I'm a research nurse who deals primarily with pediatric patients who come in fasting for OGTTs/MMTTs.  While they can drink water, a number of subjects come in dehydrated, having had no PO fluids for around 12 hours.Â
I was wondering if anyone knew of research, as opposed to anecdotal evidence, looking at how hydration status affects ease of PIV access.  Â
I was waiting to see if anyone else might respond to your question. I have not read any information about the effect of 12 hour NPO status.
We also do fasting diagnostic tests and I have not found that that length of NPO time has a significant effect on PIV access. Many times it seems that it is these very kids that are difficult anyway and difficulty is usually compounded by vasoconstriction from temperature (pt is cold).
I'm sorry I don't have anything but anecdotal info.
We know from the textbooks on fluid and electrolyte imbalances that a fluid volume deficit will result in less volume of blood to distend veins. Patients with normal hydration will have veins distend within 3 to 5 seconds, however fluid volume deficits will slow down this time or produce no venous distention at all when a tourniquet is applied. I have never seen any studies on the length of NPO time related to difficulty in venous access. Look for fluid and electrolyte text, especially those by Metheny, about the venous distention issue.
Lynn Hadaway, M.Ed., RN, BC, CRNI
www.hadawayassociates.com
Lynn Hadaway, M.Ed., RN, NPD-BC, CRNI
Lynn Hadaway Associates, Inc.
PO Box 10
Milner, GA 30257
Website http://www.hadawayassociates.com
Office Phone 770-358-7861