13.3 Blunt/Penetrating Trauma, Spinal Motion Restriction & Thermal Burns

Blunt/Penetrating Trauma, Spinal Motion Restriction & Thermal Burns

Trauma remains the leading cause of morbidity and mortality in pediatric patients past the neonatal period. Resuscitating and transporting severely injured children demands an acute appreciation of pediatric biomechanics, developmental anatomy, and physiological compensation. Children are not miniature adults: their physical proportions, pliable skeletal framework, and limited metabolic reserves transform injury patterns and mandate specialized transport interventions—from thoracic elevation for neutral cervical alignment to balanced damage-control blood transfusion and modified burn resuscitation algorithms.

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Pediatric Trauma Biomechanics & The Pliable Skeleton

Three distinct biomechanical characteristics govern pediatric trauma presentations:

1. Concentrated Kinetic Energy Dissipation: Because of a child's small body mass and compact surface area, kinetic impact energy (from motor vehicle collisions, falls, or bicycle crashes) is distributed across a significantly larger proportion of total body volume compared to adults. A localized impact in an adult becomes a multi-system, multi-cavitary insult in a child.
2. Minimal Physical Buffering: Children possess thinner abdominal walls, less subcutaneous adipose tissue, and lower muscle mass, providing negligible anatomical dampening against blunt forces. Internal organs sit closer to the body surface and are directly exposed to mechanical trauma.
3. The Compliant, Cartilaginous Skeleton:
   • Pediatric bones have high cartilaginous composition, incomplete ossification, and flexible periosteum. The pediatric thoracic cage is extraordinarily compliant and distensible.
   • Internal Organ Injury Without Fractures: Massive blunt kinetic force can severely compress the elastic rib cage inward without fracturing a single rib. The underlying kinetic energy transmits directly into the lung parenchyma and myocardium, producing extensive, life-threatening pulmonary contusions, tracheobronchial tears, and cardiac contusions without overlying skeletal fractures.
   • Clinical Corollaries: The absence of rib fractures NEVER rules out underlying visceral trauma in a child. Conversely, if rib fractures ARE identified on radiography, it indicates large impact forces and a high likelihood of serious associated injuries (and, in an infant without a clear mechanism, possible abuse; Section 13.4).

Primary Survey (ABCDE) Nuances in Pediatric Trauma

• A — Airway with Cervical Spine Protection: Assess patency and vocalization. Maintain manual in-line stabilization; avoid hyperextension.
• B — Breathing & Ventilation: Inspect for symmetrical chest excursion, flail segments, and tachypnea. Immediately decompress suspected tension pneumothorax (needle decompression via 14–16 gauge catheter at the 2nd intercostal space mid-clavicular line, or 4th/5th intercostal space anterior axillary line, followed by thoracostomy tube placement).
• C — Circulation with Hemorrhage Control: Evaluate heart rate, capillary refill, and central/peripheral pulse differential. Apply direct external pressure to active bleeding sites. Remember: hypotension is an ominous, pre-terminal indicator of shock ($>30\%\text{ to }40\%$ circulating volume lost). Target minimum acceptable systolic blood pressure: $70 + (2 \times \text{age in years})\text{ mmHg}$.
• D — Disability (Neurological Evaluation): Rapid neurological triage using the pediatric AVPU or pediatric Glasgow Coma Scale (pGCS). Assess pupillary size and reactivity. Check point-of-care blood glucose to exclude hypoglycemia.
• E — Exposure & Environmental Control: Fully expose the child to evaluate for occult injuries, lap-belt ecchymoses, burns, and penetration sites. Immediately cover with warmed blankets and set transport cabin temperature high to prevent hypothermia.

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Pediatric Spinal Motion Restriction (SMR) & Anatomical Nuances

Immobilizing the pediatric cervical spine requires specialized adaptations to accommodate developmental anatomy:

Standard Adult Backboard (Flat Surface)
┌────────────────────────────────────────────────────────┐
│                     Flat Backboard                     │
└────────────────────────────────────────────────────────┘
          ▲                            ▲
   Prominent Occiput             Thorax / Shoulders
(Pushes Head Forward)         (Lies Flat on Board)
          │
          └─► ACUTE PASSIVE CERVICAL HYPERFLEXION!
              • Pharyngeal Airway Occlusion
              • Risk of Converting Stable C-Spine Injury into Spinal Cord Transection

