Sucking Chest Wound: How to Recognize and Seal a Penetrating Chest Injury

A penetrating wound to the chest — from a gunshot, stab, or impalement — can turn an ordinary breath into a lethal one. Air gets sucked into the chest cavity through the wound instead of the airway, the lung on that side collapses, and pressure builds until the heart itself is compressed. This is the injury behind the "R" in the MARCH protocol, and the field treatment is fast and specific: seal the hole with a vented chest seal.

This guide covers how to recognize a sucking chest wound and how to treat it. The tool for the job is a purpose-built vented chest seal — and there is a reason it comes in a twin pack.

What is a sucking chest wound?

A sucking chest wound is an open wound through the chest wall that allows air to pass between the outside and the space around the lung (the pleural cavity). Normally that space is sealed, and negative pressure keeps the lung inflated. Once there is a hole, air enters on inhalation and the lung collapses — an open pneumothorax. If air keeps accumulating without escape, it can build into a tension pneumothorax, a rapidly fatal emergency.

How to recognize one

• A penetrating wound anywhere on the torso — remember the wound may be in the back, armpit, or flank, not just the front of the chest.
• A sucking, hissing, or bubbling sound at the wound as the casualty breathes.
• Frothy or bubbling blood around the wound.
• Difficulty breathing, rapid shallow breaths, or a sense of not getting enough air.

Assume any penetrating torso wound between the neck and the navel involves the chest until proven otherwise, and treat accordingly.

How to seal a sucking chest wound

1. Glove up. PPE first, always.
2. Expose the wound. Cut away clothing with trauma shears so you can see and reach bare skin around the wound.
3. Wipe the skin. Chest seals need a reasonably clean, dry surface to adhere. Wipe away blood and sweat around the wound so the seal sticks.
4. Apply a vented chest seal. Peel and place the seal centered over the wound, pressing the adhesive down firmly all the way around. A vented seal lets trapped air escape while blocking air from entering — which helps prevent tension buildup.
5. Check for an exit wound. Penetrating trauma often makes two holes. Sweep the back and sides; if you find a second wound, seal it too. This is why chest seals come in twin packs.
6. Monitor breathing. Watch for worsening distress. Rising pressure despite a vented seal is a medical emergency for EMS to manage — keep the casualty as calm and still as possible until help arrives.

Vented vs. non-vented — and why it matters here

A vented chest seal has a one-way valve or channel that lets built-up air escape, reducing the risk of tension pneumothorax. A non-vented seal blocks air in both directions. For a full comparison of when each is appropriate, read our vented vs. non-vented chest seals guide. Either way, a chest seal belongs in every serious kit — see where it fits on our IFAK contents list.

Where this fits in trauma care

Chest injuries are the third priority in the MARCH sequence, after massive hemorrhage and airway. Understand the full order in our complete trauma first aid guide, and shop respiration-stage gear in the Respiration collection. A loaded kit like the AID-PAK Gen-2 already includes chest seals alongside hemorrhage and airway tools. For hands-on training, visit our education hub.

Frequently asked questions

Can I use plastic and tape instead of a chest seal?

An improvised occlusive dressing taped on three sides is a last-resort field expedient, but a purpose-made vented chest seal adheres better and manages air far more reliably. Carry the real thing.

Why do chest seals come in packs of two?

Because penetrating trauma usually creates an entry and an exit wound. You need one seal for each. Always check the casualty's back and sides for a second hole.

What is the difference between an open and a tension pneumothorax?

An open pneumothorax is air moving through an open chest wound. A tension pneumothorax is trapped air accumulating under pressure, compressing the lung and heart — a life-threatening escalation that needs advanced care fast.

Do I remove the object if it is still in the chest?

No. Leave an impaled object in place, stabilize it, and get EMS. Removing it can cause catastrophic bleeding and worsen the air leak.

How do I know the seal is working?

Breathing should stabilize or improve and the sucking sound should stop. If the casualty gets worse — more distress, rising anxiety, worsening breathing — that is an emergency beyond field care; keep them calm and get them to EMS immediately.

Disclaimer: This article is for educational purposes only and is not a substitute for professional medical care or certified training. Seek qualified instruction (e.g., Stop the Bleed, TCCC) before relying on any trauma equipment.