These concepts have been requested from the NHS, there is already quite a bit of existing content under 364697006|Equipment observable (observable entity).
We would like feedback from this group about what a minimal set of properties would be required to make these unambiguous in use.
| Hemodialysis machine stroke volume (observable entity) |
| Hemodialysis pump head segment (observable entity) |
| Hemodialysis priming volume (observable entity) |
| Hemodialysis blood circuit connection (observable entity) |
| Hemodialysis anticoagulant infusion rate (observable entity) |
| Hemodialysis ultrafiltration volume (observable entity) |
| Ultrafiltration rate setting on hemodialysis machine (observable entity) |
| Hemodialysis pump speed (observable entity) |
| Bicarbonate level setting on hemodialysis machine (observable entity) |
| Hemodialysis extracorporeal circuit volume (observable entity) |
| Hemodialysis blood flow rate (observable entity) |
Trackers:
IHTSDO-308 - Getting issue details... STATUS
IHTSDO-1067 - Getting issue details... STATUS - has an attached document
PCP-85 - Getting issue details... STATUS
PCP-80 - Getting issue details... STATUS
4 Comments
Penni Hernandez
Daniel noted in an email:
We did some work on device settings some time ago but never concluded since no one did implement the results.
In general, the same model can be used for observables and “settables” but some way of separating the two is needed, perhaps a common primitive for the “settable” observables.
One challenge was that while it is a setting on a machine (or in software most probably…) it is also a “setting” of a procedure using the device. The stroke volume of the dialyzer is part of the “setting” of the hemodialysis procedure, where other “settings” might be e.g. duration of treatment which isn’t (necessarily) a setting on the machine itself. There are a few other similar observables, like all the “target…” observables. So, we need to decide whether there is a device observable (or ”settable”) separate from the procedure observable/settable. Also, there are “things” which might be both settable and measurable, which need to be separate concepts.
Looking through the examples I have some questions:
Do you have example values for the observable? I do understand what the stroke volume is (or so I believe) but this is the heart stroking not the machine (hemodialyzers typically have a continuous flow), is it? I also think I know what the pump (head) segment is, but what is observed about that piece of tube? So, to me it seems these are not all settings, but that some are observations that happen to happen during hemodialysis. Is this correct?
Penni Hernandez
Today I have reached out for example values for these observables.
Daniel Karlsson
Slides from previous discussions: https://docs.google.com/presentation/d/1m6g6X4yZXItsJQdTkA5tesb_WOf16z1JvzqRRQy1Iu4/edit?usp=drivesdk
Sarah Harry
Twenty years ago I was a dialysis nurse but equally some of these things are as old I think. Usually a circuit flow is continuous but sometime there is only a single point of access. Then you take blood out on one stroke into a reservoir and back in on the other with the volume of the cycle being the stroke volume. It could be programmed or determined manually by balancing two pump speed settings and read as a calculated value derived from them or measured directly. The stroke volume needs to be optimised for efficient dialysis as well as avoiding exsanguinating the patient on the first stroke of course. An average flow is calculated for KT/V purposes. Different machines do it differently and no doubt nowadays this is much more computed than manual. Prescription is also relevant. These are basically ambiguous as they are not defined as prescription, actual parameter setting, actual volume, calculated volume etc
.