35.2 Basic Surgical Principles II: Shock and Surgical Critical Care, Hemorrhagic Shock and Massive Transfusion, ATLS Primary and Secondary Survey, Chest and Abdominal Trauma, Head and Spine Injury, Pelvic Fractures and Burns

Why this area matters

Trauma is a leading cause of death in young Filipinos, mostly from motorcycle crashes, falls and violence. Burns from household fires, firecrackers during New Year celebrations and electrical injuries are common. The TOS tests recognition of shock and the first hour of trauma and burn care, the period in which most preventable deaths occur.

Types of shock

Pathophysiology and Classification of Surgical Shock

Shock is systemic hypoperfusion resulting in inadequate cellular oxygen delivery ($DO_2$), cellular dysoxia, anaerobic metabolism, lactic acidosis, and organ failure. Hemorrhagic shock is the preeminent surgical form.

Advanced Trauma Life Support (ATLS) Classification of Hemorrhagic Shock

Resuscitation Targets and Massive Transfusion Protocols

• Damage Control Resuscitation: Prioritizes permissive hypotension (systolic BP 80-90 mmHg or MAP ~65 mmHg) until active hemorrhage is surgically controlled, avoiding mechanical clot disruption.
• Massive Transfusion Protocol (MTP): Activated when blood loss exceeds 10 units of packed red blood cells (PRBCs) within 24 hours, or $> 4\text{ units}$ in 1 hour. Transfusion must follow a 1:1:1 balanced ratio (1 unit PRBC : 1 unit Fresh Frozen Plasma [FFP] : 1 unit Platelets) to prevent dilutional coagulopathy, hypofibrinogenemia, and thrombocytopenia.
• End-Points of Resuscitation: Adult urine output $\ge 0.5\text{ mL/kg/hour}$ ($1.0\text{ mL/kg/hour}$ in children), clearance of serum lactate ($< 2.0\text{ mmol/L}$), normalization of base deficit ($-2\text{ to }+2\text{ mEq/L}$), and central venous oxygen saturation ($ScvO_2 \ge 70\%$).

The ATLS Primary Survey and Resuscitation (ABCDE Algorithm)

Resuscitation occurs concurrently with evaluation. The primary survey assesses and addresses life-threatening pathology in rigid chronological order:

1. A — Airway Maintenance with Cervical Spine Motion Restriction:
   • Assume cervical spine fracture in every blunt trauma patient until proven otherwise. Restrict movement using a rigid cervical collar, head blocks, and tape, or manual in-line stabilization (never traction).
   • Assess patency (inspect for foreign bodies, dental fragments, facial fractures, blood, vomitus). Clear secretions via rigid suction.
   • Definitive Airway Indications: GCS $\le 8$ ("GCS 8, intubate"), severe maxillofacial trauma, impending airway compromise (stridor, neck hematoma, inhalation injury), or severe respiratory failure.
   • If endotracheal intubation fails or cannot be performed due to severe anatomical disruption ("cannot intubate, cannot ventilate"), perform an emergent surgical cricothyroidotomy (transverse incision through the cricothyroid membrane). Note: Needle cricothyroidotomy is preferred in children $< 12\text{ years}$ because surgical cricothyroidotomy risks damaging the cricoid cartilage.
2. B — Breathing and Ventilation:
   • Expose the chest and evaluate rate, effort, symmetry of chest expansion, tracheal position, and auscultate bilateral breath sounds.
   • Exclude immediate life threats: Tension Pneumothorax, Open Pneumothorax, Massive Hemothorax, Flail Chest, and Cardiac Tamponade.
3. C — Circulation with Hemorrhage Control:
   • Primary goal is immediate external hemorrhage control via direct digital pressure or pneumatic tourniquets on extremities. Never clamp blindly in a bleeding wound.
   • Establish access: Two large-bore ($16\text{-gauge}$ or $14\text{-gauge}$) peripheral intravenous lines in the upper extremities. If peripheral access fails, establish intraosseous (IO) access or ultrasound-guided central venous access.
   • Assess perfusion: Level of consciousness, skin color/temperature, pulse quality, and blood pressure. Initiate balanced blood transfusion (1:1:1 MTP) for Class III/IV shock.
4. D — Disability (Neurologic Status):
   • Rapid evaluation of the Glasgow Coma Scale (GCS), pupillary size, equality, and light reactivity, and gross motor lateralizing signs. Hypoglycemia must be excluded.
5. E — Exposure and Environmental Control:
   • Completely undress the patient to inspect all anatomical surfaces (including axillae, perineum, and back via log-roll).
   • Prevent Hypothermia: Hypothermia ($< 35.0^\circ\text{C}$), acidosis ($\text{pH} < 7.20$), and coagulopathy constitute the lethal Trauma Triad of Death. Warm the resuscitation bay, apply forced-air warming blankets, and infuse all IV fluids and blood products through commercial fluid warmers ($39.0-42.0^\circ\text{C}$).

