Questions on Cadd pump

cookie102 · May 3, 2007

i just "googled" it and it is the same, it is sad that the pharmacy does not know ratio calcultions

CritterLover, BSN, RN · May 3, 2007

ok, i've only posted on here once before but i have a question that i really hope someone can answer. i have a patient that po pain meds just are not working for her, our pharmacy consultant has suggested a morphine cadd pump and since her veins don't like to cooperate my don has suggested subq.
the morphine concentration is 10mg/ml and the dose is to be set at 7mg/hour as a basal rate and 3.5mg q15 minutes on demand. my question is if we are doing this subq instead of iv will the dosage stay the same??? the pharmacy i'm dealing with doesn't seem to be of much help since they didn't even seem to know that you can do this subq. i just don't want to od this patient or give her more problems than she already has.
any input would be greatly appreciated!
thanks!

i am an rn that works for an op iv pharmacy, so i'm going to try to help some, though i'm not an expert.

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[color=#483d8b]i don't think that the subq/iv routes of morphine are equivalent; however, the sub q route will need a higher level, if anything, so if you are giving an intended iv dose sub q, you won't be overdosing the patient.

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[color=#483d8b]our pharmacy is "attached" to a hospice, so we frequently send out cadd pumps with pain meds. we usually use dilaudid, with fentanyl second, but morphine does get used sometimes.

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[color=#483d8b]with a subq pump, your limiting factor is going to be how much subq tissue the patient has. that will determine how much volume you can give. then, the available concentrations of morphine will tell you how many mg of morphine you can give. where i work, it is up to the pharmacist to determine what concetration to use, and how to mix the pain meds (with input from the hospice nurses). but our pharmacists are awesome!

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[color=#483d8b]some patients can tolerate a good amout of morphine subq, since they have decent fat reserves. others, though, are very chachectic from the disease process, and have very little fat reserves. for those patients, we place a picc for iv pain meds (this is what i do -- i go out to the patient's home and place the picc. we get a moblie xray company to shoot the pcxr to confirm placement, and the patient never needs to leave his/her home.) then, the sub q pain meds are used as a "bridge" between the po meds until the picc placement can be confirmed.

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[color=#483d8b]so anyway, for your original question: i think there is a doseage adjustment, but since subq will require more pain meds, not less, i don't think you need to worry about an od. just pay attention to your patient's level of pain control. if the pain doesn't seem to be well controlled, asses the patient for possible picc placement, even if you don't have a mobile picc team in your area, you should be able to send the patient to the hospital for an op picc placement. hospice will pay for it. it is worth it to get their pain controlled. if that isn't possible, i have seen hospice run two separate sub q cadds, into two separate parts of the body (abd/thigh) to double up on the pain meds.

Rnmomajmj · May 3, 2007

Thanks for your input, I'll be starting it this afternoon so I hope all goes well. I do have a wonderful pharmacy consultant so I will double check the dosage with her before starting.

pammyf · Mar 29, 2009

hi, the ratio of po to iv morphine is 3 to 1. Subq should not alter the ratio since it is going directly into the blood stream via tissue and not thru the gut (thus the first pass issue is naught) i have worked with many a cadd pump using subqu since inserting a picc line is costly (in the old days we could place them ourselves but now the an xray is required to confirm placement) subq is a great option As for how much the tissue can absorb: No more then 3cc an hour on someone not totally cachectic. 2 cc is more managable and maybe more comfortable we have the iv pharmacist mix in very high concentrates: even up to 100mg per cc for really high dosing. go for it.......that being said we prefer no ivs......our opiod of choice is methadone for a base and roxanol for breakthru.

keep it simple and sweet. happy hospice. but since this response is from eons ago i hope this helps others

marachne · Mar 30, 2009

As someone said, this is old, but I'll add my comments: -- IV to SQ equivalents are 1:1. Where I worked we regularly considered our subq rate to max out at 5 ml/hr. Under extreme circumstances, (escalating pain, needed several hours to get a higher concentration solution mixed up), I have gone up to higher rates with no problems re: tissue and satisfactory results. If the person has high levels of pain or it is anticipated that the pain will escalate (bone mets, ES liver, etc), we tend to move away from morphine to more concentrated opiates like dilaudid. Methadone CAN be a good drug, but unless you have medical directors/NPs who are really comfortable with titration and there is close monitoring, it's tricky and I'm not as comfortable with its use.