The primary survey (ABCDE) — the trauma assessment framework

Meet the patient

A 24-year-old motorcyclist T-bones a car at speed and rolls into the resus bay agitated, cyanosed, BP 78 palpable, HR 138. His left thigh is swollen and deformed, the trouser leg is soaked, and blood is still pouring from a groin wound. The newest registrar reaches for the laryngoscope.^[3]

Stop. The thing that will kill this man in the next three minutes is not his airway — it is the femoral artery at the groin. Control the bleed first, then secure the airway. That single reordering — <C> before A — is the whole point of the modern primary survey, and the question this topic exists to drill.^[3]

The principle — treat first what kills first, then loop back

Three rules govern every primary survey, and a Fellowship candidate must reproduce all three. First, treat in the order things kill: an obstructed airway kills in minutes, a tension pneumothorax in tens, a raised intracranial pressure in hours — so the airway comes before the breathing, the breathing before the circulation. Second, resuscitate and investigate in parallel: the cannulae, the bloods, the gas and the ECG are obtained while the airway is being secured, not deferred to a tidy afterwards. Third, the survey is a cycle, not a checklist: after every intervention you return to <C> and run it again.^[1][2]

The evolution — from ABCDE to <C>ABCDE and MARCH

The original ATLS sequence, codified in 1980 from the Nebraska farmland crash that nearly killed the orthopaedic surgeon who designed it, began at the airway — because in the blunt civilian trauma of that era, airway loss was the dominant early killer. Forty years of war in Iraq and Afghanistan, plus the civilian penetrating-trauma registry data, redrew that picture: the patient exsanguinating from a limb or junctional wound dies of haemorrhage before the airway is ever threatened. Modern doctrine therefore inserts a catastrophic-haemorrhage step BEFORE the airway — the <C>ABCDE (read C-ABCDE), or its military cousin MARCH (Massive haemorrhage, Airway, Respiration, Circulation, Head injury and Hypothermia).^[3]

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The immediately life-threatening conditions — by letter

The primary survey is the systematic search for the conditions that kill fastest, and each is treated before you move to the next letter. The list below is the viva answer — reproduce it verbatim.^[1][2]

^[1]

<C> — Catastrophic haemorrhage: three tools carry the load

The <C> step is not the full circulation assessment — that is the C of ABCDE. It is the rapid, targeted control of the catastrophic external haemorrhage that will kill the patient in the next three to five minutes. Three tools carry almost the entire burden: the limb tourniquet, the pelvic binder, and direct pressure with haemostatic gauze.^[3]

The limb tourniquet — 5 to 8 cm proximal, and write the time

A catastrophic limb bleed — a partial amputation, a femoral arterial laceration, a deep knife wound to the thigh — is controlled with a windlass tourniquet (the combat application tourniquet, CAT, or equivalent) placed 5 to 8 cm proximal to the wound, never over a joint, tightened until the bleeding stops and the distal pulse disappears. Write the time of application on the patient — the forehead is the military convention — and hand it over at every transition of care. The safe ischaemic time in the awake patient is at least 2 hours with very low risk; the limb-threatening concern rises after 6 hours. Improvised tourniquets (a belt, a blood-pressure cuff inflated above systolic) are inferior and reserved for the austere setting.^[3]

The pelvic binder — at the greater trochanters, not the iliac crests

A mechanically unstable pelvic fracture — the open-book, the disrupted lateral-compression injury — can bleed catastrophically from the venous plexus and the internal iliac arteries into the retroperitoneum, a volume that is invisible externally and kills within the first hour. The pelvic binder (a circumferential sheet sling) closes the ring, reduces the pelvic volume and tamponades the bleed by approximating the bony surfaces. Apply it at the level of the greater trochanters, NOT the iliac crests, on clinical suspicion (a deformed pelvis, the mechanism, the shock) BEFORE the imaging, and leave it in place until definitive fixation or angiographic embolisation. A sheet wrapped firmly around the greater trochanters is the austere equivalent.^[3]

