Someone is lying on the ground, clutching their chest. You notice bleeding under their right arm. What do you do? Chest seals can be tricky. However, in this article, we'll help everyone understand when to use a chest seal. 

First responders use chest seals for sucking chest wounds. Chest seals can prevent the build-up of air in between the lungs and the chest wall (called the pleural space). Chest seals can be a lifesaver; however, if you don't know how to use them, you could cause more harm than good. 

In this article, you'll get a crash course on the dangers of a chest wound. Then, we'll discuss how to apply an occlusive chest seal. 

When to Use a Chest Seal? 

Chest seals are used to treat penetrating trauma to the torso. This includes the chest, the abdomen (especially the upper abdomen), the back, and the neck.

Here are several things to look for when determining if you should use a chest seal: 

• Sucking wound. If you see a bubbly wound that appears to be sucking air in and out, this means the wound penetrated the pleural cavity (the area where the lungs reside). These wounds need a chest seal. 
• Trouble breathing. Obviously, if a bullet or a knife pierced the chest, there could be some trouble breathing. However, if the knife pierced the abdomen, where it's slightly more difficult to gauge real damage, trouble breathing can indicate the chest is involved. 

Alright, before we discuss how to apply a chest seal, let's discover what a sucking chest seal actually is.

What's a Sucking Chest Wound? 

A sucking chest wound is a name given to any wound to the thorax (front chest and back – basically anything within the rib cage) that cause air to leak into the pleural space of the chest cavity. 

The pleural space is called potential space. Why? When the lungs are working properly, there is no space between the lungs and the chest wall. 

To help picture this, imagine a car tire. You've got the tire itself, and then inside, you have the inner tube, inflated within. There's no space between the inner tube and the tire tread; however, if a nail punctures the tire, the inner tube will deflate, causing air to develop between the inner tube and the tire. 

This isn't a perfect analogy, but a similar thing happens when you "pop the lung" - air collects between the lung and the chest wall. As the air builds up, it pushes on the lungs, causing them to collapse (similar to an inner tube) and inhibiting the ability to breathe. 

When air collects between the lung and the chest wall, it's called a pneumothorax. When air pushes on the lungs, restricting breathing, it's called a tension pneumothorax. Tension pneumothorax is deadly! Hence, why we apply a chest seal.

This is a simplified explanation, but it should give you an idea of how dangerous a chest wound can be. 

Now, let's talk about how to use a chest seal. 

10 Steps to Using a Chest Seal 

Using a chest seal is fairly straightforward. Instead of trying to stop the blood from escaping, you're trying to stop the air from entering. 

It's very important to treat a chest wound quickly. However, there are two maneuvers to perform first: Controlling massive bleeding (applying a tourniquet) and opening the airway. That said, once you've done these two things, it's time to treat the chest wound. 

Here are the steps to applying a chest seal: 

1. Safety. As always, try to ensure you have gloves and eye protection (if possible). Also, move the patient away from any life-threatening situations (like a car fire).
2. Treat life threats. As we already stated, make sure you treat life threats. Of course, a chest wound is a life threat; however, you want to control major bleeding and airway obstruction first. 
3. Assess. If you notice one wound to the chest, there may be more (for example, multiple stab wounds). Of course, with a gunshot wound (GSW), you may have an entry and exit wound. Be sure you assess the front and back of the patient, performing a rapid trauma exam. 
4. Cover the sucking wound. With your hand, cover the sucking chest wound while you prepare your chest seal. Covering the wound with your hand will act as a temporizing measure as you prepare the seal - similar to applying direct pressure before applying a tourniquet. 
5. Expose the wound. Tear the clothing away from the wound (trauma shears help). Trying to apply a chest seal over clothing isn't going to work. You need contact with the skin. 
6. Clean the area. Quickly clean the area. Chest seals are pretty sticky; however, a lot of blood and moisture can disrupt their ability to adhere. Using a gauze pad or a towel, clean the wound.
7. Apply the seal. Place the wound in the center of the seal. Use your hands to push the edges of the seal down, like a sticker. If you have a vented chest seal, use it for the front of the patient. If you have a non-vented chest seal, place it on the back. (more about that later). 
8. Monitor breathing. A chest seal doesn't fix the problem; it only slows it down. The patient could still develop a tension pneumothorax. If the patient begins having serious trouble breathing, you may need to "burp" the seal. You pull the seal off momentary, allowing air to escape (this should happen automatically with vented seals, but it doesn't always!), then replace the seal.
9. Needle decompression. This is beyond the scope of this article; however, professionally trained individuals operating within their protocols should know that needle decompression may be needed even with vented chest seals. 
10. Evacuation. Get to the hospital as quickly and safely as possible.

