Royal Army College

Lesson Overview

Of the things that kill a casualty quickly, heavy external bleeding is the one a first-aider can most often prevent, and the one that demands the most speed. A casualty bleeding hard from a large limb vessel can fall unconscious and die in two to three minutes, sometimes faster. There is no time in that window to fetch a better kit or read an instruction. That is why catastrophic bleeding sits first in the MARCH sequence from Lesson 02, ahead even of the airway: a blocked airway kills in a few minutes, but a torn artery can empty a casualty faster still, and firm, immediate action will very often stop it dead.

This lesson covers why catastrophic bleeding is treated first; how to recognise it, including when it hides; the three kinds of bleeding and why telling them apart matters; and its heart, a ladder of control measures climbed only as far as each step requires, from direct pressure through a pressure dressing and wound packing to the tourniquet. It also covers haemostatic dressings, the limited place of pressure points, the duty to reassess, and the link forward to shock in Lesson 05.

This is the knowledge layer. Direct pressure, pressure dressings, wound packing, and tourniquet application are physical skills that cannot be learned from a screen. Every hands-on application is taught and certified in person, under qualified supervision, on training aids and then under assessment, and you use only what you are trained and currently authorised to use. The clinical detail here follows current accepted first-aid practice and is confirmed by the College's medical staff. By the end you will be able to recognise life-threatening bleeding, distinguish arterial from venous and capillary bleeding, work the ladder in order, apply a tourniquet correctly and explain why it is not loosened once on, and state clearly where the first-aider's role ends.

Key Terms

Catastrophic (life-threatening) bleeding: blood loss heavy enough to kill quickly unless controlled, often spurting, pooling, or soaking rapidly through clothing.
Direct pressure: firm, sustained pressure applied straight onto a bleeding point to stop the flow; the first and main action.
Pressure dressing (field dressing): a dressing bandaged firmly over the bleeding point, tight enough to hold the pressure for you and free your hands.
Wound packing: firmly filling a deep wound with gauze, right down to the source of the bleeding, then holding firm pressure; used where a tourniquet cannot be placed.
Junctional wound: a wound where limb meets trunk (the groin, the armpit, the base of the neck) beyond a tourniquet's reach, so packing is needed.
Tourniquet: a device tightened around a limb above a wound to stop arterial blood flow when pressure alone fails.
Windlass: the rigid rod on a manufactured tourniquet, turned to tighten the band then locked to hold the pressure.
Haemostatic dressing: a gauze treated to help blood clot, packed or pressed onto the source of bleeding, used with direct pressure where issued.
Distal pulse: a pulse felt beyond the wound, further from the body than a tourniquet; its loss confirms arterial flow has stopped.

Why catastrophic bleeding is treated first

Here is why MARCH's first letter earns its place. A casualty with a blocked airway still has a few minutes before lack of oxygen becomes fatal, and an obstruction is often relieved by a simple change of position. But a casualty whose femoral artery, the great vessel of the thigh, is torn open loses blood with every heartbeat, pumped straight onto the ground. An adult holds roughly five litres, and losing a third to a half is enough to kill; from a major limb artery that loss can happen in the time it takes to open a casualty bag.

So MARCH is speed against the clock: you deal first with what kills fastest and what you can most readily fix, and catastrophic external bleeding is both. It is the commonest cause of preventable death in the kind of incident this course prepares you for: not the unstoppable internal injury, but the limb wound a pressed thumb, a packed handful of gauze, or a tightened tourniquet would have controlled. This lesson makes that first effective action automatic.

Recognising it, and acting at once

Catastrophic bleeding usually announces itself. Fix these signs in your mind, because recognition is the trigger for everything that follows:

bright blood spurting or pulsing from a wound, keeping time with the heartbeat, the signature of a torn artery;
blood pooling on the ground beneath or beside the casualty, more than a small amount;
clothing rapidly soaking through, a spreading dark stain that grows as you watch;
a limb partly or wholly severed, an amputation, which is catastrophic until proven otherwise even if it is not bleeding hard at the moment you find it.

But bleeding can also hide, and missing it is a common, costly error. Thick clothing, body armour, or layered cold-weather kit soaks up a great deal of blood before it shows, and a casualty on their back can pool a dangerous volume underneath them, out of sight, especially on dark or wet ground. So look deliberately: run your gloved hands quickly over the casualty where you cannot see, including underneath, behind, and on the far side, and check your gloves for fresh blood. A wound on the back of a thigh or in an armpit can bleed out unseen while you attend to a lesser injury in front.

