What rate is best to 'keep vein open'?

'Keep vein open (KVO) is an area of disagreement and dispute. There are no evidence-based guidelines on how much fluid should be infused to keep a catheter patent. It varies substantially in anecdotal reports from 5 mls/hr to 50 mls/hr! 5 mls/hr could be insufficient, but even 20 mls/hr might be too much for a patient with a heart condition.

In a recent article from Canada (Paquet & Marchionni, 2016), they conducted a literature review of the practice of KVO and surveyed their staff to find out what KVO practices nurses were using. The authors state: "The most surprising finding of the literature review was the paucity of more recent studies or discussions about this ubiquitous practice. In reviewing the articles, none offered a comparison of infusion rates in terms of efficacy for maintaining patency, nor were there any comparisons in the adult population of the use of KVO versus saline locking comparing catheter longevity." Furthermore, "INS indicates that a standard infusion rate, a so-called one size fits all, cannot be determined and needs to take into account the age of the patient, fluid and electrolyte balance, and the presence of comorbidities."

In this article, the authors chose to go with 10 mls/hr, but they rightly acknowledge there is no concrete evidence for doing so.



Paquet F, Marchionni C. What Is Your KVO? Historical Perspectives, Review of Evidence, and a Survey About an Often Overlooked Nursing Practice. J Infus Nurs. 2016;39(1):32-


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