ATLS Primary Survey and Trauma Resuscitation

Why it matters. Trauma is the leading cause of death in people aged 1 to 44 years worldwide, and injury accounts for 5.8 million deaths a year (WHO data). Road traffic crashes are the leading mechanism in young adults globally and falls the leading mechanism in elderly trauma patients; penetrating trauma is an increasing proportion in urban centres worldwide, and blast and combat injuries come from military conflict zones and terrorism.

The trimodal distribution. Trauma deaths fall in three peaks:

• Immediate (minutes): lethal injuries and haemorrhage
• Early (minutes to hours): the "golden hour", where ATLS interventions save lives
• Late (days to weeks): multisystem organ failure and sepsis

The primary survey targets the second peak, where timely, systematic intervention is most impactful, and haemorrhage is the leading preventable cause of death in that period. Up to 30 percent of trauma deaths may be preventable with timely care, and organised trauma networks reduce mortality by 15-25 percent.

The clock. The first 60 minutes from injury is the window in which intervention has the highest impact, and within it the "platinum 10 minutes" is the critical window for completing the primary survey.

The primary survey ends where three other decisions begin: how the whole patient is prioritised once resuscitated (polytrauma management), when a fracture gets a temporising external fixator instead of definitive fixation (damage-control orthopaedics), and how the trauma imaging is read once the patient is stable enough to have it (systematic trauma imaging).

The approach. The primary survey is a rapid, systematic framework for identifying and treating life-threatening injuries in order of priority: Airway with cervical spine protection, Breathing, Circulation with haemorrhage control, Disability, and Exposure. Each step is completed and addressed before moving to the next, the whole survey is completed within minutes, and simultaneous assessment and intervention by a trauma team is the standard of care.

ABCDE or cABCDE. The civilian ATLS sequence assesses the airway first. Tactical Combat Casualty Care, military and prehospital practice put a "c" in front of it: catastrophic external haemorrhage, the exsanguinating arterial bleed, is controlled before the airway with a tourniquet, direct pressure or a pelvic binder.

The ATLS 10th edition (2018) acknowledges the cABCDE approach, and in civilian practice catastrophic external haemorrhage (an exsanguinating limb, a massive scalp bleed) should be controlled simultaneously with or even before airway assessment. The tactical version of the survey is MARCH: massive haemorrhage (tourniquet, wound packing), airway with C-spine precautions, respiration (treat tension pneumothorax, chest seal for open wounds), circulation (haemorrhage control, IV access, blood products), and hypothermia and head injury (prevent heat loss, assess neurological status).

The physiological response to blood loss. Haemorrhage is graded into four classes by the volume lost and the response it produces:

Trauma-induced coagulopathy. Up to 25 percent of severely injured patients are already coagulopathic on arrival, before any fluid has been given, and this coagulopathy is an independent predictor of mortality. It is driven by:

• Tissue injury releasing tissue factor and thromboplastin
• Shock causing endothelial activation and glycocalyx disruption
• Hyperfibrinolysis (pathological clot breakdown)
• Protein C activation (the anticoagulant pathway)

It must be anticipated and treated proactively with haemostatic resuscitation from the outset.

Fat embolism syndrome. Long bone and pelvic fractures release fat globules into the circulation. The features appear typically 24-72 hours after injury: respiratory distress (the most common), cerebral dysfunction (confusion, altered consciousness) and a petechial rash over the upper body, axilla and conjunctiva, which is pathognomonic but present in only 20-50 percent. Early fracture stabilisation reduces the incidence, which is a key rationale for damage-control orthopaedics in polytrauma.

Shock in trauma. Haemorrhagic shock is the most common form, confirmed by FAST, CT or a dropping haemoglobin, and the primary survey has to distinguish it from the obstructive, neurogenic and cardiogenic types:

Differentiating the type is critical because giving volume to a patient with obstructive shock from a tension pneumothorax will not restore the blood pressure; decompression is needed first.

A: airway with cervical spine protection. Airway always comes first, because a patient who cannot breathe through a blocked airway will die before any other injury matters; the life threats at this step are airway obstruction and cervical spine injury. A talking patient has a patent airway. Inspect for secretions, blood, vomit, foreign bodies and swelling, and listen for stridor, hoarseness, gurgling or snoring. Manual inline stabilisation (MILS) is maintained throughout and a semi-rigid collar applied; MILS is required during intubation, and the collar is not removed to intubate.