The single most important idea in this lesson is that you act in the first seconds, not after a careful examination. Get pressure onto the bleeding point straight away, with whatever you have, your gloved hands first if nothing better is ready, while you or a buddy prepares a dressing or tourniquet. The speed of the first effective pressure does more to save the casualty than any later refinement. Recognise it, and your hands should already be moving.

The three kinds of bleeding

Naming the kind of bleeding tells you how urgent it is and how hard it will be to stop. Three kinds matter.

Arterial bleeding comes from an artery, a vessel carrying blood away from the heart under pressure. It is bright red, rich in oxygen, and spurts or pulses in time with the heartbeat. This is the dangerous kind. From a large vessel it is the catastrophic bleeding that can kill in minutes, and it will not stop on its own, because the pressure driving it keeps reopening any clot. It demands the firmest, fastest control, and it is the kind for which the tourniquet exists.

Venous bleeding comes from a vein, returning blood to the heart at lower pressure. It is darker red, almost purple, having given up its oxygen to the tissues, and it flows steadily rather than spurting, welling up and running from the wound. It can still be heavy, and from a large vein it can be life-threatening in its own right, but being under less pressure it usually yields to firm direct pressure more readily.

Capillary bleeding comes from the capillaries, the tiny vessels feeding the tissues, and is the bleeding of a graze or shallow cut: a slow oozing from the whole raw surface rather than from one point. It is rarely dangerous on its own and usually stops with light pressure and time, though it matters for cleanliness, and a wide raw area can lose more than it first appears.

In practice you will often see more than one kind in the same wound. What guides you is the most dangerous element present: if any part of the bleeding is bright and spurting, treat it as the arterial emergency it is, and do not be distracted by the slower ooze around it.

   THE THREE KINDS OF BLEEDING

   ARTERIAL    bright red    spurts / pulses with the heartbeat   MOST DANGEROUS
   VENOUS      dark red      flows / wells steadily               can be serious
   CAPILLARY   red ooze      seeps from the raw surface           usually minor

The bleeding-control ladder

External bleeding control is taught as a ladder. You start at the bottom rung, the simplest and most effective action, and climb only as far as the bleeding forces you. Most bleeding is stopped on the lower rungs; the higher rungs exist for what the lower ones will not hold. As a single ordered drill, the ladder means that under pressure you are never choosing from a blank page: you press, and if pressing alone will not hold it, you climb.

   BLEEDING-CONTROL LADDER  (climb only as far as the bleeding forces you)

   (4) TOURNIQUET           life-threatening LIMB bleeding that
        ^                   pressure cannot control, or cannot reach
        |
   (3) WOUND PACKING        deep or junctional wound that pressure
        ^                   on the surface will not hold
        |
   (2) PRESSURE DRESSING    bleeding that direct pressure controls,
        ^                   bandaged tight to hold it and free the hands
        |
   (1) DIRECT PRESSURE      ALL external bleeding starts here:
                            firm, straight onto the bleeding point

   Every rung is a HANDS-ON skill certified in person.
   For a limb, severe arterial bleeding may go straight to the tourniquet.

The ladder is the order for most wounds. But for clearly life-threatening, spurting bleeding from an arm or a leg, you need not climb slowly: a tourniquet applied at once is the right first action, because for that wound it is the fastest reliable control. The ladder gives the sequence; judgement, built by in-person training, tells you when severe limb bleeding lets you go straight to the top rung. What you must never do is the reverse: reach for an elaborate measure while neglecting the simple pressure that would have worked. With that in mind, take the rungs in turn.

Rung 1: Direct pressure, the first and main action

For almost all external bleeding, the first and most important action is firm, direct pressure on the wound. Press hard, straight down onto the bleeding point, with your gloved fingers, your gloved palm, or a dressing, and keep pressing. The pressure must be on the bleeding point itself, not vaguely over the area; if you can see where the blood comes from, drive it precisely there. It must be firm enough to be uncomfortable, because it is the pressure, squeezing the torn vessel closed against the tissue beneath, that stops the flow.

A few points make direct pressure work:

Hold it, do not peek. Once pressure is on and the bleeding has slowed or stopped, hold it steadily and resist the urge to lift off and look. Lifting the dressing disturbs the fragile clot and restarts the bleeding; trust the pressure and keep it on.
Soaked through, add on top. If a dressing soaks through, do not peel it off; place another on top and press harder, because removing a blood-soaked dressing strips away the clot with it. The exception is wound packing, below, where the gauze is packed in deliberately.
Let them help if they can. If the casualty is conscious and able, let them press on their own wound while you prepare the next step or attend to another threat. It controls bleeding and keeps your hands free.
Elevate only if it helps and is safe. Raising a bleeding limb can reduce the flow a little, but it never replaces pressure, and you do not move a limb that may be broken to achieve it.

