Editing Intravenous therapy (section)

===Infection and inflammation===
As placement of an intravenous line requires breaking the skin, there is a risk of infection. Skin-dwelling organisms such as [[coagulase-negative staphylococcus]] or ''[[Candida albicans]]'' may enter through the insertion site around the catheter, or bacteria may be accidentally introduced inside the catheter from contaminated equipment. Infection of an IV access site is usually local, causing easily visible swelling, redness, and fever. However, pathogens may also enter the bloodstream, causing [[sepsis]], which can be sudden and life-threatening. A central IV line poses a higher risk of sepsis, as it can deliver bacteria directly into the central circulation. A line which has been in place for a longer period of time also increases the risk of infection.<ref name=Lippincott />{{rp|358;373}}

Inflammation of the vein may also occur, called thrombophlebitis or simply phlebitis. This may be caused by infection, the catheter itself, or the specific fluids or medication being given. Repeated instances of phlebitis can cause scar tissue to build up along a vein. A peripheral IV line cannot be left in the vein indefinitely out of concern for the risk of infection and phlebitis, among other potential complications. However, recent studies have found that there is no increased risk of complications in those whose IVs were replaced only when clinically indicated versus those whose IVs were replaced routinely.<ref>{{cite journal|vauthors= Webster J, Osborne S, Rickard CM, Marsh N|date=23 January 2019|title=Clinically-indicated replacement versus routine replacement of peripheral venous catheters|journal=The Cochrane Database of Systematic Reviews|volume=1|issue=1 |pages=CD007798|doi=10.1002/14651858.CD007798.pub5|issn=1469-493X|pmc=6353131|pmid=30671926}}</ref> If placed with proper aseptic technique, it is not recommended to change a peripheral IV line more frequently than every 72–96 hours.<ref>{{cite journal | vauthors = O'Grady NP, Alexander M, Burns LA, Dellinger EP, Garland J, Heard SO, Lipsett PA, Masur H, Mermel LA, Pearson ML, Raad II, Randolph AG, Rupp ME, Saint S | title = Guidelines for the prevention of intravascular catheter-related infections | journal = Clinical Infectious Diseases | volume = 52 | issue = 9 | pages = e162-93 | date = May 2011 | pmid = 21460264 | pmc = 3106269 | doi = 10.1093/cid/cir257 }}</ref>

Phlebitis is particularly common in intravenous drug users,<ref>{{cite journal |last1=Jaffe |first1=Richard B. |title=Cardiac and vascular involvement in drug abuse |journal=Seminars in Roentgenology |date=July 1983 |volume=18 |issue=3 |pages=207–212 |doi=10.1016/0037-198x(83)90024-x|pmid=6137064 }}</ref> and those undergoing chemotherapy,<ref>{{cite journal |last1=Lv |first1=Luyu |last2=Zhang |first2=Jiaqian |title=The incidence and risk of infusion phlebitis with peripheral intravenous catheters: A meta-analysis |journal=The Journal of Vascular Access |date=May 2020 |volume=21 |issue=3 |pages=342–349 |doi=10.1177/1129729819877323|pmid=31547791 |s2cid=202745746 }}</ref> whose veins can become sclerotic and difficult to access over time, sometimes forming a hard, painful "venous cord". The presence of a cord is a cause of discomfort and pain associated with IV therapy, and makes it more difficult for an IV line to be placed as a line cannot be placed in an area with a cord.<ref>{{cite journal |last1=Mihala |first1=G |last2=Ray-Barruel |first2=G |last3=Chopra |first3=V |last4=Webster |first4=J |last5=Wallis |first5=M |last6=Marsh |first6=N |last7=McGrail |first7=M |last8=Rickard |first8=CM |title=Phlebitis Signs and Symptoms With Peripheral Intravenous Catheters: Incidence and Correlation Study. |journal=Journal of Infusion Nursing |date=2018 |volume=41 |issue=4 |pages=260–263 |doi=10.1097/NAN.0000000000000288 |pmid=29958263|s2cid=49613143 }}</ref>