PCA discrepancy (too much med?)

[General E. Speaking, RN, RN]

We use Alaris pumps. During shift change, the oncoming nurse and I were doing our 2 nurse check. I had replaced the syringe at 1400. We use the BD 50ml prefilled syringes. The patient was on PCA mode only (no basal) and hadn't pushed the button so no doses were given. We cleared the pump together. However, on the PCA screen where is says VTBI "volume to be infused" it read 50.2 ml. It should have been only 50ml cause thats all the syringe will hold. We took the syringe out to start over from scratch and made sure it was programmed right (which it was) and when it restarted it said the same thing: VTBI 50.2 ml. The oncoming nurse kept questioning me why it said this. She started to make me feel uncomfortable like I had tampered with it or something. I promise I didn't add Morphine to the syringe- lol. I guess if an addicted nurse were desperate they could try and replace some Morphine they took with NS but not really sure how the pump would know there was too much added I don't know. Maybe pump malfunction? Or overfill of syringe? The Alaris pumps are relatively new to us so I have limited experience (especially with the PCAs).

Just wondering if anyone else has experienced this?

[LouisVRN, RN]

Usually there is a little air bubble in the syringe, to ensure that all the medication is delivered to the patient, I would assume that that is making up the extra volume, but that the machine understands that although there is a volume of 50.2, only 50 may be delivered to the patient.

[Been there,done that, ASN, RN]

If you are worried about a PCA discrepancy... get pharmacy to do THEIR check.I too am very concerned regarding any narcotic discrepancies. My own father required 80 mgs of morphine an hour to control HIS pain. It was do-able, but required an anesthesia order and a pharmacist to re-program the pump.

PCA is a very complicated, heavy responsibility on the RN.

[Up2nogood RN, RN]

For whatever reason it sounds like the manufacturer set the pump up for the syringes to be set for VTBI at 50.2ml. I would check with your pharmacy. I believe the pumps are set up with your facility specs.

I know a lot of our pCA syringes are overfilled but we don't use alaris pumps:(

[General E. Speaking, RN, RN]

Yup, I am going to ask the pharmacist. I never had this occur with our old PCAs.

Thanks for the replies

[Student2Registered]

I start PCAs and replace PCAs on every shift for more than one patient every shift. Every new syringe I set up starts at 30.3 or 30.2 or even 30.5. We document the starting volume and each subsequent "pump check" should match with pt's use against VTBI minus the starting volume. I've never had an issue with this. I use Alaris too by the way and our syringes are 30ml syringes.

[HamsterRN, ADN, RN]

The pump senses the supposed volume based on the height of the plunger, this can vary slightly and I rarely see it say exactly 50ml.

[GHGoonette, BSN, RN]

We use Vygon pumps (Viking Medical-I think they're world wide), but unlike the electronic ones, there is no display showing the quantity, it's all manual; that is, you check the quantity infused by the level in the syringe. No continuous infusion, only patient-administered bolus doses, 7 minute lockout. Probably the safest I've ever come across. I have heard of accidental overdoses with certain PCAs and if this is a relatively new product, I think you should query this with the manufacturers.

[Kyrshamarks, BSN, RN]

Also the obvious answer. There could be a slight overfill of the morphine from the manufacturer. 0.2 cc overfill equates to 0.2 mg. Not a whole heck of a lot of drug.

[General E. Speaking, RN, RN]

Also the obvious answer. There could be a slight overfill of the morphine from the manufacturer. 0.2 cc overfill equates to 0.2 mg. Not a whole heck of a lot of drug.

I agree! Not a lot of med but the oncoming nurse was fixated on "why, why?" I just have never seen or noticed that it would read over 50ml...