Editing Intravenous therapy (section)

==Methods and equipment==
===Access===
{{Main|Venous access}}
[[File:Капельница.jpg|thumb|right|IV infusion set (not yet in use)]]
[[File:Intravenous attempt.jpg|right|thumb|A nurse inserting an 18-gauge IV needle with cannula]]
[[File:Needle-insertion-angles-1.png | thumb|right | A needle for intravenous access should be inserted at an approximately 25-degree angle.]]

The simplest form of intravenous access is by passing a hollow [[hypodermic needle|needle]] through the skin directly into a vein. A syringe can be connected directly to this needle, which allows for a "bolus" dose to be administered. Alternatively, the needle may be placed and then connected to a length of tubing, allowing for an infusion to be administered.<ref name="Lippincott" />{{rp|344–348}} The type and location of venous access (i.e. a central line versus peripheral line, and in which vein the line is placed) can be affected by the potential for some medications to cause peripheral vasoconstriction, which limits circulation to peripheral veins.<ref>{{cite journal |last1=Raehl |first1=CL |title=Endotracheal drug therapy in cardiopulmonary resuscitation. |journal=Clinical Pharmacy |date=July 1986 |volume=5 |issue=7 |pages=572–9 |pmid=3527527}}</ref>

A peripheral [[cannula]] is the most common intravenous access method utilized in [[hospital]]s, [[pre-hospital]] care, and outpatient medicine. This may be placed in the arm, commonly either the wrist or the [[median cubital vein]] at the elbow. A [[tourniquet]] may be used to restrict the venous drainage of the limb and make the vein bulge, making it easier to locate and place a line in a vein. When used, a tourniquet should be removed before injecting medication to prevent [[Extravasation (intravenous)|extravasation]]. The part of the catheter that remains outside the skin is called the connecting hub; it can be connected to a [[syringe]] or an intravenous infusion line, or capped with a {{visible anchor|heplock}} or saline lock, a needleless connection filled with a small amount of heparin or saline solution to prevent clotting, between uses of the catheter. Ported cannulae have an injection port on the top that is often used to administer medicine.<ref name="Lippincott" />{{rp|349–354}}

The thickness and size of needles and catheters can be given in [[Birmingham gauge]] or [[French catheter scale|French gauge]]. A Birmingham gauge of 14 is a very large cannula (used in resuscitation settings) and 24-26 is the smallest. The most common sizes are 16-gauge (midsize line used for blood donation and transfusion), 18- and 20-gauge (all-purpose line for infusions and blood draws), and 22-gauge (all-purpose pediatric line). 12- and 14-gauge peripheral lines are capable of delivering large volumes of fluid very fast, accounting for their popularity in [[emergency medicine]]. These lines are frequently called "large bores" or "trauma lines".<ref name="Lippincott" />{{rp|188–191;349}}

====Peripheral lines====
[[File:Pediatric patients receiving chemotherapy.jpg|thumb|left|An arm board is recommended for immobilizing the extremity for cannulation of the hand, the foot or the [[antecubital fossa]] in children.<ref>{{cite book |title=Roberts and Hedges' Clinical Procedures in Emergency Medicine E-Book | first1 = James R. | last1 = Roberts | first2 = Jerris R. | last2 = Hedges |edition=6th |publisher=Elsevier Health Sciences |year=2013 |isbn=9781455748594 | url = https://books.google.com/books?id=slyLreFkHuIC&pg=PA349 | page = 349 }}</ref>]]
{{main|Peripheral venous catheter}}
A peripheral intravenous line is inserted in [[Peripheral vascular system|peripheral vein]]s, such as the veins in the arms, hands, legs and feet. Medication administered in this way travels through the veins to the heart, from where it is distributed to the rest of the body through the circulatory system. The size of the peripheral vein limits the amount and rate of medication which can be administered safely.<ref name="PICChist">{{cite journal |last1=Rivera |first1=AM |last2=Strauss |first2=KW |last3=van Zundert |first3=A |last4=Mortier |first4=E |title=The history of peripheral intravenous catheters: how little plastic tubes revolutionized medicine. |journal=Acta Anaesthesiologica Belgica |date=2005 |volume=56 |issue=3 |pages=271–82 |pmid=16265830}}</ref> A peripheral line consists of a short [[catheter]] inserted through the skin into a [[peripheral vein]]. This is usually in the form of a [[cannula]]-over-needle device, in which a flexible plastic cannula comes mounted over a metal [[trocar]]. Once the tip of the needle and cannula are placed, the cannula is advanced inside the vein over the trocar to the appropriate position and secured. The trocar is then withdrawn and discarded. Blood samples may also be drawn from the line directly after the initial IV cannula insertion.<ref name="Lippincott" />{{rp|344–348}}

