Trauma Primary and Secondary Survey — Part 2: Adjuncts to Primary Survey, Secondary Survey & Hemorrhagic Shock

1. Adjuncts to the Primary Survey

Adjuncts to the primary survey are diagnostic and therapeutic interventions performed concurrently with or immediately following the ABCDE assessment. They provide additional information to guide resuscitation and disposition decisions.^{1 2}

1.1 Extended FAST (eFAST)

The eFAST expands the standard four-view FAST examination by adding bilateral anterior thoracic views to detect pneumothorax. The eFAST is performed during the primary survey and has largely replaced the initial supine chest radiograph as the first-line screening test for pneumothorax and hemothorax in many trauma centers.^{1 3}

eFAST Protocol — Six Views

eFAST Performance Characteristics

eFAST Limitations

• Operator dependent — performance varies with training and experience
• False negatives — most commonly occur with:
  • Small amounts of free fluid (< 200 mL)
  • Retroperitoneal hemorrhage (not visible on FAST)
  • Hollow viscus injury without significant free fluid
  • Isolated solid organ injury with intact capsule (contained hematoma)
  • Obesity, subcutaneous emphysema (degrades image quality)
  • Pelvic fracture blood contained in retroperitoneum
• False positives — pre-existing ascites, physiologic free fluid, pericardial fat pad mimicking effusion
• Does not identify the specific organ injured — a positive FAST identifies free fluid but does not localize the source

1.2 Chest Radiograph

A portable anteroposterior (AP) supine chest radiograph is obtained during the primary survey in all major trauma patients. It can be performed simultaneously with the primary survey without interrupting resuscitation.^{1 2}

Findings to evaluate systematically:

1.3 Pelvic Radiograph

An anteroposterior (AP) pelvis radiograph is obtained in the primary survey of all patients with blunt trauma and clinical suspicion of pelvic fracture (mechanism of injury, pelvic tenderness, instability on examination, or hemodynamic instability).^{1 2}

Key findings:

• Pubic symphysis diastasis (> 2.5 cm suggests disruption of the pelvic ring)
• Sacroiliac joint widening
• Fracture patterns: anterior-posterior compression (open-book), lateral compression, vertical shear
• A pelvic binder should already be in place before the radiograph if clinical suspicion is high

Note: In hemodynamically stable patients undergoing CT, the pelvic radiograph may be deferred in favor of the CT scan, which provides more detailed information. However, in unstable patients, the AP pelvis film is a rapid screening tool.

1.4 Foley Catheter

Placement of an indwelling urinary (Foley) catheter is performed during or immediately after the primary survey to:¹

• Monitor urine output as an indicator of renal perfusion and resuscitation adequacy (target: 0.5 mL/kg/hr in adults; 1 mL/kg/hr in children; 2 mL/kg/hr in infants < 1 year)
• Decompress the bladder before abdominal assessment or operative intervention
• Assess for gross hematuria (indicating urinary tract injury)

Contraindications to urethral catheter placement (perform retrograde urethrogram first):

If urethral injury is suspected, a retrograde urethrogram (RUG) should be performed before catheter insertion. If urethral injury is confirmed, a suprapubic catheter is placed instead.

1.5 Gastric Tube (Nasogastric or Orogastric)

Placement of a gastric tube is performed to:¹

• Decompress the stomach (reduces risk of aspiration, facilitates abdominal examination and ventilation)
• Assess for upper GI hemorrhage (blood in gastric aspirate)

Route selection:

1.6 Additional Adjuncts

2. Secondary Survey

2.1 Principles

The secondary survey is a comprehensive, systematic head-to-toe examination performed only after the primary survey is complete, resuscitation is underway, and the patient has demonstrated normalization of vital functions or is stable enough for a thorough evaluation. If the patient deteriorates at any point during the secondary survey, return immediately to the primary survey (ABCDE).^{1 2}

The secondary survey consists of:

1. A complete history (AMPLE)
2. A thorough head-to-toe physical examination
3. A complete neurologic examination
4. Appropriate diagnostic studies (CT, additional radiographs, laboratory work)

2.2 AMPLE History

The AMPLE mnemonic provides a structured framework for obtaining the essential elements of the trauma patient’s history. This information is obtained from the patient (if able to communicate), prehospital providers, family members, medical records, or medical alert identification.¹

2.3 Head-to-Toe Physical Examination

The secondary survey physical examination proceeds systematically from head to toe. Every region of the body is examined by inspection, palpation, and auscultation as appropriate.^{1 2}

2.3.1 Head and Face

2.3.2 Neck

2.3.3 Chest

2.3.4 Abdomen

2.3.5 Pelvis

2.3.6 Extremities

2.3.7 Back and Spine (Log Roll)

The patient is log-rolled with cervical spine immobilization maintained to examine the posterior surface:¹

2.4 Complete Neurologic Examination

The secondary survey neurologic examination expands on the disability assessment performed during the primary survey:¹

3. Hemorrhagic Shock — Classification and Physiologic Response

3.1 Overview

Hemorrhagic shock is the most common cause of shock in the trauma patient. It is a state of inadequate organ perfusion and tissue oxygenation caused by acute blood loss. Rapid identification of the class of hemorrhage guides the aggressiveness of resuscitation and the urgency of hemorrhage control interventions.^{1 4 5}

Estimated blood volume: Approximately 70 mL/kg in adults (approximately 5 liters in a 70-kg patient). Blood volume is proportionally higher in children (80 mL/kg) and infants (80-90 mL/kg).

3.2 Hemorrhagic Shock Classification — Classes I Through IV

The following classification system categorizes hemorrhage severity based on the estimated volume of blood loss and corresponding physiologic parameters. Note that these are guidelines — individual patient responses vary significantly based on age, comorbidities, medications (particularly beta-blockers), physical fitness, and rate of hemorrhage.^{1 4}

3.3 Important Caveats to the Classification System

The above classification represents a simplified model. In clinical practice, the following factors complicate the assessment of hemorrhagic shock:^{1 4 6}

3.4 Shock Index

The Shock Index (SI) = Heart Rate / Systolic Blood Pressure is a simple bedside tool that may be more sensitive than individual vital signs for detecting occult hemorrhagic shock.⁷

• The SI has been validated as an early predictor of the need for massive transfusion and emergent intervention
• Age-adjusted shock index (SI x age) may improve accuracy in elderly patients
• Reverse Shock Index x GCS (rSIG) = GCS / SI; rSIG < 8 predicts massive transfusion requirement

3.5 Response to Initial Fluid Resuscitation

The patient’s response to the initial fluid challenge (typically 1 liter of warm isotonic crystalloid, or blood products if hemorrhage class III-IV) provides critical information about the severity and ongoing nature of hemorrhage:^{1 4}

3.6 Non-Hemorrhagic Causes of Shock in Trauma

While hemorrhagic shock is the most common cause of shock in the trauma patient, other etiologies must be considered, particularly when the patient does not respond as expected to volume resuscitation:¹

References