How to Start an IV

Published: September 1, 2020

Last Updated: February 23, 2023

William Kelly, MSN, FNP-C

Author | Nurse Practitioner

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Learning how to start an IV is a very important skill that every nurse needs to know. Inpatient and ER nurses deal with IVs every day – whether they are inserting them, removing them, or administering fluids or medications through them. If you are new to nursing, then you will need to learn how to insert an IV with confidence and knowledge!

When to Start an IV?

The short answer to this is “when an IV is ordered”. However, it is important to critically think as a nurse, and anticipate what will need to be done. Especially as an ER nurse, you may see your patient before the Provider and can start placing an IV if indicated.

If you work as an inpatient nurse, most patients should have at least an IV, midlines, PICC lines, or other central access. These IVs often go bad, and you will need to know how to start an IV in these settings as well.

Indications for an IV:

IV Fluids or Meds

This is the main reason why an IV is ordered

Diagnostic Imaging

CTs or MRIs aoften require an IV for IV contrast to help visualize the anatomy, vasculature, and any potential abnormality going on

Inpatient Admission

Most facilities will require an IV be placed if the patient is being admitted. however, the patient can refuse this.

When to NOT Start an IV?


There is no outright contraindication to placing an IV, but certain factors will exclude specific locations. These include extremities with:


Dialysis patients may have AV fistulas or grafts. IVs should NOT be started in these limbs unless specifically allowed. 


Patients with a history of mastectomy or lymph node dissection should not have IVs placed on that side if possible. This can cause/worsen lymphedema.

Bloot clots

Patient’s with an Active DVT in their arm should not have IVs placed in the same arm – this can further cause irritation of the veins and worsen thrombi formation

Burns or Edema

Significant burns or edema should not have an IV placed if possible over the burnt or edematous area.


Do not place an IV overlying an infection like cellulitis. This can introduce bacteria into the blood and lead to sepsis.

It may be best to avoid limbs with significant motor or sensory deficits, as there is unclear evidence that may suggest increased DVT in these extremities. If their arm is numb, they also may not feel when it is infiltrated.

What IV Gauge to Use?

The IV gauge will determine how big the actual needle and catheter are. The bigger the IV – the faster fluid can be administered. Unfortunately, bigger sizes are also more painful and usually more difficult to insert. Bigger IVs also come with an increased risk of phlebitis and can cause some serious irritation to the vein.

24 gauge: The Baby Needle

These are typically used for babies and generally should be avoided in adults. They are very short, flimsy, and won’t last long.

  • Good for: Infants
  • Bad for: Most other scenarios

22 gauge: The Safe Choice

This is used for many kids and adults, especially older adults with fragile “easily-blown” veins. These are usually OK for IV contrast dye as well, but not for CTA. These are also generally easier to place.

  • Good for: Peds, many Med-Surg adult patients, easily blown veins
  • OK for: IV contrast, blood return
  • Bad for: Massive trauma or fluid resuscitation needs, CT Angiography

20 gauge: The One-Size-Fits-All

20g IVs are an ER nurse’s best friend. This is because a 20g IV is adequate for multiple fluid boluses, IV medication infusions, and most CTA requirements. They often give great blood return and labs can often be drawn without hemolysis.

  • Good for: Most adult patients, CT Angiography
  • OK for: Emergency situations (code blues, RRTs)
  • Bad for: Massive trauma or fluid resuscitation needs

18 gauge: The Big Daddy

18g IVs are your standard “large bore” IV. These are great in critical situations as they provide for rapid administration of fluids or blood products, rapid infusion of critical medications. The down-side is they tend to be a little more difficult to place in the absence of large veins.

  • Good for: Critical or emergency situations, rapid fluid administration, CTA, severe sepsis, burns, acute MI, etc
  • Bad for: Small, fragile veins

14-16g: The Monsters

The 16g and 14g IVs are very large, and unnecessary for most indications. However, in critical situations these may serve you well.

  • Good for: Rapid fluid resuscitation or critical situations as above
  • Bad for: Small veins – Unnecessary for most indications

Also Check out: “10 IV Insertion Tips for Nurses”

An Overview of the different IV gauges and which scenarios they can be used for! #ER #IV #Nursing

Clinical Note

Some nurses may tell you to place the largest IV catheter that the vein can support. However, this is contrary to good nursing judgment. If you ask my friend Brian (@TheIVGuy), he will tell you that you should choose your size based on the appropriate ordered therapy and anticipated needs. This means that for most patients, a 20-22 gauge is likely the best and safest choice.

What equipment to start an IV?

Before learning how to start an IV, you need to first know which equipment you will need. This becomes like second nature, but when starting out as a new nurse, this is often important to memorize. For an IV insertion, you will need:

IV insertion kit

These kits should include:

  • Chlorhexadine or alcohol swab
  • Tegaderm dressing
  • 2×2 gauze
  • tourniquet
  • Tape

IV Catheter

Your IV catheter of choice, usually 18-22g.


A blood transfer device will be needed if you are planning on drawing blood directly after insertion.

Extension Loop or Cap

You will need to place an IV cap or extension loop onto the IV after insertion.

Saline Flush

Make sure you have one or two flushes on hand.

Once you have your equipment, you are ready to know how to start an IV.

How to start an IV

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Prepare the patient

To start an IV, you will first want to wash your hands (always the right starting point). You will also want to use universal precautions, so put on a pair of clean gloves as you will be possibly interacting with the patient’s blood.

You should already have an idea of where you are going to place the IV and which size IV catheter you are going to use.