Alright, hopefully, these steps weren't too hard to follow. Sometimes it's easier to watch than to read, so I'll include links to videos below. 

Here's a video on how to apply a chest seal. 

Let's discuss the different types of chest seals below. 

Improvisation: Standard chest seals are great, and I recommend everybody who's trained to carry them in their trauma kit. However, you can make an improvised chest seal. 

Also, the OLAES bandage comes with a small square of plastic wrap tucked inside, allowing you to cover sucking chest wounds. However, you could use food-grade plastic wrap or the clear wrapper from a gauze pad. 

Vented Chest Seals 

First, let's talk about vented chest seals. Why would you need a chest seal that's vented? Below, I'll share a few reasons why. 

Good reasons to use vented chest seals: 

1. Allows the wound to "burp." Essentially, the vent on a chest seal is built to act as a one-way valve - no air can get in, but air can escape. In theory, vented chest seals allow air to escape, reducing the likelihood of a tension pneumothorax. 
2. You can monitor the wound. Some vented chest seals will also allow blood to drain, which can be useful if you're concerned about a hemothorax (blood building up in the chest cavity instead of air). Also, vented chest seals will usually bubble or move with the air - this can tell you how bad the wound is, as it's not always easy to gauge the size of the cavity. 

Now, let's look at the best times to use a vented chest seal: 

• Sucking chest wounds on the front of the patient. Vented chest seals work best when applied to the front of the patient. Why? If the patient lays on top of the chest seal, the vent won't likely function as it should. 

Here are few brands that make vented chest seals: 

• HALO chest seal. The Halo chest seal comes vented and non-vented. This chest seal is circular in shape. Also, Halo has slightly larger packaging than Hyfin. 
• HYFIN chest seal. Square shaped. It usually comes in a two-pack. (If you're carrying chest seals, you always should have at least two!)

If you’re curious, here’s a video on how to pack and store chest seals. Also, you can fold chest seals if needed!

Unvented Chest Seals 

Unvented chest seals are mainly applied to the back of the patient. However, they still work on the front of the patient - you just need to monitor closely for a tension pneumothorax (which you should do even with a vented chest seal!) 

In addition to sealing the chest, chest seals have some "off-label uses." 

Alternative Ways to Use a Chest Seal 

If needed, you can use a chest seal for more than just chest injuries.

Here are a few ideas:  

• Impaled object. Unless an impaled object inhibits airway management or CPR, you (generally) leave it in place. Chest seals can be cut and used to hold an object in place - sort of like medical duct tape. 
• Abdominal wounds. If someone was punctured around the belly button and no intestines protrude, you can use a chest seal to cover the wound. Though the seal doesn't offer bleeding control, it does protect the wound from contamination and peritonitis (infections within your abdomen - bad!) 

Those are just a few tricks. Now let's wrap things up. 

Final Thoughts Chest Seals

How to apply a chest seal is not always taught in basic first aid classes. However, this is an important skill. With that said, if you dedicate yourself to training, you'll be more likely to do the right thing during an emergency. 

Note: this article is not intended to supersede any local laws or protocols around medical first aid. Be sure to know and follow your local guidelines.