Two cautions belong with direct pressure. First, if an object is embedded in the wound, a fragment, a blade, a splinter of metal, do not pull it out: it may be plugging the very vessel that would otherwise bleed freely, and removing it can turn a controlled wound catastrophic. Press firmly around the object, padding either side to apply pressure without driving it deeper, and leave it for those with the means to remove it safely. Second, protect yourself with gloves and, where issued, eye protection, because catastrophic bleeding means blood under pressure that can reach your face.

Rung 2: The pressure dressing

You cannot stand pressing one wound while a second casualty waits or while you must move. The pressure dressing, often the issued field dressing, holds firm pressure for you. Place its pad directly over the bleeding point, over any packing already in the wound, and bandage it firmly around the limb or body part, tight enough to maintain real pressure on the point, not merely to cover it. A field dressing is built for this: its tails wrap and tie, or its tension bar lets you pull the wrap tight before securing.

Hold onto this principle: the pressure, not the dressing, stops the bleeding. A dressing applied loosely is a bandage, not a pressure dressing, and bleeding continues beneath it, often unseen until it soaks through. So apply it tightly, then watch it: if blood comes through, the pressure was not enough, and you add another dressing firmly on top or climb the ladder. Check too that you have not by accident wrapped a whole limb tight enough to cut off all circulation; that is a different thing from a deliberate tourniquet, and on the lower rungs it is not what you intend.

Rung 3: Wound packing

Some wounds cannot be controlled by surface pressure alone, because the bleeding vessel sits deep inside the wound, beyond the reach of a pad pressed on top. This is true above all of junctional wounds, the groin, the armpit, the base of the neck, where a tourniquet cannot be placed because there is no limb below the wound to compress. For these, where you are trained to do it, the answer is wound packing: you carry the pressure down to where the bleeding actually is.

The principle, taught and certified in person and described here only so you understand it, is this. Expose the wound and find, as best you can, the point inside it where the blood comes from. Then take gauze, plain or haemostatic if issued, and pack it firmly down into the wound cavity, pressing it right onto the bleeding vessel, feeding in more and packing each handful down hard until the cavity is full. The aim is firm, direct pressure deep inside the wound, where the surface pad could not reach. Once packed, you hold firm direct pressure on top.

Packing is not a quick gesture, and two things make it succeed:

Pack onto the source, and pack tight. Loose gauze laid in the wound achieves nothing; it must be driven down onto the bleeding point and packed firmly enough to press it closed. This is uncomfortable for a conscious casualty, and has to be done firmly all the same.
Hold, then bind, then watch. After packing, maintain steady pressure for several minutes without lifting off to peek, because a reliable clot takes time to form and inspecting the wound restarts the bleeding. When bleeding is controlled, a pressure dressing firmly over the packing holds it in place; then watch the dressing for fresh bleeding through it.

Use clean, and where possible sterile, material; packing carries some risk of infection, a price worth paying to stop life-threatening bleeding but a reason to keep the gauze as clean as you can. One caution sits above the technique: you do not pack a wound to the chest or abdomen, or one where you cannot reach the bottom, and packing the neck is a delicate matter taught with particular care, because the airway and the great vessels lie close. Within those limits, pressure applied deep inside the wound, where the bleeding is, succeeds where surface pressure fails.

Rung 4: The tourniquet

For severe, life-threatening bleeding from an arm or a leg that direct pressure has not controlled, or that you cannot reach to press, the right tool is a tourniquet: a band tightened around the limb above the wound until it squeezes the artery shut and all blood flow to the limb stops. Used correctly, on a limb, for a sensible length of time, it is safe and saves life. The old fear that a tourniquet routinely costs the limb comes from poor equipment and very long delays in the past, and should not make you hesitate: applied properly and handed over promptly, it saves limb and life, and a casualty who bleeds to death has lost far more.

Use a manufactured tourniquet wherever one is available. It is far more reliable than anything improvised: it has a strong band, a buckle, and a rigid windlass that lets you reach and hold a high pressure. An improvised windlass tourniquet, a wide strip of material and a strong rod, is a last resort only, because such devices often fail to reach the pressure an artery needs, slip, or break under the load; a narrow cord or wire must never be used, as it cuts the flesh without stopping the bleeding.