When starting an IV, place the tourniquet above the area where you plan on cannulating #StartanIVPlace the tourniquet on the patient’s arm proximal to the area of cannulation. Look for straight, large veins. Palpate them as veins may not always be visible but can still be felt. Strong veins will have a good amount of bounce to them.

Once you are happy with your vein selection, you can start prepping your area. Use a chlorhexidine (CHG) or alcohol swab to gently clean the surrounding area for 30 seconds, and allow to completely dry. Start with the center and move outward in a circular fashion with alcohol, while CHG requires a back and forth scrubbing action.

With deeper non-visible veins, some nurses will also apply alcohol to a finger of their non-dominant hand to help palpate during the procedure without “contaminating” the site.

Please note that this is not the best practice for infection control. You should never tear off the finger of your glove either, instead – learn to palpate with your gloves on.

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Prepare your IV Kit

While your site is drying, open your 10cc flush and your extension loop and/or cap.

If you are drawing blood, hook up the blood transfer device to the dry extension loop or cap. Otherwise, you can connect the flush and prime the loop or cap. Set this aside back into your kit to keep it clean.

Open up your IV, take off the needle cap, and twist the end of the catheter to make sure it is loose and ready for cannulation.

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Hold Skin taut

Hold the patient’s skin taut with your non-dominant hand to secure the vein underneath, stabilizing it from rolling, and smoothing the skin for insertion.

Holding the skin taut will help you stabilize the veins when you start an IV
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Plan the right Angle

Place the tip of the needle against the skin at a 10-30 degree angle. The deeper the vein, the more angular your approach will need to be.

When you start an IV, make sure to approach the vein at a 10 to 30 degree angle
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insert the Needle

With the bevel up, puncture the skin and advance through to the vein.

If done correctly, you should see a flashback of blood in the flash chamber and/or catheter. This location will depend on the brand and size of the specific IV catheter. Once a flashback is seen, lower the angle even more parallel with the skin, and advance the whole unit about 2-6mm.

When you start an IV, once you enter the vein you should see a flash of blood

Clinical Note

If you initially don’t see flash of blood, pull the needle and catheter both out almost completely (but do not leave the epidermis). Re-palpate the vein, adjust your angle and advance again. This is termed “digging” and some patients will not tolerate this well. However, oftentimes it may only take 2 or 3 “digs” until success.

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Advance catheter only

Now advance only the catheter forward, sliding it off of the needle and cannulating the vein. If done correctly, the catheter should easily slip into the vein without resistance. If there is dimpling of the skin, the IV is likely within the extravascular space.

Once blood flash is seen and you insert the needle an additional 2-6mm, then advance only the catheter
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Hold Pressure and retract

Before pressing the activation button to retract the needle – take off the tourniquet and apply digital pressure beyond the catheter tip.

Some brands will have a septum or shield function with gauges 20-24, which prevents the backflow of blood and negates the need for venous compression.

Press your activation button to retract the needle.

Many IV catheters will bleed if you do not place pressure over the catheter
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Draw Blood

If ordered, now is the point where you will draw your blood. Hook up your loop/cap with the blood transfer device to the IV hub.

Draw your blood tubes, and flush with a 10cc pulse flush afterward.

If blood is ordered, you can immediately draw this after placing a new IV

If you are not drawing blood, skip this step and instead just connect the primed cap or extension loop to the IV and flush.

After flushing a few mLs, make sure you can pull back blood return. This is reassurance that the IV is in the correct place. Then pulse flush the remaining amount through.

Clinical Tip

Blue Tops for coags (PT/PTT) are often drawn first, and it is necessary to fill these tubes up completely for the lab to run the tests. If you have an extension loop, that .5-1cc in the loop can unfortunately cause the tube not to be full enough and you will need to redraw it. Best practice is to waste a tube first.

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Secure the IV

Secure the IV with a securement device or tape, and a dressing like Tegaderm. Make sure the insertion site is covered. If you used an extension loop, secure the loop with tape as this can easily get caught on something and pull out the IV.

If the patient is confused or may try pulling the IV out, wrap the IV with Coban, only leaving the cap accessible.

Administer any medications or fluids through the IV as ordered.

How to Remove an IV

If the patient is discharged or if there is a compilation with the IV, it will need to be removed. Removing the IV is easier, and can be performed by a nurse or a patient care assistant.

  1. Collect 2×2 gauze and tape or bandaid
  2. Wash your hands and don clean gloves
  3. While holding the catheter in place, start peeling off the Tegaderm and/or tape. Use an alcohol pad if very sticky and painful.
  4. Once the dressing is no longer secured to the skin, place a 2×2 gauze over the insertion site, and pull out the IV in a smooth fashion.
  5. Hold pressure for 1-2 minutes until bleeding as stopped
  6. Dress with gauze and tape or bandaid

Want to learn more?

Hopefully this gave you a good grasp on the basics of how to start an IV.

But if you want to learn more and become an IV King or Queen, I HIGHLY recommend The IV Video Course by @TheIVGuy.

The IV Video course is EXACTLy what you need to take your IV skills to the next level

This course includes:

  • 57 Video modules from the IV basics to more advanced techniques, tips, and tricks
  • In-depth notes with each video module
  • Specific video lectures on how to successfully place IVs in challenging patients including geriatric, bariatric, combative, obese, and IV drug users
  • 21 video demos of basically every type of IV insertion possible
  • 2 hours of CEUs by an accredited ANCC provider

I also include some great free bonuses with the course, including:

  • IV Complications: Prevention, Detection, and Management 8-page pdf
  • IV PUSH GUIDE 15-page pdf
  • Nursing Procedure Manual: Chest Tube Insertion 13-page pdf

Check out more about the course here

These are the steps you need to know how to start an IV #StartanIV #IVstart #IV #Nursing
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