4 steps to owning the infant IV

From where to begin, to last-resort options: Tips and tricks I’ve picked up during hundreds of pediatric IV placements

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Caring for sick infants is hard. Getting IV access is even harder. Infants are wriggly, their veins are small and they often have excess adipose tissue. All these factors contribute to the difficultly of placing a line. [At the end of this article, download a printable, sharable guide to pediatric IV access points.]

The challenge is compounded by the fact that infants make up a fraction of EMS calls and even fewer need IV access. Many providers are left lacking confidence about obtaining IVs in this population.

I have worked previously as a pediatric critical care paramedic, an ER technician and now as a resident physician who still starts the occasional infant IV. Here are some tips and tricks I have picked up during hundreds of pediatric IV starts over the years.

A bright light, whether it be a small mag light, an otoscope or the flashlight on your phone can help you to visualize vasculature in pediatric patients.
A bright light, whether it be a small mag light, an otoscope or the flashlight on your phone can help you to visualize vasculature in pediatric patients. (Photo/Getty Images)

1. Selecting the right size

Size matters, but when it comes to infants, I am a firm believer the correct size is a 24. I have seen providers attempt 22 gauge IVs on these kids, but the simple fact is there is just no need.

Let’s explore the math. The average 6 month old weighs around 7 kgs. A 20 mL/kg bolus is only 140 mLs of fluid. A 24 gauge IV has a free flow rate of 20 mL/min so your bolus can, in theory, run in over 7 minutes. A 70 kg adult getting a 20 mL/kg bolus would need two 18 gauges running wide open to get a bolus in over the same time.

In other words, in our smaller patients, that 24 gauge is like a pipe! Anything bigger risks blowing the vein and causing unnecessary pain.

There are also multiple lengths of 24 gauge IVs. I have a strong preference to the shorter versions. They are easier to thread the catheter into a short vein (e.g., in the hand) without as much risk of blowing the vein. The short catheters also have faster flow rates than their longer counterparts. If you don’t believe me, Google Poiseuille’s Law. Checking to see if your department carries shorter, small-bore catheters may be worth your time.

2. Picking a site

There are a few options for where to place a pediatric IV, some better than others.

  • Feet. This is my favorite spot. Many infants have a big juicy vein running up the middle of their anterior foot. It is both easier to limit motion of the foot and to secure an IV in comparison to the hand. If you cannot see the vein, it can often be found by transilluminating with a light across the top of the foot at a slightly oblique angle. We often avoid this site in adults due to poor vascular flow and because it limits patient mobility. These are not problems in infants.
  • AC. Infants don’t always have an easy-to-find AC vein. If you can find one, this is a great option. Just don’t forget the arm board.
  • Hand. This can be a great spot. Most infants have at least one vein running up the middle of their hand. The hand is often the best site for transillumination. Hold the light snug against their palm and watch the veins light up. I will sometimes keep the light under the hand even while I am sticking so I can continue to see the vein throughout the procedure.

    The mobility of the upper extremity can make getting an adequate hold challenging. It can also be difficult to secure the IV, as it is not uncommon for the hub to stick off a smaller infant’s hand. When this occurs, I will use a wad of gauze to create a platform that can be taped to the hand to help secure the portion that is sticking off.
  • Scalp. Many medics don’t consider the scalp, but it can be a great access point if there is nothing else available. Follow your local protocols on this one. Babies’ heads are huge and subsequently get lots of blood flow.

    Good spots to access are just above the ear, either right in front or behind it. The top of the forehead around the midline area often is a great spot as well. Do not place an IV over an open suture or near the eye. Also make sure you are staying superficial and that the IV points in the direction of the vein returning blood to the heart.

    It’s important to note scalp veins do not have valves. This means air can be entrained and even small amounts of intravenous air in a tiny infant can be extremely dangerous. You need to immediately cap this or place your pigtail to prevent air entering the infant’s circulation. If removed, the site should be covered with an occlusive dressing and extra caution should be used to avoid injecting air.

    I would not run pressors or any caustic medications through these lines, but for fluids and many other medications, this is a viable option.
  • Lower leg. Well before my time, saphenous vein cut downs were a go-to access point. Physicians would access a deep leg vein by cutting into a child’s lower limb to place the line. This procedure has mostly been replaced by the IO. While most of the saphenous vein is too deep to access without a cut down, there are other more superficial veins in the lower leg.

    Look on the inner aspect of the patient’s ankle and you may find something viable. You may be able to transilluminate this area in younger infants, but make sure the juicy vein you find is not the artery! At the end of the day, this is a very challenging IV site and should be a last resort.

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3. Finding a vein

I personally find children at about 6 months old the hardest to get lines on. These miniature humans seem to have reached peak chubbiness to muscle ratio. Add in some dehydration, and finding a vein in that sea of adipose is going to be hard.

Rather than play poke and hope, I often use transillumination. You don’t need a fancy purpose-built vein finder. All you need is a bright light, whether it be a small mag light, an otoscope or the flashlight on your phone. Placing this under the infant’s hand, foot or side of the leg will allow it to shine through and you will be able to visualize the vasculature. Unfortunately, older infants are a bit too beefy for this to always work, but this has helped me on countless occasions to find a vein that was deep in the tissue.

Some warm water in a glove or a commercial neonatal heel warmer may help plump up a vein as well. Just use caution in applying conventional hot packs or putting hot water in a glove as these can cause burns to the infant’s fragile skin.

4. Immobilizing the patient

Holding the child still is arguably the most important part of starting a line on an infant. They are going to move and if they do, you will fail to get your line.

To counteract this, I papoose 100% of infants and small children who are not obtunded. I use a sheet or blanket, leaving their head and selected extremity exposed. I make sure they are snug enough they can’t wriggle out. If you have extra providers on scene, I have one keep their hands on the baby’s waist and chest to minimize movement. This is also a great job for a parent if it is just you and a partner.

I then have a crew member hold whichever extremity we have selected, applying opposing forces over the large joints so the infant cannot bend at the elbow or knee. This is easy – just have your holder grip above the elbow on the tricep and push up toward the sky. Then have them place their other hand below the elbow, pushing down toward the floor. This will immobilize the arm so it cannot flex or extend. The same technique can be applied to the leg to neutralize large joint movement.

I will use my free hand to both pull the skin taught and immobilize the foot or the hand while starting the IV with the other. If I am trying for an IV in the AC vein, I will have the holder gently rotate the hand facing toward the sky and have them directly put pressure on the base of the thumb. This will help keep the infant from twisting the arm or pulling away.

I cannot emphasize the importance of taking the time to make sure everyone has a good hold prior to starting, it will make the procedure go smoother and your chances of success will be much higher.

Keys to success

Next time you start an infant IV, make sure to take your time in finding your site, use a 24 gauge and have multiple people help you get a solid hold. If you do all these things, pretty soon you will be owning the infant IV.

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5 pediatric IV access points

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