Junctional and trunk bleeds — direct pressure and haemostatic gauze

For the junctional bleed (neck, axilla, groin — where the tourniquet cannot reach) and for the trunk, the control is direct pressure with a haemostatic dressing — chitosan-based Celox or kaolin-based QuikClot gauze — packed firmly into the wound and held for at least 3 minutes. Plain gauze is the fallback. The deep-packing principle is non-negotiable: fill the cavity under pressure; a superficial dressing over a deep cavity fails.^[3]

^[3]

A — Airway with cervical-spine control

The first question is whether the airway is patent, protected and maintainable, because an obstructed airway kills before any other problem. The cervical spine is immobilised from first contact in any patient with a mechanism compatible with spinal injury — rigid collar, head blocks and tape, with manual in-line stabilisation during intubation. The assessment is rapid and clinical: look for chest movement and abdominal breathing, listen for obstructive noise (stridor, gurgling, snoring), feel for airflow at the mouth. Clear the airway (suction, jaw thrust if the C-spine is at risk), insert adjuncts (oropharyngeal for the deeply unconscious, nasopharyngeal if not) and give high-flow oxygen. The definitive airway is the RSI.^[2]

The trauma RSI — the high-risk airway, planned for failure

The trauma RSI is a high-risk procedure: the patient may be hypovolaemic (induction drops the pressure), may have a full stomach (aspiration), may have a cervical-spine injury (in-line stabilisation impairs the view) and may have blood or swelling in the airway (poor view). Plan for failure before you start — the FONA kit is on the tray, the vasopressor is drawn up, two operators are gowned.^[2]

^[2]

The surgical airway — front-of-neck access (FONA)

The cannot-intubate, cannot-oxygenate situation in the adult is rescued by the scalpel-bougie-tube cricothyroidotomy: a transverse incision through the cricothyroid membrane, a bougie passed into the trachea, and a size 6.0 cuffed tube railroaded over it. The technique is muscle-memory, taught on the manikin, and the kit must be at the bedside before the RSI begins. The needle cricothyroidotomy has been de-emphasised in the adult because of its high failure rate (kinking, malposition, inadequate ventilation); it remains a temporising option in the child under 8 years, where the cricoid is too small for the tube.^[2]

B — Breathing and ventilation

Assess the breathing for work, effectiveness and symmetry. Count the respiratory rate over a full minute; gauge the effort by accessory-muscle use, tracheal tug and the ability to speak in full sentences; examine the chest for symmetry of movement, expansion, percussion and auscultation. Record the saturation; capillary refill bridges the breathing and circulation assessments. The immediately life-threatening breathing problems are treated before the examination is completed.^[1]

Tension pneumothorax — a clinical diagnosis, decompressed before the X-ray

Tension pneumothorax is a CLINICAL diagnosis made at the bedside: the triad of respiratory distress, hypoxia and shock, with hemithorax signs of tracheal deviation AWAY from the affected side (a late sign), unilateral hyper-resonance, absent breath sounds and distended neck veins. The chest radiograph is NOT awaited. Immediate decompression is by needle thoracostomy — the modern preferred site is the 5th intercostal space, anterior axillary line (the same site as the chest drain), which is then converted to the definitive drain. The traditional 2nd-ICS mid-clavicular site often fails in adults because the cannula is too short for the chest-wall thickness.^[1]

Open pneumothorax — the three-sided dressing

An open (sucking) chest wound is sealed with a chest seal or a three-sided occlusive dressing — the open side lets air escape on expiration, preventing conversion to a tension pneumothorax. A formal chest drain is placed at a SEPARATE site, never through the wound. If the patient deteriorates after the dressing, briefly lift the seal to release the trapped air — burping the dressing.^[1]

Massive haemothorax — drain, then decide on thoracotomy

A massive haemothorax is more than 1500 mL of blood in the pleural cavity, or an ongoing loss of more than 200 mL per hour. The patient is in shock with absent breath sounds and dullness to percussion on the affected side. Place a large-bore (28 to 36 French) chest drain at the 5th intercostal space, anterior axillary line and measure the output in a graduated collector. If the immediate output exceeds 1500 mL or the ongoing rate exceeds 200 mL per hour, the patient goes to resuscitative thoracotomy or theatre for source control.^[1]