Applying a tourniquet correctly is a small number of things, done firmly and in order. Each is a hands-on skill certified in person; what follows is the sequence so you understand it.

Place it high and tight. Put the tourniquet on the limb above the wound. Where you have time and the wound is on a bare limb, position it roughly a hand's breadth above the wound, on skin clear of any joint, because a tourniquet does not work well directly over a knee or an elbow. Where there is no time to expose and search, or the bleeding is severe, place it high on the limb, as high towards the body as it will go, over clothing if need be, provided nothing solid like a bulky pocket or a weapon is trapped underneath. A tourniquet placed high over clothing can be repositioned later by a medical professional; stopping the bleeding now comes first.
Tighten until the bleeding stops and the distal pulse is gone. Pull the band as tight as you can by hand, secure it, then turn the windlass to tighten further, and keep turning until the bright bleeding actually stops, not merely slows, and until the pulse beyond the wound, the distal pulse, can no longer be felt. Loss of that pulse is the sign that arterial flow has been cut off. A tourniquet that has only slowed the bleeding is not tight enough and may have made things worse, blocking the veins while leaving the artery open and trapping blood in the limb. A correctly applied tourniquet is painful, and the pain is not a reason to ease it.
Secure it. Lock the windlass into its clip or holder so it cannot unwind, and fasten the strap that holds it. The tourniquet must stay exactly as tight as you set it through all the handling and movement to come.
Mark the time. Write the time it went on, clearly, on its label and on the casualty; the forehead is the convention, marked for example "T 1420". This is vital information for everyone who treats the casualty after you, because how long the limb has been without blood shapes every later decision about it; an unknown application time forces those who follow to assume the worst.
Do not loosen it. Once a tourniquet is on and working, leave it on. Do not loosen it to "let blood back in", to check the wound, or because the casualty asks; loosening restarts the bleeding and washes away any clot, and repeated loosening and retightening is dangerous. It is loosened or removed only later, by or under the direction of a medical professional, and only when it is safe to do so. If one tourniquet does not stop the bleeding even when fully tightened, do not slacken it: apply a second tourniquet side by side and just above the first, on the body side, and tighten that until the bleeding stops.

Haemostatic dressings and pressure points

Where they are issued and you are trained in them, haemostatic dressings, gauzes treated with an agent that speeds clotting, are a useful addition for severe bleeding a tourniquet cannot address, such as a deep junctional wound. A haemostatic dressing works with pressure, not instead of it: it is packed into or held firmly against the source of the bleeding, exactly as for plain gauze, then pressed and held for the time that dressing requires, often a few minutes, so the agent can take effect. It makes good packing and pressure more effective; it does not replace them. Plain gauze, packed and pressed, remains effective and is what most first-aiders will have to hand.

A word on pressure points, squeezing a major artery against the bone upstream of a wound to reduce the flow into it. Current first-aid practice is clear that a pressure point is not a reliable way to control severe, life-threatening bleeding and must never replace direct pressure, packing, or a tourniquet. At most it is a brief, additional measure, holding back some flow with one hand while the means that actually work are applied with the other, and the College's medical staff confirm where, if at all, it has any place in your training. Do not rely on it, and never let reaching for it delay the pressure, packing, or tourniquet that will genuinely stop the bleeding.

Reassess, and the link to shock

Stopping the bleeding is the start of watching, not the end of the task. A controlled wound can bleed again: a clot can fail, a dressing can loosen with movement, a tourniquet can slip, and a casualty's rising blood pressure as they are warmed and treated can push blood past a control that was holding. So you reassess: look again at every wound and its dressing for fresh blood soaking through; feel, on a limb with a tourniquet, that the bleeding is still stopped; look once more for bleeding you may have missed, underneath and on the back, now the first emergency is in hand; and each time you move the casualty, check the controls have held.

Every casualty who has bled heavily is at risk of shock, the failure of the circulation that follows when too much blood has been lost. Controlling the bleeding is the first and most important treatment for shock, because it stops the loss that causes it; but a casualty who has already lost a large volume can slide into shock even after the bleeding is stopped. So having controlled it, keep them warm, handle them gently, and watch for and manage the signs of shock as Lesson 05 teaches. The two are halves of one task: stop the loss, then support the casualty the loss has weakened.