Correct Pediatric Positioning: Thoracic Elevation / Shoulder Roll (1 to 2 cm)
┌─────────────────────────────┬──────────────────────────┐
│      Prominent Occiput      │   Thoracic Shoulder Roll │
│   (Rests in Flat Cutout)    │   (Elevates Torso 1-2cm) │
└─────────────────────────────┴──────────────────────────┘
          │                                    │
          └────────────────────────────────────┴──► NEUTRAL CERVICAL ALIGNMENT
               External Auditory Meatus Aligns with Top of Shoulder

The Prominent Occiput Hazard & The Thoracic Roll

• The Anatomic Problem: Infants and young children possess a disproportionately large cranium and a prominent posterior occiput. When a young child is placed supine on a standard flat, rigid backboard, the prominent occiput forces the neck into acute passive hyperflexion.
• Pathological Consequences: Passive flexion kinks the pliable pediatric trachea, precipitating acute upper airway obstruction. Furthermore, in the presence of cervical spine trauma, flexion displaces fractured or subluxated vertebrae, transforming a non-displaced spinal fracture into complete spinal cord transection.
• The Corrective Solution: Transport clinicians must place a 1 to 2 cm padded thoracic elevation (shoulder roll) beneath the child's torso, extending from the tops of the shoulders down to the pelvis, OR place the child on an approved pediatric backboard featuring a specialized occipital recess (depression cutout).
• Anatomical Alignment Target: Elevate the torso until the external auditory meatus aligns directly with the anterior aspect of the shoulder in the horizontal plane, maintaining the cervical spine in true anatomical neutral.

Pediatric Cervical Spine Biomechanics & SCIWORA

• High Cervical Fulcrum: Due to a heavy head, weak cervical musculature, and shallow horizontally oriented facet joints, the anatomical fulcrum of cervical spine flexion is located at C1 to C3 in children under 8 years of age (versus C5 to C6 in adolescents and adults). Consequently, high cervical ligamentous injuries and atlanto-occipital dislocations dominate pediatric presentations.
• SCIWORA (Spinal Cord Injury Without Radiologic Abnormality):
  • The pediatric vertebral column and interspinous ligaments can stretch up to 5 cm (2 inches) without structural disruption or fracture.
  • In stark contrast, the fragile spinal cord within the canal can stretch only 5 to 6 mm (~0.25 inches) before undergoing irreversible mechanical disruption, traction injury, or ischemic infarction.
  • A child can sustain complete spinal cord transection or severe myelopathy with completely normal plain radiographs and CT scans.
  • Transport Mandate: Any child reporting transient paresthesias, numbness, focal motor weakness, or "electric shock" sensations following trauma must be managed with strict spinal motion restriction and transferred for emergent MRI regardless of normal initial CT imaging.

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Blunt Abdominal Trauma & Damage Control Resuscitation

Blunt abdominal trauma in children frequently damages solid organs. The liver and spleen possess less protection from the pliable lower rib cage, have thin, delicate capsules, and contain high vascularity.

• Mechanisms of Injury: Motor vehicle collisions with inappropriate restraint ("lap-belt sign" / transverse abdominal wall contusion), falls onto hard objects, and bicycle handlebar impacts ("handlebar sign" across the epigastrium).
• Clinical Assessment: Abdominal tenderness, guarding, progressive abdominal distension, and referred pain to the left shoulder (Kehr's sign, caused by diaphragmatic blood irritating the phrenic nerve from splenic rupture). Tachycardia out of proportion to pain is the earliest warning sign of occult intra-abdominal hemorrhage.
• Bedside Sonography (FAST Exam): Focused Assessment with Sonography for Trauma rapidly detects free peritoneal fluid in Morison's pouch (hepatorenal recess), the splenorenal recess, and the pouch of Douglas (retrovesical space).

