EBME Forums Forums EBME Website EBME Website KVO rate on Infusion devices

Has anyone had any problems with a Volumetric or Syringe pump set to deliver at its lowest level of administration (i.e. 0.1ml/hr)and then moving onto 0.5 or 3mls/hr KVO mode?.This might only occur within the Critical care environment but if the patient was in receipt of say an inotrope,naturally the implications of moving from 0.1 to thirty times the set rate could be serious.The KVO can be configured to run at the same rate of delivery for the devices I am using and I imagine that ideally a syringe pump should only be used for IV delivery of such a low rate.However staff here use a volumetric pump at 0.1ml/hr within the ITU and I wanted to ask anyone if you have had a similar situation.We have an equipment library and the pumps would either all need to be re-configured or individually assigned to certain areas.I would welcome your thoughts/experiences.
Regards,
John Riddle

Simple answer "Yes".

There is a perenial argument over KVO that is why it is an option to turn it on or not on modern syringe pumps and to let the hospital decide the protocol. Here, at GOSH, it is turned on except on pumps with a large red sticker, the nursing staff then decide whether they want KVO or not. Ther is no correct answer only one that is right for that situation.

I am worried that you are using IV pumps at such a low rate. it might be possible to set them but manufacturers often give a minimum recommended usable rate. The error of delivery is often given as a percentage of set rate for high rates and as an absolute for low rates. if you are using it at the minimum rate the error might be greater than the set rate. Also a slight movement of the tubing will deliver a bolus that could easily be equal to an hours dose. See the user manual for details for your pumps but I am sure IV pumps are not supposed to be used at this low a rate.

For such low rates of fluid delivery I would definitely use a syringe pump and then make sure a small syringe was used to get a decent linear speed. The rubber plunger can flex and give a pulsatile flow. For a 50ml syringe 1ml/hr is approximatele 1mm/hr linear speed, so a flex of 0.1mm (which is hardly anything) can cause a significant bolus - and below that speed...well.

As a last resort refer to the new guidance from the MDA DB2003(02) which tells you everything you need to know about infusion systems. (Free to the NHS)

Hope this helps or at least gives food for thought.
Robert

John
I'm not certain about all pumps but some pump specs indicate that in KVO mode the pump will deliver the set KVO rate or the current programmed rate whichever is less. One would hope this is generally the case.

Modern Therapy category “A “ Volumetric pumps should be ok for the delivery of drugs with a short half-life and have the advantage over syringe pumps of long term flow continuity, free-flow and air in tube protection.
Bill

John
Having just read Robert's reply I agree with his concerns re 0.1ml/hr infusions. I had assumed you were quoting a theoretical possibility, having never seen inotropes delved at < 1 ml/hr. The drug concentration should be considered if you were quoting actual practice. I should qualify my above statement re the use of volumetric pumps to &#8220;Modern Therapy category &#8220;A &#8220; Volumetric pumps should be ok for the delivery of drugs with a short half-life at flow rates above 4 ml/hr&#8221;
Bill

Thankyou very much for your replies, they are most helpful.I can only envisage that the situation develops when a drug is added to a solution greater than 50/60mls and a volumetric pump is required.Some of our syringe pumps will at least indicate that they are about to go into KVO mode,I'm not sure if the volumetrics can do that.KVO mode ,I've always thought, was more suited to a busy (understaffed) ward situation where nurses would welcome the flexibility it offers.
Regards,
John Riddle.

I seem to remember the early software vesrions on the Alaris P7000 could/would/did increase delivery on entering KVO if KVO was greater than the set rate. It got fixed I think.

KVO, whether on a volumetric pump or syringe driver works in the same fashion. At the end of the required volume the device will indicate (alarm) that this is the case and continue operating but in a KVO mode. This means that the device will either reduce the infusion rate to the programmed KVO rate if the KVO rate is less than the initial infusion rate, OR, the KVO rate will remain the same as the original infusion rate if that infusion rate is less than the programmed KVO rate.
As an aside I believe our cousins over the water (USA) do not use syringe drivers to any great extent, but do all their infusions via Volumetric pumps.

Yes if you look in the operators manual for most infusion devices you'll see an explanation for the features on the pump; such as KVO.

The latest on John's post (I work with John)

We have discovered that if the Infusion Pump concerned is running at a rate less than the KVO rate (3ml/hr in this case) then the pump will continue at it's previously set rate (e.g. 0.1ml/hr) - this means it's not the problem we first envisaged.

The users insist that they do infuse inotropes at various rates including 0.1ml/hr due to the concentration of the inotropes.

We are trying to encourage them to to use an alternative method or to dilute the inotropes further, so that a higher infusion rate may be used.

Regards, Mark

Can I recommend two books that may be interesting background reading for Nurses and clinical trainers, in particular. "A Pocketbook for Safer IV Therapy" edited by Martin Pickstone; 1999; ISBN:0-948672-32-3 and "Intravenous Therapy in Nursing Practice" Dougherty and Lamb; 1999; ISBN:0-443-05983-7.

The books include the relevent references to issues such as the delivery of specific drugs and problems encountered with IV therapy, including selection of devices and equipment maintenance considerations. They are probably on Nurses suggested reading lists anyway. I am not a clinical trainer, I have no association with the authors of these publications but I have read these books myself and found that I understand many of the, practical, clinical aspects much better than I did before. There may be more up to date, revised editions, of course.