When to Move the Blood

[Brenda K Hutson]

Our refrigerators and freezers are connected to a centralized temperature monitoring system (as well as the internal probe for the digital reading and internal upper and lower thermometers). Our centralized system probes seem to respond to temperature fluctuations before the equipment itself (and the difference seems large to me; like >1.0). We have set the alarm set points on both the internal equipment probe, as well as the upper and lower centralized system probes at 1.5 and 5.5.

Currently, the centralized system is set up to have a 5 minute delay from the time it hits one of these set points (shows as pending alarm in computer) before it sends an alert via a phone call. We are told by our Facilities dept. to rely on the centralized system as far as the "correct" temp. at any given moment. My concern has always been that within that 5 minute delay, the temperature could drop below 1 or above 6 (and of course we should move blood out before that happens; not after). Well, today we had such an occurrence. In that 5 minutes, it went from 1.5 to 0.8. The 0.8 only lasted for <1 minute in e-Centron, but I tried to tell Facilities that had I seen it getting close to 1.0, I would have moved the blood (have written approval now from MD to use blood).

What we found today was that the bottom probe for the centralized system had come out of the fluid; so perhaps someone opened the door and a rush of cold air hit the probe momentarily?? Facilities not sure what caused it (it actually happened twice).

Now, I could have them change the set points since they are unwilling to change the 5 minute delay (say we would get a lot of unncessary alarms if they did that), but here is my question (finally, you say ): Am I just being too picky? Others of you with centralized systems, do you have a delay prior to alarm just in case of a spontaneous, momentary blip? I guess my concern is that if it had not been just a "momentary" blip, it would have been 0.8 without immediately going back to temp. and we would have had a true "out of compliance" situation.

Anyway, I hope that made sense!

I would appreciate feedback.

Brenda Hutson, CLS(ASCP)SBB

[adiescast]

We have not gone live with our system yet, so you may not feel my response is relevant...

We have a 5 minute delay on our system before the alarm sounds. If you did not have a centralized system and your local alarm sounded (do you no longer have local alarms?), what would your action be? Right now we check the internal temperature with independent thermometers in the device. My plan when we go live with the centralized system is to do the same. When the warning alert is given, someone will check the independent thermometers to correlate. We also check for the source of the problem at that time and implement a correction if the source is identified. We decide whether to move the products based on the independent thermometer reading and the trend prior to the alert. If we do not move the products immediately, it is necessary to monitor the device more closely until it stabilizes or products are moved and service is called. Having said that, we have in the past allowed 5 minutes to pass between readings of the independent thermometer while monitoring. The point of having a warning at 1.5 and 5.5 is to allow time for action. You have to have leeway to decide whether the situation warrents that extreme action or not (moving products is a pain and then they can be exposed to room temperature for a period of time while you are moving them).

So the question is how long is too long for the product to be exposed to temperatures outside of the acceptable range? Will blood begin to be damaged at .8 (only .2 degrees below normal) in 5 minutes (or probably less time) so that it is unacceptable? Can it be viewed as similar to exposing them to room temperature for 5 minutes while they are manipulated (irradiated, for example) or on the floor awaiting transfusion (and then possibly returned)? I don't know how FDA would view this, but it seems to me that 5 minutes at slightly outside the usual temperature range would not be damaging enough to warrent discarding the product. Now, if you stuck a red cell in a -30 freezer for 5 minutes, I might be more concerned!

[Brenda K Hutson]

We have not gone live with our system yet, so you may not feel my response is relevant...

We have a 5 minute delay on our system before the alarm sounds. If you did not have a centralized system and your local alarm sounded (do you no longer have local alarms?), what would your action be? Right now we check the internal temperature with independent thermometers in the device. My plan when we go live with the centralized system is to do the same. When the warning alert is given, someone will check the independent thermometers to correlate. We also check for the source of the problem at that time and implement a correction if the source is identified. We decide whether to move the products based on the independent thermometer reading and the trend prior to the alert. If we do not move the products immediately, it is necessary to monitor the device more closely until it stabilizes or products are moved and service is called. Having said that, we have in the past allowed 5 minutes to pass between readings of the independent thermometer while monitoring. The point of having a warning at 1.5 and 5.5 is to allow time for action. You have to have leeway to decide whether the situation warrents that extreme action or not (moving products is a pain and then they can be exposed to room temperature for a period of time while you are moving them).

