Developed by the American College of Surgeons Committee on Trauma following a 1976 plane crash that highlighted deficiencies in trauma care, the course is now a global standard used in over 60 countries. The core philosophy involves treating the greatest threat to life first, not allowing a lack of definitive diagnosis to delay treatment, and recognizing that a detailed history is not essential to begin evaluation.

Initial Assessment and Primary Survey The hallmark of ATLS is the primary survey, structured around the ABCDE mnemonic:

• Airway: Assessment of patency while strictly maintaining cervical spine motion restriction. A definitive airway (cuffed tube in the trachea) is required for patients with airway compromise or a Glasgow Coma Scale (GCS) score of 8 or lower.

• Breathing: Identification and immediate management of life-threatening thoracic injuries, such as tension pneumothorax, open pneumothorax, and massive hemothorax.

• Circulation: Recognition of shock, predominately hemorrhagic in trauma. Management focuses on stopping the bleeding and restoring volume. Hypotension is considered hypovolemic until proven otherwise. Fluid resuscitation begins with isotonic crystalloids, moving to blood products for transient or non-responders.

• Disability: A rapid neurologic evaluation using GCS and pupillary response to establish a baseline.

• Exposure: Complete removal of clothing to identify all injuries while preventing hypothermia.

Secondary Survey and Specific Injuries Following the stabilization of vital functions, a detailed head-to-toe secondary survey is performed.

• Head and Spine: The primary goal in traumatic brain injury is preventing secondary brain injury caused by hypotension and hypoxia. Spinal motion is restricted until injury is excluded via clinical rules (NEXUS, Canadian C-Spine) or imaging.

• Abdomen and Pelvis: Unrecognized hemorrhage is a major cause of preventable death. Diagnostic adjuncts include Focused Assessment with Sonography for Trauma (FAST), Diagnostic Peritoneal Lavage (DPL), and CT scans. Unstable pelvic fractures require mechanical stabilization, such as a pelvic binder, to limit hemorrhage.

• Musculoskeletal: Limb-threatening injuries, such as vascular compromise, compartment syndrome, and open fractures, must be identified early. Compartment syndrome is a clinical diagnosis requiring immediate surgical intervention.

• Thermal Injuries: Management involves stopping the burning process and fluid resuscitation. The Parkland formula has been updated to a consensus formula starting at 2 mL/kg/%TBSA for adults to prevent over-resuscitation.

Special Populations and Logistics

• Pediatric: Children have unique anatomical characteristics and physiological reserves. A length-based resuscitation tape (Broselow) helps determine weight-based equipment sizes and drug doses.

• Geriatric: Comorbidities and medications, such as anticoagulants and beta-blockers, alter the physiological response to injury, often masking shock.

• Pregnancy: Treatment involves two patients; optimal fetal outcome depends on aggressive maternal resuscitation. The uterus should be displaced to the left to relieve vena cava compression..