Blood from a cut artery is pushed out by the pumping force of the heart, so it looks and behaves differently from an ordinary cut. It can empty a dangerous amount of blood within minutes, far faster than most wounds. Uncontrolled bleeding is the leading preventable cause of death after injury, so the first person on the scene can change the outcome with nothing more than their hands.1PubMed Central. A framework for the design and implementation of Stop the Bleed and public access trauma equipment programs
Signs That the Bleeding Is From an Artery
Colour and flow help tell the three kinds of bleeding apart. Arterial blood is bright red because it is carrying fresh oxygen from the lungs.2CPR First Aid Certification | Healthcare CPR Training. Venous vs Arterial Bleeding: Differences and First Aid Tips It spurts or pulses out in rhythm with the heartbeat.3Tennessee Vein Center. Types of Bleeding Disorders – Alcoa, TN It is much harder to stop than other bleeding.4CPR First Aid Certification | Healthcare CPR Training. Venous vs Arterial Bleeding: Differences and First Aid Tips Blood from a vein is darker red and flows out steadily rather than in pulses.5Online CPR Certification. How to Stop Severe Bleeding: A First Aid Guide Bleeding from tiny surface vessels is a slow ooze that usually stops on its own with light pressure.6Online CPR Certification. How to Stop Severe Bleeding: A First Aid Guide
The signs aren’t always clear in the moment. A deep wound can bleed from an artery and a vein at once, which mixes the colours. Spurting can be hidden if the wound is under clothing or the blood is pooling. Bleeding that soaks through a pressed cloth within moments is a warning on its own, whatever the colour. If you’re in doubt, treat it as arterial. The steps are the same, and over-treating costs little.
A cut that looks “not that bad” can still be serious. Blood pooling on a floor, soaking a sleeve, or running down inside a trouser leg can hide how fast it is coming out, so judge by how quickly cloth becomes soaked. Dark blood doesn’t rule out an artery, because blood looks darker in poor light or on dark clothing. Spurting can also weaken as blood pressure drops, so a wound that was pulsing and now only flows may be getting worse, not better.
Watch the person as well as the wound. Pale, cold or clammy skin and sweating, fast breathing and a racing heart, and confusion, dizziness or drowsiness all point to heavy blood loss. Any of these means the bleeding is already serious and help is urgent.
Some places are more likely to hide an artery. Among serious limb artery wounds, the artery on the inside of the upper arm is the one most often hit, followed by the large artery in the groin and upper thigh.7International Journal of Vascular Surgery and Medicine. Management of serious arterial injuries of the limbs The arteries of the lower leg and behind the knee are also commonly injured.8Folia Morphologica. The most common anatomical sites of arterial injury in the extremities: a review of 75 angiographically-proven cases So a deep cut to the inner arm, groin, inner thigh, or behind the knee deserves extra suspicion.
What to Do Right Away
Call your local emergency number, or have someone else call while you act. Then press firmly and directly on the bleeding point with a cloth, gauze, or your bare hand if nothing else is near.9PubMed. Hemorrhage control-Proper application of direct pressure, pressure dressings, and tourniquets for controlling acute life-threatening hemorrhage Use gloves or a plastic bag over your hand if you have them, but don’t delay pressure to search for them. Keep pressing hard without lifting to check, because lifting lets the bleeding restart. If blood soaks through, add more cloth on top rather than removing the first layer.
To press hard enough, use the heel of your hand, or both hands stacked, and lean your body weight in. Kneeling over the person lets you hold pressure longer without tiring. Hold it until help takes over, even if that is many minutes.
Cut away or pull aside clothing so you can see exactly where the blood is coming from. If a long wound is bleeding in several places, press on the point where the blood is coming out fastest. If something is stuck in the wound, such as a knife blade or glass, leave it in place and press around it rather than pulling it out.
For a deep wound in the groin, armpit or neck, where a tourniquet can’t go, pack cloth or gauze firmly into the wound and press on top. Hemostatic gauze, sold in many first aid and bleeding control kits, contains substances that speed up clotting.10PubMed Central. Design and Preclinical Evaluation of Chitosan/Kaolin Nanocomposites with Enhanced Hemostatic Efficiency In artery wounds of the thigh, these gauzes stopped bleeding reliably when packed and held.11Polish Journal of Veterinary Sciences. Safety of the long-term application of QuikClot Combat Gauze, ChitoGauze PRO, and Celox Gauze in a femoral artery injury model in swine
If you are alone and the one bleeding, call emergency services first and put the phone on speaker, then press. Sit or lie down so you don’t fall if you get faint. Wrapping a tight cloth or tying a shirt over the packing can free a hand. Unlock the door, or tell the dispatcher where you are early, so responders can reach you.