Flail chest and pulmonary contusion — the contusion is the killer

A flail segment — three or more ribs fractured in two or more places — produces a paradoxical (inward on inspiration) segment of chest wall. The flail itself is rarely the killer; the underlying pulmonary contusion is, with progressive hypoxia and shunt over the first 24 to 48 hours. Management is aggressive analgesia (regional blocks — serratus anterior plane, erector spinae plane — first-line, systemic opioids adjunct), oxygen as required, and early non-invasive ventilation (CPAP or BiPAP) for failing oxygenation or rising work of breathing. Intubation is reserved for the patient who fails NIV or has another indication.^[1]

^[5]

C — Circulation and haemorrhage control

The circulatory assessment asks whether tissue perfusion is adequate and, if not, why. Measure the heart rate, blood pressure, capillary refill, peripheral temperature and pulse character; examine the skin for pallor and sweating. Control any external haemorrhage with direct pressure, tourniquet (note the time) and pelvic binder (before the imaging). Site two large-bore cannulae, draw bloods for group and crossmatch, full blood count, coagulation, urea and electrolytes, lactate and venous gas, and obtain an ECG. The resuscitation fluid of choice in bleeding trauma is blood, not crystalloid.^[4]

Damage-control resuscitation — keep the patient warm, the pH up, the clot working

Modern circulation management is damage-control resuscitation (DCR): permissive hypotension, a haemostatic 1:1:1 ratio of plasma to platelets to red cells, minimised crystalloid, and early tranexamic acid. The principle is to avoid the three limbs of the lethal triad — hypothermia, acidosis, coagulopathy — which, once established, drag the patient into an unstoppable cycle of bleeding.^[4]

Permissive hypotension permits a systolic blood pressure of 80 to 90 mmHg (or a MAP of 65 mmHg) in the actively bleeding patient without a traumatic brain injury, on the logic that a higher pressure blows out fresh clots and increases the bleed. Crystalloid is minimised because it dilutes clotting factors, causes acidosis (normal saline has a pH around 5.5 and a high chloride that induces hyperchloraemic acidosis) and contributes to hypothermia. The 1:1:1 ratio — plasma to platelets to packed red cells in equal units — approximates the loss of whole blood.^[4]

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The four shock types — read the peripheries, the pulse pressure and the JVP

The trauma patient is most often in hypovolaemic shock (haemorrhage) but may also be in obstructive shock (tension pneumothorax, cardiac tamponade) — and recognising those at B and C, with a raised JVP and clear lungs, is the prompt to specific treatment rather than a fluid bolus.^[1]

^[1]

D — Disability: the GCS in components, the glucose on everyone

The disability assessment evaluates the central neurological function and several rapidly reversible causes of altered consciousness. Record the Glasgow Coma Score as its components (eye 1 to 4, verbal 1 to 5, motor 1 to 6 — the best motor response is the most informative single value). Examine the pupils for size, symmetry and reactivity — a unilateral fixed dilated pupil suggests uncal herniation. Check the bedside glucose on every obtunded, agitated or fitting patient (hypoglycaemia is immediately reversible). The AVPU (Alert, Voice, Pain, Unresponsive) is the rapid alternative.^[1]

The Glasgow Coma Score — record the components, not the sum

The GCS is three responses: eye (1 to 4), verbal (1 to 5), motor (1 to 6). The best motor response is the most informative single value: localising (the patient reaches above the clavicle to supraorbital pressure) implies an intact motor pathway; withdrawing (pulls away from a peripheral nailbed pressure but does not localise central pain) is one step down; abnormal flexion (decorticate) and abnormal extension (decerebrate) signal deep hemisphere and brainstem dysfunction respectively.^[1]

^[1]