[[File:Blausen 0181 Catheter CentralVenousAccessDevice NonTunneled.png|thumb|Illustration of a non-tunneled central venous access device|alt=Labelled computer-drawn illustration of parts of an inserted non-tunneled central intravenous line]]
[[File:Central line equipment.jpg|thumb|The central line kit (out of its packaging)]]

====Central lines====
{{main|Central venous catheter}}
A central line is an access method in which a catheter empties into a larger, more central vein (a vein within the torso), usually the [[superior vena cava]], [[inferior vena cava]] or the right atrium of the heart. There are several types of central IV access, categorized based on the route the catheter takes from the outside of the body to the central vein output.<ref name="Marino's">{{cite book |last1=Marino |first1=Paul L. |title=Marino's the ICU book |year=2014 |chapter=2. Central Venous Access|publisher=LWW |location=Philadelphia |isbn=978-1451121186 |edition=Fourth}}</ref>{{rp|17–22}}

==== Peripherally inserted central catheter ====
{{main|Peripherally inserted central catheter}}
A peripherally inserted central catheter (also called a PICC line) is a type of central IV access which consists of a cannula inserted through a sheath into a peripheral vein and then carefully fed towards the heart, terminating at the superior vena cava or the right atrium. These lines are usually placed in peripheral veins in the arm, and may be placed using the [[Seldinger technique]] under ultrasound guidance. An X-ray is used to verify that the end of the cannula is in the right place if fluoroscopy was not used during the insertion. An EKG can also be used in some cases to determine if the end of the cannula is in the correct location.<ref name="PICCbook">{{cite book |editor1-last=Sandrucci |editor1-first=Sergio |editor2-last=Mussa |editor2-first=Baudolino |title=Peripherally inserted central venous catheters |date=5 July 2014 |publisher=Springer |location=Milan |isbn=978-88-470-5665-7}}</ref>{{rp|Ch.1,&nbsp;5,&nbsp;6}}

====Tunneled lines====
[[File:Hickman line catheter with 2 lumens.jpg|thumb|upright=0.7|A Hickman line, a type of tunneled catheter, inserted through the skin at the chest and tunneled to insert into the [[jugular vein]] in the throat.|alt=Photograph of an inserted Hickman line, which is a type of tunneled catheter, inserted in the chest.]]

A tunneled line is a type of central access which is inserted under the skin, and then travels a significant distance through surrounding tissue before reaching and penetrating the central vein. Using a tunneled line reduces the risk of infection as compared to other forms of access, as bacteria from the skin surface are not able to travel directly into the vein.<ref>{{cite journal |last1=Agarwal |first1=Anil K. |last2=Haddad |first2=Nabil |last3=Boubes |first3=Khaled |title=Avoiding problems in tunneled dialysis catheter placement |journal=Seminars in Dialysis |date=November 2019 |volume=32 |issue=6 |pages=535–540 |doi=10.1111/sdi.12845|pmid=31710156 |s2cid=207955194 }}</ref> These catheters are often made of materials that resist infection and clotting. Types of tunneled central lines include the [[Hickman line]] or Broviac catheter. A tunnelled line is an option for long term venous access necessary for [[hemodialysis]] in people with poor kidney function.
<ref name="JVA2016">{{cite journal |last1=Roca-Tey |first1=Ramon |title=Permanent Arteriovenous Fistula or Catheter Dialysis for Heart Failure Patients |journal=The Journal of Vascular Access |date=March 2016 |volume=17 |issue=1_suppl |pages=S23–S29 |doi=10.5301/jva.5000511|pmid=26951899 |s2cid=44524962 }}</ref>

