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..

Epidemiology and Unique Characteristics Injury is the leading cause of death and disability in children, surpassing all major diseases. While management priorities (ABCDEs) mirror those of adults, pediatric care requires adjustments for unique anatomy and physiology. Children have a smaller body mass, meaning impact forces are applied per smaller unit of body area, often damaging multiple organs. Their skeletons are incompletely calcified and pliable; consequently, internal organ damage, such as pulmonary contusion, can occur without overlying bone fractures. Additionally, a child's disproportionately large head increases the frequency of blunt brain injuries. The high ratio of body surface area to mass makes children highly susceptible to hypothermia, which can complicate resuscitation.

Airway and Breathing Anatomical differences dictate airway management. The large occiput causes passive flexion of the cervical spine, potentially buckling the airway; therefore, the midface must be maintained parallel to the spine board (neutral position) rather than the "sniffing" position used in adults. Because the infant trachea is short (approx. 5 cm), tube dislodgment and right mainstem intubation are significant risks. Clinicians should use the mnemonic "Don't be a DOPE" (Dislodgment, Obstruction, Pneumothorax, Equipment failure) to troubleshoot deterioration in intubated patients. In breathing assessment, the mobility of mediastinal structures makes children particularly prone to tension pneumothorax.

Circulation and Shock Recognizing shock in children is challenging due to their increased physiologic reserve. A child can maintain a normal systolic blood pressure despite losing up to 30% of their circulating blood volume. Hypotension is a late, ominous sign of decompensated shock involving >45% volume loss. Early signs of hypovolemia include tachycardia, skin mottling, and weakened peripheral pulses rather than blood pressure drops.

Fluid resuscitation is weight-based. If weight is unknown, a length-based resuscitation tape (e.g., Broselow) is essential for estimating medication doses and equipment sizes. Venous access can be difficult; if peripheral attempts fail, intraosseous (IO) infusion is the preferred alternative. Current protocols suggest an initial bolus of 20 mL/kg of warmed isotonic crystalloid. However, strategies are shifting toward "damage control resuscitation" using balanced blood products early for those with severe hemorrhagic shock.

Head, Spine, and Abdomen Children are susceptible to secondary brain injury caused by hypovolemia and hypoxia. However, because of the long-term cancer risks associated with ionizing radiation, CT scans should be used selectively, guided by clinical decision rules like PECARN, rather than routinely. Regarding the spine, "SCIWORA" (Spinal Cord Injury Without Radiographic Abnormalities) is common; a normal x-ray does not rule out spinal cord injury. In abdominal trauma, gastric decompression is critical as swallowed air can mimic distension. Most hemodynamically normal children with solid organ injuries are managed non-operatively.

Maltreatment Non-accidental trauma is a leading cause of infant homicide. Clinicians must identify red flags, such as history inconsistent with the injury, delays in seeking care, retinal hemorrhages, or fractures in children too young to walk.

Analogy: Think of a child's cardiovascular system like a modern lithium-ion battery, while an adult's is like an old flashlight battery. An old flashlight battery dims gradually as it loses power (adults show dropping blood pressure as they lose blood). A lithium battery provides consistent, strong output until it is nearly empty, then shuts down abruptly and completely.

Effective management of trauma in pregnancy requires a dual focus on two patients: the mother and the fetus. However, the sources emphasize that the best initial treatment for the fetus is the optimal resuscitation of the mother. To provide effective care, clinicians must navigate significant anatomical and physiological changes that alter injury patterns and responses to shock.

Physiological Adaptations and Hemodynamics Pregnancy induces hypervolemia, with plasma volume increasing steadily until 34 weeks. This allows a healthy pregnant patient to lose 1,200 to 1,500 mL of blood before exhibiting typical signs of hypovolemia, such as tachycardia or hypotension. Consequently, maternal vital signs may appear stable even when the fetus is in distress due to compromised uterine perfusion. The fetal heart rate is a sensitive indicator of maternal blood volume status and must be monitored; rates outside the normal 120–160 beats per minute range suggest decompensation.

A critical procedural adaptation involves patient positioning. In the supine position, the enlarged uterus compresses the inferior vena cava, potentially reducing cardiac output by 30%. To counteract this, patients requiring spinal motion restriction should be logrolled 15–30 degrees to the left to displace the uterus and maintain venous return.

Respiratory and Anatomical Changes Oxygen consumption increases during pregnancy, making the maintenance of adequate arterial oxygenation essential. Hormonal and mechanical changes lead to increased minute ventilation and a baseline state of hypocapnia (PaCO2 of 30 mm Hg). Therefore, a PaCO2 of 35 to 40 mm Hg, which is normal in nonpregnant patients, may indicate impending respiratory failure in a pregnant trauma patient. Anatomically, as the uterus rises out of the pelvis, it pushes the bowel upward. This affords the bowel some protection from blunt trauma but makes the uterus and placenta more vulnerable.

Specific Injuries and Management The leading cause of fetal death is maternal shock/death, followed by abruptio placentae (placental separation). Abruption may present with vaginal bleeding, uterine tenderness, and tetany, though vaginal bleeding is absent in 30% of cases. Uterine rupture is rare but catastrophic, marked by shock and palpable fetal parts outside the uterus.

Standard trauma diagnostics, including x-rays and CT scans, should not be withheld due to fetal radiation concerns if they are necessary for maternal evaluation. However, if diagnostic peritoneal lavage is used, the open technique above the umbilicus is required. All Rh-negative pregnant trauma patients should receive Rh immunoglobulin within 72 hours to prevent isoimmunization. In cases of maternal cardiac arrest, perimortem cesarean section may be attempted, with the best chance of success if performed within 4 to 5 minutes of arrest.

Intimate Partner Violence (IPV) Trauma frequently results from IPV, which affects 17% of injured pregnant patients. Clinicians must maintain a high index of suspicion, looking for indicators such as injuries inconsistent with the history, delayed care seeking, or a partner who dominates the interview. Screening questions regarding safety and fear should be asked when the partner is not present