Record the best response in each component — not a sum. A GCS 8 of E1 V1 M6 (the intubated patient obeying commands) is profoundly different from a GCS 8 of E2 V3 M3 (decorticate posturing). A GCS of 8 or below is the traditional threshold for intubation — the airway is no longer protected. A unilateral fixed dilated pupil in a patient with a depressed conscious level suggests uncal herniation (third-nerve compression at the tentorial hiatus) and is a neurosurgical emergency. Check the bedside glucose on every obtunded, fitting or agitated patient — hypoglycaemia is the immediately reversible mimic of every brain injury.^[1]

E — Exposure: warm the patient, examine everywhere, log-roll last

Full exposure allows a complete head-to-toe examination while preserving dignity and preventing heat loss — a cold patient deteriorates across every system (coagulopathy, arrhythmia, slowed drug metabolism). Look for the clue that explains the presentation: a petechial rash in meningococcal disease, surgical emphysema in pneumothorax or oesophageal rupture, a hidden external haemorrhage, an obvious infection source. Measure the core temperature and correct hypothermia actively (forced-air warmer, warmed fluids).^[1]

The log-roll — a delayed procedure, never a primary-survey step

The log-roll turns the supine trauma patient through 90 degrees onto the side with spinal alignment maintained throughout by at least four staff (the leader at the head controls the C-spine, two at chest and pelvis, one at the legs, one to examine the back). It is performed AFTER the patient is stabilised on the primary survey — turning a shocked patient onto the side causes cardiovascular decompensation. During the log-roll, inspect the whole back for bruising, swelling, deformity, wounds and tenderness; palpate the spine for step-off; perform the pelvic spring test with gentle lateral compression only — never AP, which opens the book. In the shocked patient with a suspected pelvic fracture, skip the test and apply the binder.^[1]

^[1]

Temperature — the lethal triad revisited

A core temperature below 35 degrees Celsius is the hypothermia of the lethal triad: the clotting enzymes are temperature-dependent so coagulopathy worsens, fibrinolysis increases, platelet function falls and mortality rises exponentially. Active warming is standard from arrival: forced-air warmer over trunk and limbs, warmed intravenous fluids through a 37-degree blood warmer, heated humidified inspired gases if intubated. Keep the patient warm throughout resuscitation, theatre and ICU.^[2]

The adjuncts — FAST, films, bloods, tubes

The adjuncts run during or immediately after the primary survey. The FAST (focused assessment with sonography in trauma) screens for intra-abdominal and pericardial free fluid. The chest and pelvic radiographs screen for pneumothorax, haemothorax, widened mediastinum and pelvic fracture. The blood tests (group and crossmatch, coagulation, venous gas, lactate) and the urinary and gastric catheters follow — check for blood at the urethral meatus, perineal haematoma and a high-riding prostate before the urinary catheter, because a urethral injury is a contraindication. The ECG screens for arrhythmia and ischaemia.^[2]

The drug doses — the primary-survey pharmacology

The key pharmacological adjuncts of the primary survey, in one place. The induction agent is ketamine (not propofol or thiopental in the shocked); the relaxant is suxamethonium; the antifibrinolytic is tranexamic acid within 3 hours; the fluid is blood-first, crystalloid in minimal aliquots.^[2][8]

^{[2] [8]}

The transition to the secondary survey

The secondary survey — the complete head-to-toe examination, the AMPLE history and the full imaging — is performed AFTER the primary survey has identified and treated the immediately life-threatening conditions and the patient is stabilised. It never precedes the primary survey and never delays the management of a life threat. If the patient deteriorates at any point during the secondary survey, return to the ABCDE and repeat the cycle.^[1]

The mantra

Treat first what kills first — <C> before A, then reassess. Every intervention is followed by a return to the top of the survey. The framework is a cycle, not a checklist.^[1]

