FHIR Chat · Medications - IV piggyback - pre-existing model?

Stream: implementers

Topic: Medications - IV piggyback - pre-existing model?

Senthil Nachimuthu (Oct 29 2021 at 15:54):

I have a question about how to model IV piggybacks in the MedicationAdministration and possibly MedicationRequest resources. A lot of medication administration data involves one medication (such as an antibiotic) diluted (in a bag of normal saline, for example) and administered through a slow IV drip. I looked for existing formalisms to model this in FHIR but couldn't find an example. Is there a standard or accepted formalism to model this in a MedicationAdministration (and possibly MedicationRequest) resource? Thought I'd ask before creating an extension. Thanks!

Jean Duteau (Oct 29 2021 at 15:58):

To specify the Medication, you would use the Medication resource with the antibiotic as one ingredient and the saline as another. Or just the antibiotic and text (in the Medication.narrative) on how to mix them.

Then you would use the MedicationAdministration to specify dosage.dose and dosage.rate[x].

Senthil Nachimuthu (Oct 29 2021 at 15:59):

To give you some context, the IV pump has multiple controllers. You can set a rate for the "solute" (which itself is a liquid preparation, though concentrated) and the "solvent". (Perhaps 'concentrate' and 'diluent' would be better terms, but I digress). The IV pump will mix them at the correct dilution and infuse them. The IV pump will stop at a preset time/dose, or it can be manually stopped. It can transmit data to an EHR, and we can calculate the dose from the start time, stop time and infusion rate. I'm wondering what's the best way to model either the raw data from the IV pump or the actual dose that was administered.

Senthil Nachimuthu (Oct 29 2021 at 16:02):

Jean Duteau said:

To specify the Medication, you would use the Medication resource with the antibiotic as one ingredient and the saline as another. Or just the antibiotic and text on how to mix them.

Then you would use the MedicationAdministration to specify dosage.dose and dosage.rate[x].

Thanks Jean. This sounds like a feasible approach - I'll try it out. Wonder if it will help model the dilution ratio between two liquid preparations - appreciate any pointers.

Jean Duteau (Oct 29 2021 at 16:03):

ah, an IV Pump - we are actually discussing with Orders & Observations exactly how to model this, so your question is timely. It does depend on how much detail you want to provide. If you just want to convey the actual dose administered over the entire infusion, you can just send one MedAdmin that has the summary information. You can also send multiple MedAdmins for each different dose/rate, i.e. MedAdmin1 with X1 dose and Y1 rate, MedAdmin2 with X2 dose and Y2 rate, etc. You can even send both information and use the MedAdmin.partOf to tie the multiple MedAdmins to the summary one.

Jean Duteau (Oct 29 2021 at 16:07):

Senthil Nachimuthu said:

Wonder if it will help model the dilution ratio between two liquid preparations - appreciate any pointers.

I'm not sure that we will be able to handle, in the Medication resource, the structured data to represent two liquid preparations that are being diluted together. You would probably have to use different Medication resources for each MedAdmin if there were different dilution ratios (not sure if that happens). i.e. MedAdmin1 had a dilution ratio of 10%, MedAdmin2 had a dilution ratio of 8%, etc.

Senthil Nachimuthu (Oct 29 2021 at 16:19):

Jean Duteau said:

ah, an IV Pump - we are actually discussing with Orders & Observations exactly how to model this, so your question is timely. It does depend on how much detail you want to provide. If you just want to convey the actual dose administered over the entire infusion, you can just send one MedAdmin that has the summary information. You can also send multiple MedAdmins for each different dose/rate, i.e. MedAdmin1 with X1 dose and Y1 rate, MedAdmin2 with X2 dose and Y2 rate, etc. You can even send both information and use the MedAdmin.partOf to tie the multiple MedAdmins to the summary one.

Thank you. I'll try out these approaches to understand what I can represent with MedAdmin.partOf as well as the Medication resource