The firm limits, and the place of speed

Your task in catastrophic bleeding is well defined, and so is its edge. You control external bleeding by the ladder, record what you did and when, treat for shock and keep the casualty warm, and get them to those who can do more, keeping help coming throughout. Beyond that edge is not yours. Internal bleeding, into the chest, the abdomen, the pelvis, or a closed broken thigh, you cannot stop with your hands; you recognise that a casualty may be bleeding inside, treat for shock, and move them urgently to surgical help (Lesson 05). Converting or removing a tourniquet, giving blood or fluids into a vein, and surgery to tie off a vessel are medical and surgical acts, not first-aid ones, and sit outside this course as qualified medical work.

Everything here rewards speed. The interventions are simple, but their value collapses if they come late: the thumb pressed in the first ten seconds saves the casualty that the perfect dressing fetched in the third minute cannot. So practise the ladder in person until your hands know it without thought, so that when the moment comes you press, dress, pack, or tighten at once, mark the time, reassess, keep help coming, and do not stand and narrate while the casualty bleeds.

In Practice: A Roadside Incident on a Quiet Route

A small RKA detachment is moving along a quiet route, assisting the civil authorities, when a vehicle is caught by a blast and a soldier is down at the roadside. Blood is pulsing bright from the thigh and the trouser is darkening fast: arterial, catastrophic. The scene is checked for further danger first, the casualty and a buddy reach the cover of a wall, and within seconds the drill runs. A manufactured tourniquet goes on high and tight above the wound; the windlass is turned until the bright bleeding stops and no pulse can be felt at the ankle below it; it is locked, the strap secured, and "T 0744" marked on the forehead. That first effective action took seconds, not minutes, and took priority over everything else, the airway included, because nothing else was emptying the casualty that fast.

A second casualty has a deep wound in the groin, at the junction where no tourniquet will sit. Surface pressure barely touches it, so the wound is packed: gauze driven firmly down onto the bleeding point, the cavity filled tight, then firm pressure held on top for several minutes without lifting to peek, and a field dressing bound firmly over the packing to hold it. Both casualties are then kept warm and handled gently against shock, both reassessed, their dressings watched and the tourniquet checked, and a clear handover, what was done and at what time, goes to the medic and then to the civilian ambulance crew, with help summoned from the first moment. No one waited for the perfect dressing; the first minute was spent stopping the bleeding by the right rung for each wound, and that is why both were still alive to hand over.

Check Your Understanding

Why does catastrophic bleeding come first in the MARCH sequence, ahead even of the airway, and what does this tell you about how quickly you must act?
Describe the bleeding-control ladder in order, and explain when you would pack a wound rather than apply a tourniquet, and when severe limb bleeding lets you go straight to the tourniquet.
Describe the correct application of a tourniquet: where it goes, how tight (and how you know it is tight enough), what you record, and why you do not loosen it once it is working.

Reflection (write a short paragraph): This lesson says the right action done now beats the perfect action done late, and gives you a ladder so that under pressure you are never choosing from a blank page. Think about what might tempt a first-aider to hesitate at a heavily bleeding casualty, or to climb the ladder in the wrong order, and what you would want to have rehearsed in person beforehand so that you press, pack, or tighten in the first seconds rather than the first minutes.

Summary

Heavy external bleeding can kill in two to three minutes, so it comes first in MARCH; it is often both the quickest threat to kill and the quickest to stop. Act in the first seconds.
Recognise it by spurting or pooling blood, soaked clothing, or an amputation, and look deliberately for bleeding that hides underneath and behind. Tell arterial (bright, spurting), venous (dark, flowing), and capillary (oozing) apart, and treat any bright spurting as the arterial emergency it is.
Climb the ladder only as far as the bleeding forces you: (1) direct pressure, firm onto the point, held without peeking; (2) a pressure dressing applied firmly over it; (3) wound packing for a deep or junctional wound; (4) a tourniquet for life-threatening limb bleeding pressure cannot control. Leave embedded objects in place and press around them.
Apply a tourniquet high and tight above the wound, tighten with the windlass until the bleeding stops and the distal pulse is gone, secure it, mark the time, and do not loosen it; add a second above the first if one will not hold. Use haemostatic dressings with pressure where issued; do not rely on pressure points.
Reassess every control. A casualty who has bled heavily may go into shock: treat for it and keep them warm (Lesson 05), keep help coming, and hand over with times recorded. Internal bleeding and any conversion of a tourniquet are medical acts, and every hands-on skill here is certified in person.

Catastrophic Bleeding