---

Life-Threatening Thoracic Trauma

Thoracic trauma causes up to 25% of immediate and early trauma deaths. Four conditions require immediate clinical recognition without waiting for radiographic confirmation:

---

Focused Assessment with Sonography for Trauma (FAST)

The FAST examination is a rapid, non-invasive bedside ultrasound protocol designed to detect free intraperitoneal fluid (hemoperitoneum) and pericardial fluid (tamponade) in trauma patients.

The Four Standard Acoustic Windows

1. Perihepatic Space (Morison's Pouch / Hepatorenal Recess): Evaluates the interface between the liver and right kidney. This is the most dependent space of the upper peritoneal cavity in the supine patient, making it the most sensitive single window for hemoperitoneum.
2. Perisplenic Space (Splenorenal Recess): Evaluates the space between the spleen and left kidney, including the subdiaphragmatic space.
3. Pelvic Space (Suprapubic Window): Evaluates the rectovesical pouch in males and the pouch of Douglas (rectouterine pouch) in females, representing the most dependent anatomical space of the pelvis.
4. Pericardial Space (Subxiphoid Window): Evaluates for pericardial effusion between the fibrous pericardium and anterior myocardium.

• Extended FAST (e-FAST): Adds bilateral anterior-superior thoracic views to assess for pneumothorax (loss of normal "lung sliding" and appearance of the "stratosphere/barcode sign" on M-mode) and bilateral hemothorax at the lung bases.

Algorithmic Decision-Making in Abdominal Trauma

• Hemodynamically Unstable Patient (SBP $< 90\text{ mmHg}$):
  • Positive FAST: Immediate transfer to the operating room for Emergent Exploratory Laparotomy.
  • Negative FAST: Search for extra-abdominal blood loss (pelvic fracture, bilateral femur fractures, massive hemothorax) or perform diagnostic peritoneal aspiration/lavage (DPA/DPL).
• Hemodynamically Stable Patient:
  • Positive or Equivocal FAST: Proceed to Contrast-Enhanced Abdominal/Pelvic CT Scan (the gold standard for grading solid organ injury [liver, spleen, kidneys] and identifying retroperitoneal trauma).
  • Penetrating Trauma: Gunshot wounds traversing the peritoneal cavity or stab wounds with active peritonitis, evisceration, or shock mandate emergent exploratory laparotomy.

---

Traumatic Brain Injury: Glasgow Coma Scale & Extra-Axial Hematomas

The Glasgow Coma Scale (GCS)

Extra-Axial Intracranial Hematomas

• Epidural Hematoma (EDH):
  • Mechanism: Blunt trauma to the temporoparietal skull fracturing the pterion, lacerating the Middle Meningeal Artery (branch of maxillary artery).
  • Clinical Course: Classically exhibits a "Lucid Interval": Initial post-concussive loss of consciousness, followed by transient clearing of consciousness, followed by rapid secondary neurological deterioration, ipsilateral pupillary dilation (compression of CN III by uncal herniation), and contralateral hemiparesis.
  • Non-contrast CT: Hyperdense, biconvex (lenticular), lens-shaped collection that does NOT cross cranial suture lines (dura is firmly adherent at sutures) but can cross dural venous reflections.
  • Management: Emergent surgical craniotomy and hematoma evacuation if volume $> 30\text{ cm}^3$ or thickness $> 15\text{ mm}$ with midline shift $> 5\text{ mm}$.
• Subdural Hematoma (SDH):
  • Mechanism: Tearing of cortical bridging veins crossing the subdural space to dural venous sinuses; common in elderly patients, chronic alcoholics (cerebral atrophy increases strain on bridging veins), and shaken infants.
  • Clinical Course: Insidious, progressive headache, confusion, and focal neurological deficits over days to weeks (chronic) or acute coma following severe acceleration-deceleration trauma (acute).
  • Non-contrast CT: Hyperdense (acute) or hypodense (chronic), crescent-shaped (concave) collection that CAN cross cranial suture lines across an entire hemisphere, limited only by dural reflections (falx and tentorium).

---

Thermal Burn Injury: Rule of Nines & Parkland Resuscitation

Burn trauma induces massive capillary permeability, fluid extravasation, and burn shock.

Wallace Rule of Nines (Adult Total Body Surface Area [TBSA] Estimation)

Only partial-thickness (second-degree) and full-thickness (third-degree) burns are counted toward TBSA. Superficial (first-degree, like simple sunburn) burns are excluded.

• Head and Neck: $9\%$ total ($4.5\%$ anterior, $4.5\%$ posterior)
• Anterior Torso (Chest & Abdomen): $18\%$
• Posterior Torso (Back & Buttocks): $18\%$
• Each Upper Extremity: $9\%$ total ($4.5\%$ anterior, $4.5\%$ posterior) $\times 2 = 18\%$
• Each Lower Extremity: $18\%$ total ($9\%$ anterior, $9\%$ posterior) $\times 2 = 36\%$
• Perineum and Genitalia: $1\%$
• Total: $100\%$

Parkland (Baxter) Resuscitation Formula

Fluid requirements over the first 24 hours post-burn are calculated using Lactated Ringer's: $\text{Total 24-Hour Fluid (mL)} = 4\text{ mL} \times \text{Weight (kg)} \times \%\text{TBSA}$ (for burns $\ge 20\%\text{ TBSA}$).