Special populations

The paediatric primary survey uses weight-based drug doses and age-specific vital signs, structured by the paediatric assessment triangle (appearance, work of breathing, circulation to the skin). The elderly trauma patient may be seriously injured from a low-energy mechanism; comorbidity and anticoagulation lower the threshold for full trauma-team activation. The pregnant patient is managed with a left-lateral tilt (aortocaval decompression) and fetal monitoring from 20 weeks. The intoxicated patient has a GCS masked by alcohol or drug — the CT excludes the mass lesion you cannot otherwise rule out.^[2]

Exam practice

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Red flags

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Ward-round test

Three stems to close the round. Answer each before you expand the reveal.^[1]

1. Your shocked motorcyclist has a mangled thigh and a tender pelvis. The registrar reaches for the laryngoscope. What do you do first, and why?^[3]

AnswerShowHide

Control the catastrophic external haemorrhage first — direct pressure on the groin wound, a windlass tourniquet 5 to 8 cm proximal to the thigh wound, and a pelvic binder at the greater trochanters before any imaging. Do NOT spring the pelvis. Only then proceed to the airway. The femoral bleed kills before the airway is threatened.^[3]

2. The same patient has a GCS of 7 and a systolic of 80. What is your blood-pressure target, and why does the standard trauma rule not apply?^[4]

AnswerShowHide

Target a systolic of at least 110 mmHg, not the 80 to 90 of permissive hypotension. A single systolic below 90 doubles the mortality in severe traumatic brain injury — the hypotension is catastrophic for the brain. Give blood and fluid to the higher target.^[4][9]

3. During the RSI the saturation falls and you cannot see the cords. Name the three killers of the trauma RSI and the immediate rescue.^[2]

AnswerShowHide

The three killers are hypoxia during the attempt, hypotension at induction, and unrecognised oesophageal intubation. Pre-oxygenate aggressively, halve the induction dose in the shocked patient, and confirm every tube with waveform capnography. The cannot-intubate, cannot-oxygenate situation is rescued by the scalpel-bougie-tube cricothyroidotomy (FONA).^[2]

References9ShowHide

1. [1]Polmear MM, Kakalecik J, Croft C, et al. Early care of polytraumatized patients: a framework for orthopaedic surgeons. Journal of the American Academy of Orthopaedic Surgeons, 2025.PMID 39739953
2. [2]Hannon MM, Middelberg LK, Lee LK. The initial approach to the multisystem pediatric trauma patient. Pediatric Emergency Care, 2022.PMID 35639432
3. [3]Scerbo MH, Holcomb JB, Taub E, et al. The trauma center is too late: Major limb trauma without a pre-hospital tourniquet has increased death from hemorrhagic shock J Trauma Acute Care Surg, 2017.PMID 29190257
4. [4]Rossaint R, Afshari A, Bouillon B, et al. The European guideline on management of major bleeding and coagulopathy following trauma: sixth edition Crit Care, 2023.PMID 36859355
5. [5]Bemelman M, de Kruijf MW, van Baal M, et al. Rib Fractures: To Fix or Not to Fix? An Evidence-Based Algorithm Korean J Thorac Cardiovasc Surg, 2017.PMID 28795026
6. [6]Kragh JF Jr, Walters TJ, Baer DG, et al. Survival with emergency tourniquet use to stop bleeding in major limb trauma Ann Surg, 2009.PMID 19106667
7. [7]Holcomb JB, Tilley BC, Baraniuk S, et al. Transfusion of plasma, platelets, and red blood cells in a 1:1:1 vs a 1:1:2 ratio and mortality in patients with severe trauma: the PROPPR randomized clinical trial JAMA, 2015.PMID 25647203
8. [8]Shakur H, Roberts I, Bautista R, et al. Effects of tranexamic acid on death, vascular occlusive events, and blood transfusion in trauma patients with significant haemorrhage (CRASH-2): a randomised, placebo-controlled trial Lancet, 2010.PMID 20554319
9. [9]Chesnut RM, Marshall SB, Piek J, et al. Early and late systemic hypotension as a frequent and fundamental source of cerebral ischemia following severe brain injury in the Traumatic Coma Data Bank Acta Neurochir Suppl (Wien), 1993.PMID 8310858