Damage Control Hemostatic Resuscitation

• Crystalloid Restriction: Clear isotonic crystalloids (0.9% Normal Saline or Lactated Ringer's) must be strictly restricted to a single bolus of 20 mL/kg (maximum 40 mL/kg). Large crystalloid infusions dilute coagulation factors, lower core body temperature, induce hyperchloremic acidosis, and disrupt early platelet plugs ("popping the clot").
• Balanced Massive Transfusion Protocol (1:1:1 Ratio): If hypotension or signs of decompensated shock persist following the initial 20 mL/kg crystalloid bolus, immediately initiate balanced blood product transfusion: Type O-negative Packed Red Blood Cells (PRBCs), Fresh Frozen Plasma (FFP), and Platelets in an equal 1:1:1 ratio (administering 10 to 20 mL/kg aliquots of PRBCs and FFP, and 10 mL/kg of platelets).
• Tranexamic Acid (TXA): Administer TXA within 3 hours of trauma to inhibit hyperfibrinolytic clot breakdown: 15 to 20 mg/kg IV loading bolus (max 1,000 mg) over 10 minutes, followed by a continuous infusion of 2 to 5 mg/kg/hr over 8 hours.

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Pediatric Thermal Burns: Assessment & Resuscitation

Thermal burns in pediatric patients trigger profound local tissue destruction and a massive systemic inflammatory response characterized by widespread endothelial capillary leak.

Lund-Browder Chart vs Rule of Nines

The adult "Rule of Nines" (assigning 9% to the head and 18% to each leg) is dangerously inaccurate in infants and children:

• In an infant, the head represents about 19% of Total Body Surface Area (TBSA), while each lower limb represents only about 13–14%.
• As the child grows, the head-to-body proportion shifts: by about age 10 the head accounts for roughly 11%, with the legs making up a larger share, reaching adult proportions in late adolescence.
• Utilizing the adult Rule of Nines in pediatric patients drastically underestimates head surface area and overestimates leg surface area, resulting in severe fluid resuscitation errors.
• The Lund-Browder Chart dynamically adjusts TBSA percentages for age and is the recommended method for pediatric burn size estimation.
• Depth Rule: Only second-degree (partial-thickness) and third-degree (full-thickness) burns are included in the % TBSA calculation. First-degree burns (superficial erythema like sunburn) are strictly excluded.

Pediatric vs Adult Body Surface Area Differences (Lund-Browder vs Rule of Nines)

          [INFANT (<1 yr)]                      [ADULT]
             ┌───────┐                         ┌───────┐
             │  19%  │ Head                    │   9%  │ Head
             └───────┘                         └───────┘
          ┌─────────────┐                   ┌─────────────┐
       9% │  Torso 36%  │ 9%             9% │  Torso 36%  │ 9%  (Arms 9% each)
          └─────────────┘                   └─────────────┘
            ┌───┐ ┌───┐                       ┌───┐ ┌───┐
            │13%│ │13%│ Legs                  │18%│ │18%│ Legs
            └───┘ └───┘                       └───┘ └───┘

Fluid Resuscitation: The Modified Parkland Formula & Maintenance Dextrose

Partial- and full-thickness burns of about 15–20% TBSA or more in children provoke systemic capillary leak, losing massive amounts of plasma protein and fluid into interstitial spaces.

1. Resuscitation Fluid Calculation (Modified Parkland / PALS Formula): $$\text{Total 24-Hour Resuscitation Volume} = (3\text{ to }4\text{ mL}) \times \text{Weight (kg)} \times \%\text{TBSA (2nd and 3rd degree)}$$
   • Infusion Timing: Administer 50% of the calculated resuscitation volume over the first 8 hours calculated from the EXACT TIME OF INJURY (not the time of medical arrival). The remaining 50% is infused evenly over the subsequent 16 hours.
   • Fluid Choice: Lactated Ringer's (LR) is the preferred balanced crystalloid (contains sodium 130 mEq/L and lactate buffer, preventing hyperchloremic acidosis).
2. The Vital Pediatric Maintenance Dextrose Rule:
   • Infants and children weighing <30 kg have limited hepatic and muscular glycogen reserves. Resuscitating a child with large volumes of non-dextrose crystalloid while under extreme burn hypermetabolism causes rapid glycogen depletion and lethal hypoglycemia.
   • Transport Mandate: For all pediatric burn patients weighing <30 kg, transport clinicians must infuse maintenance fluids containing 5% Dextrose (e.g., D5 Lactated Ringer's or D5 0.45% NS) RUNNING IN PARALLEL with the calculated Parkland resuscitation fluids.
3. Urine Output Titration Targets:
   • Place an indwelling Foley catheter to guide fluid titration:
     • Children weighing 30 kg or less: Target about 1 mL/kg/hr (American Burn Association ABLS guidance)
     • Larger children and adolescents: Target about 0.5 mL/kg/hr (roughly 30–50 mL/hr)
     • High-Voltage Electrical Burns / Myoglobinuria: Target 1.0 to 2.0 mL/kg/hr to flush pigment casts and prevent acute tubular necrosis.