• Jaw thrust (not head tilt-chin lift), suction, oropharyngeal airway
• Nasopharyngeal airway, contraindicated in suspected base of skull fracture
• Endotracheal intubation
• Surgical cricothyroidotomy as the last resort

B: breathing and ventilation. Look at chest expansion (is it symmetrical?), respiratory rate, accessory muscle use, flail segments and open wounds. Listen for breath sounds bilaterally, added sounds and absent sounds (pneumothorax or haemothorax). Feel for tracheal position (central or deviated), subcutaneous emphysema and chest wall crepitus, and percuss: dull is haemothorax, hyper-resonant is pneumothorax. Give high-flow oxygen at 15 L via a non-rebreather mask and titrate SpO2 to 94-98 percent. The immediately life-threatening chest injuries, treated in the primary survey:

C: circulation with haemorrhage control. Haemorrhagic shock and cardiac tamponade are the life threats. Feel the pulse for rate, rhythm and quality (thready means shock) and compare radial with femoral. Blood pressure may be normal in compensated shock, and tachycardia is the earliest sign. Capillary refill is normally under 2 seconds, and a central (sternal) refill is more reliable in hypothermia; cool, pale, clammy skin is the vasoconstriction of shock. Establish two large-bore cannulae (14G or 16G) in the antecubital fossae, or intraosseous access if that fails, and draw blood for the laboratory studies listed under Investigations. Haemorrhage control and the massive transfusion protocol begin here.

D: disability. The Glasgow Coma Scale scores Eye (1-4), Verbal (1-5) and Motor (1-6) to a maximum of 15, and a GCS under 8 indicates the need for definitive airway protection by intubation. Check pupil size, equality and reactivity (a unilateral fixed dilated pupil suggests uncal herniation), lateralising signs (asymmetric motor responses, a Babinski reflex) and the spinal cord level (sensory level, motor function in all four limbs). Check a bedside glucose, since hypoglycaemia masquerades as a reduced GCS. The life threat is an expanding intracranial haematoma, and the response is CT head and neurosurgical consultation.

E: exposure and environment. The patient is fully exposed and log-rolled for the posterior examination; hypothermia and missed injuries are the threats at this step, and the secondary survey follows.

The history. The trauma history is taken as AMPLE:

Special populations. The same ABCDE applies to everyone, but two populations have physiology that will catch you out, and in both the danger is the same: normal-looking observations bought at a price the patient cannot keep paying.

The paediatric trauma patient. Children compensate, then crash: they maintain a normal blood pressure until roughly 30 to 45 percent blood loss, so hypotension is a late, pre-terminal sign and tachycardia is the earliest indicator of shock. Resuscitation is weight-based: estimate the weight (age formula or a length-based tape), give 20 mL/kg crystalloid boluses then 10 mL/kg of blood, and use intraosseous access early if IV access fails. The anatomy differs: a relatively large head and small airway, a high surface-area-to-mass ratio that makes hypothermia a major risk, compliant ribs that allow significant pulmonary contusion without rib fracture, and an immature spine that gives cord injury without radiographic abnormality (SCIWORA). Always consider non-accidental injury.

The pregnant trauma patient (after about 20 weeks). The gravid uterus compresses the IVC and aorta when the patient is supine (aortocaval compression), causing supine hypotension; manage it with 15 to 30 degrees of left lateral tilt or manual uterine displacement. Maternal blood volume is expanded by around 40 to 50 percent, so she can lose large volumes before showing signs while the fetus is already hypoperfused: resuscitate the mother to save the fetus. Assess the fetal heart rate or CTG, send a Kleihauer-Betke test for fetomaternal haemorrhage, give anti-D (Rh immunoglobulin) to Rh-negative mothers, and do not withhold essential imaging. Consider a perimortem caesarean section within about 4 to 5 minutes of maternal cardiac arrest if the gestation is around 23 weeks or more, which improves maternal and fetal survival.

Monitoring. Continuous ECG monitoring and pulse oximetry run from the outset, and end-tidal CO2 (capnography) once intubated confirms the tube position and guides ventilation. An arterial blood gas gives the lactate (over 4 mmol/L is severe shock), base deficit and pH, and a bedside glucose is checked alongside.