When and How to Use a Tourniquet
A tourniquet is a strap tightened around a limb above the wound to squeeze the artery shut. It saves lives. Bystander use before the ambulance arrives has been linked to about six times fewer deaths in people with limb artery wounds.12PubMed Central. A framework for the design and implementation of Stop the Bleed and public access trauma equipment programs Proper commercial tourniquets stopped bleeding in about 95 in 100 arm placements and 88 in 100 thigh placements.13Canadian Journal of Emergency Nursing. Comparison Of Non-clinical Tourniquet Research for Appliance Superiority & Tolerance (CONTRAST): a systematic review and meta-analysis of commercial and improvised tourniquet devices for arterial occlusion, application speed, and tolerance Designs with a winding rod or ratchet worked best, while simple stretchy bands worked worst.14Canadian Journal of Emergency Nursing. Comparison Of Non-clinical Tourniquet Research for Appliance Superiority & Tolerance (CONTRAST): a systematic review and meta-analysis of commercial and improvised tourniquet devices for arterial occlusion, application speed, and tolerance
Deciding between pressure and a tourniquet is simple in most cases. If one person can hold firm pressure and it is working, with bleeding slowed and cloth no longer soaking through, keep pressing. Move to a tourniquet when blood keeps coming through firm pressure, when there are several casualties, or when you can’t hold pressure for long. A tourniquet only goes on arms and legs, so for the neck, chest or groin, where it can’t sit above the wound, packing and pressing remains the method.
With a commercial tourniquet, slide or wrap the strap around the limb a few centimetres above the wound, between the wound and the heart, and not over a joint such as the knee or elbow. Pull the strap tight, then turn the windlass rod or ratchet until the bleeding stops completely, not just slows. Lock the rod in its clip or hold, and write down the time on the tourniquet or the person’s skin. Then check the wound again. If blood is still coming out, tighten further or put a second tourniquet right above the first.
A tourniquet that is too loose blocks blood leaving the limb but not blood entering it, so the limb fills with trapped blood and bleeding can actually get worse.15European Journal of Trauma and Emergency Surgery. The safety and efficacy of improvised tourniquets in life‑threatening hemorrhage: a systematic review Keep tightening even when the person says it hurts badly. The pain is expected.16European Journal of Trauma and Emergency Surgery. The safety and efficacy of improvised tourniquets in life‑threatening hemorrhage: a systematic review
Tourniquets were safe and effective in children and teenagers with limb wounds.17PubMed Central. Pediatric tourniquet use: Safe and effective They were harder to apply properly on younger, smaller children. On a small limb, wrap extra turns and check that bleeding has fully stopped.
A tourniquet left on for many hours can damage the limb and kidneys, but that mainly happens when getting to surgery is long delayed. Never loosen it yourself once bleeding has stopped; leave that to medical staff.
How Quickly Arterial Bleeding Becomes Dangerous
At rest the main thigh artery carries about 200 to 400 ml of blood a minute.18Responder Aid. Major Bleeding – how quickly will they bleed to death? Under stress or effort that can climb to 1,000 ml a minute or more, about a fifth of an adult’s blood.19Responder Aid. Major Bleeding – how quickly will they bleed to death? So an uncontrolled thigh artery wound can lose over 40% of the blood in about 2 minutes, which is often fatal.20Responder Aid. Major Bleeding – how quickly will they bleed to death? Losing around 40% of blood volume brings on shock, where the body can no longer keep organs supplied.21PubMed Central. Haemorrhage and Survival Times: Medical–Legal Evaluation of the Time of Death and Relative Evidence A wound near where an artery branches off is far faster than one further along a smaller branch.22PubMed Central. Haemorrhage and Survival Times: Medical–Legal Evaluation of the Time of Death and Relative Evidence
Not every artery cut bleeds at the thigh-artery rate. A smaller artery loses blood more slowly, but the risk grows with each minute pressure isn’t applied.
Keeping the person still helps. Running or struggling can multiply the heart’s output up to four times,23PubMed Central. Haemorrhage and Survival Times: Medical–Legal Evaluation of the Time of Death and Relative Evidence which shortens the time to dangerous blood loss. Have the person lie down and stay still while you press, and keep them warm with a coat or blanket.
A cut fingertip or scalp artery spurts but rarely drains enough to threaten life. It still needs firm pressure for 10 minutes or more and a medical check, and it may need stitches, including one to tie off the vessel.
Methods That Don’t Work Well
Current first aid guidelines no longer recommend raising the limb to control severe bleeding.24First Aid for Life. First aid for life threatening bleeds – How to Use an Improvised Tourniquet It slows the flow a little but won’t stop an artery bleeding.25First Aid for Life. First aid for life threatening bleeds – How to Use an Improvised Tourniquet Pressing on a pressure point higher up the limb isn’t advised for bystanders either, because each limb has more than one artery feeding it, and the points are hard to find, especially in the groin.26First Aid for Life. First aid for life threatening bleeds – How to Use an Improvised Tourniquet Trained people in controlled tests could block arteries this way, which is why older guides mention it. For a real wound, press on the wound itself.
