elevated white blood cell count" and I am always asked if I have an infection. Typically don't now, but I have to be ever watchful about it, as once you tell a Dr that you have palgar huet, they always assume that you have no infection at all. Which is what caused me to lose my right leg the day after xmas this past winter.

It doesn't matter much, the protocol is robust; if a communication error occurs it's easy to move the two closer together. Indeed on a separate thread someone commented about pre-charging a pod with insulin while the PDM was still servicing the old pod to avoid having to carry stuff around. The pod keeps on trying to contact the PDM until the PDM accepts the connection.

John Bowler