So the question is how long is too long for the product to be exposed to temperatures outside of the acceptable range? Will blood begin to be damaged at .8 (only .2 degrees below normal) in 5 minutes (or probably less time) so that it is unacceptable? Can it be viewed as similar to exposing them to room temperature for 5 minutes while they are manipulated (irradiated, for example) or on the floor awaiting transfusion (and then possibly returned)? I don't know how FDA would view this, but it seems to me that 5 minutes at slightly outside the usual temperature range would not be damaging enough to warrent discarding the product. Now, if you stuck a red cell in a -30 freezer for 5 minutes, I might be more concerned!

You bring up many good points; thank you.

Yes, we do have the local alarms on the equipment (which we check daily); however, there seems to be quite a lag time between when the centralized system hits the alarm set points (1.5 and 5.5) vs. the local alarms (and the difference, to me, is significant; like >1.0C). But we are being told by Facilities to go by the centralized system temps. With the local alarm, if you have your alarm set points at 1.5 and 5.5 such that it alarms at that point, you are correct; that gives you time to monitor it and make a decision about whether or not to move the blood. However, we do not actually "see" the centralized system (we can log onto it but would have no reason to do so unless we knew there was a problem). But rather, the centralized system "calls" us when it alarms. But since they have set a 5 minute delay, we do not actually get that call at 1.5 or 5.5 so that we can "watch" it; we get the call 5 mins. later (provided it is still out of temp.) and by then, it could have gone outside of the acceptable range.

I agree that being at 0.8C for 1 minute is not a major issue. However, my concern is a scenario where there really is a problem (like a few weeks ago; went over 6.0 for an extended period of time and we did have to move the blood).

But I will think about all that you said.

Thank You,

Brenda Hutson

[adiescast]

Can you adjust the call delay? That might help if you need less lag time. I think the delay was intended to prevent phone calls when the door is open for a short time. Maybe in your situation it would be better to get more phone calls? I certainly would not disable local alarms just because I have a centralized system. Redundancy has its points.

[Brenda K Hutson]

Can you adjust the call delay? That might help if you need less lag time. I think the delay was intended to prevent phone calls when the door is open for a short time. Maybe in your situation it would be better to get more phone calls? I certainly would not disable local alarms just because I have a centralized system. Redundancy has its points.

We have not disabled our local alarms; we simply can't depend on them to be the stop-gap for the 5 minute delay of our centralized system in that it takes the local alarm (as well as internal thermometers), longer than that to catch up to the "real" temperature (that represented by the centralized system, according to our Facilities Dept.).

My request had been that we not have the 5 minute delay. That was met with a lot of hostility from our Facilities Dept. in that they feel we will actually be responding to "more" false blips in the temperature by doing that. I also think it may be an all or nothing thing; if they change our delay, they have to change all of equipment throughout the Hospital that is on this same centralized system. That is why the only other thing I could think of was to increase our alarm set points for the centralized system in hopes that they then would not go below 1C or above 6C within that 5 minute delay (since the 5 minutes will now start sooner).

Brenda

[Steven Jeff]

In the UK the regulations state that the core temperature of a unit of blood should be maintained between 2 - 6°C. The temperatures recorded in UK blood banks are the current air temperature, the core temperature (usually from a probe immersed in 200mls of water). The chart recorder must record the temperature from core temperature probe. There are often multiple alarm settings on the blood bank refrigerators. Air temperature alarms are often set to activate when the temperature goes below 2°C or above 6 or 8°C usually with a time delay. I personally prefer 6°C set at 10minutes as it provides an early warning. With core temperatures the alarm must activate when the temperature goes below 2°C or above 6°C with no time delay. This is the time when blood components must be moved. In practice the air temperature can go out of range for some time before you witness any change in the core temperature. In summary the core temperature is the critical measurement with no tolerance outside the range of 2 - 6°C, therefore no acceptable time delays in the alarm system. Finally, there is also the door open alarm on all blood banks.

Regards

Steve

:)