5.2 Circulation, Perfusion, and Major Bleeding

The Order: Bleeding First, Then Pulse and Skin

The C in the primary assessment is circulation, and the EMR checks it in a deliberate order because the deadliest problem must be found first. Many modern protocols teach X-A-B-C or C-A-B, moving catastrophic hemorrhage control to the very front: a patient can bleed to death from a severed artery faster than from an airway problem. The circulation check therefore answers three questions:

1. Is there major external bleeding? Find it and stop it now.
2. Is there a pulse, and what is its quality? Present/absent, fast/slow, strong/weak, regular/irregular.
3. Is the patient perfusing? Skin color, temperature, moisture, and capillary refill tell you whether blood is reaching the periphery.

Pulse-check locations matter. Use the radial pulse (wrist) in a conscious adult, the carotid (neck) in an unresponsive adult or when the radial is absent, and the brachial (inner upper arm) in an infant. A present radial pulse implies a systolic blood pressure roughly above 80-90 mmHg; loss of the radial while the carotid remains is a sign of falling pressure and worsening shock. As a rough field guide, a palpable radial pulse suggests a systolic of at least about 80 mmHg, a femoral at least about 70 mmHg, and a carotid at least about 60 mmHg — so a patient with only a carotid pulse is critically hypotensive.

Mental status is also a circulation finding. The brain is exquisitely sensitive to perfusion, so a confused, restless, or anxious patient may be telling you the brain is not getting enough blood. Pairing a declining mental status with a weak fast pulse and poor skin signs strengthens the picture of shock — well before a blood-pressure cuff confirms it.

Skin Signs and Capillary Refill

Skin is the EMR's window into perfusion, because the body shunts blood away from the skin early when it is in trouble. Assess three things — color, temperature, moisture — plus capillary refill.

Capillary refill is checked by pressing a nail bed or fingertip until it blanches, then releasing and counting how long color returns. Under 2 seconds is normal; 2-4 seconds suggests impaired perfusion; over 4 seconds is critical. It is most reliable in children and less dependable in cold environments or older adults, so always interpret it alongside skin signs and pulse — never alone. A child with cool, mottled skin and a 4-second refill is poorly perfused even if a blood pressure reads normal, because children maintain pressure until they crash.

Controlling Major Bleeding

Major external bleeding is treated immediately during the primary assessment — you do not finish the survey first. The EMR follows a stepwise sequence:

1. Direct pressure with a gloved hand and gauze, firmly over the wound. This controls the large majority of external bleeds.
2. Pressure dressing — apply a tight bandage to hold pressure so your hands are free.
3. Tourniquet — for life-threatening extremity bleeding that direct pressure cannot control. Apply it 2-3 inches above the wound (not over a joint), tighten until bleeding stops and the distal pulse is gone, and note the time. Do not loosen it. A tourniquet is a first-line tool, not a last resort, for severe arterial limb hemorrhage.
4. Hemostatic dressing packed into a wound, plus direct pressure, where a tourniquet cannot be applied (neck, groin, axilla, junctional areas).

Elevation and pressure-point techniques are now de-emphasized; direct pressure -> tourniquet is the modern teaching for extremities.

Internal and Hidden Bleeding

Not all dangerous bleeding is visible. Internal bleeding into the chest, abdomen, pelvis, or thigh can be massive with no external blood. The EMR cannot stop internal bleeding in the field, but recognizing it drives a load-and-go decision. Suspect internal bleeding when there is a significant mechanism of injury plus shock signs with no obvious external source: a rigid or distended, tender abdomen; bruising over the trunk; pain with a deformed pelvis or femur; vomiting blood or coffee-ground material; or dark, tarry stool.

The treatment is the same shock care covered later — oxygen, warmth, supine positioning, and rapid transport with ALS — because definitive control is surgical.

Bleeding is also classified by source: arterial bleeding is bright red and spurts with each heartbeat (most dangerous, hardest to control); venous bleeding is darker red and flows steadily; capillary bleeding oozes and usually clots on its own. Spurting arterial blood is a primary-assessment emergency that justifies an immediate tourniquet for a limb.

Worked scenario

A construction worker has spurting blood from a deep forearm laceration; bright red blood is pooling fast. Trap: "Take a full set of vitals first." No — apply direct pressure immediately, and if bleeding is not controlled, place a tourniquet above the wound and note the time. Arterial spurting is a load-and-go life threat. Vital signs and the rest of the assessment come after the bleeding is stopped and resources are requested.