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Inhalation Injury & Burn Packaging in Transit

Early Airway Control for Inhalation Injury

Thermal injury to the upper airway and inhalation of toxic combustion products (carbon monoxide, cyanide) produce rapidly progressive, catastrophic supraglottic edema. Edema peaks between 12 and 24 hours post-injury.

• Clinical Hallmarks: Fire in an enclosed space, facial burns, singed nasal hairs or eyebrows, carbonaceous sputum, hoarseness, brassy cough, or stridor.
• The Transport Mandate: If any clinical indicators of inhalation injury or respiratory distress are identified, perform early endotracheal intubation before departure. A patent airway that is easily managed at the referral facility will become impassable at 5,000 feet in an aircraft cabin due to tissue expansion and progressive mucosal swelling. Use a cuffed endotracheal tube, verify position with video laryngoscopy and end-tidal $CO_2$, and secure the tube with umbilical tape or specialized commercial holders (adhesive tape adheres poorly to burned facial skin).

Burn Wound Packaging & The Hypothermia Peril

• The High Surface Area Hazard: Children have a very high body surface area-to-mass ratio and thin skin. Denuded, burned skin loses the ability to prevent evaporative heat loss.
• STRICT PROHIBITION OF WET OR COLD DRESSINGS: Placing cold, wet saline towels, wet dressings, or ice on pediatric burns causes immediate, severe hypothermia. Hypothermia triggers profound peripheral vasoconstriction (converting partial-thickness burns into full-thickness necrosis), lethal cardiac dysrhythmias, and severe hypothermic coagulopathy.
• Transport Packaging Protocol: Cover all partial- and full-thickness burn wounds with clean, dry, sterile sheets or non-adherent sterile dressings. Wrap the child in dry, warmed blankets, aggressively heat the transport vehicle cabin (maintain cabin temperature $>80^\circ\text{F} / 27^\circ\text{C}$), and continuously monitor core body temperature (target $\ge 36.5^\circ\text{C}$).

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Realistic Transport Scenario: Pediatric Scald Burn Resuscitation in Flight

A critical care flight team is dispatched to a regional hospital to transport a 2-year-old female (weight 12 kg) who sustained deep partial-thickness scald burns across her anterior chest, abdomen, and bilateral upper thighs when a pot of boiling water spilled. The injury occurred 2 hours prior to flight team arrival. Using the Lund-Browder chart, the team calculates a burn surface area of 25% TBSA.

The team calculates the 24-hour modified Parkland resuscitation fluid requirement: $3\text{ mL} \times 12\text{ kg} \times 25\% = 900\text{ mL}$ of Lactated Ringer's. Under the 8-hour rule, half of this volume (450 mL) must be infused within the first 8 hours from the injury. Because 2 hours have already elapsed, the remaining 450 mL must be delivered over the next 6 hours ($450\text{ mL} / 6\text{ hr} = 75\text{ mL/hr}$ of LR).

Recognizing that the 12 kg toddler has limited glycogen stores and is at acute risk of hypoglycemia, the flight nurse immediately starts a second infusion pump running D5 Lactated Ringer's at the maintenance rate of 44 mL/hr (4-2-1 rule: 4 mL/kg/hr for the first 10 kg + 2 mL/kg/hr for the next 2 kg = 44 mL/hr; the daily Holliday-Segar total of 1,100 mL is about 46 mL/hr) in parallel with the resuscitation fluid. On physical exam, the referring nurse had applied cold, wet saline gauze across the burns; the child is shivering with a core temperature of 35.2°C. The transport team immediately removes all wet dressings, pats the wounds dry, applies clean, dry sterile sheets, and wraps the child in warm blankets, raising the cabin heater. An indwelling Foley catheter is placed, confirming clear urine output that is titrated to 12 to 15 mL/hr (1.0 to 1.25 mL/kg/hr). The child is safely transported to the regional pediatric burn center with a normalized core temperature of 36.8°C and blood glucose of 108 mg/dL.

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Clinical Pearls for Pediatric Trauma & Burns