The trauma series. The traditional "triad" of X-rays is the chest, the pelvis and the lateral cervical spine:

• Chest X-ray: pneumothorax, haemothorax, mediastinal widening (aortic injury), rib fractures
• Pelvic X-ray: pelvic ring disruption; if unstable, apply a pelvic binder immediately
• Lateral C-spine: in ATLS the cervical spine is cleared clinically (Canadian C-Spine Rule or NEXUS criteria) or by CT, and a plain X-ray alone is insufficient

Practice has moved: many centres proceed directly to whole-body CT (pan-scan) in haemodynamically stable patients, replacing the traditional plain film series.

FAST. Focused assessment with sonography for trauma is bedside, rapid and repeatable, and has four standard views:

1. RUQ (Morison pouch): free fluid between liver and kidney, the most sensitive view
2. LUQ (splenorenal): free fluid around the spleen
3. Suprapubic (pelvic): free fluid in the pelvis (retrovesical in males, pouch of Douglas in females)
4. Subxiphoid (pericardial): pericardial effusion or tamponade

Extended FAST (eFAST) adds bilateral lung views for pneumothorax. FAST detects free fluid rather than solid organ injury directly, is operator-dependent, has lower sensitivity in retroperitoneal injuries and is poor in obese patients. A negative FAST does not exclude significant injury in an unstable patient: proceed to operative intervention, or to CT if the patient is stable.

Laboratory studies.

• Cross-match (type and screen), to prepare blood products
• Full blood count for a baseline haemoglobin
• Coagulation: PT/INR, aPTT and fibrinogen
• Metabolic panel: electrolytes, urea, creatinine
• Lactate and base deficit
• Blood alcohol and drug screen, for the assessment of altered consciousness
• Beta-hCG in all women of childbearing age

The initial haemoglobin may be normal in acute haemorrhage because whole blood is lost: the remaining blood is not diluted until interstitial fluid shifts into the vascular space over hours. Do not rely on a normal haemoglobin to exclude significant haemorrhage. Lactate and base deficit are far more reliable markers of tissue hypoperfusion, shock severity and the adequacy of resuscitation.

Urinary catheter and gastric tube. The catheter measures output (target over 0.5 mL/kg/hour) and detects haematuria, and is contraindicated by blood at the urethral meatus, a high-riding prostate or perineal ecchymosis, which point to urethral injury and call for a retrograde urethrogram first. A nasogastric tube decompresses the stomach and reduces the aspiration risk; the orogastric route is preferred if a base of skull fracture is suspected.

Non-compressible haemorrhage. For the trauma patient who is peri-arrest or arrested from non-compressible torso or pelvic haemorrhage, two salvage adjuncts go beyond the standard primary survey and are increasingly examined.

Resuscitative thoracotomy. The emergency department thoracotomy is a salvage procedure through a left anterolateral thoracotomy for the patient who arrests or loses vital signs from trauma. Its aims are to relieve cardiac tamponade (pericardiotomy), control intrathoracic haemorrhage, provide internal cardiac massage and cross-clamp the descending thoracic aorta, which redistributes the remaining blood to the brain and heart and limits sub-diaphragmatic bleeding. The outcomes are best in penetrating chest trauma (especially stab wounds) with signs of life recently present, and dismal in blunt trauma with prolonged CPR or no signs of life, which is the selection point.

REBOA. Resuscitative endovascular balloon occlusion of the aorta is a less-invasive temporising adjunct for non-compressible torso or pelvic haemorrhage in profound shock: a balloon catheter is passed via the femoral artery and inflated in the aorta. Zone I (descending thoracic aorta, above the diaphragm) is used for abdominal haemorrhage and Zone III (infrarenal, above the bifurcation) for pelvic or junctional haemorrhage; Zone II is a no-occlusion zone. The balloon raises proximal (cerebral and coronary) perfusion and reduces distal bleeding, buying time to definitive control by laparotomy or angioembolisation, but it is limited by distal ischaemia time and is a bridge, not definitive treatment.

What predicts survival. The best outcomes follow an organised trauma system, rapid transport (under 60 minutes), damage-control resuscitation initiated prehospital or on arrival, activation of the massive transfusion protocol, and early haemorrhage control (within 60-90 minutes). The key threshold is the lethal triad on arrival: any two of hypothermia, acidosis and coagulopathy carries a mortality of 50-90 percent if not aggressively reversed. The markers of a poor prognosis are:

• Delayed presentation
• Persistent coagulopathy despite the massive transfusion protocol
• Lactate over 4 mmol/L that fails to clear within 24 hours
• ISS over 40
• Base deficit over 6
• Core temperature under 35 degrees Celsius on arrival