Homemade tourniquets are less reliable than proper ones but may be better than nothing.27PubMed. Bleeding Control With Limb Tourniquet Use in the Wilderness Setting: Review of Science A necktie is usually too thin and a leather belt too stiff to twist tight enough by hand.28First Aid for Life. First aid for life threatening bleeds – How to Use an Improvised Tourniquet If a belt is all you have, you can loop it and twist a rod through it to gain leverage, though a wider cloth strip works better. Narrow, sharp-edged improvised bands are also more painful and more likely to injure nerves.29European Journal of Trauma and Emergency Surgery. The safety and efficacy of improvised tourniquets in life‑threatening hemorrhage: a systematic review
The better choice is a strip of cloth at least 4 cm wide with a stick twisted through it as a winding rod.30First Aid for Life. First aid for life threatening bleeds – How to Use an Improvised Tourniquet Wrap the strip twice around the limb above the wound and tie a half knot. Lay a sturdy stick, pen or spoon on the knot and tie a full knot over it. Twist the stick until bleeding stops, then tie or tape it so it can’t unwind. If bleeding continues, the band is too loose, so keep twisting or add a second above it.
What Happens at the Hospital
Paramedics in many areas can give a medicine called tranexamic acid that helps clots hold.31PubMed Central. Prehospital administration of tranexamic acid in trauma patients In badly injured people it roughly halved deaths in the first 24 hours.32PubMed Central. Prehospital administration of tranexamic acid in trauma patients It also reduced the amount of transfused blood needed by about two units on average.33PubMed Central. Effectiveness and safety of prehospital tranexamic acid in patients with trauma: an updated systematic review and meta-analysis with trial sequential analysis Tranexamic acid works best when given early after injury, and it supports stopping the bleeding but doesn’t replace pressure, a tourniquet and surgery. Some ambulance services also carry blood to give on scene.34PubMed Central. Prehospital tranexamic acid decreases early mortality in trauma patients: a systematic review and meta-analysis Surgeons then usually repair the artery by stitching the cut ends together or bridging the gap with a graft.35PubMed Central. A simple and rapid vascular anastomosis for emergency surgery: a technical case report
Tell the paramedics when the injury happened and what caused it, and the time the tourniquet went on. Mention any medicines the person takes, especially blood thinners, along with any allergies or medical conditions.
After surgery, staff check pulses and blood flow below the repair often in the first days.36PubMed. Biodegradable and flexible arterial-pulse sensor for the wireless monitoring of blood flow Expect questions about numbness, colour and warmth in the hand or foot, and report any new coldness or pain promptly.
Warning Signs in the Weeks After an Injury
An injured artery can slowly leak into a pocket of tissue, forming a leaking bulge in the artery, which doctors call a pseudoaneurysm.37PubMed Central. Delayed superficial femoral artery pseudoaneurysm following distal femoral shaft fracture: A case report Painful swelling is the most common sign, sometimes with a lump that pulses.38Formosan Journal of Surgery. Management of traumatic arterial pseudoaneurysms as a result of limb trauma It can appear weeks after the injury, in one case 6 weeks after a broken thigh bone.39PubMed Central. Delayed superficial femoral artery pseudoaneurysm following distal femoral shaft fracture: A case report Behind the knee, a large one can stop the knee straightening fully.40PubMed. Delayed presentation of traumatic popliteal artery pseudoaneurysms: a review of seven cases A new swelling near an old wound that grows, throbs or hurts needs a doctor promptly.
Unlike a bruise, which fades over days, a leaking bulge grows or stays tense and may throb with your pulse. Numbness or weakness beyond the swelling is another reason to get checked.
A bulge is more likely after a deep wound, a stab or glass injury, or a bone fracture that has damaged a nearby artery, even if bleeding was stopped at the time. An artery wall that was damaged but not cut through can weaken and slowly bulge, so a person may feel fine after the first emergency.
Being Ready to Help
Up to 40% of injury deaths come from uncontrolled bleeding, and up to about half of those happen before reaching hospital.41PubMed Central. A framework for the design and implementation of Stop the Bleed and public access trauma equipment programs Yet fear of doing harm and worries about legal trouble stop many bystanders from helping.42PubMed Central. Bystander interventions and their impact on road injury outcomes: a scoping review Short public courses such as Stop the Bleed teach pressure, packing and tourniquets in a few hours.43PubMed Central. A framework for the design and implementation of Stop the Bleed and public access trauma equipment programs Public bleeding control kits are increasingly placed alongside defibrillators in schools and workplaces.44PubMed Central. A framework for the design and implementation of Stop the Bleed and public access trauma equipment programs
For home, the car, or a workshop, a commercial windlass tourniquet performs better than improvised ones. Add clotting gauze or plain rolled gauze for packing, plus gloves and a pressure bandage. Practise putting the tourniquet on your own arm once so you know how it feels.
On legal worries, many countries have Good Samaritan laws protecting people who help in good faith. Acting to stop bleeding is what dispatchers and guidelines ask bystanders to do, and the emergency dispatcher can coach you step by step on the phone.