====Implantable ports====
{{main|Port (medical)}}
An implanted port is a central line that does not have an external connector protruding from the skin for administration of medication. Instead, a port consists of a small reservoir covered with silicone rubber which is implanted under the skin, which then covers the reservoir. Medication is administered by injecting medication through the skin and the silicone port cover into the reservoir. When the needle is withdrawn, the reservoir cover reseals itself. A port cover is designed to function for hundreds of needle sticks during its lifetime. Ports may be placed in an arm or in the chest area.<ref>{{cite journal |last1=Li |first1=Guanhua |last2=Zhang |first2=Yu |last3=Ma |first3=Hongmin |last4=Zheng |first4=Junmeng |title=Arm port vs chest port: a systematic review and meta-analysis |journal=Cancer Management and Research |date=3 July 2019 |volume=11 |pages=6099–6112 |doi=10.2147/CMAR.S205988|pmid=31308748 |pmc=6613605 |s2cid=196610436 |doi-access=free }}</ref>

===Infusions===
Equipment used to place and administer an IV line for infusion consists of a bag, usually hanging above the height of the person, and sterile tubing through which the medicine is administered. In a basic "gravity" IV, a bag is simply hung above the height of the person and the solution is pulled via gravity through a tube attached to a needle inserted into a vein. Without extra equipment, it is not possible to precisely control the rate of administration. For this reason, a setup may also incorporate a clamp to regulate flow. Some IV lines may be placed with "[[Y-Set (intravenous therapy)|Y-sites]]", devices which enable a secondary solution to be administered through the same line (known as piggybacking). Some systems employ a [[drip chamber]], which prevents air from entering the bloodstream (causing an [[air embolism]]), and allows visual estimation of flow rate of the solution.<ref name="Lippincott" />{{rp|316–321;344–348}}
[[File:Infusionspumpe.JPG|left|thumb|upright=0.75|An [[infusion pump]] suitable for a single IV line|alt=Photograph of a simple, single infusion IV pump]]
Alternatively, an [[infusion pump]] allows precise control over the flow rate and total amount delivered. A pump is programmed based on the number and size of infusions being administered to ensure all medicine is fully administered without allowing the access line to run dry. Pumps are primarily utilized when a constant flow rate is important, or where changes in rate of administration would have consequences.<ref name="Lippincott">{{cite book |title=Lippincott's nursing procedures. |date=2009 |publisher=Lippincott Williams & Wilkins |location=Philadelphia |isbn=978-0781786898 |edition=5th}}</ref>{{rp|316–321;344–348}}

===Techniques===
To reduce pain associated with the procedure, medical staff may apply a topical local anaesthetic (such as [[EMLA]] or [[tetracaine|Ametop]]) to the skin of the chosen venipuncture area about 45 minutes beforehand.<ref name="Lippincott" />{{rp|344–348}}

{{anchor|Blown vein}}
If the cannula is not inserted correctly, or the vein is particularly fragile and ruptures, blood may extravasate into the surrounding tissues; this situation is known as a '''blown vein'''<!--Bolded per MOS:BOLD because this term redirects here--> or "tissuing". Using this cannula to administer medications causes [[extravasation]] of the drug, which can lead to [[edema]], causing pain and tissue damage, and even [[necrosis]] depending on the medication. The person attempting to obtain the access must find a new access site proximal to the "blown" area to prevent extravasation of medications through the damaged vein. For this reason it is advisable to site the first cannula at the most distal appropriate vein.<ref name="Lippincott" />{{rp|355–359}}