• ATLS update: the classic Parkland formula uses 4 mL; the ATLS 10th edition starts adults at 2 mL x kg x %TBSA (3 mL in children and 4 mL in high-voltage electrical burns), then titrates to urine output. Either way, half is given in the first 8 hours.
• Infusion Schedule:
  • First 8 Hours: Administer $50\%$ of the calculated total volume, measured from the exact time of the burn injury (NOT the time of arrival at the hospital).
  • Subsequent 16 Hours: Administer the remaining $50\%$ of the calculated volume evenly over the next 16 hours.
• Physiological Resuscitation Targets: Hourly urine output is the gold-standard resuscitation guide. Target $0.5\text{ to }1.0\text{ mL/kg/hour}$ in adults ($30-50\text{ mL/hr}$) and $1.0\text{ to }1.5\text{ mL/kg/hour}$ in pediatric patients ($< 30\text{ kg}$). Avoid over-resuscitation to prevent fluid creep, pulmonary edema, and abdominal compartment syndrome.

Inhalation Injury and Escharotomy

• Inhalation Injury: Suspect in closed-space fires. Clinical signs: facial burns, singed nasal vibrissae, soot in oral cavity/sputum, hoarseness, stridor, and wheezing. Early proactive endotracheal intubation is mandatory before progressive pharyngeal edema obliterates the airway.
• Escharotomy: Full-thickness circumferential burns produce a leathery, inelastic eschar. On extremities, continuous tissue edema elevates compartmental pressure, resulting in compartment syndrome; on the thorax, it mechanically restricts ventilation. Emergent bedside escharotomy (longitudinal full-thickness incisions through insensitive necrotic eschar into viable subcutaneous fat) relieves constrictive pressure without requiring general anesthesia.

Secondary survey, spine and pelvic injuries

• Secondary survey:
  • after the primary survey and resuscitation, a head-to-toe examination with an AMPLE history (Allergies, Medications, Past history and pregnancy, Last meal, Events);
  • adjuncts: chest and pelvic X-rays, ECG, a urinary catheter (unless there is blood at the meatus, suggesting urethral injury) and a gastric tube (orogastric if a basal skull fracture is suspected);
  • tetanus prophylaxis.
• Cervical spine:
  • assume injury;
  • clear it clinically (NEXUS or Canadian C-spine rules) or with CT;
  • neurogenic shock (hypotension with bradycardia) differs from spinal shock, a temporary loss of reflexes below the injury.
• Pelvic fractures:
  • can cause life-threatening retroperitoneal bleeding;
  • apply a pelvic binder at the level of the greater trochanters;
  • treat with angioembolization or preperitoneal packing;
  • suspect urethral injury (blood at the meatus, high-riding prostate) and do a retrograde urethrogram before catheterization.
• Extremity trauma: stop bleeding with direct pressure or a tourniquet, reduce and splint fractures, check pulses, and watch for compartment syndrome.

Surgical critical care

• Sepsis in surgical patients: early antibiotics, source control (drain abscesses, repair leaks, remove infected devices), fluids and vasopressors.
• ARDS (Berlin definition: acute onset, bilateral opacities, PaO2/FiO2 of 300 or less on PEEP, not explained by heart failure) is treated with low tidal volume ventilation (6 mL/kg of predicted weight), PEEP and prone positioning in severe cases.
• Abdominal compartment syndrome: intra-abdominal hypertension with organ dysfunction after massive resuscitation or damage-control surgery. It causes oliguria and high airway pressures. Measure bladder pressure and decompress.
• Prophylaxis: VTE and stress-ulcer prophylaxis, glucose control and early enteral feeding.

Burns: depth, care and special burns

• Estimating burn area:
  • Rule of nines in adults;
  • the palm of the patient's hand (including fingers) is about 1% TBSA;
  • the Lund and Browder chart is used in children, whose heads are relatively larger.
• Wound care:
  • cool the burn with running water (not ice) within the first hours;
  • clean it;
  • apply topical silver sulfadiazine (avoided on the face and in sulfa allergy; transient leukopenia) or modern silver dressings;
  • give tetanus prophylaxis;
  • early excision and grafting of deep burns.
  • Prophylactic systemic antibiotics are not given.
• Referral to a burn center: partial-thickness burns over 10% to 20% TBSA, full-thickness burns, burns of the face, hands, feet, genitalia, perineum or major joints, electrical and chemical burns, inhalation injury, and burns in children or the elderly.
• Electrical burns:
  • small skin wounds can hide deep muscle damage;
  • risks are arrhythmias (ECG monitoring), rhabdomyolysis with myoglobinuria (keep urine output higher, about 1 to 1.5 mL/kg/hour) and compartment syndrome.
• Chemical burns: remove clothing and irrigate copiously with water, except for dry lime, which is brushed off first. Alkali burns penetrate deeper than acid burns. Eye injuries need immediate prolonged irrigation.
• Carbon monoxide poisoning: pulse oximetry is falsely normal. Give 100% oxygen, and hyperbaric oxygen in severe cases.