My first thought is that these people are prone to a vasovagal
reaction. Studies on patients having a venipuncture have shown that
this is more likely in:
1. younger patients, especially men under 40
2. those with a history of vasovagal. This should be part of your
initial assessment
3. those requiring multiple attempts at venipuncture
The literature states that vasovagal reactions are characterized
by vasodilation or loss of vasomotor tone. This is controlled by the
autonomic nervous system that innervates the tunica adventitiia. Since
we have never really looked at the exact details of all the
physiology, I am wondering is there is an initial vasoconstriction
prior to the vasodiliation. Fear and anxiety are known causes. Could
it be that we are seeing more physiology with US that we were not able
to detect without it? I would begin to pay attention to the history
and see if you can correlate any of 1-3 above to what you are seeing.
Lynn
At 9:25 PM -0500 8/11/06, Gwen Irwin wrote:
This may seem to be a weird topic, but with our years of ultrasound insertion of PICCs, we have noticed that some patients really react to vein entry BEFORE we are close to entering the vein, while observing on ultrasound the location of the needle in relation to the vein wall. When we proceed past that point, we are in the vein with excellent blood return and proceed to successful PICC insertion. Local anesthesia works only on the skin entry and doesn't prevent this reaction to vein entry. They also react differently to vein entry of the dilator/sheath introducer.
This population of patients are also the ones that complain of the most pain with IV insertions. Most staff nurses give up before entering the vein with an IV catheter, when the patient complains of this pain. If we are called to do a PIV, we don't give up at that point, but believe that we are right on top of the vein and continue past the patient's complaint to vein entry. We have a successful PIV.
This is so hard to measure for a study, but our observations have led us to believe that the innervation of the exterior of the vein is different for some people. We don't seem to see a large percentage of our patients that have this type of reaction, but it is noticeable, when it occurs. Some of these people call themselves "weenies" for IV starts. Based on the years of our observations, we don't believe that they are weenies, but that they have different innervation that actually gives them a pain signal before vein entry. We have been known to tell them that they have bad luck with their veins, since they feel the stick into the vein before it actually occurs. These also can be the patients that have more vasoconstriction observed on ultrasound, during PICC attempts. We have waited for as long as 10 minutes to observe the vein stop its vasospasm, and see the dilation that we initially saw on our original assessment.
I am wondering if anyone else is noticing this phenomenon. I am really thinking it would be useful information to share, but don't know how to study or report this subjective observation.
I would love to hear from you, if you think we are crazy or if we are noticing something that has not previously reported or discussed. We have seen it so many times that we don't think we are crazy. Your responses are always appreciated.
Gwen Irwin
Austin, Texas
--
Lynn Hadaway, M.Ed., RNC, CRNI
Lynn Hadaway Associates, Inc.
126 Main Street, PO Box 10
Milner, GA 30257
http://www.hadawayassociates.com
office 770-358-7861
Lynn Hadaway Associates, Inc.
126 Main Street, PO Box 10
Milner, GA 30257
http://www.hadawayassociates.com
office 770-358-7861
